Plant growth and production are faced with various biological and abiotic stresses,among which salt stress seriously affects the normal growth and development,quality and yield formation of plants.Plants have evolved morphological structure,physiological and biochemical reactions and genetic basis to adapt to salt stress during the long process of evolution.In terms of morphological structure,the leaves of salt-tolerant plants have waxy layer and lower stomatal density than those of salt-sensitive plants,and salt glands,microhairs,salt vesicles,and casparian strip have salt secretion or blocking functions.In terms of physiological activity regulation,on the one hand,salt-tolerant plants have high enzymatic and non-enzymatic antioxidant substances,such as SOD,CAT,phenolic substances,on the other hand,salt-tolerant plants have a high content of osmoregulatory substances,or can synthesize osmoregulatory substances under salt stress,including soluble proteins and sugars of organic substances and inorganic ions.In terms of molecular mechanism,SOS pathway is the most clearly studied ion regulation pathway,which maintains intracellular Na⁺/K⁺ balance through the synergistic action of SOS1,SOS2 and SOS3.In addition,plant hormones and carbon metabolism pathways also play an important role in the process of plant salt tolerance.This paper summarizes the research progress of salt-tolerant plants,and discusses the potential research focus and direction of salt-tolerant plants in terms of morphological structure,physiological basis,genetic molecular basis and transgenic methods in response to salt stress,which will help researchers quickly find the breakthrough point,gradually improve the mechanism system of salt-tolerant plants,and accelerate the efficient utilization of salt-tolerant plants.

Glyphosate is currently the most widely used broad-spectrum herbicide.Cultivating glyphosate tolerant crops will help improve the effectiveness of chemical control on weed in farmlands,reduce the use of pesticide,and simplify preventive and control measures.To fully detect the glyphosate tolerance(GT)loci in wheat,484 germplasm resources from the Huang-huai wheat region were used to identify glyphosate toxicity.Based on the wheat 15K SNP array data,genome-wide association analysis(GWAS)was used to explore QTL related to glyphosate tolerance in wheat.The main results were as follows:the trend of changes in glyphosate tolerance of wheat varieties cultivated in different eras was slow,and the glyphosate tolerance had not significantly improved;three glyphosate tolerant wheat germplasms(including Henong 130,Jimai 782 and Taishan 23)were selected based on the phenotypic identification results of pesticide damage;seven QTL associated with the level of wheat pesticide damage were detected by GWAS,including 19 significant SNPs,distributed on wheat chromosomes 1A(0.00—30.48 Mb),1B(6.57—30.57 Mb),1D(0.00—22.98 Mb),4A(656.09—680.09 Mb),5A(508.19—532.19 Mb),6A(54.56—85.09 Mb),and 6D(12.02—36.02 Mb);the two QTL qGlyT-1A and qGlyT-6A located on wheat chromosomes 1A and 6A were the main effector sites for glyphosate tolerance in wheat,containing a total of 16 genes that may be related to glyphosate tolerance in wheat.

The SiPRR73 gene was cloned from Yangu 11 using RT-PCR technology,and through analyzing tissue-specific expression,responsive features of SiPRR73 to different photoperiods,photo-thermal combinational treatments and five abiotic stress treatments,the regulation mode of photoperiod and temperature on SiPRR73,and the responsive pattern of SiPRR73 to abiotic stresses in foxtail millet were explored. The results showed that totally 2 928 bp cDNA sequence of SiPRR73 was obtained from Yangu 11,which included 2 283 bp CDS region,encoding 760 amino acids. The SiPRR73 proteins of C4 crops including Panicum miliaceum,Panicum hallii,Sorghum bicolor and Zea mays showed relatively close relationship with SiPRR73. The second parietal leaf was the highest expression tissue of SiPRR73,but the expression level at root,stem and panicle tissues was relatively lower. The expression level of SiPRR73 was higher at light period than that at dark period under both short-day and long-day conditions,and during the whole vegetative growth phase,SiPRR73 showed higher expression level under long-day compared to short-day,which indicated that the expression of SiPRR73 was induced by light and controlled by photoperiod. The temperature determined expression peak number of SiPRR73 and the photoperiod determined occurrence time of expression peaks,so temperature and photoperiod participated in regulating of SiPRR73 expression mutually. PEG and low temperature stresses induced SiPRR73 expression totally,NaCl induced SiPRR73 expression at early stress stage,but inhibited it at later stress stage. Fe stress inhibited SiPRR73 expression at early stage,but induced it at later stage. ABA stress caused the close responsive feature of SiPRR73 to NaCl. This study indicated that SiPRR73 showed light-dependent expression feature,and photoperiod and temperature regulated SiPRR73 by interaction pattern,suggesting that SiPRR73 participated in adaptability regulation process to different photo-thermal conditions and might play a certain role in coping with drought,low temperature,ABA,NaCl and Fe stresses in foxtail millet.

In order to alleviate the continuous cropping obstacle of millet,provide a reference for optimizing millet planting mode,millet continuous cropping(Si)was named as control(CK),millet-corn(Si-Zm),millet-potato-corn(Si-St-Zm),millet-corn-soybean(Si-Zm-Gm)and millet-soybean-potato(Si-Gm-St)were used to analyze the effects of different rotation patterns on the physiological indicators,photosynthetic characteristics,agronomic characters,yield and downy mildew incidence rate during the critical millet growth periods.The results showed that compared with CK,in the Si-St-Zm,Si-Zm-Gm and Si-Gm-St rotation patterns,the activeness of superoxide dismutase,peroxidase and polyphenol oxidase in millet flag leaves were significantly increased,with the largest increases of 45.55%,41.55% and 109.09%,respectively.In the Si-Zm-Gm and Si-Gm-St rotation patterns,millet plant height,stem thickness,root length and root branch number were significantly increased,with the largest increases of 30.48%,30.50%,31.76% and 13.79%, respectively.In addition,compared with CK,under the Si-Gm-St rotation system,the H₂O₂ and MDA content in the millet flag leaves were significantly decreased,with the maximum reductions of 18.78% and 47.29%, respectively;and the stomatal conductance,net photosynthetic rate,transpiration rate and relative chlorophyll content were significantly improved by 31.94%-101.43%,35.74%-234.00%,16.44%-46.97% and 24.15%-66.16%,respectively;with millet ear length,1000-grain weight and yield increased by 14.90%,17.09% and 10.58%,respectively;and millet downy mildew incidence rate significantly reduced by 12.33%.In short,compared with CK,the Si-Gm-St rotation system significantly increased the activeness of SOD,POD and PPO,and improved photosynthetic efficiency in millet flag leaves,meanwhile,the millet yield and disease resistance enhanced.Therefore,compared with Si-Zm,Si-St-Zm and Si-Zm-Gm rotation patterns,Si-Gm-St rotation system has the best effect on alleviating continuous cropping obstacles,which can provide a reference for optimizing millet planting system.

OFP is a class of plant-specific transcription factors that play important roles in the regulation of plant organ morphogenesis and response to abiotic stresses.In order to study the characterization of soybean OFP transcription factor family members and their roles in drought stress and salt stress,bioinformatics methods were applied to identify and analyze soybean OFP family members.The results showed that:a total of 41 GmOFPs,named GmOFP-1—GmOFP-41,were identified in soybean;these genes were unevenly distributed on 19 chromosomes of soybean,encoding 152—414 amino acids;subcellular localization predicted that soybean OFP proteins were mainly localized in nucleus,chloroplasts,and mitochondria;a total of 10 conserved motifs were identified in soybean OFP proteins,conservative Motifs 1 and 2 were present in all OFP members.Phylogenetic analysis classified soybean and Arabidopsis OFP proteins into five subfamilies ClassⅠ—Class V,of which soybean OFP family genes were mainly distributed in ClassⅠ and Class Ⅲ.The collinearity analysis revealed that 75 pairs of genes in the soybean genome had collinearity,four pairs of genes had tandem duplications,and only two genes,GmOFP-2 and GmOFP-39,did not have collinearity,which indicated that gene fragment duplication was the main reason for the increase in the number of soybean OFP family members.The expression patterns of GmOFP gene family members under drought stress and salt stress treatments were analyzed by qRT-PCR,and the results showed that,compared with the control,16 members out of 41 GmOFP genes exhibited significant differences in gene expression levels after drought treatments,with significant up-regulation of the expression of GmOFP-15,GmOFP-17,and GmOFP-32,while the GmOFP-4,GmOFP-5,GmOFP-6,GmOFP-9,GmOFP-12,GmOFP-21,GmOFP-23,GmOFP-25,GmOFP-26,GmOFP-27,GmOFP-38,GmOFP-39,and GmOFP-40 were significantly down-regulated after drought treatment.Eight members of GmOFPs showed significant differences in gene expression levels after salt treatment,among which GmOFP-7,GmOFP-14,GmOFP-31,GmOFP-32,GmOFP-36,and GmOFP-40 were significantly up-regulated,and GmOFP-1 and GmOFP-15 were significantly down-regulated.The above results suggest that the soybean OFP gene family may have important functions in response to drought stress and salt stress.

To improve the applicability of biochar in saline-alkali agroecosystem,the effect and microbial mechanism of modified biochar were studied.In a 2-year field experiment,common biochar(4.5 t/ha),nitrogen-rich modified biochar(7.5 t/ha)and phosphorus-rich modified biochar(15.0 t/ha)were added to investigate their impact on crop grain yield,soil physicochemical properties and soil microbial diversity.It had been observed that the addition of biochar enhanced the quality of saline-alkali soil,with nitrogen-rich modified biochar and phosphorus-rich modified biochar demonstrating more notable effects.Biochar could boost crop yield,improve soil structure and reduce soil bulk density in saline-alkali land.The effects of the three biochar types were not consistent.Among them,the application of 15.0 t/ha phosphorus-rich modified biochar showed favorable responses,with grain yield of(8.92±0.12)t/ha,representing a 110% increase compared to the control group.Biochar affected soil microbial diversity.Common biochar increased soil microbial diversity,whereas phosphorus-rich modified biochar decreased it.With the continuous addition of biochar,soil physical and chemical properties could affect the relationship between soil microorganisms and plant structure,weakening their relationships.In this study,the application of 15.0 t/ha phosphorus-rich modified biochar was recommended to improve saline-alkali agroecosystem.

In order to clarify the change rule of photosynthetic characteristics and the best fertilization method in different growth stages of sweet sorghum under different fertilization treatments, the field experiment was conducted to study the stomatal conductance (Gs), intercellular CO₂ concentration (Ci), transpiration rate (Tr), net photosynthetic rate (Pn), chlorophyll (SPAD), water use efficiency (WUE) and yield of New Sorghum No.3 under 8 different fertilization treatments, including CK, NK, NP, PK, NPK, M (organic fertilizer), NPKM and 1.5NPKM.The results showed that the changes of Pn, Gs, WUE and SPAD value in sorghum leaves under different fertilization treatments were the same at different growth stages, showing a trend of first increasing and then decreasing, and peaking at grain filling stage. The variation trend of Tr and Ci from flowering stage to maturity stage decreased first and then increased, and reached the lowest value in grain filling stage. At the same growth stage, the photosynthetic characteristics of different fertilization treatments were different, and the photosynthetic characteristics of leaves were affected by fertilization treatments. The Tr, Gs and Ci values of NPKM fertilization treatment at maturity stage were higher than those of other treatments, which were 3.64 mmol/(m²·s),328 mmol/(m²·s),439 μmol/mol, respectively. The correlation analysis showed that Pn of NPKM treatment at flowering stage was significant positively correlated with Tr and WUE, while Pn of NPK treatment was positively correlated with Gs and Ci. The biological yield of all fertilization treatments was significantly higher than CK, among them the biological yield of NPKM treatment reached 94.81 t/ha. The biological yield of NPKM increased 97.95%, 26.65%, 20.24%, 19.57%, 15.16%,14.98% and 11.74% respectively compared with CK, M, 1.5 NPKM, NK, PK, NPK and NP. Fertilization affects the photosynthetic parameters of the leaves of New Sorghum No.3 and was conducive to increasing yield. Therefore, it is feasible to use high photosynthetic efficiency breeding to improve biological yield. In order to alleviate the obstacle of continuous cropping of sweet sorghum, different proportion of fertilizer should be adopted. In a word, NPKM is the best fertilization mode to improve photosynthetic conditions and maximize yield, so it is preliminarily confirmed that NPKM is the best fertilization mode to promote the growth and development of continuous cropping sorghum in arid area.

