Drought and Verticillium wilt disease are two main factors that limit cotton production, which necessitates the identification of key molecular switch to simultaneously improve cotton resistance to Verticillium dahliae and tolerance to drought stress. R2R3-type MYB proteins could play such a role because of their conserved functions in plant development, growth, and metabolism regulation, however, till date a MYB gene conferring the desired resistance to both biotic and abiotic stresses has not been found in cotton. Here, we describe the identification of GhMYB36, a gene encoding a R2R3-type MYB protein in Gossypium hirsutum, which confers drought tolerance and Verticilium wilt resistance in both Arabidopsis and cotton. GhMYB36 was highly induced by PEG-simulated drought stress in G. hirsutum. GhMYB36-silenced cotton plants were more sensitive to both drought stress and Verticillium wilt. GhMYB36 overexpression in transgenic Arabidopsis and cotton plants gave rise to improved drought tolerance and Verticillium wilt resistance. Transient expression of fused GhMYB36-GFP in tobacco cells was able to localize GhMYB36 in the cell nucleus. In addition, RNA-seq analysis together with qRT-PCR validation in transgenic Arabidopsis overexpressing GhMYB36 revealed significantly enhanced PR1 expression. Luciferase interaction assays indicated that GhMYB36 are probably bound to the promoter of PR1 to activate its expression and the interaction, which was further verified by Yeast one hybrid assay. Taken together, our results suggest that GhMYB36 functions as a transcription factor that is involved in drought tolerance and Verticillium wilt resistance in Arabidopsis and cotton by enhancing PR1 expression.

中文翻译：

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GhMYB36 转录因子通过增强植物中 PR1 基因的表达来赋予对生物和非生物胁迫的抵抗力

干旱和黄萎病是限制棉花产量的两个主要因素，因此需要确定关键的分子开关，以同时提高棉花对黄萎病的抗性和对干旱胁迫的耐受性。R2R3 型 MYB 蛋白可以发挥这种作用，因为它们在植物发育、生长和代谢调节中的保守功能，然而，迄今为止，尚未在棉花中发现赋予所需的生物和非生物胁迫抗性的 MYB 基因。在这里，我们描述了 GhMYB36 的鉴定，GhMYB36是一种在陆地棉中编码 R2R3 型 MYB 蛋白的基因，它赋予抗旱性和黄萎病菌拟南芥和棉花都具有抗枯萎病的能力。GhMYB36在陆地棉中被 PEG 模拟的干旱胁迫高度诱导。GhMYB36沉默的棉花植物对干旱胁迫和黄萎病更敏感。GhMYB36在转基因拟南芥和棉花植物中的过表达提高了耐旱性和黄萎病抗性。烟草细胞中融合的 GhMYB36-GFP 的瞬时表达能够将 GhMYB36 定位在细胞核中。此外，在过表达GhMYB36的转基因拟南芥中，RNA-seq 分析和 qRT-PCR 验证显示PR1显着增强表达。荧光素酶相互作用测定表明，GhMYB36 可能与PR1的启动子结合以激活其表达和相互作用，这进一步通过酵母一杂交测定得到证实。总之，我们的结果表明，GhMYB36 作为转录因子发挥作用，通过增强PR1表达，参与拟南芥和棉花的耐旱性和黄萎病抗性。