Lipid droplets (LDs) are evolutionarily conserved organelles that serve as hubs of cellular lipid and energy metabolism in virtually all organisms. Mobilization of LDs is important in light-induced stomatal opening. However, whether and how LDs are involved in stomatal development remains unknown. We show here that Arabidopsis thaliana LIPID DROPLETS AND STOMATA 1 (LDS1)/RABC1 (At1g43890) encodes a member of the Rab GTPase family that is involved in regulating LD dynamics and stomatal morphogenesis. The expression of RABC1 is coordinated with the different phases of stomatal development. RABC1 targets to the surface of LDs in response to oleic acid application in a RABC1GEF1-dependent manner. RABC1 physically interacts with SEIPIN2/3, two orthologues of mammalian seipin, which function in the formation of LDs. Disruption of RABC1, RABC1GEF1 or SEIPIN2/3 resulted in aberrantly large LDs, severe defects in guard cell vacuole morphology and stomatal function. In conclusion, these findings reveal an aspect of LD function and uncover a role for lipid metabolism in stomatal development in plants.

中文翻译：

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拟南芥 Rab 蛋白 RABC1 通过调节脂滴动力学影响气孔发育

脂滴（LD）是进化上保守的细胞器，几乎在所有生物体中充当细胞脂质和能量代谢的中心。LD 的动员对于光诱导气孔开放非常重要。然而，LDs是否以及如何参与气孔发育仍然未知。我们在此表明​​拟南芥脂质滴和气孔 1 (LDS1)/RABC1 (At1g43890) 编码参与调节 LD 动力学和气孔形态发生的 Rab GTPase 家族成员。RABC1的表达与气孔发育的不同阶段相协调。RABC1 以 RABC1GEF1 依赖性方式响应油酸应用而靶向 LD 表面。RABC1 与 SEIPIN2/3（哺乳动物 seipin 的两个直系同源物）发生物理相互作用，SEIPIN2/3 在 LD 的形成中发挥作用。RABC1、RABC1GEF1 或 SEIPIN2/3 的破坏会导致 LD 异常大、保卫细胞液泡形态和气孔功能严重缺陷。总之，这些发现揭示了 LD 功能的一个方面，并揭示了脂质代谢在植物气孔发育中的作用。