ZmTDD1调控玉米根系形态的分子机制及演化规律研究

根系是玉米吸收水分和养分的关键器官。在玉米驯化改良过程中，根系形态发生了巨大的变化，但目前尚未有根系QTL被克隆的报道。在驯化改良过程中哪些基因和位点受到选择仍需要进一步研究。申请人在青年基金的资助下构建了高通量的根系分析平台，利用350份自交系对玉米根系性状进行关联分析，获得了一个控制玉米根系形态的候选基因ZmTDD1，重测序对基因效应进行了初步验证。本项目拟在此基础上，利用MAGIC群体和基于极端材料构建的DH群体验证ZmTDD1的遗传效应；利用突变体、敲除系、过表达株系在根系形态、组织切片、生理生化等方面明确ZmTDD1功能；通过组织表达、亚细胞定位、酵母双杂等技术阐明ZmTDD1控制根系形态的分子机制；探索ZmTDD1对玉米吸收水分和养分的作用；在野生种、地方品种和自交系中挖掘优良等位变异和单倍型，解析其演化规律。研究结果将为玉米根系遗传改良提供理论依据和关键位点。

Roots are the key organs for the absorption of water and nutrients in maize, and the root morphology has undergone tremendous changes during the domestication and improvement of maize. However, there are no root QTL has been cloned in maize. Which root related genes or loci are selected in the process of domestication and improvement still needs further research. A high-throughput root analysis systems was developed, and GWAS was conducted for root traits in a diverse panel including 350 inbred lines. A candidate gene ZmTDD1 controlling maize root morphology was identified, and the gene effect was preliminarily validated by gene resequencing. Based on these results, the genetic effects of ZmTDD1 will be validated by a MAGIC population and DH population. The gene function will be identified in root morphology, tissue section, physiological and biochemical levels using mutants, knockout lines, and overexpressing lines. The molecular mechanism of ZmTDD1 controlling root morphology will be elucidated by tissue expression, subcellular localization and yeast hybrid. Transgenic materials will be used to explore the contribution of ZmTDD1 in water and nutrient uptake. The gene will be resequenced in wild, landrace and improved maize lines to mine the elite alleles and haplotypes. The findings could contribute to understanding the molecular genetic mechanism of root traits in maize, and that the gene and its favorable allele may be an important genetic resource for maize root improvement.