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.

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.

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.

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.

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.

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.

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.

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 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.

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.

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.

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.

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 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 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.

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.

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.

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.

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.

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.

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.

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.

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.

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 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.

In order to promote the further promotion of green manure planting in Tianjin, a field experiment was adopted, and 9 spring Brassica napus L. varieties were overturned with spring fallow fields as a control to study the effects of different spring Brassica napus L. on soil potassium content and maize nitrogen metabolism.The results showed that there were differences in the biomass and nutrient content of different spring Brassica napus L. varieties. Among them, Zhongyoufei 1901(7 716.50 kg/ha), 1804(6 577.02 kg/ha), and 1907(6 457.03 kg/ha) had higher biomass and nutrient content.The change trend of soil total potassium and available potassium in 2019 was the same as 2020. Among them, the content of total potassium and available potassium in the soil under the treatment of spring Brassica napus L. of Zhongyoufei 1901, 1804, and 1907 was higher than that of other tested varieties in different periods, and the total potassium and available potassium content of soil in 2020 were higher than those in 2019.The potassium uptake by the whole plant of maize and the total potassium uptake by the hectare of the three varieties of maize were higher than those of other tested varieties. Compared with 2019, the potassium uptake of the whole plant of maize treated with different spring Brassica napus L. in 2020 increased by 15.70%-24.34%;the NR and GS activities of the ear leaves in different spring Brassica napus L. treatments increased by 2.16-14.22 nmol/(min · g), 0.99-2.30 μmol/(h · g), respectively. The top 3 NR and GS activities of the maize ear leaves were the same as the potassium uptake of the whole maize plant. Compared with spring fallow, spring Brassica napus L. treatments' yield of maize increased by 10.02%-33.47%, which was 1.09-1.41 times of the spring fallow, and the highest yield in two years was 15 700.94 kg/ha (2020 Zhongyoufei 1901). It could be seen from the path analysis that the nitrate reductase activity of the leaf at the ear position had a direct effect on the protein content of corn grains.In the indirect effect, leaf protein content contributed the most to maize grain protein through leaf nitrate reductase activity.Correlation analysis showed that there were significant and extremely significant positive correlations among Brassica napus L. total potassium, soil potassium, maize potassium uptake, key enzymes in maize leaf nitrogen metabolism, maize leaf protein content, and maize grain protein content.

In order to explore stress resistance genes in wheat and study the molecular mechanism of calmodulin-like genes in plant stress resistance,a calmodulin-like gene TaCML8-A was cloned from wheat by electronic cloning combined with RT-PCR.Bioinformatics analysis showed that the open reading frame length of the gene was 519 bp,encoding 172 amino acid sequences,including PTZ00184 and FRQ1 superfamily,four EF-hand domains,including four calcium binding sites.The molecular weight of the encoded protein was 18.31 ku and the isoelectric point was 4.54.It belonged to acidic protein.Subcellular localization showed that TaCML8-A protein was distributed in the nucleus and cell membrane.Nucleotide sequence alignment showed that TaCML8-A had the closest genetic relationship with rice OsCML14,with a similarity of 79.17%.qRT-PCR results showed that the expression of TaCML8-A gene in shoot and root of wheat increased under salt,osmotic and cold stress,indicating that plants might respond to thoese stresses by increasing the expression of TaCML8-A.During heat shock,TaCML8-A gene was induced and inhibited in root and shoot,respectively,so as to play different functions.The calmodulin-like gene TaCML8-A was successfully cloned from wheat and analyzed for expression.It is preliminarily speculated that the gene might be involved in regulating abiotic stress of plants,so as to provide basic theoretical support for the follow-up study of its biological function.

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.