In order to investigate the physiological regulation mechanism of exogenous H₂O₂ on the cotton seedlings under NaCl stress,the cotton variety Xinluzao 48 was used as the test material in an outdoor potting method.Two-factor random combinations of salt stress (NaCl,concentration gradients of 0,100,200 mmol/L) and H₂O₂ (concentration gradients of 0,0.005,0.010,0.020,0.050 mmol/L) were set,to study the change rule of fresh weight,dry weight,chlorophyll content,chlorophyll fluorescence parameters,photosynthetic gas parameters,antioxidant enzyme activities and osmotic regulation system of cotton seedlings.The results showed that exogenous H₂O₂ effectively alleviated the inhibitory effect of salt stress on the growth of cotton seedlings,increased chlorophyll content,photosynthetic gas parameters and chlorophyll fluorescence parameters of cotton seedlings,maintained the normal operation of photosynthesis of cotton seedlings and ensured the accumulation of dry matter.Meanwhile,exogenous H₂O₂ could increase the activity of antioxidant enzymes (POD,APX,CAT),accelerated the removal of ROS from cotton seedlings.Exogenous H₂O₂ reduced the electrolyte leakage rate,MDA content,the content of osmoregulation substances such as pro,free amino acid and SS,and improved the salt resistance of cotton seedlings.Among all treatment,0.020 mmol/L exogenous H₂O₂ had the best effect in alleviating the salt stress suffered by cotton seedlings.In summary,exogenous H₂O₂ improves the adaptation of cotton seedlings to salt stress by improving photosynthetic performance,keeping stable photosynthesis in cotton seedlings,and maintaining the dynamic balance between ROS production and elimination in cotton seedlings.

In order to study the tolerance of heterologously overexpressed Atvip1 gene in sorghum to defense saline-alkali stress and the corresponding growth, NaHCO₃:Na₂CO₃ of 5:1 solution with 75 mmol/L and pH 9.63 was used in sorghum at the stage of three leaves and one heart. The root growth index, chlorophyll content, antioxidant enzyme activity and MDA content were measured at 0, 4, 12, 24, 72, and 120 h of stress. The results indicated that the heterologous overexpression of Atvip1 gene could alleviate the damage of saline-alkali stress on the growth of sorghum seedlings, increase the root surface area and root volume, the number of root tips and branches, and also cause the browning of sorghum main roots to appear later and mild symphonys, and the earlier and more lateral roots occurrence. The new leaves could still be normally extended at 72 h and present little effect on the growth of aboveground. Overexpression of Atvip1 gene could increase the activity of O₂^-· resistance, decrease the content of MDA and enhance the activities of antioxidant enzymes in transgenic sorghum roots. SOD, CAT and GR had obvious effects at 4-12 h during the early stage of stress, respectively. All enzymes played roles during the middle of stress at 24-72 h. CAT and GSH-PX played important roles at the later stage of stress at 120 h. On the base of differential transcriptome analysis of saline-alkali stress, COG analysis of differentially expressed genes(DEGs) showed that defense mechanisms accounted for a relatively large proportion during various periods, and 42 DEGs related to antioxidant enzymes were obtained. Heterologous overexpression of Atvip1 gene can improve the resistance of transgenic sorghum to saline-alkali stress by alleviating the effects on photosynthesis, growth and development, reducing the damages of reactive oxygen species and membrane damage.

Soybean P34 protein mainly exists in soybean seeds,and its upstream promoter was likely to regulate the high expression of downstream genes in seeds.In order to further study the tissue expression pattern of soybean P34 protein gene and the regulatory activity of soybean P34 protein gene promoter,qRT-PCR was used to detect the expression of soybean P34 protein gene in soybean tissues.The 5'upstream sequence of soybean P34 protein gene(GmP34P)was cloned.The transcription initiation sites and cis-elements were analyzed by bioinformatics.The expression vector was constructed and the tobacco was transformed by Agrobacterium-mediated leaf disk method to detect GUS expression in transgenic tobacco.The results showed that the expression of P34 protein gene in soybean seeds was significantly higher than that in roots,stems,leaves and flowers.The length of GmP34P sequence obtained by cloning was 1 380 bp.Predictive analysis showed that the transcriptional start site of this sequence was base A at position 1 342,and the sequence contained a variety of cis-acting elements related to high seed expression,such as RY element,Skn-1 motif,2S seed protbanapa,etc.The plant expression vector pCAM-GmP34P containing GUS gene driven by GmP34P promoter was obtained.The positive transgenic plants were screened by hygromycin,PCR and RT-PCR.The results showed that GUS gene expression was extremely significant in transgenic tobacco seeds compared with other tissues by qRT-PCR with positive pCAM-GmP34P transgenic tobacco plants.GUS histochemical staining showed that the GmP34P promoter could regulate the high expression of downstream GUS gene in seeds.

To elucidate the mechanisms of cold response and explore superior cold-tolerance gene resources in wheat,this study employed transcriptome sequencing to uncover key regulatory networks underlying wheat cold response,and performed functional validation of the candidate gene TaGGCT18-6A.The results demonstrated that 4 ℃ cold treatments induced 10 893 and 18 784 differentially expressed genes(DEGs)in wheat seedlings after 6 h and 24 h cold treatment,respectively.KEGG analysis revealed significant enrichment of DEGs in pathways including MAPK signaling transduction and glutathione metabolism.A γ-glutamyl cyclotransferase gene TaGGCT18-6A was cloned through screening key genes in glutathione metabolism.This gene had a length of 1 772 bp,encoding 218 amino acids with conserved GGCT-like superfamily and ChaC core domain.Promoter cis-acting element analysis identified stress-responsive elements such as low-temperature-responsive(LTR)and dehydration-responsive (DRE)elements; consistently,expression pattern analysis showed sustained upregulation of TaGGCT18-6A under 4 ℃ cold treatments. Functional validation in transgenic rice revealed that overexpression lines OE#1, OE#2 and OE#3 exhibited significantly enhanced survival rate,plant height,and biomass. Overexpression lines OE#1 and OE#2 exhibited significantly enhanced plant height, while overexpression lines OE#1, OE#2 and OE#3 exhibited significantly reduced relative electrolyte leakage under -4 ℃ freezing treatments.After 4 ℃ treatment,overexpression lines accumulated higher levels of osmolytes(proline and soluble sugars),decreased malondialdehyde(MDA)content,and increased activities of superoxide dismutase(SOD),peroxidase(POD),and catalase(CAT).These findings collectively demonstrated that TaGGCT18-6A enhanced plant cold tolerance by regulating glutathione metabolism to improve antioxidant capacity.This study will provide a theoretical foundation and valuable genetic resources for molecular breeding of cold-tolerant wheat.

The transcription factor BnHY5-2 is associated with plant stress resistance.In order to reveal the response of Brassica napus L.transcription factor BnHY5-2 to salt alkali stress in B.napus,the response of BnHY5-2 to light and salt and alkali was analyzed by transient overexpression,qRT-PCR analysis and subcellular localization.The results revealed that under light conditions,the expression level of the BnHY5-2 gene in B.napus leaves and stems was 29.22 and 3.15 fold higher,respectively,compared to dark conditions.The higher sensitivity to light in leaves suggested that they were the primary site for light signal response.Under light conditions,the expression of BnHY5-2 in leaves and stems was significantly downregulated by 53.1% and 31.0%,respectively,when B.napus was planted in Dalian coastal saline-alkali soil;after applying saline-alkali treatment under dark conditions,the expression of BnHY5-2 was downregulated by 48.2% in the stem,while the difference in expression in the leaves was not significant,indicating organ differences,indicating that the leaves had stricter requirements for light conditions.In B.napus leaves with transient overexpression of BnHY5-2,two out of six genes related to saline-alkali stress(BnNAC32 and BnGS)showed upregulation by 1.25,3.28 fold,respectively,while the other four genes(Bnamy,BnAsp,BnNHX7,BnTPS)were downregulated by 24.8%,25.4%,71.0%,and 82.0%,respectively.Meanwhile,the content of the resistance substance betaine in B.napus increased from 0.256 to 0.573 mg/g,indicating an enhancement by 1.24 fold,suggesting that the overexpression of BnHY5-2 gene could improve the saline-alkali tolerance of B.napus.Subcellular localization results showed that the transcription factor BnHY5-2 was localized in the nucleus and regulates the expression of functional genes.Therefore,BnHY5-2 is not only related to light signaling but also participates in the saline-alkali resistance of Brassica napus L.

To investigate the role of calcium-dependent protein kinase (CDPK) in wheat growth and stress response,the TaCDPK17 gene was cloned from common wheat and its sequence structure,expression pattern,and stress resistance function were preliminarily analyzed.The results showed that the length of the TaCDPK17 gene coding region was 1 701 bp, encoding 566 amino acids and possessing typical structural features of the CDPK family, including one conserved serine/threonine kinase domain and four EF hand shaped domains. Evolutionary tree analysis of TaCDPK17 and CDPK17 from 12 other plants showed that TaCDPK17 had high homology with the CDPK17 sequence of gramineous crops,especially Aegilops tauschii and barley.The promoter region of TaCDPK17 gene contained multiple cis regulatory elements related to hormone signaling pathways,light response.Among them, there are more abscisic acid (ABA) responsive elements (ABRE) and methyl jasmonate responsive elements (CGTCA). The expression analysis based on Real-time Fluorescence Quantitative PCR showed that the expression level of TaCDPK17 increased to varying degrees after induced by 100 μmol/L ABA, 100 μmol/L methyl jasmonate, 20% PEG6000, and 250 mmol/L NaCl. Under stress conditions of 2 μmol/L ABA and 100 mmol/L NaCl, the germination rate of Arabidopsis seeds overexpressing TaCDPK17 was significantly higher than that of the wild type. Meanwhile, overexpression of TaCDPK17 alleviated the inhibitory effects of ABA or osmotic stress treatments on seedling root growth. During stomatal closure, transgenic plants overexpressing TaCDPK17 are more sensitive to ABA and exhibit a stronger stomatal closure trend compared to wild-type plants. These results indicated that TaCDPK17 plays an important role in stress response and hormone signaling in wheat.

