Based on quantitative trait locus(QTL)mapping of grain weight and grain shape-related traits in a backcross inbred line(BIL)population derived from the cross between indica rice variety Changhui 891 and japonica rice variety 02428,this study provided valuable genetic resources for elucidating the genetic basis of grain development and molecular breeding for high yield and quality in rice.A high-density genetic map was used to conduct QTL analysis for thousand-grain weight,grain length,grain width,grain thickness,and length-width ratio under two environments.Transcriptome data of developing grains at 5,10,and 15 days after flowering from both parents were integrated to analyze candidate genes within QTL regions.Frequency distribution indicated that grain weight and shape traits in the BIL population exhibited typical quantitative characteristics,confirming the suitability for QTL mapping.A total of 37 QTLs were detected across both environments,including 18 specific to Hainan(Sanya),12 specific to Jiangxi(Nanchang),and 7 consistently identified in both locations.These QTLs were distributed on chromosomes 1—5,7,8,11,and 12,comprising 7 for thousand grains weight,5 for grain length,7 for grain width,11 for length-width ratio,and 7 for grain thickness.The analysis showed that the LOD values of these QTLs ranged from 2.79 to 43.10,with a contribution rate of 1.36% to 46.12%.By integrating differentially expressed genes from developing grains of both parents at three stages,28 candidate genes were prioritized from the 37 QTL regions.Among these,LOC_Os11g10480 and LOC_Os11g10100 were identified as key candidates for further functional validation.
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The screening of aromatic rice germplasm resources and the rapid identification and utilization of aromatic genes have practical significance for the genetic breeding of aromatic rice.In order to clarify the aroma types of aromatic rice materials in Heilongjiang Province and improve the breeding efficiency of aromatic rice varieties,180 aromatic rice varieties approved and promoted in Heilongjiang Province were sequenced.Compared with the reference genome Nipponbare,the sequencing results were divided into two types of mutations.The first type was the 8 bp deletion of exon 7 and three base substitutions(Badh2-E7 type),including 177 varieties.The second type was the 7 bp deletion of exon 2(Badh2-E2 type),which contained only three varieties.According to these two mutation types,two specific KASP molecular markers were designed to accurately detect the aroma types of E7 and E2 in rice.Through the identification of 180 aromatic rice varieties,the typing results were consistent with the sequencing results.Two hybrid populations were constructed by using E7 aromatic rice variety Wuyoudao 4 and E2 aromatic rice variety Songkejing 134 with non-aromatic japonica rice varieties Weinong 101 and Dongfu 114,respectively.The F2 generation of the hybrid population was screened and identified for aroma genes,and the identification results were consistent with 100%,which verified the accuracy of KASP molecular markers.The 620 japonica rice parents created and collected by our laboratory were further identified by KASP markers,and 248 aromatic rice materials were screened.It was found that these parents were all Badh2-E7 type genes.At the same time,the existing 1 220 F7 generation materials with E7 aromatic rice as parents were genotyped,including 293 aromatic rice materials,906 non-aromatic rice materials and 21 heterozygous rice materials.Five aromatic and non-aromatic rice materials were randomly selected for sequencing verification.The sequencing results verified that the KASP molecular marker typing was correct.This study provided new markers and materials for breeding new fragrant rice varieties in cold regions by using molecular marker assisted selection.
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To investigate the expression characteristics of OsASL1.1 and its role in the drought stress response,the subcellular localization of OsASL1.1 protein and cis-acting elements in the promoter region of OsASL1.1 gene were analyzed.Additionally,Real-time Quantitative PCR(qRT-PCR)was used to examine the expression patterns of OsASL1.1 in response to abscisic acid(ABA),mannitol,and polyethylene glycol 6000(PEG6000).CRISPR/Cas9 gene editing technology was employed to generate Cas9-OsASL1.1 mutants with Kitaake as background,and the mutation types were characterized.The abscisic acid(ABA)sensitivity and drought tolerance of mutants were analyzed.The results indicated that OsASL1.1 protein was primarily localized in plastids.The promoter region of OsASL1.1 contained cis-acting elements responsive to low temperatures and plant hormones(ABA and auxin),including five ABA responsive cis-acting elements(ABREs).OsASL1.1 expression was induced by ABA,mannitol and PEG6000.Two homozygous mutant types,Cas9-6 and Cas9-12,were generated.Cas9-6 harbored a 17 bp insertion that caused premature translation termination,whereas Cas9-12 had a 12 bp deletion that resulted in the loss of four amino acids.Under ABA treatment,root elongation of Cas9-OsASL1.1 mutants and wild type were inhibited;however,the inhibition was less severe in the mutants than that in the wild type.Under 150 mmol/L mannitol treatment,the survival rates of both Cas9-6 and Cas9-12 mutants were significantly lower than that of wild type,with Cas9-6 showing the lowest survival rate.In summary,the Cas9-OsASL1.1 mutants show reduced sensitivity to ABA and decreased drought tolerance,indicating that the loss of OsASL1.1 function diminishes rice sensitivity to ABA and drought tolerance.
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In recent years,soil acidification and aluminum ion toxicity in southern cultivated land have intensified.To explore the gene loci related to aluminum tolerance in rapeseed,the F2 population obtained by crossing the aluminum tolerant variety R248 with the aluminum sensitive variety S120 was used as the experimental material.The extreme mixed pool of aluminum toxicity tolerance was constructed by phenotypic identification,and QTL localization analysis was performed by BSA-seq.The phenotype identification results showed that the aluminum toxicity tolerance of the F2 population exhibited a continuous normal distribution.After sequencing,mutation detection,and association analysis,a total of 4 intervals related to aluminum toxicity tolerance were obtained,distributed on chromosomes A07,C02,C03,and C08,with a total length of 0.73 Mb and 98 genes.Based on the enrichment analysis results and gene annotation information,it is predicted that BnaA07g35600D,BnaA07g35660D,BnaA07g35700D,BnaA07g3570D, and BnaC03g39670D will participate in the synthesis and transportation of aluminum tolerance hormones in rapeseed,BnaC03g39840D participates in the synthesis of cell wall pectinesterase,BnaC03g39750D and BnaC08g20580D were transcription factors with MYB structure,BnaC03g39850D and BnaC03g39980D were involved in amino acid metabolism.These genes are highly correlated with aluminum tolerance in rapeseed,laying the foundation for the cloning and functional research of aluminum tolerance genes in the next step.
