两个紧密连锁的水稻剑叶大小基因的鉴定与功能分析

Leaf is a principle organ for photosynthesis in plants. Leaf type and size (length, width and area) is a major determinant of plant architecture, and strongly affects yield potential in crops. The flag leaf, which is the last leaf to emerge before panicle, is generally regarded as the panicle's major source of photosynthetic products. This project proposes to resolve a pleiotropic region on the short arm of chromosome 1 affecting flag leaf size and yield components in rice. The tasks of the project involve fine mapping and validation of two closely linked loci (qFL1 and qFW1) in this target region for flag leaf size by using heterogeneous inbred families and near-isogenic lines that segregated or differed at the region; isolation and characterization of the genes with regard to its underlying molecular mechanisms through an integrated strategy of map-based cloning, association analysis with candidate genes, and expression profiling; molecular,genetic and physiological dissection of the relationship of the leaf size and yield. The project will apply molecular marker-assisted selection approach to pyramid desirable alleles of the leaf size and yield, and to improve leaf stature and yield of rice. The outputs of this project are expected to provide theoretical and practical bases for refining leaf size in rice plant-type breeding of super high yield.

叶片是植物进行光合作用的主要器官，其形态和大小不仅决定植物的株叶型态，而且影响作物的产量潜力。剑叶是小穗出现之前、最后发育的一片叶，通常被认为是穗部所需碳水化合物最重要的来源。本项目拟针对水稻第1染色体短臂上一个影响剑叶大小和产量性状的多效性区段进行遗传剖析；利用杂合自交系和近等基因系对该区段上紧密连锁的两个影响剑叶大小的数量性状位点（qFL1和qFW1）进行验证和精细定位;利用图位克隆策略，结合候选基因关联分析和表达谱分析等手段，分离鉴定剑叶大小的基因,剖析qFL1和qFW1调控水稻叶片大小的分子机制;从分子遗传和生理等角度探讨其与产量形成的关系。应用分子标记辅助选择技术，聚合剑叶大小和产量等有利基因，培育具有优良叶型的新品系。预期结果将为合理调节叶片大小进行水稻超高产株型育种提供理论和实践依据。

叶片是植物进行光合作用的主要器官，其形态和大小不仅决定植物的株叶型态，而且影响作物的产量潜力。剑叶通常被认为是穗部所需碳水化合物最重要的来源。本项目利用图位克隆策略分离鉴定到一个影响水稻剑叶大小的数量性状位点（qFL1）。该基因编码磷脂酰乙醇胺结合蛋白，其第1外显子上的单核苷酸位点变异导致ZS97与9311的功能差异，有功能的等位基因推迟水稻抽穗、增加剑叶长度和宽度，同时增加每穗颖花数。比较测序发现该基因在水稻种质主要存在3种单倍型：无功能的ZS97类型和中花11类型，有功能的9311类型。本项目还将第7染色体上长臂末端的主效位点 qFL7精细定位到13.4 kb的区间范围内，确定了其候选功能基因。利用培育的qFL1、qFL7及产量基因GS6近等基因系开展杂交聚合试验，表明qFL1和GS6聚合系能显著提高单株产量。研究结果为明确剑叶大小和产量相关性状的分子调控机理、合理调节叶片大小进行水稻超高产株型育种奠定了理论和实践基础。