小麦孕穗期根深相关基因液泡分选受体TaVSR功能解析及单倍型分析

根深对作物吸收土壤深层水分和养分具有重要作用。孕穗期是小麦产量形成的关键时期，孕穗期根深直接影响小麦的产量和抗逆性。然而由于小麦根系研究难度大，针对根深的研究非常少。项目组以小麦自然群体为材料，通过全基因组关联分析筛选到1个孕穗期控制根深的基因：液泡分选受体TaVSR。研究发现拟南芥和小麦VSR突变均导致根系变短，小麦不同材料间TaVSR启动子区转座子差异是影响孕穗期根深的主要因素。本项目拟在前期工作的基础上，通过转基因及突变体分析TaVSR对根尖平衡石、PIN蛋白和生长素含量及分布影响，揭示其调控根系发育的分子机理；同时通过比较自然群体材料中TaVSR启动子区转座子有无、DNA甲基化水平高低、基因表达差异，揭示不同单倍型差异表达的分子机理，并通过转基因验证不同单倍型的功能，确定控制根深的优异单倍型，为阐释小麦根系发育提供理论依据，为小麦育种提供优异基因和种质资源。

Root depth plays an important role in absorbing soil deep water and nutrients. Booting stage is the key period affecting wheat yield, so root depth at this stage is of great significance to improve wheat yield potential and stress resistance. Given the difficulties of wheat root research, the molecular genetic basis for root depth in wheat is still rare. To bridge the gap, we used a natural population composed of 323 accessions to perform genome wide association study (GWAS), and a candidate gene encoding a vacuolar sorting receptor (VSR) was identified which controls root depth at booting stage in wheat. Our further analysis showed the mutation of VSR in both Arabidopsis and wheat led to a shorter root phenotype. Haplotype analysis showed transposon insertion/deletion in TaVSR promoter region is the key factor controlling root depth at booting stage. The present research will further elucidate the role of TaVSR in regulating root depth. Transgenic plants overexpressing TaVSR and mutant will be used to characterize the influence of TaVSR on content and distributions of statolith starch, PIN protein and auxin in roots. Simultaneously, the DNA methylation status in TaVSR promoter region and expression level of TaVSR gene will be identified to discover the differential expression mechanism of TaVSR haplotypes. Furthermore, different haplotypes of TaVSR will be transferred into wheat to clarify their functions. This project will enhance our understanding of the molecular mechanism of deep root, and provide elite alleles for wheat breeding.