MYB transcription factors (TFs) participate in many biological processes. However, the molecular mechanisms by which MYB TFs affect plant resistance to apple ring rot remain poorly understood. Here, the R2R3-MYB gene MdMYB73 was cloned from “Royal Gala” apples and functionally characterized as a positive regulator of the defense response to Botryosphaeria dothidea. qRT-PCR and GUS staining demonstrated that MdMYB73 was strongly induced in apple fruits and transgenic calli after inoculation with B. dothidea. MdMYB73 overexpression improved resistance to B. dothidea in apple calli and fruits, while MdMYB73 suppression weakened. Increased resistance to B. dothidea was also observed in MdMYB73-expressing Arabidopsis thaliana. Interestingly, salicylic acid (SA) contents and the expression levels of genes related with SA synthesis and signaling were greater in MdMYB73-overexpressing plant materials compared to wild-type controls after inoculation, suggesting that MdMYB73 might enhance resistance to B. dothideavia the SA pathway. Finally, we discovered that MdMYB73 interacts with MdWRKY31, a positive regulator of B. dothidea. Together, MdWRKY31 and MdMYB73 enhanced B. dothidea resistance in apples. Our results clarify the mechanisms by which MdMYB73 improves resistance to B. dothidea and suggest that resistance may be affected by regulating the SA pathway.

中文翻译：

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R2R3-MYB转录因子MdMYB73赋予增加抗真菌病原体杨树dothidea侵染在苹果通过水杨酸途径

MYB转录因子（TFs）参与许多生物学过程。但是，MYB TFs影响植物对苹果环腐病抗性的分子机制仍然知之甚少。在此，从“ Royal Gala ”苹果中克隆了R2R3-MYB基因MdMYB73，并在功能上被表征为对Botryosphaeria dothidea防御反应的积极调节剂。qRT-PCR和GUS染色表明，接种B. dothidea后，MdMYB73在苹果果实和转基因愈伤组织中被强烈诱导。MdMYB73过度提高到性B. dothidea侵染苹果愈伤组织和水果，而MdMYB73抑制能力减弱。到阻力增加B. dothidea侵染中也观察到MdMYB73 -表达拟南芥。有趣的是，接种MdMYB73的植物材料中的水杨酸（SA）含量以及与SA合成和信号传导相关的基因的表达水平高于接种后的野生型对照，表明MdMYB73可能通过SA增强了对双歧杆菌的抗性。途径。最后，我们发现MdMYB73与B. dothidea的阳性调节子MdWRKY31相互作用。MdWRKY31和MdMYB73一起增强了B. dothidea苹果的抗药性。我们的研究结果阐明这MdMYB73提高了抵抗的机制B. dothidea侵染和建议性可以通过调节SA途径的影响。