Plant Cell | 沈阳农业大学王爱德研究组揭示茉莉酸促进果实乙烯合成分子机制

近日，沈阳农业大学园艺学院王爱德研究组以‘苹果’为试材，阐明了茉莉酸信号通路中的重要转录因子MdMYC2通过转录调控和蛋白互作促进果实乙烯合成的分子机制，相关研究成果论文“The Jasmonate-Activated Transcription Factor MdMYC2 Regulates ETHYLENE RESPONSE FACTOR and Ethylene Biosynthetic Genes to Promote Ethylene Biosynthesis during Apple Fruit Ripening”于2017年5月26日在线发表在The Plant Cell（五年IF=10.529）。

Figure 10. Model Showing the Promotion of Ethylene Biosynthesis by MdMYC2 through the Regulation of MdERFs and Ethylene Biosynthetic Genes. 

茉莉酸是一种重要的植物激素，在植物发育的多个生理过程中起作用。在过去的几十年内，研究者发现茉莉酸可以促进园艺作物果实（苹果，番茄，李和芒果等）乙烯合成并且加快果实的成熟，但是茉莉酸促进果实乙烯合成的分子机理尚未清楚。

该团队研究发现，茉莉酸诱导其信号途径中的关键转录因子MdMYC2的表达，而MdMYC2可以直接结合乙烯合成基因MdACS1和MdACO1的启动子并促进其转录；MdMYC2也可以结合MdERF3的启动子并促进其转录进而促进MdACS1的转录；此外，MdMYC2可以在蛋白水平上与MdERF2互作，这种互作一方面直接促进了MdACS1的转录，另一方面削弱了MdERF2与MdERF3的互作从而释放更多的MdERF3促进MdACS1的转录。以上结果阐明了茉莉酸通过MdMYC2促进MdACS1和MdACO1的转录从而促进苹果果实乙烯合成的分子机制。

本文的通信作者为沈阳农业大学园艺学院王爱德教授，第一作者为沈阳农业大学园艺学院博士研究生李通，该研究工作在沈阳农业大学独立完成，得到了国家自然科学基金面上项目（31672121）的资助。

Abstract：

The plant hormone ethylene is critical for ripening in climacteric fruits, including apple (Malus domestica). Jasmonate (JA) promotes ethylene biosynthesis in apple fruit, but the underlying molecular mechanism is unclear. Here we found that JA-induced ethylene production in apple fruit is dependent on the expression of MdACS1, an ACC synthase gene involved in ethylene biosynthesis. The expression of MdMYC2, encoding a transcription factor involved in the JA signaling pathway, was enhanced by MeJA treatment in apple fruits, and MdMYC2 directly bound to the promoters of both MdACS1 and the ACC oxidase gene MdACO1 and enhanced their transcription. Furthermore, MdMYC2 bound to the promoter of MdERF3, encoding a transcription factor involved in the ethylene-signaling pathway, thereby activating MdACS1 transcription. We also found that MdMYC2 interacted with MdERF2, a suppressor of MdERF3 and MdACS1. This protein interaction prevented MdERF2 from interacting with MdERF3 and from binding to the MdACS1 promoter, leading to increased transcription of MdACS1. Collectively, these results indicate that JA promotes ethylene biosynthesis through the regulation of MdERFs and ethylene biosynthetic genes by MdMYC2.

(转载自    植物科学最前沿)