To reveal the mechanism of drought resistance of different resistant rice during germination period,Rice drought-sensitive materials(Calrose,Jingning 10,Shanxing 86)and drought resistance materials(Farry,Songjing 3,Ningjing 36)were studied on the effects of simulated drought stress(15% PEG-6000)on the growth index,physiological indexes and corresponding gene expression of different rice seeds.The results showed that under normal conditions,there were no significant differences in the expression levels of growth indicators and stress-related genes between drought-sensitive and drought-resistant cultivars.However,changes in physiological indicators were shown that there were no significant differences in the activities of superoxide dismutase(SOD) and peroxidase(POD),the contents of soluble sugar(SS) and hydrogen peroxide(H₂O₂) among different genotypes.The contents of malondialdehyde(MDA) and superoxide anion($\mathrm{O}_{2}^{\bar{.}}$) in the drought-sensitive cultivar Shanxing 86 were significantly higher than those in other materials,and the contents of catalase(CAT),proline(Pro) and soluble protein(SP) of drought resistant Ningjing 36 were significantly higher than those of other materials as well.Under drought stress,the relative germination potential(RGP),relative bud length(RSL),germination drought resistance index(GDRI)and vitality index(VI)of germinating seeds increased by 0.03—0.07 percentage,0.32—0.39 percentage,0.12—0.18 percentage and 92.41%—108.39%,respectively;MDA and reactive oxygen species($\mathrm{O}_{2}^{\bar{.}}$,H₂O₂) contents in germinating seeds of drought-resistant cultivars decreased by 2.54%—61.64%,19.60%—46.30% and 35.61%—62.02% respectively compared with drought-sensitive cultivars.The contents of osmotic regulating substances(Pro,SS,SP) increased by 5.93%—18.29%,1.08%—7.97% and 3.47%—6.03% respectively.The activities of antioxidant enzymes(SOD,POD, CAT) were increased by 17.29%—33.12%,15.24%—76.06% and 14.68%—18.61% respectively.The relative expression levels of OsP5CS,antioxidant enzyme synthesis genes (OsALM1, OsPOX1, OsCATC) were up-regulated by 2.66%—182.31% and 57.14%—513.27%,0.38%—109.06% and 63.39%—184.25% respectively.Comprehensive analysis showed that drought stress inhibited the germination of rice seeds and affected the physiological characteristics of seeds and the expression of corresponding genes during germination.Under drought stress,vigor index(VI),peroxidase(POD)and peroxidase synthesis gene(OsPOX1)are the key indicators affecting rice seed germination,whether it is drought-resistant or drought-sensitive materials.In addition to the above indicators,soluble protein(SP),proline synthesis gene(OsP5CS)and catalase gene(OsCATC)are other key indicators affecting drought-resistant materials.Relative shoot length(RSL),hydrogen peroxide(H₂O₂)and superoxide dismutase gene(OsALM1)are other key indicators affecting drought-sensitive materials.

To clarify the regulatory effect of nitrogen(N)fertilizer reduction and postponing on the productivity of wheat-maize double cropping system in Huang-Huai-Hai Plain.The annual N fertilizer experiment of summer maize and winter wheat was established of four N application systems:annual N fertilizer application 400 kg/ha of traditional farmer treatment(F₄₀₀),10% reduction of annual N fertilizer(FN),20% reduction of annual N fertilizer(FH),and 30% reduction of annual N fertilizer(FL)from 2020 to 2023 at Jiyang Experimental Base of the Shandong Academy of Agricultural Sciences in Jinan.The grain yield,aboveground N accumulation characteristics,N use efficiency,and the nitrate residue after harvest in the 0—200 cm soil layer of wheat-maize double cropping system were tested,in order to provide the theoretical basis for further optimization of N fertilizer management in Huang-Huai-Hai Plain.The results indicated that N fertilizer postponing was optimized the grain yield of summer maize and winter wheat under the condition of N reduction,and the averaged across the three years,FL significantly increased by 9.2%—18.1%,13.5%—20.5%,and 11.1%—19.1%,respectively,compared with F₄₀₀ and FN.N fertilizer postponing improved the N accumulation rate,and promoted aboveground N accumulation at wheat-maize different growth stages,and the averaged across the three years,FL significantly increased plant N accumulation by 5.7%—12.3% and 5.0%—12.8% under silking and maturity,respectively,compared with F₄₀₀,FN,and FH,as well as 8.2%—17.2% in grain N accumulation.For winter wheat,FL and FH treatments were significantly higher than F₄₀₀ and FN at jointing,anthesis,and maturity,and the averaged across the three years,FL and FH significantly increased by 23.4%—28.1%,20.7%—26.3%,and 12.6%—20.8%,respectively,compared with F₄₀₀,FN and FH,at the same time the grain N accumulation under FL significantly increased by 16.4%,15.0% and 5.8%,respectively,compared with F₄₀₀ and FN.N fertilizer postponing optimized the N use efficiency of wheat-maize double crop system,the averaged across the three years,FL significantly increased N uptake efficiency by 4.8%—57.7% and 32.0%—72.4% of summer maize and winter wheat,respectively,compared with F₄₀₀,FN,and FH;and FL significantly increased N partial factor productivity by 68.8% and 40.4% in summer maize,respectively,compared with F₄₀₀ and FN,as well as by 38.4%—71.8% in winter wheat compared with F₄₀₀,FN,and FH.At harvest of summer maize and winter wheat,the soil nitrate residue was mainly enrichment in the 0—40 cm soil layer under four N application systems,the averaged across the three years,accounted for 40.0%,38.9%,44.9%,42.5% and 37.3%,36.9%,46.7%,38.3% of the 0—200 cm soil layer,respectively.In addition,the obvious accumulated effects in 0—200 cm soil layer nitrate residue under F₄₀₀ and FN treatments at harvest of summer maize and winter wheat,but there was the relative balance was achieved under FL and FH treatments.In conclusion,a 30% reduction of annual N fertilizer by N fertilizer postponing could optimize plant N accumulation characteristics and realized synergistic improve grain yield and N use efficiency.Therefore,FL treatment was an optimal N application system for realizing the collaborative target of high-yield,high-efficiency,and environment-friendly of wheat-maize double cropping system in Huang-Huai-Hai Plain.

In order to explore the role of RPM1 in sorghum disease resistance,a sorghum SbRPM1 gene was obtained from sorghum smut resistant variety SX44B by homologous cloning method.The bioinformatics analysis results showed that the total length of the cDNA of SbRPM1 gene was 2 802 bp,encoding 933 amino acids,and its protein had a theoretical molecular weight of 106.1 ku and an isoelectric point of 7.11,which was a hydrophilic protein.The SbRPM1 protein had no transmembrane structure,and its subcellular localization was in the cytoplasm.Conservative domain analysis showed that SbRPM1 protein contained RX-CC-like,NB-ARC and LRR domains,and belonged to CNL proteins in the NLRs family.Phylogenetic analysis showed that SbRPM1 protein was most closely related to the RPM1 protein of Miscanthus lutarioriparius.The expression pattern of SbRPM1 gene was detected by Real-time quantitative PCR,and the results showed that the expression of SbRPM1 gene was higher in leaves and inflorescence,followed by roots,and the lowest in stem.The expression of SbRPM1 gene was significantly up-regulated at 24—72 h in disease-resistant varieties after inoculation with Sporisorium reilianum pathogen,suggesting that this gene could be induced by S.reilianum and played an important role in sorghum disease resistance.In this study, the CDS sequence of the SbRPM1 gene was cloned for the first time in sorghum, and the structure, nature and expression of the gene were characterized.

NRL(NPH3/RPT2-Like)is a type of light-responsive protein unique to plants and plays a vital role in the phototropic signal pathway. To reveal the NRL gene maize genome's characteristics and expression,we analyzed them using bioinformatics methods combined with qRT-PCR technology. The property,structure,evolution of their encoded proteins,and growth period tissue expression and stress expression were analyzed. 31 ZmNRL genes identified were located in nine maize chromosomes,encoding protein amino acids 464-749 aa,which predicted to have chloroplast,nuclear and cytoplasmic locations. According to protein conservation,ZmNRL family was divided into four categories. Their gene structure also presented certain conservation,the most contained four exons. Analysis of the cis-elements of gene promoters revealed a large number of abscisic acids,jasmonic acid,light response,and anti-oxidation elements,among which G-box and Sp1 were two types of light-related elements. The expression of ZmNRL family genes in tissues during the growth period showed a temporal and spatial specificity,and the majority expression level was not high. Only ZmNRL2,ZmNRL4,ZmNRL24,and ZmNRL29 highly expressed. Furthermore,the characteristic modules were produced based on the data of the tissue co-expression genes. And the GO enrichment analysis of a particular leaf growth module containing six ZmNRL genes,mainly associated with the plastid organization biological processes and rRNA binding molecular functions. The expression of ZmNRL5,ZmNRL7,ZmNRL12,and ZmNRL19 genes were analyzed by qRT-PCR under salt,drought,high temperature,and Rhizoctonia solani inoculation treatments. The results showed that ZmNRL12 was significantly up-regulated in maize seedlings treated with high temperature,while ZmNRL5,ZmNRL7 and ZmNRL19 genes were down-regulated in drought,salt and pathogen treatments. In summary,31 ZmNRL genes were identified in the maize genome. They not only had apparent specific tissue expression but also participated in biotic and abiotic stress responses.

Phytosulfokine receptor(PSKR)plays an important role in promoting plant cell proliferation and is involved in plant response to abiotic stresses.To explore the sequence characteristics and the function of wheat PSKR genes,the cDNA sequences of three homologous genes of TaPSKR1 were cloned from wheat variety Jinmai 47 by homologous cloning technology,named TaPSKR1-6A,TaPSKR1-6B and TaPSKR1-6D because of their locations on chromosome 6A,6B and 6D,respectively.The gene structure,protein physical and chemical properties,cis acting elements,functional domains and evolutionary relationships were analyzed by bioinformatics analysis.The expression patterns of TaPSKR1 genes in different tissues and under different stresses were detected by qRT-PCR.The results showed that TaPSKR1-6A,TaPSKR1-6B and TaPSKR1-6D all contained one exon.The open reading frame(ORF)of the three TaPSKR1 genes were 3 153,3 132,3 156 bp,respectively,which encoded 1 050,1 043 and 1 051 amino acid residues.Bioinformatics analysis showed that TaPSKR1 proteins were located on the cell membrane,containing signal peptide,transmembrane domains,eight LRRs type domains and intracellular kinase domain,which belonged to PSKR gene family.Phylogenetic analysis showed that TaPSKR1 proteins had closely relationship with its related species and rice,which were clustered into the same subgroup.The results of expression analysis showed that TaPSKR1 genes were expressed in roots,stems,leaves and seeds,and the expression levels in roots were the highest.Under drought and salt stress treatments,the expressions of three homologous copies of TaPSKR1 genes were sharply upregulated in leaves,suggesting that TaPSKR1 might play an important regulatory role in wheat defense to abiotic stresses.

In order to clarify the effects of drought stress on the photosynthetic characteristics in flag leaf in the afternoon during grain filling stage and grain yield of winter wheat with different drought resistance,an experiment with two winter wheat cultivars and four water levels was conducted under the condition of rainproof pond cultivation in 2018—2019 and 2019—2020.The two winter wheat cultivars were Jinmai 47(JM47,strong drought resistance)and Yanzhan 4110(YZ4110,weak drought resistance).The four water treatments included severe drought(W1:65% MFC(maximum field water capacity)before sowing + 45%—55% MFC after jointing),moderate drought(W2:75% MFC before sowing + 55%—65% MFC after jointing),mild drought(W3:75% MFC before sowing+65%—75% MFC after jointing),suitable water supply(W4:75%MFC before sowing+75%—85% MFC after jointing).The net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO₂ concentration(Ci),transpiration rate(Tr),instantaneous water use efficiency(IWUE),maximum photochemical efficiency of PS Ⅱ (Fv/Fm)and actual photochemical efficiency of PS Ⅱ(ΦPS Ⅱ)in flag leaf from 14:00 to 16:00 during the early,medium and medium-late grain filling stage and the grain yield and its components at maturity were investigated.The results showed that both water and cultivars had significant effects on the photosynthetic and fluorescence characteristics in flag leaf in the afternoon during the grain filling stage and the grain yield at maturity of winter wheat.From the two-year average,compared with W4,the Pn,Gs and ΦPSⅡ in flag leaf in the afternoon during the grain filling stage under drought stress(W1,W2 and W3)respectively decreased by 2.07%—68.92%,-3.23%—50.00% and -1.89%—30.19% in JM47,and decreased by 7.71%—80.19%,11.11%—59.26% and 0—73.47% in YZ4110;the flag leaf Tr values in the afternoon during the medium grain filling stage in JM47 and YZ4110 respectively decreased by 6.30%—32.87% and 6.49%—41.74%,and the flag leaf Fv/Fm values in the afternoon during the medium-late grain filling stage decreased by 1.20%—18.52% and 2.50%—30.00%.In general,for all the above indexes,the decreasing amplitude for the same index was JM47<YZ4110.Compared with YZ4110,the Pn,Gs,ΦPSⅡ and Fv/Fm in flag leaf in the afternoon during the grain filling stage under drought stress(W1,W2 and W3)of JM47 respectively increased by 0.86%—64.89%,8.33%—36.36%,1.96%—184.62% and 1.25%—17.86%,and the grain yields of JM47 were respectively increased by 28.91%,8.06% and 5.40%.Except for IWUE,the flag leaf photosynthetic parameters in the afternoon during the grain filling stage were significantly and extremely significant correlated with grain yield,but the correlation indexes varied with variety and grain filling stage.For JM47,the correlation indexes between the grain yield and flag leaf photosynthetic parameters were highest for Pn,Gs and Fv/Fm during the medium-late grain filling stage,for ΦPSⅡ during the medium grain filling stage,and for Tr during the early grain filling stage.For YZ4110,the correlation indexes were highest for Pn,Gs and Tr during the early grain filling stage,for ΦPSⅡ during the medium grain filling stage and for Fv/Fm during the medium-late grain filling stage.In summary,drought stress decreased the photosynthetic function of flag leaf in the afternoon during grain filling stage and thus decreased the grain yield of winter wheat,the strong drought resistance variety could maintain better flag leaf photosynthetic characteristics in the afternoon during the grain the filling stage under drought stress condition,and significantly improved the ΦPSⅡ of flag leaf in the afternoon during the medium grain filling stage and the Pn,Gs and Fv/Fm of flag leaf in the afternoon during the medium-late grain filling stage,thereby increasing the grain yield.