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This study seeks to develop a highly efficient dual-base editing tool for solanaceous crops to address the challenges of poor compatibility and low editing efficiency associated with existing base editing systems in these plants. The research involved fusing the nickase Cas9 enzyme (nCas9),which has partially lost its nuclease function,with components such as the highly efficient adenine deaminase ABE8e,the optimized cytosine deaminase sdd7-mini,and the uracil glycosylation inhibitor UGI. Systematic optimization was conducted based on the promoter preferences and codon usage frequencies specific to solanaceous crops. Ultimately,the dual-base editor TPDBE-S was constructed. In transient transformation experiments using tomato and eggplant protoplasts,this editor exhibited exceptionally high editing efficiency. In the stable transformation system of tobacco,targeting the PDS gene verification revealed that four out of five positive transgenic families exhibited pronounced albinism phenotypes,thereby confirming the stable editing capability. The editing window of this editor aligns closely with the characteristics of ABE8e and sdd7-mini. Furthermore,optimizing codon preference and promoter activity in Solanaceae crops significantly enhances editing efficiency and adaptability. The construction of TPDBE-S employs a modular design. The multi-target expression cassette,based on the tRNA self-cleaving mechanism,can be rapidly assembled through one-step gene synthesis,which is both cost-effective and straightforward. This tool addresses the gap in double-base editing specifically for Solanaceous crops.
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To clarify the genetic characteristics of total leaf number and leaf number above the ear in maize,and reveal their regulatory effects on maize yield potential,biomass accumulation,and lodging resistance,experiments on QTL mapping and gene mining for controlling maize leaf number were conducted.By using SLAF-seq technology for high-throughput sequencing of Chang 7-2,PHB1M,and 138 F2∶3 families,combined with two planting density treatments(E1:60 000 plants/ha;E2:120 000 plants/ha)QTL mapping was performed on leaf number phenotypic data,and gene mining was performed on the mapping results.The results showed that two total leaf number QTLs distributed on chromosome 8 were the main effect QTLs,contribution rates were 16.96% and 23.08%,respectively,and the additive effect value was negative;the QTL for the leaf number above the ear distributed on chromosomes 2 and 4,with a positive additive effect value.the two QTLs distributed on chromosome 4 were the main effect QTL,contribution rates were 10.18% and 14.75%,respectively;the QTLs for total leaf number and leaf number above the ear were distributed in different chromosomal regions and might be subject to relatively independent genetic regulation.Gene functional analysis revealed genes screened involvement in carbohydrate metabolism,plant hormone signal transduction,and selected some transcription factors.The results of this study provide richer theoretical support for further revealing the genetic basis of maize leaf number and offer targets for marker-assisted breeding.
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To investigate the structure and function of the potato molybdenum cofactor sulfurase(LOS5)gene,StLOS5 was cloned from the potato cultivar Zicai No.3 using PCR,followed by bioinformatics analysis,subcellular localization assays,yeast stress-tolerance assays,and expression pattern analysis under drought stress.The results showed that the CDS region of the potato StLOS5 gene was 2 460 bp in length,encoding 819 amino acids,with a molecular weight of 91.50 ku,a theoretical isoelectric point of 6.78,and a GRAVY value of -0.268,indicating that the protein was hydrophilic.Phylogenetic analysis revealed that the StLOS5 protein had the highest homology with tomato LOS5,suggesting that the two proteins may possess similar functions.Multiple cis-acting elements related to abiotic stress were detected in the promoter region.Subcellular localization showed that StLOS5 was primarily localized in the nucleus.Yeast stress-tolerance assays indicated that StLOS5 enhances tolerance to osmotic stress.Quantitative Real-time PCR analysis demonstrated that StLOS5 exhibits tissue-specific expression,with higher transcript levels in leaves,and responds rapidly to drought stress,with its expression in leaves peaking 12 h after treatment with 8%PEG.These results indicated that StLOS5 plays a role in the potato response to drought stress.
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Aquaporins(AQPs)are primarily responsible for the transmembrane transport of water molecules and are involved in processes such as plant growth,development, and responses to environmental stress. Garlic is an important vegetable crop widely cultivated worldwide, but there are currently few reports on salt-tolerance genes in garlic.It aimed to clone the genes AsPIP1;1 and AsTIP2;1, encoding plasma membrane intrinsic protein (PIP) and tonoplast intrinsic protein (TIP) respectively, from garlic, analyze their sequence characteristics, investigate their expression patterns under salt stress conditions, and evaluate their potential roles in garlic salt tolerance. We cloned the AsPIP1;1 and AsTIP2;1 genes from garlic using RT-PCR. Bioinformatics methods were employed to analyze the open reading frames, encode amino acid sequences, and conserve domains of the cloned genes. Furthermore, the expression profiles of AsPIP1;1 and AsTIP2;1 in different tissues and under salt stress conditions were detected using Quantitative Real-time PCR. The results showed that the open reading frames of the AsPIP1;1 and AsTIP2;1 genes were 867, 747 bp in length, encoding 288,248 amino acids, respectively, with the conserved NPA motifs. AsPIP1;1 and AsTIP2;1 were highly expressed in garlic leaves and roots, and salt stress strongly induced changes in the transcriptional levels of both genes. Furthermore,AsPIP1;1 and AsTIP2;1 may interact with other AQP proteins, cell wall-associated proteins, and transporter proteins to adapt to the salt stress environment. These results indicate that the AsPIP1;1 and AsTIP2;1 genes may be involved in the garlic plant's response to salt stress.
