State Key Laboratory of Pharmaceutical Biotechnology, School of Life Sciences, Nanjing University, Nanjing, 210023, China.
J Plant Physiol. 2020 Mar-Apr;246-247:153142. doi: 10.1016/j.jplph.2020.153142. Epub 2020 Feb 22.
WRKY transcription factors have been suggested to play important roles in response and adaptation to drought stress. However, how sorghum WRKY transcription factors function in drought stress is still unclear. Here, we identify a WRKY transcription factor of sorghum, SbWRKY30, which is induced significantly by drought stress. SbWRKY30 is mainly expressed in sorghum taproot and leaf. SbWRKY30 has transcriptional activation activity and functions in the nucleus. Heterologous expression of SbWRKY30 confers tolerance to drought stress in Arabidopsis (Arabidopsis thaliana) and rice by affecting root architecture. In addition, SbWRKY30 transgenic Arabidopsis and rice plants have higher proline contents and SOD, POD, and CAT activities but lower MDA contents than wild-type plants after drought stress. As a homologous gene of the drought stress-responsive gene RD19 of Arabidopsis, SbRD19 overexpression in Arabidopsis improved the drought tolerance of plants relative to wild-type plants. Further analysis demonstrated that SbWRKY30 could induce SbRD19 expression through binding to the W-box element in the promoter of SbRD19. These results suggest that SbWRKY30 functions as a positive regulator in response to drought stress. Therefore, SbWRKY30 may serve as a promising candidate gene for molecular breeding to generate drought-tolerant crops.
WRKY 转录因子被认为在响应和适应干旱胁迫方面发挥着重要作用。然而，高粱 WRKY 转录因子在干旱胁迫下如何发挥作用尚不清楚。在这里，我们鉴定了一个高粱 WRKY 转录因子 SbWRKY30，它受干旱胁迫显著诱导。SbWRKY30 主要在高粱主根和叶片中表达。SbWRKY30 具有转录激活活性，并在核内发挥作用。SbWRKY30 的异源表达通过影响根的结构，赋予拟南芥和水稻对干旱胁迫的耐受性。此外，干旱胁迫后，SbWRKY30 转基因拟南芥和水稻植株的脯氨酸含量、SOD、POD 和 CAT 活性较高，而 MDA 含量较低。作为拟南芥干旱胁迫响应基因 RD19 的同源基因，SbRD19 在拟南芥中的过表达相对于野生型植物提高了植物的耐旱性。进一步的分析表明，SbWRKY30 可以通过结合 SbRD19 启动子中的 W-box 元件来诱导 SbRD19 的表达。这些结果表明 SbWRKY30 在响应干旱胁迫中起正向调节因子的作用。因此，SbWRKY30 可能作为一种有前途的候选基因，用于分子育种以产生耐旱作物。
