Silencing GhIAA43, a member of cotton AUX/IAA genes, enhances wilt resistance via activation of salicylic acid-mediated defenses
Silencing GhIAA43, a member of cotton AUX/IAA genes, enhances wilt resistance via activation of salicylic acid-mediated defenses
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DOI：
10.1016/j.plantsci.2021.111126
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发表时间：
2021-11-26
期刊：
影响因子：
5.2
通讯作者：
Wang, Xinyu
中科院分区：
文献类型：
--
作者：
Su, Yaxin;Wang, Guilin;Wang, Xinyu
生长素介导的Aux/IAA蛋白降解是生长素信号转导的关键步骤。最近的研究表明，Aux/IAA成员也在生物和非生物胁迫中发挥作用。例如，假单胞菌感染引起拟南芥Aux/IAA蛋白（AXR 2，AXR 3）周转。在此，通过分析RNA-seq数据，我们发现几个棉花Aux/IAA基因对大丽轮枝菌（Verticillium dahliae）感染有反应，其中一个名为GhIAA 43的基因被研究其在棉花防御大丽轮枝菌感染中的作用。我们证明了GhIAA 43的转录水平对大丽轮枝菌感染和外源IAA应用都有响应。通过产生过量表达GhIAA 43-GUS融合蛋白的转基因拟南芥植株，我们表明IAA处理和大丽轮枝菌感染促进了GhIAA 43蛋白的周转。沉默GhIAA 43基因可增强棉花对枯萎病的抗性，表明GhIAA 43基因在棉花抗黄萎病中起负调控作用。通过监测SA标记基因表达和测定GhIAA 43沉默棉花植株中SA含量，我们发现GhIAA 43沉默棉花植株中SA相关防御的增强是由于SA相关防御的激活，并且激活的防御特异性地发生在大丽轮枝菌的存在下。此外，外源IAA的施用提高了棉花对枯萎病的抗性。我们的研究结果提供了新的连接生长素信号和SA相关的防御棉花V. dahliae攻击。
Auxin-mediated degradation of Aux/IAA proteins is a crucial step in auxin signaling. Recent researches indicate that Aux/IAA members also play a role in biotic and abiotic stresses. For example, Pseudomonas syringae infection causes Arabidopsis Aux/IAA protein (AXR2, AXR3) turnover. Here, by analyzing RNA-seq data we found that several cotton Aux/IAA genes are responsive to Verticillium dahliae infection, one of these named GhIAA43, was investigated for its role in cotton defense against V. dahliae infection. We demonstrate that the transcript levels of GhIAA43 were responsive to both V. dahliae infection and exogenous IAA application. By producing transgenic Arabidopsis plants overexpressing GhIAA43-GUS fusion, we show that IAA treatment and V. dahliae infection promoted GhIAA43 protein turnover. Silencing GhIAA43 in cotton enhanced wilt resistance, suggesting that GhIAA43 is a negative regulator in cotton defense against V. dahliae attack. By monitoring SA marker gene expression and measurement of SA content in GhIAA43-silenced cotton plants, we found that the enhanced resistance in GhIAA43-silenced cotton plants is due to the activation of SA-related defenses, and the activated defenses specifically occurred in the presence of V. dahliae. Furthermore, exogenous IAA application improve wilt resistance in cotton plants tested. Our results provide novel connection between auxin signaling and SA related defenses in cotton upon V. dahliae attack.