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.

中文翻译：

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SbWRKY30 增强植物的耐旱性并调节高粱中的干旱胁迫响应基因 SbRD19

WRKY 转录因子被认为在响应和适应干旱胁迫中发挥重要作用。然而，高粱 WRKY 转录因子在干旱胁迫中的作用尚不清楚。在这里，我们鉴定了高粱的 WRKY 转录因子 SbWRKY30，它是由干旱胁迫显着诱导的。SbWRKY30 主要在高粱主根和叶中表达。SbWRKY30 在细胞核中具有转录激活活性和功能。SbWRKY30 的异源表达通过影响根结构赋予拟南芥（拟南芥）和水稻对干旱胁迫的耐受性。此外，SbWRKY30 转基因拟南芥和水稻在干旱胁迫后具有较高的脯氨酸含量和 SOD、POD 和 CAT 活性，但 MDA 含量低于野生型植物。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提高了植物相对于野生型植物的耐旱性。进一步的分析表明，SbWRKY30 可以通过与 SbRD19 启动子中的 W-box 元件结合来诱导 SbRD19 表达。这些结果表明 SbWRKY30 作为响应干旱胁迫的正调节因子发挥作用。因此，SbWRKY30 可作为分子育种产生耐旱作物的有前景的候选基因。这些结果表明 SbWRKY30 作为响应干旱胁迫的正调节因子发挥作用。因此，SbWRKY30 可作为分子育种产生耐旱作物的有前景的候选基因。这些结果表明 SbWRKY30 作为响应干旱胁迫的正调节因子发挥作用。因此，SbWRKY30 可作为分子育种产生耐旱作物的有前景的候选基因。