The Arabidopsis RING Finger E3 Ligase RHA2a Is a Novel Positive Regulator of Abscisic Acid Signaling during Seed Germination and Early Seedling Development
The Arabidopsis RING Finger E3 Ligase RHA2a Is a Novel Positive Regulator of Abscisic Acid Signaling during Seed Germination and Early Seedling Development
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拟南芥环指 E3 连接酶 RHA2a 是种子萌发和早期幼苗发育过程中脱落酸信号的新型正调节因子
DOI：
10.1104/pp.109.135269
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发表时间：
2009-05-01
期刊：
影响因子：
7.4
通讯作者：
Li, Chuanyou
中科院分区：
文献类型：
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作者：
Bu, Qingyun;Li, Hongmei;Li, Chuanyou
众所周知，植物激素脱落酸（ABA）在整合环境约束与植物发育程序中的调节作用。本文研究了拟南芥（Arabidopsis thaliana） RING-H2蛋白RHA2a在ABA信号传导中的生物学功能。在种子萌发和幼苗早期发育过程中，rha2a突变体对ABA的敏感性低于野生型，而过表达rha2a的转基因植株对ABA敏感，表明rha2a正调控ABA介导的种子萌发和幼苗早期发育。对几种已知的ABA不敏感突变体的双突变分析表明，rha2a在ABA信号传导中的作用独立于转录因子ABI3、ABI4和ABI5。我们提供的证据表明，在种子萌发和幼苗早期发育过程中，RHA2a也积极调节植物对盐和渗透胁迫的反应。RHA2a是一种功能性E3泛素连接酶，其保守的RING结构域可能对RHA2a在ABA信号传导中的生物学功能很重要。综上所述，这些结果表明E3连接酶RHA2a在种子萌发和幼苗早期发育过程中是ABA信号的重要调节因子。
The phytohormone abscisic acid (ABA) is well known for its regulatory roles in integrating environmental constraints with the developmental programs of plants. Here, we characterize the biological function of the Arabidopsis (Arabidopsis thaliana) RING-H2 protein RHA2a in ABA signaling. The rha2a mutant is less sensitive to ABA than the wild type during seed germination and early seedling development, whereas transgenic plants overexpressing RHA2a are hypersensitive, indicating that RHA2a positively regulates ABA-mediated control of seed germination and early seedling development. Double mutant analyses of rha2a with several known ABA-insensitive mutants suggest that the action of RHA2a in ABA signaling is independent of that of the transcription factors ABI3, ABI4, and ABI5. We provide evidence showing that RHA2a also positively regulates plant responses to salt and osmotic stresses during seed germination and early seedling development. RHA2a is a functional E3 ubiquitin ligase, and its conserved RING domain is likely important for the biological function of RHA2a in ABA signaling. Together, these results suggest that the E3 ligase RHA2a is an important regulator of ABA signaling during seed germination and early seedling development.