Peng De, Li Liqun, Wei Aosong, Zhou Ling, Wang Bingxin, Liu Mingliu, Lei Yanhong, Xie Yanzhou, Li Xuejun
State Key Laboratory of Crop Stress Biology in Arid Areas and College of Agronomy, Northwest A&F University, 3 Taicheng Rd, Yangling, 712100, Shaanxi, China.
Planta. 2024 Jul 13;260(2):52. doi: 10.1007/s00425-024-04485-0.
TaMYB44-5A identified as a transcription factor negatively regulates drought tolerance in transgenic Arabidopsis. Drought can severely reduce yields throughout the wheat-growing season. Many studies have shown that R2R3-MYB transcription factors are involved in drought stress responses. In this study, the R2R3-MYB transcription factor MYB44-5A was identified in wheat (Triticum aestivum L.) and functionally analyzed. Three homologs of TaMYB44 were isolated, all of which localized to the nucleus. Overexpression of TaMYB44-5A reduced drought tolerance in Arabidopsis thaliana. Further analysis showed that TaMYB44-5A reduced the sensitivity of transgenic Arabidopsis to ABA. Genetic and transcriptional regulation analyses demonstrated that the expression levels of drought- and ABA-responsive genes were downregulated by TaMYB44-5A, and TaMYB44-5A directly bound to the MYB-binding site on the promoter to repress the transcription level of TaRD22-3A. Our results provide insights into a novel molecular pathway in which the R2R3-MYB transcription factor negatively regulates ABA signaling in response to drought stress.
TaMYB44-5A被鉴定为一种转录因子，它在转基因拟南芥中负向调控耐旱性。干旱会在整个小麦生长季节严重降低产量。许多研究表明，R2R3-MYB转录因子参与干旱胁迫响应。在本研究中，在小麦（Triticum aestivum L.）中鉴定出R2R3-MYB转录因子MYB44-5A并对其进行了功能分析。分离出TaMYB44的三个同源物，它们均定位于细胞核。TaMYB44-5A的过表达降低了拟南芥的耐旱性。进一步分析表明，TaMYB44-5A降低了转基因拟南芥对脱落酸（ABA）的敏感性。遗传和转录调控分析表明，干旱和ABA响应基因的表达水平被TaMYB44-5A下调，并且TaMYB44-5A直接与启动子上的MYB结合位点结合以抑制TaRD22-3A的转录水平。我们的结果为一种新的分子途径提供了见解，即R2R3-MYB转录因子在响应干旱胁迫时负向调控ABA信号传导。
