Rice G-protein subunits qPE9-1and RGB1 play distinct roles in abscisic acid responses and drought adaptation
Rice G-protein subunits qPE9-1and RGB1 play distinct roles in abscisic acid responses and drought adaptation
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DOI：
10.1093/jxb/erv350
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发表时间：
2015-10-01
影响因子：
6.9
通讯作者：
Liang, Jian-Sheng
中科院分区：
文献类型：
--
作者：
Zhang, Dong-Ping;Zhou, Yong;Liang, Jian-Sheng
异源三聚体GTP结合蛋白(G蛋白)介导的脱落酸(ABA)和干旱胁迫反应在许多植物中都有报道。然而，我们对水稻G蛋白亚基在ABA信号转导和耐旱性中的功能了解还很有限。本研究探讨了G蛋白亚基在水稻ABA反应和抗旱性中的作用。结果表明，随着ABA浓度的增加，qPE9-1(水稻G-γ亚基)的转录水平逐渐降低，qPE9-1的缺失表明水稻植株的抗旱性增强。相反，ABA处理显著上调了Rgb1(水稻Gβ亚基)的mRNA水平，Rgb1的缺失导致了抗旱性的降低。此外，结果表明，qPE9-1通过抑制参与ABA和胁迫反应的关键转录因子的表达来负向调节ABA的响应，而Rgb1通过上调正常和干旱胁迫条件下NCED基因的表达来正向调节ABA的生物合成。综上所述，Rgb1是水稻ABA反应和干旱适应的正向调节因子，而qPE9-1受Rgb1调控，在ABA依赖的干旱胁迫反应中起负调节作用。
Heterotrimeric GTP-binding protein (G-protein)-mediated abscisic acid (ABA) and drought-stress responses have been documented in numerous plant species. However, our understanding of the function of rice G-protein subunits in ABA signalling and drought tolerance is limited. In this study, the function of G-protein subunits in ABA response and drought resistance in rice plants was explored. It was found that the transcription level of qPE9-1 (rice G gamma subunit) gradually decreased with increasing ABA concentration and the lack of qPE9-1 showed an enhanced drought tolerance in rice plants. In contrast, mRNA levels of RGB1 (rice G beta subunit) were significantly upregulated by ABA treatment and the lack of RGB1 led to reduced drought tolerance. Furthermore, the results suggested that qPE9-1 negatively regulates the ABA response by suppressing the expression of key transcription factors involved in ABA and stress responses, while RGB1 positively regulates ABA biosynthesis by upregulating NCED gene expression under both normal and drought stress conditions. Taken together, it is proposed that RGB1 is a positive regulator of the ABA response and drought adaption in rice plants, whereas qPE9-1 is modulated by RGB1 and functions as a negative regulator in the ABA-dependent drought-stress responses.