Stomata that are bordered by pairs of guard cells are specialized for regulating gas exchange and transpiration in plants. The stomatal morphology of grass is unique, characterized by two dumbbell-shaped guard cells flanked by two lateral subsidiary cells. This morphology and developmental pattern enable grass stomata to respond to environmental signals efficiently. In this study, we demonstrated that knockout either OsBC1L1 or OsBC1L8, two close homologs of OsBC1L family causes no discernible defects in rice stomatal development, however, the double knockout mutant osbc1l1 osbc1l8 exhibits excess stomatal production and stomatal clustering. OsBC1L1 overexpression also causes abnormal stomatal patterning in rice. Moreover, osbc1l1 osbc1l8 has many defective stomata complexes with only one subsidiary cell. The expression of OsSPCH2 and OsFAMA, two genes key to stomatal development is both down-regulated in osbc1l1 osbc1l8. In contrast, overexpressing OsBC1L1 suppresses only the expression of OsSPCH2. Both OsBC1L1 and OsBC1L8 could be detected to be localized at the cell plate and plasma membrane during cell division of guard mother cells and subsidiary mother cells. Taken together, these results suggest that OsBC1L1 and OsBC1L8 play essential roles in the development of rice stomatal complex likely through their involvement in cell reproduction.

由成对保卫细胞包围的气孔专门用于调节植物中的气体交换和蒸腾作用。草的气孔形态是独特的，其特征是两个哑铃形保卫细胞，两侧有两个侧向附属细胞。这种形态和发育模式使草气孔能够有效地响应环境信号。在这项研究中，我们证明敲除OsBC1L1或OsBC1L8（OsBC1L家族的两个密切同源物）不会导致水稻气孔发育出现明显缺陷，然而，双敲除突变体osbc1l1 osbc1l8表现出过多的气孔产生和气孔聚集。OsBC1L1过度表达还会导致水稻气孔模式异常。此外，osbc1l1 osbc1l8有许多缺陷的气孔复合体，只有一个附属细胞。OsSPCH2和OsFAMA 这两个对气孔发育至关重要的基因在osbc1l1 osbc1l8 中的表达均下调。相反，过量表达OsBC1L1仅抑制的表达OsSPCH2。在保卫母细胞和附属母细胞的细胞分裂过程中，可以检测到 OsBC1L1 和 OsBC1L8 都定位在细胞板和质膜上。综合起来，这些结果表明OsBC1L1和OsBC1L8 可能通过参与细胞繁殖在水稻气孔复合体的发育中发挥重要作用。