The plant NADPH oxidase Rbohs(Respiratory burst oxidase homologs) is the main source of reactive oxygen species (ROS),which participate in various physiological processes such as plant growth,development,stress resistance and plant-microorganism interaction.In order to explore the function and mechanism of Rbohs in symbiotic nitrogen fixation,GmRbohL,a member of soybean Rbohs gene family,was cloned in this study.The gene expression pattern,protein subcellular localization and gene function were studied by molecular biology,cell biology and genetics,respectively.The results revealed that: GmRbohL gene was induced by rhizobia and expressed specifically in soybean roots and nodules.Subcellular localization analysis indicated that the gene-encoded protein GmRbohL was a membrane protein.The plant gene silencing (RNAi) vector of GmRbohL was constructed,and the transgenic hairy roots were obtained by the transformation of soybean hairy root mediated by Agrobacterium rhizogenes K599.Gene silencing of GmRbohL resulted in a significant reduction in the number of nodules of transgenic hairy roots,and the production of ROS was also inhibited. Gene silencing of GmRbohL reduced the infection of rhizobia at the stage of root nodule organogenesis,and the expression level of nodulation marker genes also decreased with the decrease of GmRbohL expression.The root nodule tissue sections showed that gene silencing of GmRbohL significantly reduced the number of symbionts in the infected area of root nodules,and the nitrogenase activity of root nodules also decreased accordingly.The above data indicated that gene silencing of GmRbohL significantly inhibits the symbiotic nodulation process of soybean by reducing the production level of ROS.It is speculated that GmRbohL may play an important positive regulatory role in organogenesis of soybean nodules and regulation of nitrogen fixation function.

In order to improve the blast resistance of Shuijing 3,an excellent food-flavor rice variety,CRISPR/Cas9 gene editing technology combined with gene chip technology were used to pyramid the R gene Pigm and the non-R gene bsr-d1 into Shuijing 3.Firstly,Bsr-d1 was selected as the target gene to construct a recombinant expression vector using the CRISPR/Cas9 gene editing system,and transformed into the excellent food-flavor rice Shuijing 3 by Agrobacterium-mediated method.The homozygous bsr-d1 mutant lines without T-DNA elements,including five mutation types as T insertion,G insertion,GA deletion,CGCA deletion and CGCAGA deletion,were screened out.The japonica line Jinyu 1 containing a broad-spectrum blast resistance gene Pigm was used as the gene donor parent to cross with the homozygous bsr-d1 mutant lines without transgenic components.The Pigm gene was introduced into bsr-d1 mutant lines by cross,backcross and self-cross combing molecular breeding chip to simultaneously perform Pigm gene and background-assisted selection.The improved lines SJ3-G1,SJ3-G2,SJ3-G3,SJ3-G4,SJ3-G5,which were homozygous for the disease resistance genes(carrying both bsr-d1 and Pigm genes)and whose background recovery rates were all above 96%,were finally obtained.The improved strains of Shuijing 3 displayed enhanced leaf blast resistance compared with the wild type in inoculated identification test using Magnaporthe grisea strain GUY11.After inoculation with M.oryzae,the POD activities in the improved strains of Shuijing 3 were significantly lower than that of the wild-type control,while the H₂O₂ contents were significantly higher than that of the wild-type control.The improved Shuijing 3 lines with blast resistance carrying both bsr-d1 and Pigm genes are obtained by CRISPR/Cas9 gene editing technology combined with gene chip technology.

The effect of different concentrations salt stress on seedling growth and expression of related genes were explored in this study. Firstly, salt tolerant variety Yura Hama Daikon and susceptible variety Wujinhong were selected according to germination under salt stress conditions among 11 cultivars.And then the seedling height(SH) and the leaf scorch index(LSI) of Yura Hama Daikon and Wujinhong were investigated under salt stress treatment.The results showed that SH decreased and LSI increased under salt stress in both varieties.Compared with the salt-sensitive variety Wujinhong,the salt-tolerant variety Yura Hama Daikon had a smaller decrease in SH and lower LSI.Under 200 mmol/L salt stress,SH and LSI of salt-tolerant Yura Hama Daikon were 46.18% and 20.56,respectively,while those of salt-sensitive Wujinhong were 75.25% and 56.11.The transcription of RsCAT and RsSOD genes was studied in salt-tolerant and susceptible varieties under different salt concentrations by qPCR.The expression of RsCAT gene was first increased and then decreased under low salt concentration treatment,and reached the maximum at 7 day.When treated with high salt concentration,the transcription of RsCAT in Wujinhong was the highest at 48 h,while the expression level in salt-tolerant varieties increased gradually and maintained for a longer time,reaching the highest at 7 day.After high salt concentration treatment,the transcription of RsSOD gene reached the highest expression level at 24 hours,and then maintained a higher level in salt-tolerant variety.In salt-sensitive varieties,the maximum expression level of RsSOD appeared at 14 day.The above results will lay foundation for revealing the mechanism of salt stress in radish and provide technical support for radish salt-tolerant breeding.

MYB transcription factor proteins are ubiquitous in plants and play an important role in biological and abiotic stresses. To explore the function of cotton MYB gene, the paper cloned a MYB gene from cotton leaves using homologous cloning technology, and analyzed its bioinformatics and expression under different stresses. The results showed that a new MYB transcription factor gene GhMYBPA1 (gene entry site XM_016869420) was successfully cloned from Gossypium hirsutum cv. Zhongmian 35, the full of cDNA was 825 bp in length with a 630 bp ORF, which encoded a 210 amino acids peptide. Bioinformatics analysis results showed that the molecular weight of GhMYBPA1 was 20.183 ku, GhMYBPA1 contained two conserved DNA-binding domains at N-terminal, which belonged to R2R3-MYB transcription factors. Amino acid homology analysis showed that GhMYBPA1 had higher identification with GaMYB12-like from Gossypium arboreum. Based on qRT-PCR analysis, GhMYBPA1 was constitutively expressed in cotton roots, stems, leaves, and it was dominantly expressed in flowers and then was leaves. Moreover, the results of plant treated with various stresses showed that the expression of GhMYBPA1 gene changed under high salt, low temperature and drought stress, it was suggested that GhMYBPA1 might play an important regulatory role in the abiotic stress process of cotton. The results could lay a theoretical foundation for further researches on the function of GhMYBPA1 gene.

The hexameric Paf1 (RNA polymerase Ⅱ associated factor 1) complex is a crucial transcription regulator in eukaryotes.Paf1-regulated expression of specific genes in plants is closely related to diverse biological processes including growth,development,and stress responses.In order to get information on the responses of Paf1 to abiotic stresses in common wheat,homologous sequence searches were performed to identify all of the genes encoding each of the Paf1 subunits in the wheat genome.mCherry fusions of the wheat Paf1 subunit proteins were expressed in protoplasts and tobacco leaves for determination of protein subcellular localization by fluorescence microscopy.qRT-PCR assays were conducted to profile the expression of wheat Paf1 subunit genes in response to different abiotic stresses.The results showed that,in wheat,five of the Paf1 subunits,TaVIP3,TaVIP4,TaVIP5,TaVIP6,and TaPHP,were each encoded by one set of homeologous genes while the sixth subunit TaVIP2 was encoded by two sets.Plant VIP2 sequences had an N-terminal proline-rich region with variable length,and wheat TaVIP2 sequences had an additional glutamine-rich region.Protein subcellular localization assays revealed the nuclear localization of TaVIP2,TaVIP4,TaVIP5,and TaVIP6 proteins and the nuclear and cytoplasmic localization of TaVIP3 and TaPHP proteins.Gene expression analyses revealed similar tissue-dependent constitutive expression variations and similar stress-induced expression patterns of wheat Paf1 subunit genes.These genes coordinately responded to the stress of high temperature by expression upregulation and to the stresses of salt and drought by expression downregulation.Collectively,our results suggested the involvement of expression regulation of Paf1 subunit genes in the responses of wheat to abiotic stresses.

The ubiquitination pathway is one of the key signaling pathways in response to drought stress.In order to clarify the biological function of E3 ubiquitin ligase TaSINA101 gene in response to drought stress,the TaSINA61,TaSINA101 and TaSINA105 genes were cloned from JM47,an excellent drought-resistant wheat cultivar,and their sequence characteristics were analyzed by bioinformatics methods,and the expression levels of the three genes in wheat roots and leaves were detected by qRT-PCR under PEG-6000,NaCl,low temperature and ABA treatments.The heterologous expression of TaSINA101 in transgenic rice was used to analyze the biological function of TaSINA101 in response to drought stress.The results showed that the TaSINA61,TaSINA101 and TaSINA105 genes contained one intron and two exons,and the encoded proteins were composed of 282 amino acids.The qRT-PCR expression analysis showed that the expression of these three genes was induced by various abiotic stresses such as drought stress in roots and leaves.Phenotypic analysis of TaSINA101 transgenic rice under drought stress showed that the leaf fresh weight and dry weight, maximum root length, average root diameter and leaf relative water content of transgenic rice lines OE-1, OE-2 and OE-3 were significantly lower than those of wild type,while the relative conductivity of leaves of transgenic rice lines OE-1 and OE-2 was significantly higher than that of wild type.Therefore,TaSINA101 negatively regulates drought stress tolerance in rice.This study provides a basis for in-depth analysis of the biological function of TaSINA101 gene in wheat.

Tiller higher than main stem is one of the important reasons that make the uniformity of sorghum varieties and mechanized production of sorghum complicated.In order to clarify the mechanism of the gene that regulates the tiller height in sorghum,improve the uniformity of sorghum varieties and breed sorghum varieties suitable for mechanized production,based on the mapping results of our previous studies,15 of the sorghum variety whose tiller height was consistent with main stem height as well as 17 of the sorghum variety whose tiller height was higher than main stem height,were selected to form the natural population to have the candidate genes tested.It was found that it was the SNP3 locus belonging to the gene Sobic.009G2133001.v3.2 located in the conserved domains of Hydrolase_4 affects the tiller height,it was named SbTH.With two sorghum varieties K35-Y5 and 1383 taken as material,the expression patterns of gene SbTH in different sorghum tissues were analyzed by Real-time fluorescence quantitative PCR.The results showed that the SbTH gene got expressed in both the roots and the leaves.Though the expression levels were different,the trends were basically the same.In the stem of variety 1383 whose tiller was higher than main stem,the expression level and trend were almost the same.Only in variety K35-Y5 whose tiller height was consistent with main stem height,at anthesis of main stem,reverse expression pattern was observed.While the expression level of main stem reached the maximum,the expression level of tiller was lowered to the minimum.From above results,we concluded that the expression level of SbTH was low in the tiller of K35-Y5,thus the overgrowth of the tiller internodes got controlled,forming the plant phenotype whose stem and tiller had the same height.The expression level of SbTH was high in the tiller of variety 1383,thus the growth of tiller internodes was promoted,which made the tiller be higher than the stem.Therefore,it is believed that the differential expression of gene SbTH at anthesis of main stem is the key to tiller height regulation.

