类受体激酶LENS整合光与BR信号通路调节水稻生长的分子机理研究

在光与内源激素调节植物生长的过程中，细胞壁的结构也发生了动态变化，这一变化应被实时感知，并传递给胞内的光信号或激素信号，以此来维持细胞结构和生长的有序性，然而能直接感受细胞壁动态变化的膜表面信号分子目前了解不多。我们最近从水稻中筛选到一个负调节细胞伸长的类受体激酶LENS，它的胞外域能结合果胶，胞内域有激酶活性。并且LENS在暗下降解，光下稳定，意味着它的功能受到了光的调节。此外，LENS过表达株系呈现了与BR激素不敏感突变体类似的表型，并且LENS与BR的受体OsBRI1互作，说明LENS可能通过影响BR信号来调节水稻生长。本项目拟在已有研究基础上，主要利用遗传学与生物化学等方法，重点研究光、细胞壁动态对LENS活性调节的分子机理，并深入解析LENS对OsBRI1的精细调节机制，旨在揭示“光-细胞壁果胶动态-LENS-OsBRI1-BR信号”途径在调控水稻生长中的重要作用。

During the light- and phytohormone-mediated regulation of plant growth, the structure of the cell wall changes dynamically. These changes are sensed and transmitted to intracellular light and phytohormone signaling pathways, leading to the maintenance of cell structure and growth. However, the molecules that directly sense these cell wall signals are rarely reported. Recently, we found that the receptor-like kinase LENS negatively regulates cell elongation; thus, it controls several agronomic traits in rice. LENS binds cell wall pectins through its extracellular domain, and it possesses kinase activity in its intracellular domain. Interestingly, LENS is stable in the light but degraded in the dark, indicating that its function is regulated by light-dark cycles. Additionally, LENS-overexpressing rice plants exhibited phenotypes that were similar to those of brassinosteroid (BR)-insensitive mutants. Meanwhile, LENS was found to interact with the BR receptor OsBRI1, suggesting that LENS alters rice growth by regulating BR signaling. Based on these results, we will study the molecular mechanism underlying light and cell wall pectin dynamics in the regulation of LENS activity and the mechanism whereby LENS regulates OsBRI1. In this project, we will use biochemical and genetic strategies to uncover the key functions of the “light-cell wall pectin dynamics-LENS-OsBRI1-BR signaling pathway” in regulating rice growth.