Plant symptoms are derived from specific interactions between virus and host components. However, little is known about viral or host factors that participate in the establishment of systemic necrosis. Here, we showed that helper component proteinase (HCPro), encoded by Chilli veinal mottle virus (ChiVMV), could directly interact with catalase 1 (CAT1) and catalase 3 (CAT3) in the cytoplasm of tobacco (Nicotiana tabacum) plants to facilitate viral infection. In vitro, the activities of CAT1 and CAT3 were inhibited by the interaction between HCPro and CATs. The C-terminus of HCPro was essential for their interaction and was also required for the decrease of enzyme activities. Interestingly, the mRNA and protein level of CATs were up-regulated in tobacco plants in response to ChiVMV infection. Nicotiana tabacum plants with HCPro overexpression or CAT1 knockout were more susceptible to ChiVMV infection, which was similar to the case of H₂O₂-pre-treated plants, and the overexpression of CAT1 inhibited ChiVMV accumulation. Also, neither CAT1 nor CAT3 could affect the RNA silencing suppression (RSS) activity of HCPro. Our results showed that the interaction between HCPro and CATs promoted the development of plant systemic necrosis, revealing a novel role for HCPro in virus infection and pathogenicity.

中文翻译：

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辣椒脉斑驳病毒 HCPro 与过氧化氢酶相互作用，促进烟草中的病毒感染。


植物症状源自病毒和宿主成分之间的特定相互作用。然而，人们对参与全身性坏死建立的病毒或宿主因素知之甚少。在这里，我们发现，由辣椒脉斑驳病毒（ChiVMV）编码的辅助成分蛋白酶（HCPro）可以直接与烟草（ Nicotiana tabacum ）植物细胞质中的过氧化氢酶1（CAT1）和过氧化氢酶3（CAT3）相互作用，以促进病毒的传播。感染。在体外，HCPro和CAT之间的相互作用抑制了CAT1和CAT3的活性。 HCPro 的 C 末端对于它们的相互作用至关重要，也是酶活性降低所必需的。有趣的是，烟草植物中 CAT 的 mRNA 和蛋白质水平因 ChiVMV 感染而上调。 HCPro过表达或CAT1敲除的烟草植物更容易受到ChiVMV感染，这与H ₂ O ₂预处理的植物的情况相似，并且CAT1的过表达抑制ChiVMV积累。此外，CAT1 和 CAT3 均不会影响 HCPro 的 RNA 沉默抑制 (RSS) 活性。我们的结果表明，HCPro 和 CAT 之间的相互作用促进了植物系统性坏死的发展，揭示了 HCPro 在病毒感染和致病性中的新作用。