Abstract: Tetraploid wheat is the ancestor specie of common wheat and an important food crop.Aiming to provide new resistance sources for wheat variety breeding,the resistance tetraploid wheat germplasm was explored and their resistance genes were identified.TDI-1 is a cultivated emmer wheat that has been immune to powdery mildew in the field for many years.To determine the resistance genes carried by TDI-1,and provide a theoretical basis for genetic improvement of wheat resistance,a durum wheat TDU-1 that was susceptible to powdery mildew was used to hybridize with TDI-1,and their F₁ plants,F₂ population,and F_2:3 lines were obtained.Genetic analysis of resistance was conducted on parents TDI-1,TDU-1,and their hybrid offspring that were inoculated with powdery mildew isolate E09.Then,bulked segregant analysis method combined with molecular markers was used to map the resistance gene.The results showed that TDI-1 was susceptible to E09 during the seedling stage but immune during the adult stage.F₁ plants derived from the cross of TDI-1 and TDU-1 were immune to E09 during the adult stage.The resistance of adult F₂ individuals was separated,and the ratio of resistant and susceptible plants was 3:1($χ_{3:1}^{2}$=0.11,P=0.74);the ratio of the number of homozygous resistant,separated resistant,and homozygous susceptible F_2:3 lines was 1:2:1($χ_{1:2:1}^{2}$=0.47,P=0.79),indicating that the resistance to powdery mildew in the adult stage of TDI-1 was controlled by one dominant gene,temporarily named PmTDI-1.Subsequently,a set of molecular markers was used to amplify the parents and their F₂ population,and then four markers on chromosome 2A,including Xwmc407,NRM-2AS29,NRM-2AS45 and NRM-2AS84, confirmed to be linked to PmTDI-1. PmTDI-1 was between the flanking markers NRM-2AS45 and NRM-2AS84,with genetics distances of 1.8 cM and 4.6 cM,respectively.Therefore,the adult stage powdery mildew resistance gene PmTDI-1 was preliminarily localized on chromosome 2A.This study identified a novel dominant adult-plant-resistance powdery mildew gene PmTDI-1 from tetraploid wheat TDI-1.

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.

Twenty-one maize inbred lines were used to study the effects of potassium fertilizer on stem phenotype,stem lodging resistance,ear traits,yield-related traits and grain quality of maize inbred lines with different yield types.The results showed that compared with 0K,the stem diameter of high-yield,middle-yield and low-yield maize inbred lines under 45K treatment increased by 14.21%,11.60% and 8.41%;the bending strength of stem increased by 30.58%,27.52% and 24.59%;the ear diameter increased by 3.61%,2.57% and 1.72%;the ear tip barrenness decreased by 10.19%,7.41% and 4.81%;the 1000-grain mass increased by 4.97%,3.55% and 2.23%;the yield increased by 7.50%,5.57% and 4.45%;the grain protein content increased by 0.62,0.40,0.20 percentage points respectively.Application of potassium fertilizer could improve maize stem morphology and mechanical index,improve maize lodging resistance,promote maize plant growth and development,and then affect maize yield and quality.The results showed that high-yield type>middle-yield type>low-yield type of maize inbred lines with different yield types.The increase of plant height,ear height,stem diameter,stem puncture strength,stem compressive strength,stem bending strength,grain number per ear and 1 000-grain mass,as well as the decrease of ear tip barrenness of maize inbred lines could significantly improve maize yield. Therefore,the above indexes can be used as screening indexes of yield of maize inbred line under potassium fertilizer application.This experiment provided a theoretical basis for breeding high-yield and high-quality maize materials,selecting suitable basic materials for studying the physiological characteristics of maize inbred lines with different yield types,and provided a reference basis for high-yield and high-efficiency maize breeding and rational utilization of potassium fertilizer in China in the future.

