水稻抽穗期相关基因的分子遗传变异及适应机制

Breeding varieties with diverse heading date has been a key factor to ensure stable production and expand planting area in rice. With evident regulotary network, high level of phenotype diversity within species as well as easy observation, the heading date of rice is a excellent model system for the molecular genetic mechanisms of phenotype diversity. In the our preliminary work, the evolution history and mode of several genes associated with regulation of flowering have been well strudies. However, these known genes could not be used in molecular design breeding without knowledge of their allelic variation and interactions. In this proposed project, we will compare the molecular diversity existing in one hundred representative cultivated and wild rice accessions to build coalescent models for each regulation gene for heading date. By coalescent simulation, we will identify the genes associated heading date diversity(adaptive genes) in flowering network during rice domestication. Using 300 rice varieties, distribution of heading date alleles at these loci will be investigated and the correlation between allelic variation and heading date will be confirmed through association mapping.Then,we study the rice area distribution characteristics of these genes and interactions using phylogeography methods. Overall, the outputs of this project that understand the natural variation and ecological adaptation of these genes will provide fundamental information required for molecular design breeding for different farming systems and ecological environments.

培育抽穗期适中的品种是扩大水稻生产面积保证水稻稳产的关键因素。目前水稻抽穗期的调控机制基本清楚，加上该性状丰富的生态多样性和易观察性，水稻抽穗期已经成为性状多样化遗传机制研究难得的模式系统。申请人前期已经对该调控网络中多个基因的进化历史和进化模式进行了深入研究，但整个调控网络内基因的等位效应及互作关系仍不清楚。本项目拟以100份全球各稻作区有代表性的栽培品种及其近缘野生种为研究材料，利用群体遗传学的方法比较这些基因在栽培稻亚类群间以及野生稻中遗传多样性的差异，从而找到整个调控网络中影响抽穗期多样性的基因(适应性基因)。再将上述基因在300份栽培稻群体中进行关联分析，阐明这些基因的等位变异和品种抽穗期的相关性。然后利用亲缘地理学的方法研究这些基因的稻区分布特点及互作关系，掌握栽培品种抽穗期的遗传变异规律及其适应机制，为不同生态环境和耕作制度下的分子设计育种提供重要参考。

培育抽穗期适中的品种是扩大水稻生产面积保证水稻稳产的关键因素。目前已经克隆出19个基因与水稻抽穗期相关，本项目以269份全球各稻作区有代表性的栽培品种及其87份近缘野生种为研究材料，利用群体遗传学的方法比较这些基因在栽培稻和野生稻中遗传多样性的差异，从而找到整个抽穗期调控网络在驯化中7个受选择受选择的基因（DTH8、Ghd7、OsPRR37、DTH2、 Hd1、 Hd3a 和 RFT1），对上述受选择的基因在269份自然群体中进行关联分析，阐明受选择基因的等位变异和品种抽穗期的相关性，稻区分布特点及利用价值。进一步对 QTL 贡献率较大的四个长日照抑制基因研究，发现这些基因能解释长日照条件下栽培稻抽穗期多样性的 52.3%。这些基因的等位基因功能的有无是影响栽培稻抽穗期多样性的主要原因。这些结果为特定环境和耕作制度利用抽穗期相关基因进行分子设计育种以及改良杂交品种超亲晚熟的缺陷提供理论基础和材料资源。