CP-interacting Protein-L (IP-L) is a host protein interacting with tomato mosaic virus (ToMV) coat protein (CP) in Nicotiana benthamiana plant. In this study, we analyzed the relationship between IP-L, photosynthesis and virus infection. Our results showed that the promoter of IP-L contained many light-responsive elements, and its expression was regulated by light rhythms, light quality and light intensity. We tried to construct IP-L overexpression transgenic N. benthamiana, but the plant shows homologous co-inhibition to IP-L, which resulted in the endogenous IP-L silencing. RNA-Seq of IP-L silenced N. benthamiana revealed that IP-L was mainly involved in photosynthesis, light harvesting, photosystem II and chlorophyll binding. Strikingly, IP-L exerted a marked influence on multiple light-dependent pathways such as light stimulus, photosynthesis and chloroplast. IP-L silencing increased the expression of photosynthesis-related proteins PsbO, PsaD, PsaF and PetE, while silencing these 4 proteins increased the expression of IP-L. However, only silencing PsbO had a certain regulatory effect on the infection of TMV-GFP. Silencing PsbO could significantly reduce the content of chlorophyll b and cause the leaves to fade green and slightly yellow. All in all, for the first time we proved the relationship between IP-L and photosynthesis, clarified the coordination between virus, IP-L and photosynthesis, and provides a new clue for understanding the molecular mechanism of virus infection affecting photosynthesis.

CP交互蛋白L（IP-L）是与本生烟草植物中的番茄花叶病毒（ToMV）外壳蛋白（CP）相互作用的宿主蛋白。在这项研究中，我们分析了IP-L，光合作用和病毒感染之间的关系。我们的结果表明，IP-L的启动子包含许多光响应元件，其表达受光节律，光质量和光强度的调节。我们试图构建IP-L过表达的转基因本氏烟草，但该植物显示出对IP-L的同源共抑制作用，从而导致内源IP-L沉默。IP-L沉默本氏烟草的RNA-Seq揭示IP-L主要参与光合作用，光收集，光系统II和叶绿素结合。令人惊讶的是，IP-L对多种光依赖性途径（例如光刺激，光合作用和叶绿体）产生了显着影响。IP-L沉默增加了光合作用相关蛋白PsbO，PsaD，PsaF和PetE的表达，而沉默这4种蛋白则增加了IP-L的表达。但是，只有沉默的PsbO对TMV-GFP的感染具有一定的调节作用。沉默PsbO可以显着降低叶绿素b的含量并使叶子退色为绿色和淡黄色。总之，我们首次证明了IP-L与光合作用之间的关系，阐明了病毒，IP-L与光合作用之间的协调性，为了解病毒感染影响光合作用的分子机制提供了新的线索。