气孔是植物与外界环境进行气体交换的主要通道，调节植物的光合作用和水分利用，其发育过程是研究图式形成和细胞分裂分化的理想模型。双子叶植物气孔发育的调控机理己经取得了重要进展，但是，单子叶植物气孔发育信号通路的研究却非常有限。我们筛选到水稻中首个气孔系细胞命运决定紊乱、细胞分裂异常的功能缺失突变体sfc，该突变基因编码一个单子叶植物特有的F-box蛋白家族成员SFC。本项目以该突变体为切入点，通过研究SFC在气孔发育过程中的功能，阐明其在单子叶气孔系细胞命运决定中的作用；利用文库筛选、质谱分析、遗传分析等方法寻找SFC下游参与气孔发育的靶蛋白，对其进行蛋白质泛素化降解研究，揭示SFC介导的泛素化-蛋白降解途径在水稻气孔系细胞的极性建立和命运决定中的关键作用。本研究不仅对揭示单子叶植物气孔发育的调控机制具有重要意义，而且在提高农作物的逆境适应方面也有重要的应用前景。

Stomata are gas exchange channels between plants and environment. They regulate efficiency of photosynthesis and water use in planta. Stomatal development represents an ideal model system for studying pattern formation and cell division and differentiation. Great advancement has been achieved in studying the regulatory mechanism of stomatal development in dicots. However, the signaling pathway of stomatal development in monocots is poorly understood. We have obtained the first loss-of-function mutant sfc with defective cell-fate determination and cell division in stomatal lineage in rice. SFC gene encodes a protein belonging to an F-box family, which is specifically identified in monocots. In this proposal, we propose to elucidate the function of SFC in cell-fate determination of stomatal lineage cells in monocots. To identify the direct targets of SFC in stomatal development, we plan to carry out cDNA library screening, co-IP/MS assay, and genetic analyses. Once the targets are identified, we will perform research on their ubiquitination and degradation mediated by SFC, and finally reveal the crucial function of this pathway on stomatal lineage cell polarity establishment and cell-fate determination in rice. These studies are critical for uncovering the molecular mechanisms of stomatal development in monocots, which will provide strategies for our future crop improvement for better adaptation in adverse environmental conditions.