水稻G蛋白信号转导途径粒形调控基因的挖掘及其功能解析

稻米粒形直接影响稻米产量，是一个驯化和育种的重要靶标性状，粒形与稻米的外观品质、加工品质、蒸煮与食味品质也有着紧密的相互影响的关系。前期，大量稻米粒形QTL位点被克隆，但是对这些基因参与的信号转导途径及其粒形调控机理认识有限。目前，我们针对稻米粒长最主效QTL基因GS3参与的G蛋白信号转导途径稻米粒形的调控机理开展深入研究。主要包括通过IP-MS鉴定新的G蛋白循环复合体蛋白，通过创造G蛋白基因敲除突变体材料挖掘新的粒形调控基因，并进一步通过GTPase活性验证、扫描电镜以及透射电镜解析其粒形调控的生化和细胞学机制。最后，突变体在533份微核心种质中的基因分型、比较表达对突变基因的遗传多样性和相关性分析，确定适合水稻遗传改良的优良等位基因，为培育优质兼高产的稻米品种提供基因资源和理论基础。

Grain size directly affects grain yield of rice. It is an important target trait of domestication and breeding. Gain size also has tight relationships with its appearance quality, milling quality, cooking and eating quality of rice grain. In previous studies, a large amount of rice grain size QTL gene were cloned. However, they joined signal transduction pathways and grain size regulation mechanisms were rarely known. Recently, we aimed on intensively studies in grain size regulation mechanisms of rice seed length major QTL gene GS3 and its G protein signaling pathway. The studies included identifying new G protein cycle members in G protein complex, digging new grain size regulation genes by knockout mutants of G protein cycle genes, resolving their biochemical and cytology mechanism of grain size regulation by GTPase activity analysis and scanning electron microscope. Finally, genetic diversity and association analysis of mutant genes in 533 rice mini-core accessions to identify favorable alleles will be used to find good alleles for rice breeding. Together all will provide gene resources and theoretical foundation for breeding rice varieties with good quality and high yield.