开花植物的有性生殖依赖花粉管极性生长将精细胞输送至雌配子，其中小G蛋白ROP1在花粉管极性生长的建立和维持过程中发挥了关键作用。但如何调控顶端膜ROP1活性的分子机理尚不清楚。通过化学遗传学筛选，我们分离到一个由低浓度微丝解聚化合物Latrunculin B处理导致花粉管膨大的ROP1增强子srt1 (subapical regulator of tip growth 1)。实验观察发现定位于花粉管侧面膜的SRT1扩散至顶端膜后花粉管停滞生长。这一现象暗示SRT1抑制ROP1并调控花粉管的周期性极性生长。本项目拟通过一系列的分子生物学、细胞生物学、遗传学及蛋白质组学等研究，阐明花粉管周期性生长过程中侧面膜分布的SRT1调控顶端膜ROP1活性的分子作用机理，为细胞极性生长过程中极性蛋白分布的维持及交互调控机制提供新的理论依据。

The molecular switch ROP1 GTPase plays a central role in establishment and maintenance of pollen tube polar and tip growth which plays a critical role in sperm transmission for plant fertilization. However, the molecular mechanism for regulation of ROP1 singaling is still far away to understand. ROP1 enhancer srt1 screened by low-dose actin depolymerized drug Latrunculin B (LatB) showed pollen tube depolarized growth and SRT1 dynamic distribution is closely correlated to the growing-nongrowing growth mode of pollen tube. Hence, we proposed a hypothesis that the lateral STR1 inhibited apical ROP1 activity and distribution for Arabidopsis pollen tube polar growth. Our research wills provide new insights in the regulatory mechanism for the crosstalk and distribution maintenance of lateral and apical polar factor for pollen tube tip and polar growth.