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Sunflower is an important oil crop with strong salt tolerance in China.However,the production of sunflower is severely restricted by the intensification of salinization in main producing areas.To understand the salt tolerance mechanism of salt tolerance-related traits at the seedling stage of sunflower,and to identify SNP loci and candidate genes significantly associated with salt tolerance at the seedling stage of sunflower,124 sunflower germplasm accessions were used as materials.Under the stress of 250 mmol/L NaCl,genome-wide association analysis and mining of salt-tolerance loci/genes were performed based on 5 traits including plant height,leaf area,aboveground fresh weight,underground fresh weight,and SPAD value.The results showed that after 14 days of salt stress,the five trait indexes of relative plant height,relative leaf area,relative fresh weight of the above-ground part,relative fresh weight of the underground part and relative SPAD value at seedling stage had significant variations and normal distributions,and the most obvious influences were the relative fresh weight of the underground part and relative leaf area (with a coefficient of variation of over 46.57%).Eighteen significantly-associated SNP loci were obtained by genome-wide association analysis,among which Chr35448-18789497 was detected in several salt-tolerant traits;gene searches were conducted at 80 kb each in the upstream and downstream of associated loci,45 related candidate genes were screened out.Through scanning and gene annotation analysis of the associated locus intervals,four candidate genes that might be related to the salt tolerance trait of sunflower seedlings were discovered.A genome-wide association analysis was conducted using the phenotypes of salt tolerance identification at the seedling stage and genomic SNP data for sunflower germplasm accessions.SNP loci significantly associated with salt tolerance at the seedling stage were detected,and candidate genes related to salt tolerance at the seedling stage of sunflower were selected,which laid the foundation for the subsequent verification of salt-tolerant genes.
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To fully utilize the effect of foliar fertilizer on increasing soybean yield,an experiment was conducted to study the effects of foliar fertilizer application frequency and timing on soybean growth,photosynthesis,yield and grain quality.The results showed that F1 (spraying at the beginning of flowering stage)was more beneficial than F2 (spraying at the beginning of pod stage)and F3(spraying at the beginning of filling stage)for increasing fresh leaf weight per plant,dry leaf weight per plant,fresh root weight,dry root weight,fresh root weight growth rate,dry root weight growth rate and dry matter accumulation rate of population,and spraying foliar fertilizer twice F4 (initial of flowering stage+initial of pod stage),F5 (initial of flowering stage+initial of filling stage),F6 (initial of pod stage+initial of filling stage)in improving the above indexes were better than spraying foliar fertilizer once F1,F2,and F3.Spraying foliar fertilizer once F2 was the most beneficial for increasing chlorophyll content and photosynthetic rate,while F1 had the highest canopy photosynthetically active radiation;spraying foliar fertilizer twice F4 had the highest values of chlorophyll content,photosynthetic rate and canopy photosynthetically active radiation,compared to F1,F2,and F3,F4 significantly increased chlorophyll content and canopy photosynthetically active radiation at filling stage by 8.22%,7.08%,9.89% and 9.25%,13.36%,16.78%,respectively.Compared to spraying foliar fertilizer once,spraying foliar fertilizer twice significantly increased the dry weight of soybean population,and compared to CK,spraying foliar fertilizer once and twice could enhance yield by 82.34—327.86 kg/ha and 318.91—463.98 kg/ha,respectively.Although spraying foliar fertilizer twice was more beneficial for increasing the protein content of soybean grain when compared to spraying foliar fertilizer once,the effect was insignificant,spraying foliar fertilizer at the initial of flowering stage+initial of pod stage was the most effective way to increase protein content.Overall,spraying foliar fertilizer once at the beginning of the flowering period was the most beneficial for improving soybean growth,photosynthetic characteristics and yield,while spraying at the beginning of the pod stage was the most beneficial for improving protein content,and spraying foliar fertilizer twice at the beginning of flowering stage+beginning of the pod stage had the best effect.
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This study aimed to investigate the effects of acidic soil on the growth metabolism and photosynthesis of Hainan green sweet orange (Citrus sinensis L.)and to elucidate its antioxidant regulatory mechanisms under acid stress.A pot experiment was conducted to analyze the physiological metabolic changes,antioxidant responses,and expression patterns of key antioxidant enzyme regulatory genes in green sweet orange under acid stress.The results showed that the plant height growth,leaf area and fresh weight of green sweet orange plants decreased significantly under a strongly acidic soil environment,with the most serious effect of pH 3.5 treatment;the weakly acidic(pH 6.5)soil could promote the growth of plants,which manifested as positive growth in the amount of each growth index.Strong acid treatment significantly impaired photosynthesis and normal growth metabolism of green sweet orange leaves,manifested as negative growth in transpiration rate(Tr)and stomatal conductance(Gs)were significantly reduced.Superoxide dismutase(SOD)and phenylalanine ammonia-lyase(PAL)activities increased by 6.60-fold and 5.90-fold at 24 h post-treatment under pH 3.5.The malondialdehyde(MDA)content in leaves treated with pH 3.5 increased by 6.47-fold compared to the initial time point(0 h),significantly higher than that under pH 6.5.Principal component analysis(PCA)and redundancy analysis(RDA)revealed a significant negative correlation between enzyme activity and physiological-biochemical indices(R2=0.82).Gene expression analysis demonstrated that CsSOD and CsPAL reached peak levels at 24,48 h post-stress respectively and remained upregulated within 72 h,showing 2.33-fold and 2.64-fold increases compared to 0 h,respectively.In summary,strongly acidic soil inhibits the growth and development of green sweet orange by reducing photosynthetic pigment content and metabolic efficiency.SOD and PAL serve as key antioxidant enzymes in response to acid stress,with CsSOD and CsPAL genes dynamically regulating enzymatic activity to mitigate stress.
