Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, China.
Hubei Engineering Research Center for Protection and Utilization of Special Biological Resources in the Hanjiang River Basin, College of Life Sciences, Jianghan University, Wuhan, China.
Mol Plant Pathol. 2023 Feb;24(2):107-122. doi: 10.1111/mpp.13279. Epub 2022 Nov 15.
Many host factors of plants are used by viruses to facilitate viral infection. However, little is known about how alpha-momorcharin (αMMC) counters virus-mediated attack strategies in tomato. Our present research revealed that the 2b protein of cucumber mosaic virus (CMV) directly interacted with catalases (CATs) and inhibited their activities. Further analysis revealed that transcription levels of catalase were induced by CMV infection and that virus accumulation increased in CAT-silenced or 2b-overexpressing tomato plants compared with that in control plants, suggesting that the interaction between 2b and catalase facilitated the accumulation of CMV in hosts. However, both CMV accumulation and viral symptoms were reduced in αMMC transgenic tomato plants, indicating that αMMC engaged in an antiviral role in the plant response to CMV infection. Molecular experimental analysis demonstrated that αMMC interfered with the interactions between catalases and 2b in a competitive manner, with the expression of αMMC inhibited by CMV infection. We further demonstrated that the inhibition of catalase activity by 2b was weakened by αMMC. Accordingly, αMMC transgenic plants exhibited a greater ability to maintain redox homeostasis than wild-type plants when infected with CMV. Altogether, these results reveal that αMMC retains catalase activity to inhibit CMV infection by subverting the interaction between 2b and catalase in tomato.
许多植物的宿主因子被病毒利用来促进病毒感染。然而，对于α-杏仁苦肽（αMMC）如何对抗病毒介导的攻击策略，人们知之甚少。我们目前的研究表明，黄瓜花叶病毒（CMV）的 2b 蛋白直接与过氧化氢酶（CATs）相互作用并抑制其活性。进一步分析表明，CAT 的转录水平被 CMV 感染诱导，并且与对照植物相比，CAT 沉默或 2b 过表达的番茄植物中病毒积累增加，表明 2b 和 CAT 之间的相互作用促进了 CMV 在宿主中的积累。然而，αMMC 转基因番茄植物中的 CMV 积累和病毒症状都减少了，表明αMMC 在植物对 CMV 感染的反应中发挥了抗病毒作用。分子实验分析表明，αMMC 以竞争性方式干扰 CATs 和 2b 之间的相互作用，CMV 感染抑制了αMMC 的表达。我们进一步证明，αMMC 减弱了 2b 对 CAT 活性的抑制作用。因此，与野生型植物相比，当感染 CMV 时，αMMC 转基因植物表现出更强的维持氧化还原平衡的能力。总之，这些结果表明，αMMC 通过颠覆 2b 和 CAT 之间的相互作用来保持 CAT 活性，从而抑制番茄中的 CMV 感染。