Yuanjiang common wild rice(YP)is a germplasm material known as a living fossil in plants,which also has a large number of resistance(R)genes.Therefore,knowing the R genes in YP will help to apply different R genes to cultivated rice.Here,we identified the bacterial blight(BB)R genes in Yuanjiang common wild rice(YP),progeny of introgression lines(L214 and G252)and its susceptible parent,cultivated rice line 35(HX35).Meanwhile,the resistance of YP and its introgression lines to several Xanthomonas oryzae pv.oryzae (Xoo)strains was determined at the late tillering stage of rice.Under indoor control conditions,YP and its introgression lines showed resistance to 9 different Xoo strains(C1,C2,C3,C4,C5,C6,C7,C9 and PXO99^A),indicating that they had broad-spectrum resistance to BB.The results of bacterial blight resistance gene detection showed that YP contained homologous genes of Xa10,while HX35,L214 and G252 contained susceptible homologous genes of xa23.The sequence alignment results showed that the sequence of the effector binding element (EBE_AvrXa10) region of the disease resistance gene Xa10 was significantly different from that of the Xa10 promoter in YP. Similarly, the recessive susceptible gene xa23 was consistent with the effector binding element (EBE_AvrXa23) region of the xa23 promoter in HX35, L214 and G252. The qRT-PCR results showed that the immune responses in YP,HX35,L214 and G252 were activated after inoculation with strain PXO99^A,but Xa10 in YP and xa23 in HX35,L214 and G252 were not induced to be expressed.It is thus hypothesized that YP,L214 and G252 may contain new genes for resistance to bacterial blight.

Basic leucine zipper(bZIP)transcription factor protein is a kind of transcription factor with conservative structure and function in animals,plants and microorganisms.In order to clarify the function and mechanism of bZIP transcription factor in plant pathogenic fungi,and further determine its relationship with the growth,development and pathogenicity of the pathogen,the StbZIP9 gene was cloned from Setosphaeria turcica 01-23(GenBank No.XM _ 008032179.1).StbZIP9 is a member of the bZIP transcription factor family.The analysis of the gene structure and protein characteristics showed that the DNA sequence was 788 bp in length,with an open reading frame of 726 bp,encoding 241 amino acids.The encoded protein contained a highly conserved homologous domain BRLZ in fungi.The RNA-seq data of the gene during the growth and development of the pathogen and the process of infecting the host were analyzed.It was found that the expression level of StbZIP9 was 2 to 4 times higher than that in the appressorium and germ tube period compared with the mycelium period.After 24,72 h of infection of maize leaves,the gene expression increased from scratch and continued to increase,indicating that StbZIP9 was associated with appressorium development and germ tube formation and played an important role in the process of pathogen infecting host cells.Further,bioinformatics techniques were used to predict its binding conserved motifs and regulatory target genes.The binding motif was NNTWACGTNN,including the bZIP transcription factor recognition core sequence ACGT,and the downstream target genes of StbZIP9 were predicted according to the sequence.Combined with the expression pattern analysis using the RNA-seq data,four downstream target genes(protein IDs in the JGI database were :132893,163024,162798,40466)were obtained,and the functional annotation table was obtained.The functional annotation revealed its involvement in many biological processes, such as polymerization and transport of cell wall components, host infection, and spore dormancy. It will provide the basis for further elucidation of the molecular mechanism involved in the regulation of pathogen infection.

