GhMYB4 downregulates lignin biosynthesis and enhances cotton resistance to Verticillium dahliae
GhMYB4 downregulates lignin biosynthesis and enhances cotton resistance to Verticillium dahliae
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GhMYB4 下调木质素生物合成并增强棉花对大丽黄萎病的抗性
DOI：
10.1007/s00299-021-02672-x
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发表时间：
2021
影响因子：
6.2
通讯作者：
Longfu Zhu
中科院分区：
文献类型：
--
作者：
Shenghua Xiao;Qin Hu;Jili Shen;Shiming Liu;Zhaoguang Yang;Kun Chen;Steven J. Klosterman;Branka Javornik;Xianlong Zhang;Longfu Zhu
GhMYB 4基因是木质素合成的负调控因子，其作用是改变细胞壁的完整性，激活棉花的防御反应。挖掘棉花抗病基因，阐明棉花抗病的分子机制，对棉花抗病育种具有重要意义。防御诱导的木质化在植物中是先天免疫所必需的，并且有报道称增加的木质化与抗病性之间存在相关性。在这项研究中，我们提出了一个例子，在棉花植物中，减少木质素含量也表现出增强的抗病性。我们确定了木质素合成的负调控因子，在棉花GhMYB 4编码。GhMYB 4基因在棉花中的过量表达增强了棉花对V.大丽花具有减少的木质素沉积。此外，GhMYB 4可以结合参与木质素合成的几个基因的启动子，如GhC 4 H-1，GhC 4 H-2，Gh4 CL-4和GhCAD-3，并损害其表达。过量表达GhMYB 4的棉花木质素含量的降低导致细胞壁完整性（CWI）的改变，并释放出更多的寡聚半乳糖醛酸（OGs），这些寡聚半乳糖醛酸可能作为损伤相关分子模式（DAMPs）刺激植物的防御反应。外源多聚半乳糖醛酸（PGA）处理棉花，可激活茉莉酸（JA）的生物合成，并激活JA介导的抗病反应。大丽花，类似于描述的棉花植物过表达GhMYB 4。该研究为棉花抗病育种提供了新的候选基因，并加深了对木质素合成、OG释放与植物免疫之间关系的理解。
Key messageGhMYB4 acts as a negative regulator in lignin biosynthesis, which results in alteration of cell wall integrity and activation of cotton defense response.AbstractVerticillium wilt of cotton (Gossypium hirsutum) caused by the soil-borne fungusVerticillium dahliae(V. dahliae) represents one of the most important constraints of cotton production worldwide. Mining of the genes involved in disease resistance and illuminating the molecular mechanisms that underlie this resistance is of great importance in cotton breeding programs. Defense-induced lignification in plants is necessary for innate immunity, and there are reports of a correlation between increased lignification and disease resistance. In this study, we present an example in cotton whereby plants with reduced lignin content also exhibit enhanced disease resistance. We identified a negative regulator of lignin synthesis, in cotton encoded in GhMYB4. Overexpression ofGhMYB4in cotton andArabidopsisenhanced resistance toV. dahliaewith reduced lignin deposition. Moreover, GhMYB4 could bind the promoters of several genes involved in lignin synthesis, such asGhC4H-1,GhC4H-2,Gh4CL-4,andGhCAD-3, and impair their expression. The reduction of lignin content inGhMYB4-overexpressing cotton led to alterations of cell wall integrity (CWI) and released more oligogalacturonides (OGs) which may act as damage-associated molecular patterns (DAMPs) to stimulate plant defense responses. In support of this hypothesis, exogenous application with polygalacturonic acid (PGA) in cotton activated biosynthesis of jasmonic acid (JA) and JA-mediated defense againstV. dahliae, similar to that described for cotton plants overexpressingGhMYB4. This study provides a new candidate gene for cotton disease-resistant breeding and an increased understanding of the relationship between lignin synthesis, OG release, and plant immunity.