Plant sodium-hydrogen antiporter(NHX,Na⁺/H⁺ antiporter)plays a crucial role in plant sodium and potassium ion balance and cellular pH regulation.In order to investigate the relationship between salt tolerance and ScNHXs,it was conducted to identify and analyze the ScNHXs by bioinformatics process,and to examine the expression pattern of ScNHXs under salt stress by RT-qPCR,which can provide the reference information for the investigation of the potential functions of ScNHXs as well as the mining of salt tolerance genes in rye.A total of 10 rye NHX gene family members(ScNHX1—ScNHX10)were identified,and the phylogenetic tree analysis showed that they could be divided into two subfamilies,Vac and Endo,containing four and six genes,respectively.Physicochemical property analysis of the encoded proteins showed that most of the molecular weight ranged from 27.92 to 59.72 ku,the number of amino acids from 253 to 546 aa,and the isoelectric point between 5.17 and 8.81,with most of proteins being classified as acidic proteins.Signal peptide prediction indicated the absence of signal peptides in the members,and transmembrane structure analysis revealed that all members possessed transmembrane structures.The subcellular localization prediction indicated that ScNHXs were located in the plasma membrane and vesicles.Spatial structure prediction showed that their secondary structures mainly consisted of α-helices and irregular convolutions.Gene structure and motif analyses revealed that the number of exons of the ScNHXs varied from 13 to 24,and all of them possessed a conserved Na⁺/H⁺ exchange structural domain.In addition,cis-acting element analysis revealed that numerous elements related to hormone response and abiotic stresses were found in the promoter region of ScNHXs.Analysis of rye transcriptome data revealed significant differences in the expression patterns of ScNHXs in different tissues of rye.RT-qPCR analysis showed that ScNHXs responded differently to different concentrations of NaCl stress,and were able to persistently respond to salt stress over a long period of time.In summary,ScNHXs may be involved in the biological regulation during salt stress in rye.

In order to understand the dynamic rules of sugars, starch, protein and trace elements of different types of wheat during grain filling stage under drought stress, and to identify the difference of nutriment between drought and irrigation in the process of grain-filling by high-yield wheat, high-quality wheat and water-saving wheat, the wheat varieties of Jimai 325, Jimai 418 and Jimai 323 in the North of Huang-Huai Region were used as experimental materials. The plants heading and flowering on the same day were selected for marking, and the grains of each variety were taken every 6 days after 7-31 days after anthesis. The effects of drought during grain filling on the contents of total soluble sugar, sucrose, glucose, fructose, protein, Fe, Zn, Mn, Cu, amylose and amylopectin accumulation, starch accumulation rate and the activities of key enzymes in starch synthesis were studied. The results showed that the content of sucrose and glucose in wheat grains was significantly decreased under drought stress, and the effect on fructose content was relatively small, and the sucrose and fructose of high-yielding variety Jimai 325 were less affected by drought in the filling process. Drought stress decreased the content of amylopectin and total starch in wheat grains, but had relatively little effect on the content of amylose. The effect of drought stress on starch content of high-yield and high-quality varieties was significantly greater than that of drought-tolerant variety Jimai 418. The activity of starch synthase was increased in the early and middle stages of filling stage under drought stress, and decreased rapidly in the middle and late stages compared with irrigation control. The content and accumulation of four mineral elements in wheat grains were Mg>Fe>Zn>Mn. With the progress of grain filling, the content of trace elements showed a downward trend. The accumulation of Fe, Zn and Mg in grains of Jimai 325 was higher. The difference of nutrient accumulation in grain filling process of different types of wheat under drought conditions were studied to provide theoretical data and reference basis for optimizing cultivation measures and realizing high quality, high yield and water saving of special wheat.

Fusarium head blight(FHB)is a devastating fungal disease that seriously threatens the safety of wheat production.Marker-assisted selection(MAS)and pyramiding of resistance genes represent efficient strategies for FHB-resistant breeding.To establish a high-throughput screening system for FHB resistance genes and enhance wheat resistance in Sichuan Province,we performed genome-wide genotyping using a 100K SNP array on 14 Sichuan wheat varieties(lines)along with three FHB-resistant genetic materials.Based on the reported genetic linkage intervals of major FHB resistance genes(Fhb2,Fhb4,Fhb5),we identified SNPs co-segregating with Fhb5 or linked to Fhb2,Fhb4,and subsequently developed kompetitive allele-specific PCR(KASP)markers.Results showed that the genetic relationship of 17 wheat varieties(lines)could be clustered into two major groups:two northern wheat-derived resistant materials(NMAS070 and NMAS069)formed an independent cluster distinct from the Sichuan varieties(lines)while the remaining 15 varieties(lines)were clustered together and subdivided into two subgroups.Functional gene profiling revealed FHB-resistant parents carried superior resistance loci,whereas agronomic parents harbored favorable alleles for yield and quality traits.Through SNP screening,we identified 8 critical SNPs within the linkage intervals of Fhb2,Fhb4 and the co-segregation region of Fhb5.These SNPs enabled the successful development of 4,2,and 2 high-specificity KASP marker systems for Fhb2,Fhb4 and Fhb5,respectively.Validation experiments confirmed all KASP markers achieved precise genotyping and were effectively implemented in molecular breeding for FHB-resistance.This study established a high-efficiency KASP marker system for Fhb2,Fhb4 and Fhb5,providing a robust technical platform for improving FHB resistance breeding of wheat varieties in Southwest China.

To study the effects of salt stress on growth and physiological characteristics of sorghum at different growth stages(elongation, flowering, and maturity), two sorghum varieties with different salt tolerances, Gaoliangzhe(salt tolerance) and Henong No.16(salt sensitive), were planted at four salt treatment levels(CK:0 g/kg, S3:3 g/kg, S5:5 g/kg, S7:7 g/kg). Moreover, the two varieties were compared under different salt treatment levels, plant morphology, root morphology, leaf photosynthetic characteristics and antioxidant enzyme activities at different growth stages. The results showed that with increasing salt treatment concentration, the antioxidant enzyme activity and relative chlorophyll content(SPAD) of the two varieties increased first and then decreased. The antioxidant enzyme activity reached the maximum value under S3 or S5 treatment, and there were significant differences between the maximum and CK. With the increase of salt treatment concentration, the malondialdehyde(MDA) of the two sorghum varieties increased significantly, which S7 treatment was significantly higher than CK. Under the same treatment, the antioxidant enzyme activity of salt-tolerant varieties(Gaoliangzhe) was higher than that of salt-sensitive varieties(Henong No.16), but the content of MDA was lower than that of salt-sensitive varieties. The photosynthetic capacity of the two varieties was significantly affected by salt stress. In elengation, S7 treatment significantly reduced the Pn of Gaoliangzhe, and Ci of the two varieties under S7 treatment was higher than that of CK. Under salt stress, the growth of the sorghum aerial portion and underground portion of sorghum were affected. The basal stem diameter, total length of root, root surface area, number of root tips, and number of root branches for two varieties reached the maximum under S3 treatment. And basal internode length, plant height, total length of root and root volume reached the lowest value under S7 treatment. In addition, grain fat content and grain starch content in two sorghum varieties decreased under salt stress.The grain tannin content was significantly higher than CK in low-salt (S3, 3 g/kg). In general, low-salt can promote the growth of sorghum, while medium-salt (S5, 5 g/kg) and high-salt (S7, 7 g/kg) conditions have a significant inhibitory effect on sorghum growth. And Gaoliangzhe is more salt-tolerant than Henong No.16.

This study investigated the accumulation and distribution of dry matter,nitrogen(N)and zinc(Zn)of summer maize under N and Zn fertilization,to provide a basis for reasonable application of zinc fertilizer and combined fertilization.Split-split design was used with three N rates(90,180,225 kg/ha N)as the main factor,two Zn rates(0,4.5 kg/ha ZnSO₄·7H₂O)as the second factor,two varieties(ZD958 and GSY66)as the third factor.The effect of N and Zn application on the grain yield,dry matter accumulation dynamic and N and Zn absorption,accumulation and distribution of each organ of different maize varieties by field experiment.The results showed that the grain yield achieved 9.77,10.42 t/ha under the N rates of 180,225 kg/ha,respectively,increased by 18.0% compared with 90 kg/ha.The treatment of 225 kg/ha N had the highest plant dry matter accumulation after silking,while the treatment of 90 kg/ha had higher ratio of cob and grain dry matter at the mature stage.Highest N concentration in each organ,Zn concentration in the stem and N and Zn accumulation in the leaf and grain were obtained in the treatment of 225 kg/ha,while highest Zn concentration in the sheath,bract and grain and ratio of grain N and Zn were found in the treatment of 90 kg/ha.No effect was found in the grain yield and dry matter accumulation and distribution under two Zn treatments.Zn application significantly increased N and Zn concentration and accumulation but decreased distribution ratio of grain N and Zn by 6.93,6.86 percentage points,respectively.Relative to GSY66,ZD958 had higher grain yield and dry matter ratio,and increased dry matter by 29.2% at maturity.Besides this,ZD958 decreased grain N and Zn concentration by 8.9% and 5.3%,respectively,but improved grain accumulation and distribution ratio.Correlation analysis showed that grain yield and N concentration in the stem,leaf and grain were significantly positively correlated.There was also a significantly or extremely significantly positive correlation between Zn concentration in the leaf and N concentration in the sheath and grain,between Zn concentration in the cob and N concentration in the sheath,cob and bract.These results suggested that combination of N and Zn fertilizers could increase yield and plant dry matter accumulation,enhance the N and Zn absorption and accumulation in each organ especially grain,but decrease distribution ratio of N and Zn in the grain.

In order to explore the effects of nutrient expert (NE) management on nitrogen (N) use efficiency and soil organic carbon (SOC) sequestration in the wheat-maize rotation system and improve its management practices, a long-term experiment was set up in 2009 to compare NE management with farmer's practice (FP) management. Through 9-years experiment, the crop yield, N use efficiency, SOC content, SOC sequestration rate and SOC sequestration efficiency were measured and analyzed. The advantages of long-term NE management in wheat-maize crop rotation system were evaluated. The results showed that long-term NE management reduced the amount of N fertilizer application rate, compared with FP management, but maintained the crop yields (no significant difference with FP). Compared with FP management, the average accumulative recovery efficiency of N, agronomic efficiency of N, and partial productivity of N in NE management system increased by 7.4 percentage points, 39.7%, and 28.4% in maize production system, and increased by 8.0 percentage points, 28.9%, and 32.8% in wheat production system, respectively After 9-years experiment, both NE and FP increased the SOC contents, with NE management increased faster than FP. The annual SOC contents rise rates of NE treatment in 0-5 cm, 5-10 cm and 10-20 cm soil profile were 0.28, 0.27, 0.34 g/(kg·a), respectively, which were 7.7%, 68.8% and 126.7% higher than those of FP treatment. The average annual carbon input of NE and FP treatment from straw returning were 8.5, 8.7 t/(ha·a), respectively, and the SOC sequestration rates were 1.35, 0.68 t/(ha·a),respectively, and the SOC sequestration efficiencies were 18.6% and 0.4%, respectively, which shown a significant difference. NE management could improve N use efficiency and increase SOC sequestration. Long-term NE management is one of the important measures for fertilizer saving, efficiency strengthen and SOC pool richen in wheat-maize rotation system. It would play a crucial role in ensuring food security and realizing agriculture green development.