This study investigated the dynamics of soil phosphorus,yield responses to soil phosphorus and phosphate fertilizer in winter wheat-summer maize rotation system in the last decades,which was important for the scientific application of phosphate fertilizer in continuous high-yielding cropping.A combined method that included in situ phosphate fertilizer experiment under different soil fertility conditions,the analysis of changes of soil available P since 1978,the response of yield to phosphate fertilizer was used.Average content of soil available P of winter wheat-summer maize rotation area was 22.43 mg/kg,and the soil available P of the piedmont plain of Taihang mountain was greater than the alluvial plain.During 1996-1999,the soil available P content of the the piedmont plain and the alluvial plain was 15.09,11.90 mg/kg in cultivated land,respectively,the application rate of P₂O₅ in the winter wheat season of the rotation system was 180 kg/ha;the soil P supply capacity for winter wheat in these two regions piedmont were 83.9%,75.8%,respectively,and for summer maize they were 83.3%,89.7%,respectively.Under the condition of winter wheat straw returning,soil P surplus of these two regions was estimated to be 52.8%,55.4%,respectively.During 2010-2012,the soil available P of the piedmont plain of Taihang mountain was 27.22 mg/kg,the application rate in winter wheat and summer maize season were 108,60 kg/ha,respectively.The soil P supply capacity in winter wheat season was 84.6%,90.1% in summer maize season.Soil P surplus was estimated to be 6.7% in winter wheat season,and soil P of deficit was estimated to be 47.1% in summer maize season without straw returning.The application rate of P₂O₅ for the maximal yield production of winter wheat and summer maize were calculated according to the yield responses of winter wheat and summer maize to the P fertilization rates at multiple sites during 2002-2006 and 2012-2016.For winter wheat they were 107.3,125.1 kg/ha,respectively,and for summer maize they were 52.0,58.9 kg/ha,respectively.The accumulated P increaded the yield of winter wheat and summer maize for excess application 3 time of P fertilizer in 3 years 6 crop.The recommendation of P₂O₅ rate for winter wheat and summer maize with wheat straw returning were 90-100 kg/ha and 30 kg/ha,respectively,and they were 100-120 kg/ha and 45 kg/ha without wheat straw returning.

To investigate the genetic mechanism behind Annong 1687's ability to resist stripe rust,expedite the dissemination of Annong 1687 wheat variety,offer guidance for enhancing the genetics of novel wheat varieties,and mitigate the damage inflicted by wheat stripe rust on Chinese wheat production.This study employed Annong 1687(Annong 1687 is a semi-winter wheat type with resistance to the less significant physiological species CYR32.It was developed through the crossing of Annong 1106 and Xinong 822)with its sister lines,and parents.The wheat 55K SNP microarray was used to scan the entire genome of Annong 1687 as well as parents and sister lines.Concurrently,Annong 1687 and sister lines were inoculated and characterized employing the physiological race CYR32.The resistance to stripe rust grades was noted at the adult stage of the plant,and the resulting combined inoculation and field phenotypes were evaluated for stripe rust resistance of the wheat lines.The study revealed that Annong 1687 and five sister lines (lines 24,26,28,30 and 140) exhibited moderate resistance to stripe rust,while two sister lines (lines 89 and 105) displayed moderate susceptibility to this disease.Based on genomic differential data comparing Annong 1687 to its sister strains,there was evidence of enriched differential SNP loci in the 31—37 Mb segment of chromosome 2A's short arm,indicating possible presence of a gene or genes responsible for the result.To eliminate any potential interference from other stripe rust resistance genes,we verified the known stripe rust resistance genes present on the parental and chromosome 2A.Our findings indicated the possibility of a new stripe rust resistance gene in the 31—37 Mb interval of the short arm of chromosome 2A in Annong 1687.Experimental and bioinformatic analyses demonstrated that the TraesCS2A01G070700 gene exhibited disparity in the NBS structural domain of resistant and susceptible lines within this interval.Additionally,susceptible lines possessed three missense mutations within the NBS structural domain.It was hypothesised that TraesCS2A01G070700 represented a candidate gene for resistance to stripe rust in Annong 1687.

In order to preliminarily explore the key regulatory networks and genes involved in maize cold resistance,identify the key regulatory pathways and genes in response to low temperature stress,which laying a foundation for further research on the molecular mechanism of cold stress resistance.Here,a cold tolerance variety Mintian 6855 was employed to determine the gene expression pattern at 24,48 and 72 hours post low temperature of 5 ℃ stress by using transcriptome technique.The PCA analysis revealed that the repeated samples were well clustered together and significantly separated from CK samples.The results of difference analysis showed that about 4 000—7 000 difference genes expressed after cold stress treatments,while,only about 100—2 000 showed difference expressing among low temperature treated samples,indicating that low temperature was the main factor results in genes difference expressing,and the difference expression genes were mainly responded in the early stage.Meanwhile,KEGG annotation analysis results revealed that the differentially expressed genes were enriched in pathways of plant hormone signal transduction and MAPK,suggesting that these two signaling pathways actively respond to cold stress.In addition,different express genes were also enriched in plant-pathogen interaction as well as circadian rhythm plant,strongly implied that there were overlapping or common regulatory pathways in biological and abiotic stress pathways,while,genes that regulate circadian rhythms also playing a key role in plant adaptation to low temperatures.

