气孔是植物地上表皮上的一种特殊的结构，在调节光合作用和蒸腾作用中发挥着重要的作用。气孔的形成经历多种细胞分裂和分化，是研究植物发育理想系统。内膜囊泡运输介导众多的发育调控，但是否参与气孔发育调控还不清楚。ARF-GEF是小G蛋白ADP核糖基化因子的鸟苷酸交换因子，参与囊泡运输调控。拟南芥ARF-GEF包含GBF和BIG两个亚家族。我们前期研究结果显示GBF亚家族的GNOM基因突变所导致气孔世系小细胞群和气孔簇表型，与极性蛋白BASL突变体表型相似。BIG亚家族多基因突变也导致了叶片气孔簇形成，但却抑制了下胚轴气孔产生，表明ARF-GEF蛋白参与调控气孔发育功能各异并有器官特异性。本项目拟利用分子生物学、生物化学、细胞生物学和遗传学等方法，通过验证ARF-GEF是否介导了气孔发育调控蛋白，如BASL、BRI1受体蛋白的囊泡运输过程，揭示ARF-GEF依赖的囊泡运输参与气孔发育的信号调控途径。

Stomata are plant-specific epidermal structures that control gas and water exchange between plants and the atmosphere. Stomatal development involves a series of cell divisions and differentiation, which provides an ideal research system for understanding the development of multicellular higher plants. Endomembrane vesicular trafficking mediates many aspects of plant development, however the roles of which in regulating stomatal development is far from clear. ARF-GEFs are ADP-ribosylation factors (ARF small GTPases) guanine nucleotide exchange factors that play regulatory roles in endomembrane vesicular trafficking. Arabidopsis ARF-GEFs can be classified into GBF- and BIG-subfamilies. Mutation of GBF-subfamily GNOM induced the formation of small stomatal lineage cells and stomata clusters, a similar phenotype that is observed in the mutant of BASL as well. Furthermore, mutations of multiple BIG-subfamily genes caused stomata clusters in leaves but suppression the production of stomata in hypocotyls compared with wild-type, indicating that the ARF-GEF family proteins have diverse but redundant roles in regulating the organ-specific stomatal development. In this study, we will employ molecular biology, biochemistry, cellular biology and genetics strategies to study whether the subcellular localization of key stomatal regulators, such as BASL and BRI1, are regulated by ARF-GEF mediated vesicular trafficking pathway. The results of this study will enrich our understanding of the function of ARF-GEF mediated vesicular trafficking in signaling pathway and stomatal development.