拟南芥LSR1调控叶片衰老的分子机制研究

Senescence is the final stage of leaf development and is strictly regulated by internal and external cues. The study of plant senescence not only helps to reveal the regulatory mystery of plant development, but also provides theoretical support for agricultural production. Although many regulatory factors involved in plant senescence have been found in recent years, it is still far from sufficient to elucidate the mechanism of senescence. A new gene involved in the regulation of leaf senescence was found at our previous work, which was named LSR1 (LEAF SENESCENCE RELATED 1). Ectopic expression of LSR1 resulted in earlier leaf senescence in the transgenic Arabidopsis, and the knockout T-DNA insertion mutant showed the delayed leaf senescence when compared with the wild-type plants. However, the molecular mechanism of LSR1 is unknown. This project will use the advanced technologies and methods to investigate the expressional patten, subcellular localization, genetic pathway and biochemical properties of LSR1. The study is expected to clarify the function of LSR1 in regulating plant leaf senescence, and to reveal its molecular mechanism.

衰老是植物发育后期由内部发育机制和外部环境因素协同调控的过程。研究衰老不仅有利于揭示植物发育调控之谜，同时也为农业生产实践提供理论支撑。近年来有多个参与叶片衰老的调控因子陆续被发现，但这远不足以全面阐明植物衰老的调控机理。本项目组在之前的研究中发现了一个新基因参与叶片衰老调控，将其命名为LSR1(LEAF SENESCENCE RELATED 1)。在拟南芥中过量表达LSR1导致转基因植株表现出明显的早衰，其T-DNA插入突变体lsr1-1与野生型对照植株相比叶片衰老显著延迟。LSR1调控叶片衰老的分子机制还不清楚。本项目拟利用现代生物学先进的技术和方法，深入研究LSR1的基因表达模式、蛋白亚细胞定位、发挥功能的遗传通路以及蛋白生化性质等。研究有望明确LSR1调控叶片衰老的功能，揭示其发挥功能的分子机制。

衰老是植物生长发育的最后一个阶段，该过程受到内部和外部环境因素协同调控。本课题组发现并克隆了一个新基因LSR1参与了植物叶片衰老调控。在拟南芥中过量表达LSR1导致转基因植株衰老显著提前，其T-DNA插入突变体 lsr1-1与野生型对照植株相比叶片衰老明显推迟。通过克隆LSR1启动子驱动GUS基因表达构建proLSR1-GUS株系，发现LSR1的表达主要集中在叶片特别是叶片的维管组织中，且越成熟的叶片中表达量越高。将LSR1的蛋白编码序列与绿色荧光蛋白GFP进行蛋白融合表达，发现LSR1蛋白特异定位于叶绿体中，同时也存在于细胞间隙中。进一步的研究表明LSR1编码一个脂类运输蛋白，负责将具有调控衰老功能的脂类物质在不同细胞的叶绿体中进行转运，用以协调整个植株不同叶片的衰老过程。本研究明确了LSR1调控植物叶片衰老的功能，揭示了其作为转运载体蛋白运输具有调控衰老功能的脂类物质，从而协调植株不同部位衰老过程的分子机制。本课题的研究不仅有利于揭示植物调控叶片衰老之谜，同时也为农业生产实践提供理论支撑。项目资助在国际期刊上发表论文2篇。