多年生黑麦草转录因子LpNAL的互作蛋白鉴定及协同调控逆境诱导叶片衰老的作用机制

Perennial ryegrass (Lolium perenne L.) is a major forage grass used in mixed pasture and rangeland in temperate and subtropical hilly ground regions in our country. Yet, perennial ryegrass are susceptible to stress conditions that typically cause premature leaf senescence leading to reduced biomass yield and lower forage quality. NAC transcription factors are involved in regulating stress-induced premature leaf senescence, and their functions are affected and regulated by their respective interacting proteins at the post-translational level. A unique NAC gene, LpNAL, was cloned in perennial ryegrass that had relatively high expression levels in senescent leaves, yet overexpressing LpNAL delayed leaf senescence. Therefore, LpNAL was likely regulated at the post-translational level by its interacting proteins that were further pooled out by Y2H method. This project will further investigate the function，interacting protein network, and effects of interacting proteins on post-translational regulation of LpNAL, in order to reveal the cooperative role(s) of LpNAL and its interacting protein(s) in the regulation of premature leaf senescence in perennial ryegrass.

多年生黑麦草（Lolium perenne L.）是我国温带和亚热带丘陵地区的主要禾本科饲草，广泛应用于混播草地和草山草坡中。但其抗逆性差，叶片易在逆境诱导下早衰，影响其产量和饲草品质。NAC家族转录因子参与调控逆境诱导的叶片早衰，翻译后修饰是调控NAC功能的重要分子机制。多年生黑麦草的一个NAC家族基因“LpNAL”在早期衰老叶片中表达量高，但过量表达该基因却延迟了叶片衰老。申请人推测LpNAL在翻译后水平上受其互作蛋白的调控，并通过Y2H实验筛选到一批候选互作蛋白。该课题拟通过明确LpNAL的功能，探析LpNAL的互作蛋白网络，和认识互作蛋白对LpNAL的翻译后调控等方面开展深入研究，以期揭示LpNAL与其互作蛋白协同调控多年生黑麦草叶片早衰的分子机制。

多年生黑麦草（Lolium perenne L.）是我国温带和亚热带丘陵地区的主要禾本科饲草，广泛应用于混播草地和草山草坡中。但其抗逆性差，叶片易在逆境诱导下早衰，影响其产量和饲草品质。该课题对多年生黑麦草的一个NAC家族基因“LpNAL”在叶片衰老调控机理开展了研究。结果表明LpNAL通过直接绑定并抑制叶绿素a和叶绿素b降解基因表达，从而延缓了衰老。此外，LpNAL在翻译后水平上收到泛素化修饰，并在绿色功能叶片中被泛素化降解。该研究结果表明，LpNAL是黑麦草叶片衰老调整中的刹车元件。此外，该项目还对一系列叶绿素降解基因的表达调控及其在衰老和黑麦草耐热性的功能开展了研究。相关研究结果对黑麦草叶片衰老和耐热性调控机理具有理论意义，所创制的遗传资源和基因标记对于黑麦草及其他多年生禾本科草的品种选育具有指导意义。