EOD4与DA1协同调控植物种子大小的分子机理研究

植物种子大小同产量直接相关。DA1基因是一个调控种子大小的关键基因，且在作物育种上具有很好的应用潜力。da1-1突变体的种子显著变大。为了鉴定新的能够使种子变大的基因，并进一步研究DA1基因调控种子大小的分子机理，申请人前期在da1-1背景下筛选到一个使da1-1种子进一步变大的突变eod4-1。图位克隆及互补实验显示EOD4编码一个DEATH结构域的蛋白。体内免疫共沉淀（Co-IP）实验初步显示EOD4和DA1在蛋白水平上可以互作。遗传学分析显示EOD4和DA1在调控种子大小的功能上具有协同效应。这些初步结果表明EOD4是一个新的种子大小调控因子，而且很可能通过和DA1相互作用来协同调控种子的大小。本研究拟通过遗传学、细胞生物学、生物化学、分子生物学等手段，对EOD4和DA1协同调控种子大小的分子机理进行研究。另外本项目也将评估EOD4在提高作物产量方面的应用潜力。

Seed size is directly associated with crop yields. The DA1 gene is an important gene involved in regulating seed size. The da1-1 mutant forms large seeds. Recent studies have shown that the DA1 gene could be employed for improving seed yield in maize and rapeseed. To identify new genes that could be used for increasing seed size, and further understand the molecular mechanisms of DA1 in seed size control, we performed a genetic screen to identify enhancers of da1-1. An enhancer, eod4-1, can increase the seed size of the da1-1 mutant. We identified the EOD4 gene by map-based cloning. EOD4 encodes a DEATH domain-containing protein. Co-Immunoprecipitation (Co-IP) analyses suggest that EOD4 and DA1 could interact with each other. Genetic analyses support that EOD4 and DA1 act synergistically to regulate seed size. Thus, these preliminary studies showed that EOD4 is a new regulator of seed size, and may acts synergistically with DA1 to regulate seed size. In this project, we will further study the molecular mechanisms of synergistic regulation of plant seed size by EOD4 and DA1. We will also evaluate the potential of employing EOD4 to improve crop yields. This study will make a breakthrough in plant seed size control and provide new gene resource for engineering high yield crop.