In order to explore the role of citrus MYB96 gene in the process of citrus stress resistance,four MYB transcription factor genes were cloned from sweet orange,lemon,kumquat and ponkan,and named CsMYB96,ClMYB96,FmMYB96 and CrMYB96,respectively.Their bioinformatics and expression patterns under different abiotic stress treatments were analyzed.The results showed that the open reading frame of CsMYB96,ClMYB96,FmMYB96 and CrMYB96 were 1 032,1 035,1 035 and 1 032 bp,respectively.The citrus MYB96 proteins were composed of 343,344,344 and 343 amino acids,respectively,with a molecular weight of about 38.16, 38.27, 38.22 and 38.13 ku and an isoelectric points of 6.31,6.35,6.35 and 6.31,these proteins were all unstable hydrophilic proteins and the prediction results of subcellular localization were all located in the nucleus.The secondary structures of four MYB96 proteins were similar,mainly composed of α-helix and random curls.And all of four MYB96 proteins had a highly conserved R2 and R3 domains.In terms of evolutionary relationship,the proteins encoded by these four genes are most closely related to Citrus clementine CcMYB96 protein.The promoter of CsMYB96 gene contained abscisic acid response element(ABRE),low temperature response element(LTR),anaerobic response element(ARE),MYB binding site(MBS)involved in drought induction and other abiotic stress response related cis acting elements.Real-time quantitative PCR analysis showed that CsMYB96 could be induced by low temperature and drought stress,while ClMYB96 and FmMYB96 were induced under high salt stress.The expression of CrMYB96 was down-regulated in different degrees under low temperature,drought and high salt stress.

To investigate the effects of different dosages of biochemical fulvic acid (BFA) on the improvement of soda saline-alkali soil and the response mechanism of maize growth,a pot experiment was conducted using soda saline-alkali soil from Inner Mongolia as the test soil and maize Dongdan 181 as the test variety.Four BFA application rates were set as 0(CK),2(FA2),4(FA4),8 g/kg(FA8).Soil nutrients,microbial diversity,maize salt tolerance,biomass,and other indicators were measured.The results showed that compared to the CK,soil pH decreased with increasing BFA dosage.The soil available phosphorus content increased significantly after the application of BFA,but there was no significant difference among the three treatments of FA2,FA4 and FA8 at 30,62 and 80 days after sowing.Soil salinity increased with the increase of BFA dosage,with an increase of 23.30%—89.32%.Soil exchangeable potassium content increased with increasing BFA dosage,while exchangeable calcium content gradually decreased.The proportion of <0.053 mm silt and clay fractions in the soil decreased by 6.49,9.92 and 13.97 percentage points under FA2,FA4,and FA8 treatments,respectively,compared to the CK treatment.Meanwhile,the proportion of 0.053—0.250 mm aggregates increased by 5.90,8.99 and 13.75 percentage points,the proportion of 0.250—2.000 mm aggregates increased by 0.55,0.87 and 0.21 percentage points,while the proportion of >2.000 mm aggregates increased by 0.04,0.06 and 0.01 percentage points,respectively,under the FA2,FA4,and FA8 treatments relative to the CK.Soil microbial diversity was significantly higher than that of CK after the application of BFA,but the FA8 treatment was lower than the FA4 treatment.The Na⁺/K⁺ ratio in both shoots and roots of maize was lower under FA2 and FA4 treatments than under the CK treatment,while the FA8 treatment increased the Na⁺/K⁺ ratio in the shoots.Maize biomass significantly increased in the mid-to-late growth stages under FA2 and FA4 treatments,while biomass significantly decreased under the FA8 treatment.In summary,the application of 2 g/kg or 4 g/kg of biochemical fulvic acid can positively reduce the alkalinity of soda saline-alkali soil,increase the content of available phosphorus in the soil,improve soil structure,improve soil microbial diversity,and enhance maize salt tolerance and biomass.However,exceeding this dosage range will significantly increase soil salinity and inhibit maize growth.

To clarify the alterations of rice straw decomposition,nutrients release and chemical components in coastal saline paddy soils under different nitrogen (N) application rate,for optimizing the technology of straw returning and realizing the efficient utilization of straw resources in coastal areas.The experimental site was located in Caofeidian District,Tangshan City,Hebei Province.The decomposition characteristics of rice straw and its lignocellulose,as well as the nutrient release characteristics of N,phosphorus (P) and potassium (K) were studied,using a 360-day straw-bag burying method with four different N fertilizer levels,including N0 (0 kg/ha),N1 (225 kg/ha),N2 (300 kg/ha) and N3 (375 kg/ha).Pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) method was used to study the dynamic alterations of principal chemical components of the rice straw residues.The results showed that:the decomposition period of rice straw was divided into three stages,namely,rapid decomposition (0—30 d),slow decomposition (30—210 d) and slow decomposition (210—360 d),and the average decomposition rate of rice straw was 72.5% after 360 days with different N application rates.Increasing N application significantly increased the decomposition rate of rice straw.Compared with the N0 treatment,the N1,N2 and N3 treatments,increased the straw decomposition rate by 6.1, 7.4 and 9.2 percentage points,respectively.The trend of straw carbon (C) release rate was similar to that of straw decomposition rate,while the C release rate was only 43.2% at the end of the experiment.The nutrient release rates of rice straw were as follows:K>P>N.The N,P and K rapid release periods of rice straw was in the 0—30th (38.4%),0—60th (63.7%) and 0—15th (76.7%) days after straw decomposition,respectively.Both N and P of rice straw were enriched during the decomposition period.N application significantly increased the release of N from straw during the decomposition period,P in the early (0—15 d) and late (150—360 d) period,and K in the early period (0—15 d).Compared with the N0 treatment,the N1,N2,and N3 treatments,increased the straw N release by 6.6, 11.1, and 14.7 percentage points,P release by 2.2, 4.0, and 5.6 percentage points,and K release by 1.4, 2.1, and 2.8 percentage points,respectively.The lignocellulose decomposition rates of rice straw were as follows:hemicellulose>cellulose>lignin.Increasing N application significantly promoted the cellulose and hemicellulose decomposition rate of rice straw from day 0—90 and the lignin decomposition rate after day 90.Compared with the N0 treatment,the N1,N2,and N3 treatments,increased the cellulose decomposition rate of rice straw by 5.4, 7.3, and 8.4 percentage points, hemicellulose decomposition rate by 4.9, 6.4, and 7.4 percentage points,and lignin decomposition rate by 2.1, 5.1, and 5.7 percentage points, respectively.2-methoxy-4-vinylphenol,hydroxyacetone,2,3-dihydrobenzofuran,acetosyringone,eugenol,n-hexadecanoic acid,p-methylphenol,2,6-dimethoxyphenol,guaiacol,p-ethylphenol,and stigmasta-3,5-diene were the major (>1% relative) chemical components of straw residues during the decomposition period.Correlation analyses showed that straw decomposition rate,C release rate and cellulose,hemicellulose and lignin decomposition rates,were significantly positively correlated with eugenol,acetosyringone and 2,3-dihydrobenzofuran,while significantly negatively correlated with hydroxyacetone;straw P release rate was significantly positively correlated with hydroxyacetone and significantly negatively correlated with p-ethylphenol,eugenol and acetosyringone;straw K release rate was significantly correlated with p-ethylphenol,eugenol,acetosyringone and 2,3-dihydrobenzofuran,while significantly positively correlated with hydroxyacetone.In conclusion,increasing N application could promote the decomposition rates of rice straw and its lignocellulosic cellulose,and the nutrients release of straw N,P and K in coastal saline paddy field.The recommended optimal N application rate was 300 kg/ha under straw returning 10 500 kg/ha in coastal saline soils.p-ethylphenol,eugenol,acetosyringone,2,3-dihydrobenzofuran,hydroxyacetone,and stigmasta-3,5-diene could indicate the process of straw decomposition in straw residues.Py-GC-MS technique shows a good capability to monitor the chemical components alterations of straw residues,further deepening the understanding of straw decomposition mechanism.

bZIP transcription factors are widely found in plants and play an important role in regulating plant growth and development and abiotic stress response.In order to explore the functional role of bZIP transcription factor in maize drought stress response,transcriptome sequencing technology was used to analyze the expression changes of transcription factors in maize seedlings treated with drought stress for 5 days and rehydration for 3 days,and a bZIP transcription factor(ZmbZIP26)was screened from transcriptome data in response to drought and rewatering treatment.Co-expression network analysis revealed that ZmbZIP26 was at the core node of network regulation.The gene contained a 558 bp open reading frame encoding 185 amino acids,which was a hydrophilic protein.Phylogenetic tree and conserved sequence analysis showed that ZmbZIP26 protein had high homology with homologous proteins of sorghum and Miscanthus,and also had the same conserved motifs at the same amino acid positions.Cis-element analysis showed that the upstream 2 000 bp region of the ATG site contained drought response elements,hormone response elements and light response elements.qRT-PCR analysis showed that ZmbZIP26 was a constitutively expressed gene,which was highly expressed in young stems,female panicles and roots.ZmbZIP26 positively responded to drought,high temperature,high salt and nitrogen stress and the process of restoring,which might play an important role in the process of plant resistance.Subcellular localization analysis revealed that ZmbZIP26 was a nuclear protein localized in the nucleus.Protein interaction prediction showed that ZmbZIP26 might interact with zinc finger protein,serine protein,Ca-dependent protein and glutathione transfer protein to construct a regulatory network,which cooperatively regulated maize growth and development and stress response process.

Investigating the predominant genotypes of Bovine viral diarrhea virus(BVDV)infecting cattle in Tongliao,Inner Mongolia,to provide reference for the BVDV epidemiology and prevention and control.In the preliminary phase of the experiment,fecal samples from diarrheic calves were collected at a cattle farm in Tongliao,Inner Mongolia.These samples were tested using PCR to detect BVDV positivity.Positive fecal samples were then inoculated into madin-darby bovine kidney cells(MDBK)for isolation.The isolated strains were identified using RT-PCR and indirect immunofluorescence staining.Subsequently,the full-length genome of the isolates was sequenced,followed by genetic evolution analysis and genotype determination based on sequences of the 5'UTR,N^pro,and E2 genes.The results indicated that this experiment successfully isolated a strain of BVDV,designated as NM-21.Inoculation of NM-21 into MDBK did not induce cytopathic effects,indicating it was a non-cytopathic strain(NCP).Both RT-PCR and indirect immunofluorescence staining confirmed its positivity,with a virus titer of 10^-3 TCID₅₀/mL.Based on the full-length genomic sequence,and homology and genetic evolution analysis of the 5'UTR,N^pro,and E2 gene sequences,the isolate NM-21 showed the highest nucleotide homology with the BVDV-1c subtype strain NM2103(GenBank accession number ON337882.1)from Inner Mongolia,China.

