Melatonin synthesis enzymes interact with ascorbate peroxidase to protect against oxidative stress in cassava
Melatonin synthesis enzymes interact with ascorbate peroxidase to protect against oxidative stress in cassava
复制标题
褪黑激素合成酶与抗坏血酸过氧化物酶相互作用，防止木薯氧化应激
DOI：
10.1093/jxb/eraa267
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发表时间：
2020-09-19
影响因子：
6.9
通讯作者：
Shi, Haitao
中科院分区：
文献类型：
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作者：
Bai, Yujing;Guo, Jingru;Shi, Haitao
褪黑素是动植物体内重要的吲哚胺类激素。催化褪黑素合成的酶通过调节活性氧（ROS）的积累来积极调节植物的胁迫反应。然而，褪黑素生物合成酶与活性氧清除酶之间的关系尚未明确。在本研究中，我们在体外和体内实验中证明了马尼奥藤褪黑素合成途径中的两种酶（MeTDC2和MeASMT2）直接与抗坏血酸过氧化物酶（MeAPX2）相互作用。值得注意的是，在MeTDC2和MeASMT2存在下，MeAPX2蛋白的活性和抗氧化能力明显高于纯化后的MeAPX2蛋白。这些结果表明，MeTDC2-MeAPX2和MeASMT2-MeAPX2相互作用可以激活APX活性并增加抗氧化能力。此外，MeTDC2、MeASMT2和MeAPX2的组合增强了大肠杆菌对过氧化氢的抗性。此外，该组合还积极调节木薯的氧化应激耐受性。综上所述，这些发现不仅揭示了MeTDC2、MeASMT2和MeAPX2之间的直接相互作用，而且强调了这种相互作用在调节木薯氧化还原稳态和逆境耐受性中的重要性。
Melatonin is an important indole amine hormone in animals and plants. The enzymes that catalyse melatonin synthesis positively regulate plant stress responses through modulation of the accumulation of reactive oxygen species (ROS). However, the relationship between melatonin biosynthetic enzymes and ROS-scavenging enzymes has not been characterized. In this study, we demonstrate that two enzymes of the melatonin synthesis pathway in Manihot esculenta (MeTDC2 and MeASMT2) directly interact with ascorbate peroxidase (MeAPX2) in both in vitro and in vivo experiments. Notably, in the presence of MeTDC2 and MeASMT2, MeAPX2 showed significantly higher activity and antioxidant capacity than the purified MeAPX2 protein alone. These findings indicate that MeTDC2-MeAPX2 and MeASMT2-MeAPX2 interactions both activate APX activity and increase antioxidant capacity. In addition, the combination of MeTDC2, MeASMT2, and MeAPX2 conferred improved resistance to hydrogen peroxide in Escherichia coli. Moreover, this combination also positively regulates oxidative stress tolerance in cassava. Taken together, these findings not only reveal a direct interaction between MeTDC2, MeASMT2, and MeAPX2, but also highlight the importance of this interaction in regulating redox homoeostasis and stress tolerance in cassava.