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To identify the suitable sowing date and planting density for the synergistic improvement of yield and quality of strong gluten wheat,the strong gluten wheat variety Kexing 3302 was used as the experimental material.Two sowing dates(October 18(S1)and October 28(S2))and five densities(basic seedlings of 180×104 plants/ha(D180),225×104 plants/ha(D225),270×104 plants/ha(D270),315×104 plants/ha(D315),and 375×104 plants/ha(D375))were set.Field experiments were conducted in 2021—2023 to investigate the effects of sowing date and density on physiological indicators,yield,and quality of wheat plants.The results showed that the relative chlorophyll content(SPAD)of wheat leaves generally decreased with the increase of planting density,and reached its maximum at most growth stages under low-density treatment.With the delay of the sowing date,the relative chlorophyll content of leaves showed an upward trend,with S1 sowing date being lower than S2.As planting density increased,the normalized difference vegetation index(NDVI)generally showed an upward trend,and the NDVI value at S2 sowing date was significantly lower than that at S1 sowing date.The number of spikes and grain yield decreased with the delay of the planting density,but increased with the increase of planting density,with the highest yield under D375 treatment.With the delay of the sowing date,both protein content and wet gluten content generally showed a slight downward trend,but the grain protein content of all treatments was above 13.5%.The total starch content of wheat grains generally decreased with the increase of density at S1 sowing date,but increased with the increase of density at S2 sowing date.In addition,the peak viscosity,trough viscosity,final viscosity,and breakdown value generally increased with the increase of density under the two sowing dates.Parameters such as dough stability time and water absorption rate did not exhibit obvious regular pattern under different sowing dates and planting density,but all met the standards for strong gluten wheat.In summary,at sowing date S1,the planting density of Kexing 3302 at 315×104—375×104 plants/ha can achieve high quality and high yield.
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To investigate the effects of row spacing and chlormequat chloride application on lodging resistance and yield performance of foxtail millet in Southeastern Shanxi,a two-factor randomized block design was employed,utilizing Jingu 21 as the experimental material.The experimental design included three row spacing levels(30,40,and 50 cm,designated as D30,D40,and D50,respectively)and three chlormequat chloride treatment regimes:spraying with water only(CK),single application at the six-leaf stage(T1),and sequential applications at both the six-and eight-leaf stages(T2).This resulted in a total of nine treatment combinations.The study evaluated the impacts of these treatments on stem morphological characteristics,lodging incidence,grain yield,and its component traits.Results showed that chlormequat chloride application under varying row spacing conditions significantly improved stem breaking resistance while significantly reducing plant height,center-of-gravity height,and field lodging rate.The D40+T2 treatment exhibited the highest stem breaking resistance(94.59 N)and concurrently achieved the lowest values for plant height(161.53 cm),center-of-gravity height(80.3 cm),and lodging rate(16.31%).In terms of yield,as row spacing increased,the yield of CK,T1,and T2 treatments all showed a decreasing trend.Among them,the D30+T1 treatment achieved the highest yield of 4 923.83 kg/ha.Correlation analysis indicated that under different row spacing and chlormequat treatments,millet yield was mostly positively correlated with plant height and panicle traits,while consistently negatively correlated with lodging rate.This demonstrates that optimizing row spacing and chlormequat application can effectively regulate key agronomic traits.In conclusion,optimizing row spacing along with appropriate chlormequat treatment can effectively minimize the risk of lodging while maintaining yield.The D30+T1 treatment demonstrated superior overall performance and is therefore recommended for broader adoption in foxtail millet cultivation in Southeastern Shanxi.
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To investigate the effects of long-term fertilization on yield formation and its physiological regulation mechanisms in double cropping late rice,it utilized a long-term fertilization experiment(initiated in 1981)in red paddy soils of Jinxian.Four typical treatments were selected:no fertilization(CK),single application of nitrogen-phosphorus-potassium(NPK),double dose of NPK(HNPK),and combined organic-inorganic fertilization(NPKM).Comparisons were made on double cropping late rice yield,dry matter accumulation,chlorophyll dynamics,and differential gene expression in leaves at fullheading and filling stages in the 42nd year of long-term fertilization.Results showed that long-term fertilization resulted in yields ranked as NPKM>HNPK>NPK>CK,with HNPK and NPKM treatments significantly surpassing NPK,showing increases of 29.63% and 57.18% respectively.Compared with NPK,both NPKM and HNPK significantly improved yield components:effective panicles,grains per panicle,and grain density increased by 16.98%—46.42%,8.68%—15.26%,3.69%—7.37%,respectively.Regarding dry matter accumulation,NPKM and HNPK significantly enhanced dry matter weight at all growth stages and promoted translocation of stem-leaf dry matter to panicles from filling to maturity.The contents of chlorophyll in NPKM and HNPK treatments were significantly higher than those in CK and NPK treatments at all stages,and NPKM delayed the decay of chlorophyll from filling stage to maturity stage.Correlation analysis revealed significant positive relationships between yield and dry matter accumulation from tillering to heading(△DM1)and filling to maturity(△DM3),while showed extremely negative correlation with chlorophyll reduction from grain filling to maturity(△S3).Transcriptome analysis demonstrated that long-term fertilization significantly affected gene expression in leaves during fullheading and filling stages,with differentially expressed genes primarily enriched in photosynthesis,carbon/nitrogen metabolism,signal transduction,and stress-related pathways.In conclusion,long-term fertilization regulates gene expression and combined organic-inorganic fertilization improved yield components,enhanced early-stage dry matter accumulation,promoted assimilate translocation from vegetative organs to panicles during grain filling,maintain higher chlorophyll levels,and delayed leaf senescence post-grain filling.This comprehensive mechanism achieves yield enhancement through strengthening source(enhancing photosynthetic capacity),expanding sink(increasing dry matter storage),and facilitating flow(promoting assimilate transport).
