紫花苜蓿是我国乃至全球种植面积最广的豆科牧草，但其种子的实际产量却远低于潜在产量。此外，作为"牧草之王"，该牧草的公共数据库（如EST）严重落后于其他农作物，迫切需要加强其分子生物学平台建设。在前期工作的基础上，本研究拟从紫花苜蓿转录组的角度入手，结合模式植物蒺藜苜蓿miRNA和基因芯片相关数据，通过基因组比较，首次在全基因组水平揭示紫花苜蓿种子发育的分子特征，拟获得并公布紫花苜蓿高质量Unigene 60000个左右。同时，拟通过RNAi技术、原位杂交、启动子克隆和显微观察等方法，对5-10个紫花苜蓿种子发育候选基因进行表达模式分析、功能分析和作用机理分析。该项目的实施和完成，不但可以阐明紫花苜蓿种子发育的分子机理，而且对挖掘紫花苜蓿种子的生产潜力和建设该物种的分子生物学共享平台都具有重要意义。

With the most cultivated area in legume, alfalfa has been widely used in our country and the whole world. However, the actual seed yield of alfalfa is greatly lower than its potential yield. As the "king of forage", the public databases (such as EST) of this species has seriously lagged behind other agronomical crops. Therefore, it is urgent to strengthen the molecular biology platform of alfalfa. On the basis of our previous study, and in combination with the miRNA and microarray data of Medicago truncatula, the present research intends to reveal the molecular characteristics of the alfalfa seed development on genome-wide scale for the first time. This project plans to gain and release the number of about 60000 high-quailty Unigenes in alfalfa. Furthermore, 5-10 candidate genes involved in alfalfa seed development will be researched in the expression pattern, the gene function assay and the mechanism assay, using the methods of the RNAi, the in situ hybridization, the promoter cloning and the microscopic observation. By the implementation and completion of the project, it can not only elucidate the molecular mechanism of the alfalfa seed development, but also play significant importance in exploring the potentiality of alfalfa seed production and constructing the molecular biology platform of this species.