Nitrate transporter (NRT) in plants can effectively regulate and transport NO₃^- and improve nitrogen utilization efficiency. In order to investigate the relationship between Poa pratensis L. NRT2.4 and nitrogen stress, Poa pratensis L. was selected as the material for the cloning and bioinformatics analysis of NRT2.4 gene, and the regulation of this gene expression was observed under treatment by nitrogen nutrient solution. The cloned NRT2.4 gene of Poa pratensis L.belonged to the Nitrate/nitrite transporter NarK superfamily, and was highly homologous to that of Brachypodium distachyon (L.) Beauv. and Aegilops tauschii Coss. Between the 6th and 7th transmembrane domain (TMD), there was a sequence with signature of G-X3-D-X2-G-X-R unique to the MFS family. The 4th TMD had a typical NO₃^-/NO₂^- transporter signature sequence of A-G-W-G/A-N-M-G. There was a conservative protein kinase C motif (S/T-X-R/K):SKR after the 8th TMD.The expression level of Poa pratensis L.NRT2.4 gene was tissue-specific, with the most expressed in leaves. Nitrate nitrogen was conducive to the expression of NRT2.4 gene, both nitrogen starvation and the treatment by nitrogen nutrient solution with a high NaNO₃ were beneficial to the expression of NRT2.4 gene. The results above have provided a theoretical bad for the application of Poa pratensis L.NRT2.4 in stress-tolerance gene engineering in turfgrass.

To identify and analyze the expression of the splicers of OsHSP40 using bioinformatics, RT-PCR, TA cloning and sequencing. Firstly, there were 4 kinds of variable splices of OsHSP40 based on bioinformatics analysis. Specific primers were designed for RT-PCR amplification according to the sequence information of different variable splice variants, and combined with TA cloning, successfully identified four kinds of variable splice variants of OsHSP40. To investigate the expression pattern, total RNA was isolated from different tissues such as root, stem, leaf, panicle and seed of WT. RT-PCR results revealed that the expression patterns of OsHsp40.4 and OsHsp40.1234 were different. Finally, the expression of different splice variants under high salt and high temperature conditions was analyzed.The expressions of OsHsp40.4 and OsHsp40.1234 increased under high salt conditions, but the increase range of OsHsp40.4 was relatively low. In addition, after high temperature treatment, the expression of OsHsp40.1234 showed no significant difference at 2 h, and increased significantly at 4 h treatment, while the expression of OsHsp40.4 increased significantly at 2 h treatment. In conclusion, successfully identified four splice variants of OsHSP40, and found differences in the expression of OsHsp40.4 and OsHsp40.1234 in the process of high salt and high temperature stress. These results lay the foundation for further research on the biological function of this gene.

