豆科为农业提供了重要的作物资源和牧草资源。我国当前豆科产业和牧草业相对落后，所需大豆和牧草紫花苜蓿大量依赖进口，因此在我国开展相应的研究，发掘豆科基因资源极为必要。BIG SEEDS1 (BS1)基因为豆科中控制侧生器官如叶和种子大小的关键基因。申请人前期的工作表明，在豆科植物蒺藜苜蓿和大豆中，突变或沉默BS1都引起了侧生器官的增大，生物量和牧草品质的提升。虽然该基因表现出了巨大的应用价值，但其深入的工作机理还未知，应用研究也尚未深入开展。本项目通过研究该基因与互作蛋白互作调控下游基因的详细机理，探讨其分子工作机制，更新其在大豆中的应用设计和挖掘紫花苜蓿的直系同源基因资源。本研究的开展不仅能够深入了解BS1调控豆科侧生器官大小和生物产量的分子工作机理，而且将为其在大豆和紫花苜蓿中的应用打下坚实基础，从而为我国挖掘豆科基因资源，培育有自主知识产权的豆科栽培品种带来实质性贡献。

Legumes (Fabaceae) provide many important crops and forage resources to the global agriculture. However in our country, the legume agriculture is not well developed, and the consumed soybean and forage legume alfalfa (Medicago sativa) are largely depending on import. It is very necessary and urgent for our country to conduct the relevant genetic research to mining the genetic resource and improve legume crop cultivars. BIG SEEDS1 (BS1) is a critical gene controlling the lateral organ size in legumes. The previous work indicates that, in the model legume Medicago truncatula and grain legume soybean (Glycine max), mutation and silencing of BS1 significantly increase the lateral organ size such as leaves and seeds, and enhance biomass production and forage quality. However, though BS1 has shown the great potential application value, the molecular working mechanism is still large unknown, and the application is also to be further studied. This project will (1) perform the molecular mechanism study for BS1 by screening and investigating its interacting partner which forms the complex with BS1 to regulate the downstream gene expression; (2) update the silencing design to restrict the gene silencing event in soybean seed pods and seeds; (3) investigating and silencing the orthologues in alfalfa aiming to downregulate the orthologues expression in alfalfa. The result of the project will not only extensively gain the critical knowledge regarding the molecular mechanism of BIG SEEDS1, but also build the solid foundation for the future utilization of this valuable gene. Collectively it will substantially contribute to the legume crop and forage breeding in our country.