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To investigate the effects of optimizing basal-to-topdressing ratios combined with nitrogen application rates on nitrogen metabolism and nitrogen uptake/utilization in flue-cured tobacco,a field experiment was conducted using the cultivar Yueyan 97.Five treatments were designed:conventional basal-to-topdressing ratio (6∶4)+conventional nitrogen rate (CK),basal-to-topdressing ratio (4∶6)+conventional nitrogen rate (T1),basal-to-topdressing ratio (4∶6)+10% nitrogen reduction (T2),basal-to-topdressing ratio (4∶6)+20% nitrogen reduction (T3),and basal-to-topdressing ratio (4∶6)+30% nitrogen reduction (T4).It analyzed the impacts of these treatments on nitrogen metabolism,photosynthetic characteristics,dry matter accumulation,nitrogen uptake,nitrogen use efficiency,and nitrogen balance.The results showed that after optimizing the basal-to-topdressing ratio to 4∶6,the activities of key nitrogen metabolism enzymes,including glutamate dehydrogenase (GDH),aspartate transaminase (AST),and ferredoxin-glutamate synthase (Fd-GOGAT),were all higher than those under the traditional basal-to-topdressing ratio of 6∶4.When combined with nitrogen reduction treatments,the activities of nitrogen metabolism enzymes decreased.Specifically,T2 (10% nitrogen reduction) showed no significant difference from CK,while T3 and T4 (20%—30% nitrogen reduction) exhibited marked declines in enzyme activity.Optimizing the basal-to-topdressing ratio to 4∶6 also improved photosynthetic rate,SPAD values,dry matter accumulation,and nitrogen accumulation,with significant differences observed during the late growth stages.Furthermore,the optimizing 4∶6 ratio significantly enhanced nitrogen use efficiency.Compared to CK,nitrogen agronomic efficiency,partial factor productivity,recovery efficiency,and economic utilization efficiency increased by 20.68%,6.89%,4.06 percentage points,and 3.78 percentage points,respectively.Nitrogen reduction treatments reduced soil nitrogen surplus by 17.04—33.36 percentage points compared to CK.In conclusion,optimizing the basal-to-topdressing ratio from 6∶4 to 4∶6 in southern tobacco-growing regions enhances nitrogen metabolism during mid-to-late growth stages,improved photosynthetic performance,promotes dry matter and nitrogen accumulation,and increased nitrogen use efficiency.Coupled with 10% reduction in fertilizer can also reduce fertilizer input,mitigetes soil nitrogen surplus,and prevent environmental risks.
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In order to explore the effect of straw interlayer on soil respiration and the chemical structural stability of organic carbon components during the remediation of saline-alkali soil,two experimental treatments were set up in the alfalfa-planting farmland at the Saline-Alkali Soil Improvement Experimental Demonstration Base in the Agricultural High-Tech Zone of Dongying City,Shandong Province:a straw interlayer treatment (S,with a 5 cm thick straw layer buried at a 35 cm depth) and a control (CK,without an interlayer). Soil respiration characteristics of the different treatments were analyzed,and comprehensive discussions were conducted in conjunction with soil pH,electrical conductivity(EC),organic carbon component content,and chemical structure characteristics of the soil profile.The results showed that:compared with CK,the S treatment significantly increased the soil respiration rate during the alfalfa growth period, with a maximum increase of 79.84%. Furthermore, the S treatment reduced soil EC in the straw interlayer (35—40 cm) and the overlying soil layer (0—35 cm), effectively inhibiting the upward migration of salt. The 40—50 cm soil layer was identified as a critical zone for organic carbon transformation. In this layer, the S treatment significantly increased SOC content (by 16.67%) and highly significantly elevated particulate organic carbon (POC) and dissolved organic carbon (DOC) contents (by 208.07% and 83.41%, respectively) compared with CK. Characterization of the molecular structure of organic carbon in the 40—50 cm layer revealed distinct responses. For DOC, the S treatment reduced the magnitude-weighted averages of unsaturation (by 30.60%) and aromaticity index (by 4.84%) compared with CK, decreasing the proportion of unstable carbon. For POC, the S treatment increased the relative abundances of alkyl C(10.32 percentage points)and O-alkyl C (8.39 percentage points) while reducing carboxyl C (14.24 percentage points), thereby enhancing POC structural stability. However, for bulk SOC, the S treatment decreased the proportions of alkyl C(3.14 percentage points) and aromatic C(3.38 percentage points) while increasing O-alkyl C(5.17 percentage points)and carboxyl C(1.56 percentage points). This shift indicated a decrease in recalcitrant carbon and an increase in labile carbon, resulting in reduced SOC structural stability. Correlation analysis showed that the significant increased in soil respiration was highly significantly and significantly positively correlated with POC and SOC contents in the critical soil layer, respectively. Specifically, the accumulation of O-alkyl C(a labile component) in the chemical structure of SOC reduced the stability of organic carbon,which was the main reason for the increase in soil respiration.In conclusion,incorporating a straw interlayer significantly increased soil respiration in the short term,which was closely related to the reduction in the stability of the organic carbon chemical structure in the key soil layer.Under future "carbon neutrality" strategies,research on the selection of interlayer materials should be considered.
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To explore the relationship between soil bacterial community diversity and soil enzyme activity of Qinqiong(Q) and Magnum(M) under salinity stress treatment,the bacterial community structure and soil enzyme activity of Qinqiong and Magnum for 0,6,12,24,48 h were compared and analyzed by using high-throughput sequencing of bacterial 16S rRNA and colorimetry.The results indicated that at the phylum level,the relative abundances of Actinobacteria and Proteobacteria in the rhizosphere soil of Qinqiong were higher than those in Magnum.At the genus level,the relative abundances of Bacillus and Arthrobacter in the rhizosphere soil of Qinqiong were greater than those in Magnum,while the relative abundance of Pseudomonas was lower compared to Magnum.After 48 hours of saline-alkali stress,the activities of soil polyphenol oxidase(S-PPO),soil catalase(S-CAT),soil dehydrogenase(S-DHA),and soil invertase(S-AI) in the rhizosphere of Qinqiong were 1.32,1.53,1.38,and 1.28 times higher than those of Magnum,respectively.Furthermore,the S-CAT activity exhibited a significant positive correlation with the bacterial ACE and Chao diversity indices.Qinqiong may influence changes in bacterial community structure by altering the relative abundances of dominant bacterial groups,thereby enhancing the bacterial community diversity index and soil enzyme activity.In contrast,the changes in the bacterial community within the rhizosphere of Magnum were not significant.The diversity of soil microbial communities is a critical factor determining the saline-alkali tolerance of oat varieties.