To ascertain the effect of applying bio-organic fertilizer for 4 consecutive years on tomato fruit and soil biological characteristics, physiological and biochemical methods and high-throughput sequencing technology were combined to analyze its regulation effect on tomato fruit quality, soil nutrient content and microbial community structure.The results showed that,with chemical fertilizer replaced by bioorganic fertilizer, the sugar acid ratio, content of Vc and lycopene of tomatoes were significantly increased by 11.1%, 7.2% and 12.4% respectively. Soil nutrient measurement exhibited that, the high-efficiency nitrogen-fixing bacteria contained in bioorganic fertilizer could meet the nitrogen demand of tomato growth, and soil available phosphorus, available potassium and organic matter content were significantly increased by 147.0%, 38.8% and 35.6% respectively. High-throughput sequencing showed that, application of bioorganic fertilizer for four consecutive years could improve the relative abundance of soil Streptomyces, Ureibacillus and Bacillus, among which the activation effect on B. asahii was most significant. In addition,Coverage and Simpson index of tomato-planted soil microbial treated by bioorganic fertilizer for four consecutive years were both higher than those treated by common chemical fertilizer, which indicated that the bioorganic fertilizer containing high-efficiency nitrogen-fixing bacteria could improve soil microbe coverage and dominance to some extent. Obviously, continuous application of bioorganic fertilizer is helpful to improve tomatoes fruit quality, soil fertility and soil micro-ecological environment.

WRKY transcription factor is a family of transcription factors unique to plants.Studies have demonstrated that WRKY transcription factor played an important role in plant growth and development and in plant response to biological and abiotic stress.In order to reveal the function of tomato WRKY gene,two inbred lines of tomato with high resistance to bacterial wilt Hm 2-2(R)and high susceptibility to bacterial wilt BY 1-2(S)were used as experimental materials based on the preliminary transcriptome data,and a WRKY transcription factor SlWRKY75 gene(Solyc05g015850.3)was cloned.The structure,expression pattern and function of the gene and its encoded protein were analyzed by bioinformatics analysis,multiple alignment of amino acid sequences,phylogenetic tree construction,Real-time Quantitative PCR(qRT-PCR)and virus induced gene silencing(VIGS).The results showed that the full length of the cDNA of this gene was 653 bp,its maximum open reading frame was 519 bp,encoding 172 amino acids,the relative molecular weight of the protein was 19.878 51 ku,the theoretical isoelectric point was 9.32.The protein belonged to the hydrophilic non-secreted protein,and there was no transmembrane structure.Meanwhile,the protein had a highly conserved WRKY domain and a CX₄CX₂₃HXH zinc finger motif,which belonged to the Class Ⅱ family.Phylogenetic tree analysis showed that SlWRKY75 was closely related to Solanum pennellii SpWRKY75 and clustered into a group with other Solanaceae,while it was far related to Hevea brasiliensis HbWRKY75 and Gossypium hirsutum GhWRKY75 and was in different branches in the phylogenetic tree.The results of qRT-PCR analysis showed that the expression of SlWRKY75 gene were tissue-specific and could be induced by Ralstonia solanacearum,salicylic acid and jasmonic acid.VIGS result showed that silencing SlWRKY75 reduced plant resistance to bacterial wilt,indicating that SlWRKY75 positively regulated tomato resistance to bacterial wilt.These results suggested that SlWRKY75 gene played an important role in regulating tomato resistance to bacterial wilt.

For the development of a large number of SNP for the construction of high quality genetic map of cultivated strawberry(Fragaria×ananassa,2n=8X=56),Hongxing×Benihoppe crossing populations were sequenced by SLAF-seq that yielded 565 919 066 reads, with Q30 value of 95.36% and GC content of 39.68%. 717 881 SLAFs and 2 136 939 SNPs were identified.Total 56 237 SNPs showed high quality for genetic map construction, of which 14 412 were successfully mapped to 28 linkage groups spanning a total of 4 022.16 cM with an average interval genetic distance of 0.28 cM. It was showed that the greater part of each individual was derived from the parents by evaluating the monomer source of the genetic map. The results of heat map showed that the sequence of most markers on each linkage group was consistent with the genome, the sequence of markers was correct, which could show that the map was of high quality.A high-density genetic map of cultivated strawberry by SLAF-seq could be laying a foundation for genetic research and molecular marker-assisted breeding of cultivated strawberry.

