MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China.
J Integr Plant Biol. 2012 Mar;54(3):169-79. doi: 10.1111/j.1744-7909.2012.01100.x.
The phytohormone abscisic acid (ABA) plays crucial roles in plant development and plant responses to environmental stresses. Although ABA receptors and a minimal set of core molecular components have recently been discovered, understanding of the ABA signaling pathway is still far from complete. In this work, we characterized the function of ROP11, a member of the plant-specific ROP small GTPases family, in the ABA signaling process. ROP11 is preferentially expressed in guard cells in all plant organs with stomata. Expression of a constitutively active ROP11 (CA-ROP11) suppresses ABA-mediated responses, whereas reduced expression of ROP11 or expression of its dominant-negative form (DN-ROP11) causes the opposite phenotypes. The affected ABA-mediated responses by ROP11 include seed germination, seedling growth, stomatal closure, induction of ABA-responsive genes, as well as plant response to drought stress. Furthermore, we showed that ROP11 and its closest-related family member, ROP10, act in parallel in mediating these responses. ABA treatment does not affect ROP11 transcription and protein abundance; however, it causes the accumulation of CA-ROP11 in the nucleus. These results demonstrated that ROP11 is a negative regulator of multiple ABA responses in Arabidopsis.
植物激素脱落酸（ABA）在植物发育和植物对环境胁迫的反应中起着至关重要的作用。尽管最近发现了 ABA 受体和一组最小的核心分子成分，但对 ABA 信号通路的理解还远远不够。在这项工作中，我们研究了 ROP11 的功能，ROP11 是植物特异性 ROP 小 GTPases 家族的成员，在 ABA 信号过程中。ROP11 在所有具有气孔的植物器官的保卫细胞中优先表达。组成型激活 ROP11（CA-ROP11）的表达抑制 ABA 介导的反应，而 ROP11 的表达减少或显性负突变体（DN-ROP11）的表达导致相反的表型。ROP11 影响的 ABA 介导的反应包括种子萌发、幼苗生长、气孔关闭、ABA 响应基因的诱导以及植物对干旱胁迫的反应。此外，我们表明 ROP11 和它最相关的家族成员 ROP10 在介导这些反应中是平行的。ABA 处理不影响 ROP11 的转录和蛋白丰度；然而，它导致 CA-ROP11 在核内积累。这些结果表明 ROP11 是拟南芥中多个 ABA 反应的负调节剂。
