Flavonoid biosynthesis is strongly influenced by phytohormones. For example, methyl jasmonate (MeJA) enhances the flavonoid accumulation in pear. However, the molecular mechanism underlying the MeJA-induced flavonoid biosynthesis in pear is largely uncharacterized. Therefore, the transcriptome of pear calli treated with MeJA was analyzed to elucidate the mechanism regulating MeJA-mediated flavonoid biosynthesis. The application of exogenous MeJA significantly enhanced flavonoid accumulation, especially anthocyanin, in pear calli. A weighted gene co-expression network analysis identified the differentially expressed genes associated with MeJA-induced flavonoid biosynthesis. The MeJA treatment upregulated the expression of the flavonoid biosynthesis pathway structural genes (PcCHS, PcCHI, PcF3H, PcDFR, PcANS, PcANR2a, and PcLAR1). The MYB family members were the main transcription factors regulating the MeJA-induced flavonoid biosynthesis, but the bHLH, AP2-EREBP, NAC, WRKY, and TIFY families were also involved. In addition to PcMYB10, which is a known positive regulator of anthocyanin biosynthesis in pear, several novel MYB candidates that may regulate flavonol and proanthocyanidin biosynthesis were revealed. Yeast two-hybrid and bimolecular fluorescence complementation assays demonstrated that PcMYB10 and PcMYC2 can directly interact with each other and bind to JAZ repressors (PcJAZ1 and PcJAZ2). The PcMYB10–PcMYC2 molecular complex is likely involved in the regulation of jasmonate-mediated flavonoid biosynthesis at the transcript level. The data generated in this study may clarify the transcriptional regulatory network associated with the MeJA-induced flavonoid accumulation in pear calli and provide a solid foundation for future studies.

中文翻译：

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转录组分析为梨愈伤组织中茉莉酸甲酯诱导的类黄酮生物合成的转录调控提供了新的见解。


类黄酮生物合成受植物激素的强烈影响。例如，茉莉酸甲酯（MeJA）可增强梨中类黄酮的积累。然而，MeJA 诱导梨中类黄酮生物合成的分子机制在很大程度上尚不清楚。因此，通过分析 MeJA 处理的梨愈伤组织的转录组，以阐明 MeJA 介导的类黄酮生物合成的调节机制。外源MeJA的应用显着增强了梨愈伤组织中黄酮类化合物的积累，尤其是花青素。加权基因共表达网络分析鉴定了与 MeJA 诱导的类黄酮生物合成相关的差异表达基因。 MeJA 处理上调了类黄酮生物合成途径结构基因（PcCHS、PcCHI、PcF3H、PcDFR、PcANS、PcANR2a 和 PcLAR1）的表达。 MYB家族成员是调节MeJA诱导的类黄酮生物合成的主要转录因子，但bHLH、AP2-EREBP、NAC、WRKY和TIFY家族也参与其中。除了已知的梨花青素生物合成正调节剂 PcMYB10 之外，还发现了几种可能调节黄酮醇和原花青素生物合成的新型 MYB 候选物。酵母双杂交和双分子荧光互补测定表明，PcMYB10 和 PcMYC2 可以直接相互作用并与 JAZ 阻遏物（PcJAZ1 和 PcJAZ2）结合。 PcMYB10-PcMYC2 分子复合物可能参与转录水平上茉莉酸介导的类黄酮生物合成的调节。本研究产生的数据可能阐明与 MeJA 诱导的梨愈伤组织中类黄酮积累相关的转录调控网络，并为未来的研究提供坚实的基础。