The NAC(NAM,ATAF1/2,CUC2)gene is an important regulatory factor in the stress signal transduction network.Cloning the NAC gene in castor,studying its molecular characteristics and expression characteristics,aiming to provide data support for the potential function of the castor NAC gene.The RcNAC100-like gene of Tongbi No.5 was cloned by RT-PCR technology,and its molecular characteristics were analyzed,including bioinformatics,subcellular localization,expression patterns,and transcription activation domain analysis.The results showed that the full length of RcNAC100-like gene cDNA was 1 244 bp,including a 1 086 bp coding sequence(CDS),encoding 361 amino acids.The protein had more irregular coil and α-helix structures,and was a hydrophilic,non-secretory protein.Phylogenetic analysis showed that the RcNAC100-like protein was most closely related to NAC proteins in Manihot esculenta and Hevea brasiliensis,with highly similar motif composition and positioning.The subcellular localization of RcNAC100-like protein was consistent with the predicted results,located in the nucleus.The predicted cis-acting elements in the RcNAC100-like promoter region indicate the presence of multiple environmental response and growth-related elements.Expression pattern analysis showed that the RcNAC100-like gene had tissue-specific expression,with the highest relative expression level in the roots.Additionally,the gene could respond rapidly to adverse environments(drought,salt,cold,and ABA stress)and actively express,indicating that the RcNAC100-like gene might be a key gene in the castor's response to stress.Transcription activation assay results showed that the RcNAC100-like transcription factor has transcriptional activation activity in yeast.In summary,the RcNAC100-like gene may play an important role in the castor's resistance to adversity.

The aims were to study the effect of maize straw returning on soil fertility and productivity under wheat-maize rotation system in North China,and to explore the best way and suitable amount of maize straw returning.From 2021 to 2023,a field split-plot experiment was conducted in Quzhou County,Hebei Province to compare the effects of different maize straw returning methods and amounts on wheat growth,yield composition and soil organic matter content.There were two treatments in the main area,which were cutting and crushing.The sub-area was the amount of straw returning to the field,4 levels,which were 0,0.5,1.0,and 1.5 times of the amount of maize straw in the year.The results showed that compared with straw crushing,the yield of wheat increased by 4.3% under straw cutting treatment,the number of spikes increased by 7.6%,and the harvest index increased by 1.4%,with all significant difference in 2023.The N content of wheat straw was significantly increased by 0.04 percentage points,the N and P uptake of wheat aboveground were significantly increased by 10.8% and 14.3%,respectively(2022),but the K content of wheat straw was significantly reduced by 0.13 percentage points(2023).Cutting treatment could significantly promote the growth of wheat before and after winter,and the NDVI value at jointing stage significantly increased by 11.9%(2022).Soil pH increased by 0.22 units(2023).With the increase of maize straw returning amount,wheat yield and NDVI value at jointing stage showed parabolic model of first increased and then decreased,the N,P and K absorption of above ground wheat showed a significant downward trend,and soil organic matter showed a continuous significant increase trend.Based on the growth potential and yield of wheat,the suitable returning ratio of straw cutting treatment was 58%—62%,and the suitable returning ratio of crushing treatment was 29%—42%.Under the conditions of this experiment,maize straw cutting returning has obvious advantages in promoting wheat growth,and increasing wheat yield.It can be popularized and applied in wheat-maize rotation areas that 58%—62% maize straw is returned into the soil.

To elucidate the molecular mechanisms underlying peanut pod responses to water stress,this study employed pot experiments combined with transcriptomic analysis.Using well-watered conditions as the control, we systematically investigated the effects of periodic drought and waterlogging stress during the flowering-pegging stage on yield,quality,and gene expression in peanut pods. Results demonstrated that both drought and waterlogging stresses significantly reduced peanut pod yield(by 26.43% and 77.69%,respectively)and crude fat content in kernels (by 9.46, 6.71 percentage points,respectively).Transcriptomic analysis further revealed 1 525 and 1 382 differentially expressed genes(DEGs)in the drought-stress and waterlogging-stress groups compared to the control, respectively, with down-regulated expression being predominant in both sets of DEGs. Specifically, drought stress suppressed six key metabolic processes related to lipid and fatty acid metabolism in peanut pods,with 88.38% of associated genes showing downregulated expression,indicating that lipid metabolic disruption may be the primary cause of yield and quality reduction under drought. Waterlogging stress predominantly interfered with pod metabolism and defense functions by downregulating genes associated with catalytic activity,transmembrane transport,redox reactions,and biosynthesis of secondary metabolites.Moreover, KEGG enrichment analysis indicated that metabolic pathways and biosynthesis of secondary metabolites were significantly affected under both water stress conditions. Key gene validation via qRT-PCR corroborated the RNA-seq data, confirming the reliability of the transcriptomic findings. In summary, this research elucidates the molecular basis of peanut pod response to water stress at the transcriptome level, demonstrating that lipid metabolic disruption is the primary factor underlying yield reduction and quality deterioration under drought stress, whereas peanut pods mitigate the adverse effects of waterlogging mainly by modulating the expression of genes associated with redox homeostasis and metabolic pathways.

The aim of the study was to explore differential expression of genes and metabolites in Zhengdan 958 and Xianyu 335 exposed to high temperature for 7,14 d during grain filling stage and identify the key candidate genes,transcription factors and metabolites,so as to understand molecular mechanism of high temperature tolerance in maize. The ear-leaf samples collected before high temperature treated(CK),7 d high temperature treated,14 d from Zhengdan 958 and Xianyu 335 were used for RNA-sequencing using Illumina HiSeq^TM 2500 high-throughput sequencing technology. Metabolome variations analyzed using liquid-chromatography-mass spectrometry-based metabolomics. A total of 214.81 Gb clean sequence was obtained by transcriptome sequencing. In Zhengdan 958,49 DEGs were detected after 7 days of high temperature treated,of which 24 were up-regulated genes. 306 DEGs were detected after 14 d,130 of which were up-regulated genes. 1 462 DEGs were detected from 7 d samples compared with 14 d samples,of which 647 were up-regulated genes. In Xianyu 335,381 DEGs were detected after 7 days of high temperature treated,of which 164 were up-regulated genes. 299 DEGs were detected after 14 d,226 of which were up-regulated genes. 2 481 DEGs were detected from 7 d treated samples compared with 14 d treated samples,of which 1 275 were up-regulated genes. Comparing Zhengdan 958 samples treated for 7 d with Xianyu 335 samples treated for 7 d,6 646 DEGs were detected,of which 3 253 up-regulated genes. Comparing Zhengdan 958 samples treated for 14 d with Xianyu 335 samples treated for 14 d,5 958 DEGs were detected,of which 3 110 up-regulated genes. A total of 654 metabolites were detected by metabolomics sequencing. In Zhengdan 958,28 DEMs were detected after 7 days of high temperature treated and were annotated into 5 metabolic pathways. 54 DEMs were detected after 14 days,9 of which were up-regulated,and were annotated into 13 metabolic pathways. In Xianyu 335, 98 DEMs were detected after 7 d of high temperature treated,43 of which were up-regulated and were annotated into 24 metabolic pathways. 38 DEMs were detected after 14 d,14 of which were up-regulated,and were annotated into 13 metabolic pathways. Compared Zhengdan 958 with Xianyu 335,144 DEMs were detected after 7 days,81 of which were up-regulated,and were annotated into 36 metabolic pathways.158 DEMs were detected after 14 days,81 of which were up-regulated,and were annotated into 40 metabolic pathways.

In order to clarify the regulatory network of oil accumulation in Brassica napus and breed oilseed rapeseed varieties with high oil content.The seed transcriptome data of four rapeseed inbred lines at 25,35,and 45 days after flowering were used to identify candidate genes affecting oil content by transcriptome analysis and correlation analysis.Consequently,a total of 1 530 genes were identified exhibiting differential expression across all three period,comprising 986 up-regulated genes and 544 down-regulated genes.GO enrichment analysis of these differentially expressed genes detected 83 lipid biosynthesis genes,79 lipid degradation genes,21 lipid transporter genes and 80 transcription factors.To further analysis of these differentially expressed transcription factors,genes including BnTT8,BnGL2,and BnNAC082 were identified.Combined with the oil content data of 50 semi-winter rapeseed in three different regions over two years,four SNPs were identified in the exons region of the BnNAC082-A03 significantly associated with oil content using genome-wide association studies.Two haplotypes were detected in the region of this gene and BnNAC082-A03_Hap1 corresponding accessions showed significantly higher oil content than that of Hap2.Additionally,it utilized these transcriptomic data to construct co-expression analysis network,and in the sub-network revealed that BnNAC082-A03 was directly connected with BnTT8-A09 and BnGL2-C06,forming a potential molecular regulatory network affecting seed lipid accumulation.

In order to explore the gene expression regulation mechanism in the formation of reactive oxygen species (ROS) induced by heat stress,heat stress treatments were set at seedling,heading and filling stage to investigate the dynamic change of ROS accumulation in rice,respectively.And the Quantitative Real-time PCR (qRT-PCR) was used to analyze the expression pattern of nine respiratory burst oxidase homologue (Rboh) encoding genes (OsRboh1-OsRboh9) in rice under different growth stages.Results showed that the ROS accumulation in rice leaves and grains significantly increased with the extension of heat stress.The ROS content increased slowly after 7 days of heat stress at seedling stage, while increased continuously after heat stress during the heading stage and early filling stage (1-10 d) in rice grains. Expression levels of the nine OsRboh family genes continuously increased with the extension of heat stress at seedling and heading stages,and OsRboh7 and OsRboh5 showed higher expression levels under heat stress.The expression levels of OsRboh1,OsRboh5 and OsRboh9 were continuously increased,while other genes showed a change tendency of increasing initially and then decreasing under heat stress at filling stage.The expression levels of OsRboh7 and OsRboh5 were all reached to a high level at seedling,heading and filling stage under heat stress.Furthermore,higher expression levels of OsRboh7 and OsRboh5 were showed in various tissues and organs of rice such as seedling leaves,flag leaf,floret,lemma,palea,stamen,pistil and grain.The higher induced range of gene expression levels in OsRboh7 and OsRboh5 by heat stress was shown in seedling leaves,floret,stamen,pistil and grain.Taken together,OsRboh7 and OsRboh5 were mostly remarkably responsive to heat stress at different growth stages among the OsRboh family genes in rice,which indicated that OsRboh7 and OsRboh5 played a vital role in the regulation of ROS formation pathway in rice under heat stress condition.

The adult plant resistance gene Lr12 exhibits excellent resistance in production systems.To fine map and develop reliable molecular markers for Lr12,a cross was made between the susceptible variety Thatcher and the resistant near-isogenic line RL6011 containing the Lr12 gene.The F₁ generation resulting from this cross was self-pollinated to generate F₂ individual plants and F_2∶3 families.Field evaluations were conducted using a mixture of five highly virulent leaf rust pathotypes (PHTT, THKS, THTT, PHTS, and PHKS) to inoculate F₂ individual plants and F_2∶3 families for adult plant resistance assessment and genetic analysis of resistance.Subsequently,genotyping was performed using a 16K liquid chip on 10 resistant and 10 susceptible individuals from the F₂ generation to identify SNP markers closely linked to Lr12.This enabled the determination of the chromosomal physical interval containing the resistance gene,the development of SSR molecular markers,and the construction of a genetic linkage map.The results indicate that the segregation ratio of resistance to leaf rust in 3 494 F₂ individuals derived from the RL6011(Lr12)/Thatcher cross was consistent with a 3∶1 ratio ( {\mathrm{\chi }}_{3:1}^2=0.14;P=0.71). In the assessment of 685 F_2∶3 families, the segregation ratio among resistant individuals, resistant heterozygous individuals, and susceptible individuals conformed to a 1∶2∶1 ratio ( {\mathrm{\chi }}_{1:2:1}^2=2.01;P=0.37), suggesting that Lr12 is a dominant gene and the population segregation follows Mendelian single-gene inheritance patterns. Genetic linkage map analysis localized the adult plant leaf rust resistance gene Lr12 between SSR molecular markers YK12817 and YK12928,within a genetic interval of 0.38 cM.This corresponds to a physical interval of 2.09 Mb within the physical range of 579.44 Mb to 581.53 Mb on chromosome 4BL of the Chinese Spring reference genome(IWGSC.Ref.V1.0).These findings provide a solid basis for predicting candidate genes.