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In order to the issues of carbon-nitrogen balance and emission reduction in greenhouse soil,a field experiment was carried out to explore the impacts of the combination of summer catch sweet corn and biochar on nitrogen absorption and carbon emission reduction in greenhouse soil.Four treatments were designed for this experiment:control(T1),catch crop(T2),biochar(T3),atch crop+iochar(T4).The research results showed that the dry biomass and nitrogen absorption of T4 corn were 10.18% and 9.49% higher than those of T2,respectively.The organic carbon in the surface soil of T3 and T4 increased by 25.26% and 50.01% compared to before the experiment,respectively.The total nitrogen in the surface layer of T4 decreased by 10.13%,and the C/N increased to 14.9.The nitrate nitrogen in the 60—80 cm and 80—100 cm soil layers of T4 decreased by 13.02% and 5.68% compared to before the experiment,with a significantly greater reduction than other treatments.The non-root microbial biomass carbon and nitrogen of T4 increased by 26.00% and 20.33% compared to the control,with the increase in the non-root area being lower than that in the non-root area.The average CO2 emission of T4 was 603.90 mg/m3,which was 24.61% lower than that of the control.In summary,the combination of fallow sweet corn and biochar significantly promoted nitrogen absorption,increased microbial biomass carbon and nitrogen,reduced carbon and nitrogen leaching and emissions,and improved soil C/N,providing theoretical basis support for carbon and nitrogen management in the summer fallow period of facility farmland.
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To evaluate the effects of microbial inoculants on soil microbial population and physicochemical properties,this study investigated the effects of the microbial inoculants,including Bacillus velezensis BPC6(B), Streptomyces lydicus (S), and their combined inoculants(BS) on the soil microbial abundance and physicochemical properties of field-grown and potted peach trees in Pinggu District,Beijing.The results showed that applying microbial inoculants(B,BS,and S) significantly increased the abundance of bacteria,fungi,and actinomycetes in field soils.Additionally,the microbial inoculants enhanced soil nutrient utilization efficiency by increasing the contents of soil organic matter,total carbon,total nitrogen,available nitrogen(alkaline-hydrolysis nitrogen),nitrate nitrogen,ammonium nitrogen,available potassium,total phosphorus,and available phosphorus,while no significant effect was observed on total potassium.Among them,during the peach harvest period,application of microbial inoculants B,BS,and S significantly increased soil available nitrogen by 11.89%,15.19%,and 35.27%,respectively,compared to the control.Available potassium increased significantly by 35.58%,22.92%,and 41.75%,respectively,while available phosphorus rose significantly by 37.97%,3.65%,and 62.60%,respectively.Correlation analysis further revealed that soil microbial abundance was significantly influenced by multiple soil environmental factors,particularly showing a strong positive correlation with available potassium content.The effect of improving soil fertility with different microbial inoculants(B,BS,and S) was as follows:microbial inoculant S was the most effective,and the combination application of B and S was better than that of individual application of inoculant B.The pot experiment further confirmed the important role of microbial inoculants in increasing soil available nitrogen levels.Compared to the control,application of microbial agents B,BS,and S significantly increased soil available nitrogen in potted peach Zhongpan 100 by 15.65%,16.67% and 13.45%,respectively;while microbial agents BS and S significantly increased available nitrogen in Zhongtao 14 by 13.65% and 18.13%,respectively.Overall,microbial inoculants effectively improved soil microbial abundance and fertility,providing scientific support and practical references for sustainable peach production.
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The aim was to reveal the role of effector protein Pt2567 secreted by Puccinia triticina(Pt) in the pathogenesis and to lay a foundation for clarifying the interaction mechanism between effector protein and wheat.Tobacco transient expression technology,bacterial type Ⅲ secretion system,host induced gene silencing (HIGS) and other technologies were employed to carry out the subcellular localization,inhibition of BAX (mouse Bcl-2 family death promoting protein),effects on callose deposition and reactive oxygen species accumulation and preliminary function analysis of Pt2567.The results showed that the effector protein Pt2567 was subcellular located in the nucleus,and could inhibit BAX-induced programed cell death (PCD).Compared with control group,overexpression of effector protein Pt2567 in TcLr28 significantly enhanced the callose deposition and could increase the active oxygen accumulation at 24 h after the overexpression of the effector protein Pt2567 significantly.The silencing of effector protein Pt2567 on the TcLr28 inoculated with physiological race THTT significantly reduced the disease resistance of TcLr28,and increased the number of uredinium of Pt,and histological observation by confocal laser showed that silencing effector protein Pt2567 accelerated the development of wheat leaf rust.These results all suggest that effector protein Pt2567 plays a positive regulatory role in TcLr28,and is presumed to be a candidate avirulent gene for Lr28.
