Both autophagy and melatonin play important roles in plant development and stress response. However, the direct correlation between autophagy and melatonin as well as the underlying mechanism remains elusive in plants. In this study, we discovered that the expression of three autophagy‐associated genes (MeATG8b , 8c , and 8e ) and autophagic activity were induced by exogenous melatonin treatment in cassava. In addition, three melatonin biosynthesis enzymes (tryptophan decarboxylase 2 (MeTDC2), N‐aceylserotonin O‐methyltransferase 2 (MeASMT2), and MeASMT3) positively regulate endogenous melatonin level and autophagic activity. Further investigation showed that these melatonin biosynthesis enzymes interacted with MeATG8b/8c/8e in vivo and in vitro. Consistently, MeTDC2 , MeASMT2 , and MeASMT3 also positively regulate endogenous melatonin level and autophagic activity in cassava. Notably, overexpression of MeATG8b , 8c , and 8e facilitated the protein expression level of MeTDC2, MeASMT2, and MeASMT3 in vivo. Taken together, melatonin synthesis enzymes (MeTDC2, MeASMT2/3) interact with MeATG8b/8c/8e and thus coordinate the dynamics of melatonin biosynthesis and autophagic activity in cassava, highlighting the links between melatonin biosynthesis and autophagic activity in cassava.

中文翻译：

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褪黑激素生物合成酶在木薯褪黑激素生物合成和自噬协调中的双重作用。

自噬和褪黑激素在植物发育和应激反应中都发挥着重要作用。然而，自噬和褪黑激素之间的直接相关性以及潜在机制在植物中仍然难以捉摸。在这项研究中，我们发现外源褪黑激素处理木薯中的三个自噬相关基因（MeATG8b、8c和8e）的表达和自噬活性被诱导。此外，三种褪黑激素生物合成酶（色氨酸脱羧酶 2 (MeTDC2)、N-乙酰血清素O‐甲基转移酶 2 (MeASMT2) 和 MeASMT3) 正调节内源性褪黑激素水平和自噬活性。进一步的研究表明，这些褪黑激素生物合成酶在体内和体外与 MeATG8b/8c/8e 相互作用。一致地，MeTDC2、MeASMT2和MeASMT3也正调节木薯中的内源性褪黑激素水平和自噬活性。值得注意的是，MeATG8b、8c和8e 的过度表达促进了体内 MeTDC2、MeASMT2 和 MeASMT3 的蛋白质表达水平。总之，褪黑激素合成酶（MeTDC2、MeASMT2/3）与 MeATG8b/8c/8e 相互作用，从而协调木薯中褪黑激素生物合成和自噬活性的动力学，突出了木薯中褪黑激素生物合成和自噬活性之间的联系。