To study the resistance mechanism of TaHis gene to Fusarium head blight(FHB)in wheat,the full-length coding sequence of TaHis was cloned,and the bait vector pGBKT7-TaHis was constructed,which was then used as bait for screening a yeast two-hybrid library of wheat ear induced by FHB.After obtaining the interacting proteins,yeast two-hybridization and bimolecular fluorescence complementation were further used to verify the interaction between these proteins,and RT-qPCR was used to analyze the expression pattern of TaHis interacting protein induced by FHB in resistant and susceptible cultivars respectively.The results showed that the bait vector pGBKT7-TaHis was successfully constructed,and 18 yeast monoclones were obtained on the four deficient selection medium(SD/-Leu/-Trp/-His/-Ade)after yeast two-hybrid library screening.Blast analysis showed that a total of 5 proteins were obtained,and the coding sequence of serine/arginine-rich mRNA splicing factor SR45a-like(TaSR)was identified in 6 colonies.We cloned the full-length coding region of TaSR gene from Bainong 4299 and constructed pGADT7-TaSR vector.The experiment of yeast two-hybrid showed that the yeast cells co-transformed with pGADT7-TaSR and pGBKT7-TaHis grew well and appeared blue on SD/-Leu/-Trp/-His/-Ade/ X-α-Gal/AbA,indicating that TaSR and TaHis directly interacted in yeast cells.The vectors of YC-TaHis and YN-TaSR were constructed,and the bimolecular fluorescence complementary experiments were performed.The results showed that strong fluorescence signals were generated in tobacco cells co-transferred with YC-TaHis and YN-TaSR,which further verified the interaction between TaSR and TaHis.RT-qPCR analysis of TaSR gene expression showed that TaSR expression was up-regulated in resistant cultivar Bainong 4299,while down-regulated in susceptible cultivar Bainong 607 upon FHB infection,indicating a positive correlation between TaSR expression level and FHB resistance in wheat.To sum up,the interaction between wheat TaSR and TaHis was proved,and TaSR expression level was positively correlated with FHB resistance in wheat.

As a key regulating factor in response to various abiotic stresses,plant heat shock transcription factor (Hsf) has a big family,and diverse structure,characteristics and functions.Hsf not only directly regulates Hsp and other relative gene expression and participates in the processes of response and adaption to various abiotic stresses,but also mediates many life activities regulation.Since the first Hsf was cloned from yeast in the 1980s,more and more Hsfs from other species have been identified and studied.In the previous reports,the identification of the Hsf family in plants was performed only in model species such as Arabidopsis and tomato.Furthermore,the studies is mainly focused on the HsfA subfamily,with few studies on the HsfB subfamily.And,the precise function of HsfC family is also largely unknown.With global climate change,the frequent occurrence of extremely high temperature events has seriously threatened the yield and quality of wheat,maize and other crops.To deal with the threat posed by heat stress,unraveling the mechanism of thermotolerance,identifying functional the targeted Hsfs and improving stress tolerance of crop through biotechnology methods is important.The number of Hsf family in field crops is various,the genome is complex,and the related research started lately compared with model species.To this end,our laboratory began to study the Hsf family of crops in 2009.Based on the latest genomic information,we confirmed the number of members,the modular structure and the spatio-temporal expression pattern of Hsf family.At the same time,with the help of transgenic wheat and mutant by genetic transformation and the CRISPR/Cas9 clustered regularly interspaced palindromic repeats (CRISPR)/CRISPR-associated protein mediated genome editing technology,several Hsfs were cloned and their regulatory functions of thermotolerance were identified,and some mechanism of thermotolerance was clarified.Our research not only enriched the theoretical basis of thermotolerance,but also provided new germplasm for biological breeding.At present,many studies have reported on functional identification and transcriptional regulation of Hsfs,however,evidences lack on which upstream component mediate Hsf's participation in regulation of thermotolerance,and the related mechanism is still unknown.Based on previous research results about wheat and maize Hsf families of lab,and many relative reports published in public,we reviewed the roles and mechanisms of plant Hsf in regulating process reported in recent years,aiming to promote research in illustrating the extensive and special roles and regulation network of plant Hsf family further,and dig useful genes and selective QTLs for biological breeding for plant thermotolerance.

In order to improve blast resistance of the maintainer line Ruanhua B,to carry rice blast resistance genes Pi46 and Pi2 high-quality Indica H281 as the donor parent,Ruanhua B as recurrent parent,using marker-assisted selection(MAS)technology combined with pedigree breeding method,polymerization of two foreign genes with improved maintenance line Ruanhua B resistance,Ruanhua B was carried out on the characteristics of stable strain identification of resistance to rice blast,rice quality analysis,etc.Two BC₁F₆ populations,two BC₂F₅ populations and two BC₃F₄ populations with two homozygous target genes were obtained by backcrossing,multi-generation self-crossing and molecular marker detection.Field naturally induced identification showed that the improved lines of different backcrossing generations were resistant to rice blast.The sterility of backcross generation to sterile lines ranged from 52.7% to 100.0%.Agronomic traits and rice quality analysis showed that the improved lines basically conserved the main agronomic characters and rice quality characteristics of Ruanhua B.The results of SNP gene chip analysis showed that the background response rate of BC₁F₆ was 74.42%—77.77%,that of BC₂F₅ was 86.42%—87.75%,and that of BC₃F₄ was 92.27%—92.59%.Multiple resistance genes can be effectively polymerized by continuous backcross,self-cross and marker-assisted selection techniques to obtain a new maintainer line resistant to rice blast,and achieve rapid molecular improvement of maintainer line Ruanhua B.

In order to study the stability of the endogenous reference genes in Brassica napus under aluminum stress, and discover new reference genes in the root tissues that were mainly poisoned by aluminum, the root tissues of aluminum-tolerant variety Ganyouza 7 and aluminum-sensitive variety Rongyou 18 in Brassica napus at seedling stage were used as the research materials, and the control groups(0 h) and 2 time gradients(3, 24 h) of aluminum stress(100 μmol/L AlCl₃, pH 4.5) treatment groups were set respectively in nutrient solution culture. Firstly, five candidate endogenous reference genes(Actin7, ARFA1E, SAP5, UXS3, UBC9) which met the characteristics of housekeeping genes were selected by transcriptome sequencing with reference genome(RNA-seq) and differential gene expression analysis(FPKM). Subsequently, real-time fluorescence relative quantitative PCR analysis, amplification plot and melt curve analysis, amplification efficiency analysis(LinRegPCR), gene expression stability analysis(geNorm, NormFinder, BestKeeper) and relative expression level analysis(REST 2009) were used successively. Results indicated that new primers of candidate endogenous reference genes developed in this study had high specificity. The expression stability of the four candidate endogenous reference genes(Actin7, ARFA1E, SAP5, UXS3) selected from the transcriptome sequencing data had been verified. According to the comprehensive ranking of expression stability from high to low, the order was UXS3, SAP5, ARFA1E, Actin7, and the optimal combination was SAP5 and UXS3. In summary, the new primers of candidate endogenous reference genes developed had high specificity, and could improve the accuracy of real-time fluorescence relative quantitative PCR experiments in aluminum stress experimental system, and newly discovered endogenous reference genes(Actin7, ARFA1E, SAP5, UXS3) could be used in real-time fluorescence relative quantitative PCR experiments of aluminum stress experimental system as new endogenous reference genes.

To explore the effects of nitrogen application rate on nitrogen uptake and translocation characteristics,nitrogen use efficiency,and the formation mechanisms of yield and quality in soft wheat under weak light stress during the after anthesis stage,under pot conditions,the soft wheat variety Quanmai 725(QM725)was used as the material,and the ¹⁵N tracer method was used.Two nitrogen rates were set in the experiment,namely N1(N 120 kg/ha),N2(N 180 kg/ha),and two shading treatments were set at the wheat filling stage(7-35 d after anthesis)under each nitrogen application rate,namely CK(no shading),SH(30% shading).The relationship between nitrogen application rate and grain yield and quality of soft wheat under weak light after anthesis was analyzed,and the effects of different nitrogen application rates on nitrogen accumulation,transport,grain yield and quality of soft wheat under weak light after anthesis were studied.The results showed that compared with the control,under the conditions of N1 and N2,the nitrogen accumulation of plants at flowering stage and vegetative organs at maturity stage was significantly reduced by weak light treatment after anthesis,and the proportion of nitrogen from fertiliser was significantly higher than that from soil nitrogen,while the proportion of nitrogen accumulation in grains at maturity stage from soil nitrogen was significantly higher than that from fertiliser nitrogen.Under the same nitrogen application rate,the proportion of basal nitrogen fertiliser was greater than that of topdressing nitrogen fertiliser.Under the same weak light treatment conditions,compared with N1,N2 increased the accumulation of fertiliser nitrogen at flowering stage,the accumulation of total nitrogen and fertiliser nitrogen at maturity stage,and the accumulation of total nitrogen,fertiliser nitrogen and soil nitrogen at maturity stage.Under N1 and N2 treatments,the nitrogen harvest index,nitrogen harvest index,nitrogen production efficiency,grain number per spike,1000-grain weight and grain yield of wheat decreased significantly with the decrease of light intensity after anthesis.The content and accumulation of protein and starch in soft wheat grains increased significantly with the increase of nitrogen fertilizer.However,under the same nitrogen application rate,weak light stress reduced the starch content,protein and starch accumulation in grains.Weak light stress after anthesis significantly affected the nitrogen accumulation of soft wheat plants,reduced the transport efficiency of storage substances from vegetative organs to grains after anthesis,resulting in a decrease in the contribution rate of vegetative organs to grains,which was not conducive to the overall nitrogen transport efficiency of plants.With the increase of nitrogen application rate,the nitrogen harvest index,nitrogen harvest index,nitrogen production efficiency and nitrogen use efficiency of wheat were significantly improved.Under the same nitrogen application rate of N1 and N2,after anthesis weak light stress significantly reduced the accumulation of protein and starch in soft wheat grains,which in turn affected the formation of grain weight,resulting in a decrease in yield.

To assess the peanut rhizosphere bacteria community structure in response to salt stress at different development stages, the peanut variety Huayu 25 was used as experimental material, and a pot experiment was set with three salt concentrations to study the effect of salt stress on peanut yield and analyze the changes of microbial community structure of peanut rhizosphere at flowering and harvest stage under salt stress by high-throughput sequencing technology. The results showed that the rhizosphere microbial composition of peanut were basically similar under different salt stress treatments, but the diversity and richness significantly varied between flowering and harvest stage. Under higher salt stress, the diversity and richness of rhizosphere bacterial community were increased at the flowering and needling stage but decreased at the harvest stage. The dominant bacteria phyla of all soil groups were Proteobacteria, Actinobacteria, Chloroflexi, Acidobacteria, Verrucomicrobia, Bacteroidetes, and Patescibacteria. The relative abundance of Cyanobacteria, Gammaproteobacteria, Verrucomicrobiae and Bacteroides significantly increased under salt stress, especially at the flowering and needling stage. Hierarchical clustering revealed that the microbial community diversity was markedly altered by the salt concentrations and growth stages, samples of the same growth period were clustered into one group under salt stress. KEGG functional prediction analysis indicated that sequences related to carbohydrate metabolism, amino acid metabolism, energy metabolism, and metabolism of cofactors and vitamins were enriched, whereas that of signal transduction mechanisms, lipid metabolism, replication and repair, xenobiotics biodegradation and metabolism, metabolism of other amino acids, and folding, sorting and degradation were decreased. Among them, salt stress increased the abundance of functional groups involved in substance and energy metabolism, membrane transport, translation, replication and repair, and signal transduction, but decreased the 100 fruit weight and 100 kernel weight of peanut resulted in the decrease of peanut yield. Therefore, salt stress had a great impact on the peanut rhizosphere bacterial community structure and peanut yield. The salt tolerance of peanut could be enhanced by improving soil microbial environment. The results provided a theoretical basis for the development of peanut production in saline-alkali areas.