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Bacillus thuringiensis(Bt)produces multiple insecticidal proteins and serves as a vital biological control agent.This study aims to identify Bt strains with insecticidal activity against lepidopteran pests,thereby alleviating pest resistance pressure and expanding resource reserves.A total of 109 Bt strains were selected from soil of Hebei Province.The shape of parasporal crystals was observed under an oil microscope,and the insecticidal protein genotypes of the Bt strains were identified by PCR using 40 pairs of primers(including cry,cyt,and vip genotypes).The insecticidal activity bioassay was performed using five lepidopteran pests,including Plutella xylostella and Spodoptera litura.The molecular weight of crystal proteins was detected via SDS-PAGE.The shape of parasporal crystals from 90 strains was spherical,and the crystals from the remaining 19 strains were diamond-shaped.The detection rate of insecticidal protein genotypes reached 93.6%,with 29 distinct cry genotypes,1 cyt genotype,and 3 vip genotypes identified.A total of 91 strains possessed combinations of at least two insecticidal protein genotypes,among which 26 strains contained six or more,predominantly exhibiting cry+vip patterns.We found that 19 Bt strains showed high insecticidal activity against various lepidopteran pests such as P.xylostella. These strains primarily expressed proteins at 130,65 ku,encompassing lepidopteran-killing genotypes such as cry1,cry2,and cry15,consistent with PCR identification results.Here,we identified broad-spectrum insecticidal and highly toxic Bt strains against lepidopteran pests,and revealed its insecticidal genes.Our work provides an important candidate for the development of bioinsecticide.
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To detect and identify the pathogenic species of pepper root rot in Xigaze,Tibet,16 samples of chili root susceptible plants were collected from four districts,namely,Pengcang village,Bazha township,Bailang county;Pankong village,Nerixiong township,Sangzhuzi District;Deji village,Dazi township,Jiangzi county;and Yuze village,Lazi township,Lazi county,Tibet,from July to September 2024.A total of 25 strains of pathogenic fungi were isolated and purified by conventional tissue isolation method,and 3 types of fungal isolates were grouped into LJ1,LJ2 and LJ3.Using molecular biology and phylogenetic analysis,LJ1 was identified as Fusarium solani,LJ2 as Rhizoctonia solani AG 4 HG-Ⅰ,and LJ3 as Fusarium oxysporum.The pathogenicity of the fungi was evaluated by the seedling prick inoculation method.All three types of fungal isolates were able to infect pepper seedlings causing root rot,and F.oxysporum had the strongest pathogenicity.There were differences in the dominant fungal pathogens of pepper root rot across Xigaze,with F.oxysporum being the dominant pathogen with 52.0% isolation frequency, F.solani with 32.0% isolation frequency and R.solani with 16.0% isolation frequency.The root rot of pepper in the Xigaze region of Tibet was caused by a complex infection of F.oxysporum,F.solani, and R.solani AG 4 HG-Ⅰ,both F.solani and R.solani AG 4 HG-Ⅰ were isolated and identified for the first time in Tibet.
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To reveal the effects of konjac infection with southern blight disease on the defense enzymes and the phyllosphere microorganism of petiole,the activities of catalase (CAT),peroxidase (POD),superoxide dismutase (SOD),polyphenol oxidase (PPO),and chitinase (CHI) in konjac petioles after inoculation with Sclerotium rolfsii (Sr) were determined using a defense enzyme activity kit (spectrophotometer method),and the structure and diversity of phyllosphere bacterial and fungal communities were investigated using Illumina high-throughput sequencing.The results indicated that the defense enzyme activities in konjac were significantly enhanced after Sr inoculation.Specifically,the activities of CAT and PPO peaked on the third day after Sr inoculation,reaching 6.34 and 5.29 times that of the control group,respectively.The activity of POD continued to increase significantly until the sixth day,reaching 36.98 times that of the control group.The activity of SOD was approximately 1.91 times that of the control group after Sr inoculation,while the activity of CHI was about 5 times that of the control group after Sr inoculation.Analysis of the phyllosphere microbiome revealed that,compared to healthy konjac,the diversity and richness indices of bacterial communities in the leaf petiole phyllosphere showed no significant differences after Sr inoculation,but the richness index exhibited a continuous downward trend.For fungal communities in the leaf petiole phyllosphere,there were no significant differences in diversity and richness indices on the 1st day after Sr inoculation.By the 3rd day,the fungal community diversity index showed no significant difference,while the richness index significantly decreased.By the 6th day,both the diversity and richness indices of the fungal communities were significantly reduced. In healthy A. konjac, the dominant bacterial genera in the petiole phyllosphere were unclassified Enterobacteriaceae, Planomicrobium, and Pseudomonas, while the dominant fungal genera were Phoma, Plectosphaerella, and Cladosporium. On day 1 after Sr inoculation, the dominant bacterial genera shifted to Enterobacteriaceae and Pantoea. By days 3 and 6, the dominant bacterial genus became Alcaligenaceae, and the dominant fungal genus shifted to Sclerotinia. The functional pathways of bacterial communities in the leaf petiole phyllosphere of both Sr-inoculated and healthy konjac primarily included secondary metabolite biosynthesis pathways,microbial metabolism in diverse environments,ABC transport,and two-component system metabolic pathways.The fungal communities in the petiole phyllosphere of healthy konjac mainly consisted of ten functional groups,including endophytes-saprotrophs-lichen parasites-litter saprotrophs-plant pathogens-soil saprotrophs-wood saprotrophs (31.29%),plant pathogens (27.68%),and animal pathogens-endophytes-lichen parasites-plant pathogens-wood saprotrophs (20.27%).As the duration of Sr inoculation increased,the functional groups of fungi gradually became more homogeneous,with the relative abundance of the functional group comprising fungi-leaf saprotrophs-lichen parasites-lichenized plant pathogens-wood saprotrophs continuously increasing.Correlation analysis revealed that the activity of POD,PPO,CAT,and CHI were positively correlated with most phyllosphere bacteria.The activity of POD and CAT activities were negatively correlated with some phyllosphere fungi,while the activity of POD and SOD were positively correlated with the Sclerotium.