Field experiment was established in Hebei Province in 2014-2015 and 2015-2016. To clarify the effect of irrigation time, density on wheat yield at different sowing date under irrigation once in spring, experiment was designed by split zone include 3 sowing dates(Oct 10, Oct 15 and Oct 20), 2 different densities at each sowing date planted according to the principle of delayed sowing and densification(330×10⁴ ear/ha and 420×10⁴ ear/ha, 420×10⁴ ear/ha and 510×10⁴ ear/ha, 510×10⁴ ear/ha and 600×10⁴ ear/ha), and one water carried out at 3 different irrigation times (erecting stage, jointing stage and 7 d after jointing stage)in the whole growing period. The result indicated that under irrigating once in the whole growth period, the average yield of wheat decreased with delayed sowing date and densification, but at the same sowing date of two years, wheat yield decreased (-4.5%, -1.8%) with higer density sown on October 10 and increased (4.6%, 1.9%) on October 20, however, difference occurred on October 15 because of different distribution of rainfall, it decreased with higher density under less rainfall before and more after in the whole growth period, otherwise, it increased. For the different irrigation time, wheat yield was the highest irrigating at the erecting stage(7 933.1 kg/ha), and the lowest at the jointing stage sown on October 10, nevertheless, the yield of wheat at jointing stage was the highest at delayed sowing date.Wheat yield of irrigating at erecting stage decreased for sowing with higher density, others decreased first and then increased and there were higher yield and less difference between the density of 330×10⁴ ear/ha and 600×10⁴ ear/ha.For more rainfall before and less after in the whole growth period, yield of different irrigation time showed 7 d after jointing>jointing>erecting and change could not happened in different irrigation time because of increased density. For the three factors of wheat yield, the difference of water at the earlier stage of the whole growth period affected the number of grains per spike, and the increase of spike number was the key to achieve higher yield for late sowing wheat. Therefore, irrigation time should be adjusted according to the rainfall before irrigation and sowing date under one water during the whole growth period, so as to increase the number of ears or grain number per ear and then achieve higher yield of wheat.

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.

This study was to develop an efficient and sensitive nano PCR for the detection of Streptococcus suis (SS). The specific primers were synthesized for the Glutamate dehydrogenase gene (gdh) of SS. Then, the annealing temperature and primer concentration reaction conditions were optimized. The results of specificity assay showed that the method could only amplify 687 bp specific sequence from SS samples, and there was no cross reaction with Actinobacillus pleuropneumoniae (APP), Haemophilus parasuis (H. parasuis), swine Escherichia coli (swine E. coli), Salmonella suis (S. suis) and (S. hyicus). Moreover, the method also could detected the main serotypes 1, 2, 7 and 9 type of SS, respectively. The results of sensitivity assay showed that the lowest SS concentration detected by the nano PCR method was 10 cfu/mL, and its sensitivity was 100 times higher than ordinary PCR of SS. The SS nucleic acid was detected three times, and the results were consistent. Finally, 44 suspected SS infection samples which collected from clinical cases were detected by nano PCR and routine PCR, respectively. The clinical sample testing showed that the positive rates were 72.7% (32/44), 54.5% (24/44), respectively. In conclusion, the nano PCR detection method of SS was established in this study can accurately and efficiently detect SS, which provides technical support for the clinical diagnosis and epidemiological investigation of S. suis disease.

