水稻粒形和粒重是重要的品质和产量性状，我们的前期研究发现水稻T-DNA插入突变体short grain 2 (sg2)的粒长和粒重显著减小，遗传分析证明T-DNA与表型共分离，初步分析表明SG2编码一个新型的植物特异的PLATZ转录因子，进一步的转基因功能互补以及过表达试验表明SG2能够正调控水稻的籽粒长度和千粒重。本项目拟在前期研究的基础上进一步深入研究SG2调控水稻粒形的细胞学和分子机制，通过细致分析SG2的表达模式、亚细胞定位、转录活性等特性，以及结合ChIP-seq和基因芯片等方法鉴定SG2调控的候选靶基因并进行验证，阐明SG2调控水稻粒形和粒重的分子机制。此外，尽管已有16个水稻粒形、粒重相关的基因被克隆，但它们如何通过相互作用控制粒形的分子机制仍不清楚，本项目将研究SG2与已知粒形、粒重控制相关基因的可能相互作用和控制机制。这些结果可能为水稻粒形控制的分子调控提供基础。

The rice grain shape and grain weight are important quality and production phenotypes. Our study found that the T-DNA insertion mutant short grain 2 (sg2) show a significant decrease in grain length and grain weight. SG2 encodes a new type plant specific PLATZ transcriptional factor, and genetic analysis revealed that T-DNA was co-segregated with the mutant phenotype. Further genetic complement analysis by transfering SG2 genomic segment to the mutant background can completely rescue the mutant phenotype; over expression of SG2 in the wild type significantly increases grain length and weight, suggesting SG2 positively regulates grain length and weight. This study plans to further analyze the expression pattern, sun-cellular localization, transcriptional activities of SG2. The cellular mechanism for the regulation of grain shape will also be studied. On the basis of these, ChIP-seq and DNA microarray will be used to identify the target genes of SG2. The target genes will further be verified by EMSA and ChIP. Although 16 rice seed shape and weight related genes have been cloned, their signaling pathways for controlling grain shape still unknown. This study will determine the potential interaction and control mechanism between SG2 and other known rice seed shape and weight related factors. These results will provide support for study the molecular regulatory network of rice grain shape.