我们前期发现，紫云英的一个B_lectin-S_locus类受体激酶（RLK，receptor-like kinase）AsNIP43与华癸根瘤菌效应蛋白NopP相互作用，可能调制宿主细胞内信号通路，在介导根瘤菌侵染中发挥重要作用。为揭示其功能作用机制，拟从3个层面开展研究：1）在功能定位层面，确证AsNIP43在共生条件下与NopP的原位互作与定位；2）在功能机制层面，阐明AsNIP43激酶活性与NopP的互作关系，以及AsNIP43与NopP／LPS之间潜在的竞争互作；3）在作用途径层面，筛选和鉴定与AsNIP43互作的下游宿主蛋白，全局分析AsNIP43调制共生防御中的关键基因与途径。预期研究结果将首次阐明宿主豆科植物RLKs与根瘤菌效应蛋白发生相互作用、控制根瘤菌入侵的信号途径，为该领域提供自主创新研究成果和进展。还可提供新视角深入探究根瘤菌-宿主互作中共生与防御的相互关系。

It is imperative to elucidate the symbiotic receptor and signaling pathway in legume host plant in response to the rhizobial effector protein Nops (nodulation outer proteins). In our latest research progress, a B_lectin-S_locus plant receptor-like kinase in Astragalus sinicus, namely AsNIP43, was isolated. It was identified that AsNIP43 interacts with a type III effector protein NopP of Mesorhizobium huakuii. It is speculated that this interaction can modulate the signaling pathway of host plant cells and plays an important role in rhizobial infection. This project aims to reveal the symbiotic interacting mechanism and pathway of AsNIP43 during the processes of rhizobia invasion into the host plant. The project will be carried out through the following three approaches. Firstly, with the aspect of spatial functional localization of AsNIP43 protein, the studies of protein-protein interactions will be conducted, and the symbiotic interactions in vivo, (sub) cellular and (co)-localization of AsNIP43-NopP will be confirmed and characterized; Secondly, with the aspect of functional mechanism of AsNIP43, the interactive relationships between AsNIP43 protein kinase activity and NopP, as well as the potential competitive interacting between NopP and LPS (lipopolisaccaride) with AsNIP43, will be examined and determined; Thirdly, with the aspect of functional pathway mediated by AsNIP43, downstream proteins of the host plant interacting with AsNIP43 will be screened and identified by yeast two-hybrid technique, the symbiotic phenotypes of the target proteins in the rhizobial infection will be corroborated. Meanwhile, a global overview analysis will be performed in regard to the candidate key genes and pathways modulated by AsNIP43 in terms of symbiotic defense. The results of this study will, for the first time, reveal the functional mechanism and signaling pathway of a novel legume host plant RLK to recognize a rhizobial effector protein Nop, by which to control the successful infection of rhizobia. It will produce achievement and advances with indigenous innovation and intellectual property in this research field. In addition, this study is able to provide a new perspective and pointcut to profoundly explore the inter-relationship of signaling pathway between symbiosis and defense during the legume-rhizobium interactions.