Extraction Of VDAC Family Genes And Identification Of Excellent Alleles Of BADH-A1,P5CS And HDZ34 Genes In Common Wheat

Wheat is one of the most important food crops in China,its production is related to national food security and social stability.However,wheat yield is not only affected by external factors such as environment,but also by internal factors of wheat growth and development.Forming excellent yield characters is of great significance to increase wheat yield.Drought and salt stress have become one of the important factors to reduce wheat yield due to the increase of extreme climate.At the same time,the exploration,verification and utilization of genes related to drought resistance,salt tolerance and yield traits and their excellent alleles can provide theoretical basis and excellent genetic resources for wheat breeding.（1）In this study,whole-genome data of wheat（Chinese spring）were obtained from Ensemble Plants database,and the whole gene family of voltage anion channel（VDAC）was identified and analyzed.Drought resistance and salt tolerance of transgenic Arabidopsis thaliana with TaVDAC1-B gene were analyzed at molecular,physiological and phenotypic levels.Furthermore,TaVDAC family members and their comprehensive information were excavated to verify the function of TaVDAC1-B gene in response to drought and salt stress.（2）Drought resistance of 119 wheat varieties（lines）at germination stage was identified at physiological level,i.e.The accumulation of proline in wheat leaves after drought treatment was used to verify the drought resistance of wheat varieties（lines）and analyze the polymorphism of pyrrolin-5-carboxylic acid synthase（P5CS）gene sequence between the two groups of cultivars with extreme drought resistance at germination stage,so as to excavate excellent alleles of TaP5CS gene and develop functional molecular markers related to drought resistance.（3）The alleles of betaine aldehyde dehydrogenase（BADH）gene on chromosome6A of 19 wheat cultivars were excavated,and excellent alleles were identified at molecular,physiological and phenotypic levels by natural populations and genetically isolated populations,and functional molecular markers were developed.The geographical distribution and frequency of different alleles were investigated in microcore germplasm and natural population,and the degree of selection of different alleles of TaBADH-A1 gene in wheat breeding was expected to be obtained.（4）mining cognate fields in wheat varieties leucine zipper transcription factor of 34（HDZ34）three homologous gene allelic variation,and adopt to the Chinese spring and Yanfu 188 as the parent,China Spring and Ning 9940 F₆is better for parents to build two sets of generation of recombinant inbred lines group identification related to yield superior combination of allelic variation,and the development of functional molecular markers;The geographical distribution and frequency of different allelic combinations of TaHDZ34 gene were investigated in microcore germplasm and natural population,and the degree of selection of different allelic combinations of TaHDZ34 gene in breeding was expected to be obtained.The main research results are as follows:1.The TaVDAC gene family members and their comprehensive information were identified,and the overexpression of TaVDAC1-B gene in Arabidopsis thaliana can improve its salt tolerance and reduce its drought resistance.Twenty-six TaVDAC genes were identified in common wheat,and all of their proteins hadβsurge structure.The gene structure and protein conserved motifs of TaVDAC family were diverse among different subfamilies,and stress-related and hormone-related elements were predicted in promoter regions,and their positions on chromosomes were not evenly distributed.The expression levels of TaVDAC1-A～TaVDAC4-D and TaVDAC9-A～TaVDAC9-D were higher in different tissues and organs,while the expression levels of other genes were lower.Subsequently,compared with the wild type,transgenic Arabidopsis thaliana with TaVDAC1-B gene showed strong salt resistance and weak drought resistance at germination and adult stage.Under salt stress,At NRX1 gene expression was up-regulated and superoxide dismutase activity was increased,which led to the decrease of reactive oxygen species.Under drought stress,the trend of the above three is completely opposite to that under salt stress.This study explored the TaVDAC gene family members and their comprehensive information in wheat,providing a theoretical basis for wheat breeding.2.An excellent allele,BADH-A1b,was identified to improve drought resistance and salt tolerance of wheat.A total of 7 haplotypes of Tabad H-A1 gene were identified.According to the insertion or deletion（In Del）of 254 bp DNA transposon in the third intron of TaBADH-A1gene,this gene was divided into two alleles in wheat:BADH-A1a and BADH-A1b,and the molecular marker 6AM was developed.Under drought and salt stress,the TaBADH-A1 gene expression level,betaine content,average relative germination rate and survival rate of wheat varieties（lines）carrying BADH-A1b were significantly higher than those carrying BADH-A1a.Furthermore,in the microcore germplasm and 121 wheat varieties（lines）,BADH-A1a was more widely distributed and accounted for more than BADH-A1b.This study provided excellent genetic resources and rapid selection method for the breeding of drought-tolerant and salt-tolerant wheat.3.Identify the excellent allele,TAP5CS-1A-a,which can improve the drought resistance of wheat at germination stage.The drought resistance of 119 wheat varieties（lines）at germination stage was different,and there was a positive correlation between drought resistance and leaf proline accumulation.There were two single nucleotide polymorphisms（SNPs）in the full-length sequence of TaP5CS-1A genome DNA between two groups of wheat cultivars with extreme drought resistance.According to the SNPs in the fifth intron,they were divided into two allele types:TAP5CS-1A-a,and TAP5CS-1A-b,and the CAPS molecular markers were developed.The average relative germination rate of TAP5CS-1A-a,cultivars（lines）was 60.7%,which was significantly higher than that of TAP5CS-1A-b cultivars（44.6%）（P<0.01）.This study provided excellent genetic resources and rapid selection method for drought resistant wheat breeding.4.An excellent allelic combination,HDZ-A34a Hd Z-B34a HDZ-D34a,was identified that could improve grain number per spike,1000-grain weight,effective spikelets number and flag leaf area of wheat.TaHDZ-34A promoter region 259 bp（In Del）,TaHDZ-34B promoter region242 bp（In Del）,TaHDZ-34D 3’untranslated region 160 bp（In Del）.They were divided into two allelic variation types and developed multiple molecular markers,which were then combined into eight allelic variation combinations.The allelic combinations of HDZ-A34a Hd Z-B34a HDZ-D34a had higher spikelet number per spike,1000-grain weight,effective spikelet number and flag leaf area.Furthermore,TaHDZ-A34 protein is expressed in the nucleus,and the proteins interacting with TaHDZ-A34 involve biochemical pathways such as protein synthesis and hydrolysis,energy transfer and transformation,and photosynthesis.Subsequently,HDZ-A34a HDZ-B34b HDZ-D34b and HDZ-A34a HDZ-B34b HDZ-D34a were the preferred allelic combinations in the breeding process.This study provided excellent genetic resources and rapid selection method for high yield wheat breeding.