磷脂酸在赤霉素受体亚细胞定位及赤霉素信号转导中的作用研究

Phospholipase D (PLD) hydrolyzes membrane phospholipids to produce phosphatidic acid (PA) and a free head group. Accumulating evidence indicated that PA, a lipid second messenger, is involved in various biological processes in plants. Recently, I have identified a novel rice pldn mutant. Preliminary study shows that rice pldn mutant is less sensitive to gibberellin acid treatment than wide type, and exogenous addition of phosphatidic acid could restore its response to gibberellin acid. This study will further elucidate the biochemical and molecular characteristics of this phospholipase D (such as substrate preference and major regulatory factors) and also the function of PLDn in rice lipid metabolism. From the perspective of lipid and protein interaction, we will identify key areas (sites) of GID1 for interacting with phosphatidic acid and further explore the effect of binding between gibberellin receptor and phosphatidic acid in gibberellin receptor subcellular location. Via the combination of biochemistry, cell biology and genetics, the study will reveal the mechanism of PA involve in gibberellin signaling transduction and further affect gibberellin acid response of cells and plants. The completion of study will help us to better understanding the crosstalk between lipid signal and gibberellin signal.

磷脂酶D（PLD）水解各种磷脂生成磷脂酸（PA）和相应极性头部基团。越来越多的研究结果表明，PA作为脂质第二信使参与了植物多种生物学过程。最近，申请人在模式植物水稻中鉴定了一个新的磷脂酶D基因（PLDn）突变体，发现其对赤霉素处理不敏感，而且外源添加磷脂酸能恢复其对赤霉素的响应。本研究将在前期研究的基础上，阐明该磷脂酶D的生化和分子特征（如酶对底物的选择性及主要调节因子）及其在水稻脂质代谢中的作用；从脂质与蛋白互作的角度出发，鉴定赤霉素受体GID1中与磷脂酸结合的关键区域（或位点），并进一步探究磷脂信号分子磷脂酸 (PA) 与赤霉素受体蛋白GID的互作对赤霉素受体亚细胞定位的影响；通过生物化学、细胞生物学和遗传学方法，揭示PA参与赤霉素信号的传递，进而影响细胞和植株对赤霉素的响应的机制，并进一步探讨磷脂酸信号和赤霉素信号间的互作。