水稻籽粒主效基因的克隆及其功能解析

Increasing grain yield and improving grain quality of food crops have been among the most important goals of plant basic and applied science research. Grain shape in rice is an important yield trait, an quality trait and a target trait of crop domestication. Grain chalkiness in rice greatly affects the grain milling, cooking and eating and nutrition qualities of grain, so it is a highly undeirable trait in both rice breeding prorgrams and rice marketing processes. However, litte is known on the mechanism of grain traits for crops and very limited genes controlling the traits are identified. This project focuses on the impotant grain shape to indentify and confirm two new functional genes for the two traits using the map-based cloning method. We will also perform insights into the subcellular, physiological and molecular ananlyses of the GS5 gene for grain width recently isolated by our group. This project also focuses on the molecular mechanisms on the formation of grain shape and chalkiness by identifying the inteacting genes with the cloned four major genes controing the traits by the yeast-two-hybrid, Co-IP and BiFC analyses. The rerults of this project will not only contribute to the knowledge of the molecular mechanisms, making important sense in science, but also provide good genes and theroies for improving grain yield with good quality in rice and other crops.

粮食高产、优质是植物基础科学和应用科学研究的重要目标。水稻粒形是一个重要的产量性状和育种的靶目标，但是人们对农作物该籽粒性状的分子机理知之甚少。本项目拟以水稻粒形为重点研究对象，首先利用图位克隆法分离克隆新的分别控制水稻粒长和粒厚的功能基因GS1, GS3.2, GS3.3和GT3，并验证其生物学功能；并对本课题组最近分离克隆的粒宽基因GS5进行深入的细胞学、生理学和分子调控机理研究；另外，拟以上述分离克隆的控制籽粒的主效功能基因为出发点，利用酵母双杂交、免疫共沉淀和双分子荧光互补技术分别鉴定其上下游互作基因，确定籽粒形成的基本分子框架，探索水稻高产、优质的分子机理。本研究结果不仅将有助于阐明作物高产、优质的分子机理，具有重要科学意义，而且还将为培育高产、优质水稻提供基因资源和理论依据。

粮食高产、优质是植物基础科学和应用科学研究的重要目标。水稻粒形是一个重要的产量性状、外观品质性状和作物驯化的靶标性状。本研究利用图位克隆法分离克隆了3个新的控制水稻粒长、粒厚等相关基因SNG1、qGT3和qGl3.3等。初步功能研究表明，发现SNG1是一个正调控粒长、粒宽和粒重的基因，它编码一个己糖激酶，主要通过调控糖代谢和赤霉素的合成来调节细胞大小，进而影响种子大小和粒重。qGT3确定为1个OsMADS相关基因，该基因具有明显籼粳分化，并在粳稻亚群影响粒长。qGl3.3是一与BR相关基因，其主要通过BR和生长素相关基因共同调节籽粒的大小。qGT3与qGl3.3均具有重要的驯化选择作用。同时发现GS3GW5组合可以增加柱头外露率、改善籽粒品质并提高产量。GW5gs3这种基因组合具有最高的柱头外露率和产量。以上这些重要发现将有助于阐明作物高产、优质的分子机理，具有重要科学意义，还将为培育高产、优质水稻提供基因资源和理论依据。