Salt-alkali stress has become one of the important factors restricting agricultural production in my country.Exploring the molecular mechanism of salt tolerance of crops has important theoretical and practical value for crop breeding.The purpose of this study is to clone the ZmMPI gene in corn and transform corn plants.First,qRT-PCR was used to analyze the ZmMPI expression changes in plants treated with saline-alkali solutions.Then DNAMAN software was used to perform multiple comparison analysis of the ZmMPI protein sequence.MEGA 7.0 software was used to construct a phylogenetic tree,and a series of software were used to analyze the ZmMPI protein sequence.ZmMPI performed bioinformatics analysis.Finally,molecular cloning technology was used to successfully clone the coding sequence of the ZmMPI gene,construct a plant overexpression vector,and use Agrobacterium-mediated genetic transformation method to transform the corn inbred line B104.The overexpression transgenic plants were transformed at the genome level,transcription level and protein level.Identify and analyze changes in expression levels.The results showed that the expression level of the ZmMPI gene showed an overall trend of first increasing and then decreasing after being subjected to salt-alkali stress;the ZmMPI protein sequence comparison result showed a similarity rate of 64.15%,and the phylogenetic tree showed that ZmMPI had the highest homology with Zea mays subsp.parviglumis ABA34115.1.The protein contained a protein domain Potato_inhibit,which had an α-helix,a random coil and a β-turn.It was relatively hydrophobic and had 10 predicted Potential phosphorylation sites;the identification results of the 49 transformation events obtained showed that the ZmMPI gene in 13 over-expressed transgenic lines could be expressed normally at the genome level,and the ZmMPI gene in 10 over-expressed transgenic lines could be transcribed and translated normally.Finally,10 overexpression transgenic lines capable of normal transcription and translation were obtained,laying the foundation for further exploring the molecular mechanism of ZmMPI gene in response to salt-alkali stress.

In order to study the role and function of the nuclease AtCaN2 gene in plant growth and development,the AtCaN2 gene was cloned from Arabidopsis thaliana. Bioinformatics analysis,subcellular localization analysis,protein induction,expression,purification and functional were carried out to study this gene. The results showed that the isoelectric point of AtCaN2 protein was 8.45,the chemical formula was C₁₁₁₆H₁₇₈₈N₃₁₀O₃₃₅S₃,which contained 3 552 atoms and it was a hydrophilic protein; AtCaN2 had high homology with Camelina sativa,the homology was 87.89%,and it had low homology with Setaria italic, Sorghum bicolor and Zea mays,the homology was 56.42%,57.35% and 56.47% respectively,among the amino acid sequences,there was a highly conserved D-X-D sequence; evolutionary tree analysis showed that AtCaN2 was closely related to C.sativa,but far from S.italic and Z.mays,whis were consistent with the results of amino acid sequence alignment; subcellular localization results showed that it was located in cytoplasm,which was consistent with the predicted results; the His-AtCaN2 fusion protein was induced and purified to be about 35 ku in size; Western Blot analysis showed that the fusion protein was correctly translated and expressed without structural breakage or degradation; the fusion protein of His-AtCaN2(M)was expressed in small amount and large amount of induction,and the single band of His-AtCaN2(M)was obtained after purification; enzyme activity analysis showed that His-AtCaN2 fusion protein had the ability to degrade the nucleic acid substrate,showing high activity,while the His-AtCaN2(M)point mutation fusion protein had no ability to degrade the nucleic acid substrate,and the substrate was basically not degraded.The results of this study provide a basis for further study of the related mechanism of AtCaN2 in plants.

For study the differences of structure and characters of protein and starch between wheat and foxtail millet, and find new ways to improve the quality of wheat, the total protein, glutenin and gliadin of wheat and foxtail millet were extracted by total protein extraction method, the extraction of high and low molecular weight glutenin method, and alcohol soluble protein extraction methodrespectively,and the protein bands were identified by SDS-PAGE(total protein and glutenin) and A-PAGE(glidain). The differences of structure of protein and starch between wheat and foxtail millet were observed and analyzed by scanning electron microscopy (SEM). The results showed that the grain of foxtail millet almost not contained glutenin, and contained some alcohol-soluble protein with polymorphisms.The grain of wheat contained A, B, C three kinds of starch, while the grain of foxtail millet was found two kinds of starch only.And the starch of foxtail millet is polygonal and smaller than that of wheat. Above all, the structure, shape and composition of starch and protein of foxtail millet and wheat were quite different.It may provide a new way to improve the quality of foxtail millet by modifying starch and protein synthesis genes like wheat.