干旱已成为影响我国小麦生产最严重胁迫因素之一，选育和推广抗旱品种是确保小麦高产稳产最经济最有效途径之一，解析抗旱基因的功能可为抗旱新品种的选育提供理论依据。课题组前期利用小麦自然群体、重组自交系群体、近等基因系和转拟南芥研究表明，小麦的TaNRX-B1基因与抗旱性相关。本项目拟对其功能进行解析。通过分析过表达和RNAi沉默小麦转基因后代，进一步鉴定该基因的抗旱性功能；通过研究TaNRX-B1基因在拟南芥和洋葱瞬时表达，以及启动子5’系列缺失片段驱动GUS基因在小麦响应水分胁迫瞬时表达，明确TaNRX-B1基因表达蛋白的细胞部位并初步揭示启动子响应水分胁迫的机制；通过小麦转基因后代和野生型的转录组测序和分析，筛选与抗旱相关的下游靶基因；用酵母双杂交和双分子荧光互补技术，鉴定互作蛋白；通过小麦原生质体培养和转化技术并结合GUS和LUC报告基因研究，揭示TaNRX-B1基因调控下游靶基因的机理。

Drought has become one of the most serious stress factors affecting wheat production in China. It is one of the most economical and efficient means of ensuring wheat high and stable yield to breed and plant cultivars with drought resistance. It is very important for breeding drought resistant cultivars to interpret the function of drought resistant genes. Our previous studies showed that gene TaNRX-B1 in wheat was related to drought resistance using a population of recombinant inbred lines, natural population with a large number of wheat cultivars, near-isogenic wheat lines differing at the TaNRX-B1 locus, and its Arabidopsis overexpression transgenic lines. The mechnism of the gene under drought stress will be dissected in this project. In order to further prove the drought resistance of the gene TaNRX-B1, wheat transformation lines with overexpression or suppressing (RNA interference) expression of the gene will be obtained by transformation technology, respectively. Morphological, physiological and biochemical properties related to drought resistances, and spatio-temporal expression of the gene TaNRX-B1 in the seedlings of wheat transformation lines and their wild type under different water treatments will be analyzed. To determine the action site of TaNRX-B1, a subcellular localization assay will be conducted by transiently expressing TaNRX-B1-GFP fusion protein in onion epidermal cells and Arabidopsis protoplasts. Various plasmid vectors with 5’-truncated TaNRX-B1 promoters fused with the reporter gene GUS will be constructed and transformed into wheat callus, respectively. Activity of the gene TaNRX-B1 promoter under different water treatments will be analyzed. RNA-Seq will be used for gene expression analysis in response to water stress treatments in the seedlings of wheat transformation lines and their wild type. Differentially expressed genes related to plant stress response were validated by qPCR. Downstream target genes of the gene TaNRX-B1 will be screened out. Interaction proteins of TaNRX-B1 will be screened out using yeast two-hybrid and bimolecular fluorescence complementation. Expression of reporter genes GUS and LUC in wheat callus will be detected. Regulation of downstream target genes of gene TaNRX-B1 will be illustrated.