Transcriptome sequencing reveals that photoinduced gene IP-L affects the expression of PsbO to response to virus infection in Nicotiana benthamiana

Abstract

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.