Rice G-protein subunits qPE9-1 and RGB1 play distinct roles in abscisic acid responses and drought adaptation

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Dong-Ping Zhang, Yong Zhou, Jian-Feng Yin, Xue-Jiao Yan, Sheng Lin, Wei-Feng Xu, František Baluška, Yi-Ping Wang, Yi-Ji Xia, Guo-hua Liang, Jian-Sheng Liang
Journal of Experimental Botany, 2015, 66(20): 6371-6384  DOI: 10.1093/jxb/erv350;      追溯原文......本站官方QQ群:62473826
Abscisic acid; drought; G-protein subunits; qPE9-1RGB1; rice.

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 Gγ 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 Gβ 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.

水稻G蛋白亚基qPE9-1RGB1在脱落酸响应以及干旱适应性中发挥不同作用

异源三聚体GTP结合蛋白(G蛋白)介导的脱落酸(ABA)和干旱胁迫响应在多种植物中已经有了一定研究。但是对于水稻G蛋白亚基在ABA信号和干旱耐受性中功能的理解仍比较少。本文研究分析了水稻中G蛋白亚基在ABA响应以及抗旱性中的功能。我们发现qPE9-1(水稻Gγ亚基)的转录水平随着ABA含量增加而逐步降低,缺乏qPE9-1的水稻植株表现出耐旱性增强。相比之下,ABA处理会显著上调RGB1(水稻Gβ亚基)mRNA水平,缺少RGB1会降低耐旱性。此外,这些结果表明qPE9-1通过抑制参与ABA和胁迫应答的关键转录因子的表达,负调控ABA响应,而正常和干旱胁迫条件下RGB1通过上调NCED基因表达,正调控ABA合成。综上所述,我们认为RGB1是水稻ABA响应和干旱适应性的一个正调控因子,而qPE-9受到RGB1介导,作为一个负调控因子在ABA介导的干旱胁迫响应中发挥功能。


基因列表
  异三聚体G蛋白γ亚基; 直立型密穗基因; 直立穗基因 DEP1; DN1; qPE9-1; qNGR9
  异三聚体G蛋白β亚基 OsRGB1