PCE | 浙江农科院洪高洁团队揭示高温下CsHSFA-CsJAZ6模块介导山茶类黄酮代谢

以下文章来源于植物胁迫与抗逆研究 ，作者吴昕扬

近日，浙江农科院病生所洪高洁团队在PCE发表了题为《The CsHSFA-CsJAZ6 module-mediated high temperature regulates flavonoid metabolism in Camellia sinensis》的研究论文，揭示了高温下CsHSFA-CsJAZ6模块介导山茶类黄酮代谢。

高温严重影响茶叶的产量和品质。儿茶素来源于类黄酮途径，是有助于茶叶风味的特征化合物。在这项研究中，作者首先表明，在高温条件下，茶叶中的类黄酮含量显著降低；然后证明了两种转录因子CsHSFA1b和CsHSFA2在高温处理过程中被激活并负调控类黄酮的生物合成。

茉莉酸盐（JA）是一种防御激素，在植物适应环境胁迫中起着关键作用。然而，关于其参与茶叶中高温响应的报道很少。在此，作者证明了CsHSFA1b和CsHSFA2通过直接与启动子中的热休克元件结合来激活CsJAZ6的表达，从而抑制JA途径。

大多数次生代谢产物都受到茉莉酸的调节，包括茶叶中的儿茶素。本研究的结果显示，CsJAZ6直接与CsEGL3和CsTTG1相互作用，从而减少儿茶素的积累。

由此，作者提出了一个儿茶素生物合成的CsHSFA-CsJAZ6介导的高温调节模型。作者还确定了CsHSFA及其同源物对JA途径的负调控在拟南芥中是保守的。这些发现拓宽了HSF转录因子调节JAZ的适用性，并进一步表明JA途径是对于耐高温育种和栽培的重要候选途径。

High temperatures (HTs) seriously affect the yield and quality of tea. Catechins, derived from the flavonoid pathway, are characteristic compounds that contribute to the flavour of tea leaves. In this study, we first showed that the flavonoid content of tea leaves was significantly reduced under HT conditions via metabolic profiles; and then demonstrated that two transcription factors, CsHSFA1b and CsHSFA2 were activated by HT and negatively regulate flavonoid biosynthesis during HT treatment. Jasmonate (JA), a defensive hormone, plays a key role in plant adaption to environmental stress. However, little has been reported on its involvement in HT response in tea. Herein, we demonstrated that CsHSFA1b and CsHSFA2 activate CsJAZ6 expression through directly binding to heat shock elements in its promoter, and thereby repress the JA pathway. Most secondary metabolites are regulated by JA, including catechin in tea. Our study reported that CsJAZ6 directly interacts with CsEGL3 and CsTTG1 and thereby reduces catechin accumulation. From this, we proposed a CsHSFA-CsJAZ6-mediated HT regulation model of catechin biosynthesis. We also determined that negative regulation of the JA pathway by CsHSFAs and its homologues is conserved in Arabidopsis. These findings broaden the applicability of the regulation of JAZ by HSF transcription factors and further suggest the JA pathway as a valuable candidate for HT-resistant breeding and cultivation.

本文转载自植物胁迫与抗逆研究

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