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In order to explore the structure and biological function of Ras related nuclear protein gene(RAN)in yak and resolve how it regulates the proliferation of yak cells and participates in protein synthesis,the CDS region sequence of RAN gene of Sangsang yak was cloned by RT-PCR using Sangsang yak kidney tissue cDNA as template,and bioinformatics analysis was carried out by a variety of software and online tools,the expression of the RAN gene in seven tissues of Sangsang yaks was detected by qPCR technology.The results showed that the CDS region of RAN gene in Sangsang yak was 651 bp in length,encoding 216 amino acids.Through homology comparison,it was found that the genetic relationship between Sangsang yak and wild yak and zebu was the closest,with a similarity of 99.2%,and the farthest from chicken,reaching 86.6%.The prediction results of RAN protein analysis showed that the molecular weight of the protein was 24.423 11 ku,the theoretical isoelectric point was 7.01,the total number of atoms was 3 449,and the molecular composition was C1109H1725N295O313S7.RAN protein had no transmembrane structure and no potential sites for N-glycosylation,with 36 phosphorylation sites.The affinity and hydrophobicity were predicted and the instability coefficient was calculated,and it was found that the protein was a stable hydrophilic protein.According to the subcellular localization,the protein was found to be present in the Golgi apparatus,mitochondria,nucleus and cytoplasm in yak cells.Predictions of the RAN protein structure revealed that its higher-order structure consisted mainly of α-helices and did not contain β-turns.Protein interaction network results showed that there was an interaction between the RAN protein and RAN Binding Protein 1(RANBP1),RAN Binding Protein 2(RANBP2),RANGTPase activating protein 1(RANGAP1)and other proteins of Sangsang yak,and there was also an interaction between them.The expression level of the RAN gene in yak testicular tissue was significantly higher than in other tissues,while no expression was detected in muscle tissue.It successfully cloned the CDS region of the RAN gene and completed its bioinformatics analysis,and the expression of this gene in the tissue of Sangsang yak was also studied,and it was found that it played an important role in the development of the reproductive system,cell proliferation,disease prevention and control,and participation in protein synthesis.
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The aim is to explore the biological function of the Lon gene in Glaesserella parasuis and its impact on the pathogenicity of the bacterium.A fusion gene fragment containing the homologous arms of the Lon gene and the kanamycin resistance gene selection marker was amplified using overlapping PCR,and a recombinant suicide plasmid pToPo-LR-Kana containing this gene fragment was constructed.The pToPo-LR-Kana was transformed into the parent strain ZJ1208 using natural transformation.The Lon gene-deleted strain ZJ1208-ΔLon was identified by kanamycin resistance screening,PCR,and sequencing.The differences between the wild-type strain ZJ1208 and the gene-deleted strain ZJ1208-ΔLon were compared through determination of growth rate,observation by transmission electron microscopy,stress resistance test,ultraviolet resistance test,serum resistance test,the biofilm formation assay,determination of capsule polysaccharide content and virulence test.The results showed that the Lon gene deletion strain ZJ1208-ΔLon was successfully obtained.The deletion strain had a significantly longer cell size,but its growth rate and number of outer membrane vesicles were similar to those of the wild-type strain ZJ1208.ZJ1208-ΔLon had significantly decreased tolerance to osmotic stress,oxidative stress,and heat stress,as well as significantly decreased resistance to ultraviolet radiation. Compared with the parent strain ZJ1208,the biofilm production capacity of ZJ1208-ΔLon and ZJ1208 was similar,but the capsular polysaccharide content of ZJ1208-ΔLon increased significantly,and the serum resistance and virulence in mice decreased significantly.The above results indicate that the deletion of Lon gene has an impact on multiple biological characteristics of G.parasuis,providing new information for further analysis of the biological function of Lon gene in G.parasuis.
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The Bacillus safensis ST7 strain has strong manganese oxidation activity,in which the expression of the multicopper oxidase protein family gene BSL056-RS03010(cotA)is significantly upregulated under manganese stress,which may be involved in Mn(Ⅱ)oxidation and make the strain have strong manganese tolerance.In order to verify the manganese oxidation ability of the cotA in B.safensis,the cotA gene was cloned and an expression vector was constructed,and then transformed to Escherichia coli for heterologous expression to study the effect of cotA gene overexpression on the manganese oxidation activity and removal rate of E.coli,so as to validate the function of the cotA gene,and to provide a technological means for constructing highly efficient manganese oxidizing strains to treat manganese pollution.Using PCR,RT-qPCR and SDS-PAGE,the cotA gene of B.safensis ST7 was cloned,ligated into the pET28a(+)expression vector,and efficiently expressed in E.coli BL21(DE3)induced by isopropyl thiogalactoside.The growth curve,manganese tolerance concentration,manganese oxidation activity and manganese removal rate of the cotA gene transformed strain were determined.The cloning and sequence analysis showed that the coding region of the cotA gene of B.safensis ST7 was 1 533 bp,encoding 510 aa with a molecular mass of about 58.8 ku.The expression of the recombinant plasmid pET28a-cotA was significantly up-regulated in E.coli BL21(DE3)cells without inhibition of the growth of the bacterium.The cotA gene was highly efficiently expressed under 0,250,1 000 mg/L manganese stress with time and concentration dependence.The manganese oxidizing activity of the recombinant strain was 0.9-fold higher than that of the control,the manganese tolerance concentration was 1.0-fold higher.The CotA protein of B.safensis has manganese oxidizing activity,and overexpression of the cotA gene can improve the oxidizing activity,tolerance and removal efficiency of Mn(Ⅱ)in E.coli cells,which is of great significance for the construction of manganese oxidizing strains with high efficient cotA gene for manganese pollution management.
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Bimonthly, Started in 1962
CN 13-1101/S
ISSN 1000-7091
CODEN: HHUOA6
Responsible Institution: Hebei Academy of Agriculture and Forestry Sciences
Sponsored by: the Academy of Agricultural Sciences and Agricultural Association of Hebei, Beijing, Tianjin, Shanxi, Henan and Inner Mongolia.
Editor-in-chief: Qiang Zhang
Edited and Published by: Editorial Department of Acta Agriculturae Boreali-Sinica
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