Catechins constitute abundant metabolites in tea on account of their potential health benefits and high economic value. It has been intensively studied that the biosynthesis of tea catechins is regulated by environmental factors and hormonal signals. However, little is known about the coordination of phosphate (Pi) signaling and Jasmonic acid (JA) pathway on biosynthesis of tea catechins. We found that Pi-deficiency caused changes in the content of catechins and modulated the expression level of genes involved in catechins biosynthesis. Herein, we identified two transcription factors of phosphate signaling in tea, named as CsPHR1 and CsPHR2, respectively. Both regulated the catechins biosynthesis by activating the transcription of CsANR1 and CsMYB5c. We further demonstrated CsSPX1, a Pi pathway repressor, suppressing the activation of CsPHR1/2 on CsANR1 and CsMYB5c. JA, one of the endogenous plant hormones, has been reported to be involved in the regulation of secondary metabolism. Our work demonstrated that JA signaling repressor CsJAZ3 negatively regulated the catechins biosynthesis via physical interaction with CsPHR1 and CsPHR2, respectively. Thus, the CsPHRs-CsJAZ3 module bridges the nutrition and hormone signal, contributing to targeted cultivation of high-quality tea cultivars with high fertilizer efficiency.

中文翻译：

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CsPHRs-CsJAZ3 结合磷酸盐信号传导和茉莉酸途径来调节茶树中儿茶素的生物合成


儿茶素因其潜在的健康益处和高经济价值而成为茶叶中丰富的代谢物。人们深入研究茶儿茶素的生物合成受环境因素和激素信号的调节。然而，人们对磷酸盐（Pi）信号和茉莉酸（JA）途径在茶儿茶素生物合成中的协调作用知之甚少。我们发现Pi缺乏会引起儿茶素含量的变化，并调节儿茶素生物合成相关基因的表达水平。在此，我们鉴定了茶中磷酸信号传导的两个转录因子，分别命名为 CsPHR1 和 CsPHR2。两者均通过激活 CsANR1 和 CsMYB5c 的转录来调节儿茶素生物合成。我们进一步证明了 CsSPX1（一种 Pi 通路阻遏物）可抑制 CsPHR1/2 对 CsANR1 和 CsMYB5c 的激活。 JA 是内源植物激素之一，据报道参与次生代谢的调节。我们的工作表明，JA 信号传导阻遏物 CsJAZ3 分别通过与 CsPHR1 和 CsPHR2 的物理相互作用对儿茶素生物合成进行负调节。因此，CsPHRs-CsJAZ3模块架起了营养和激素信号的桥梁，有助于定向培育高肥效的优质茶品种。