Insights into geminiviral pathogenesis: interaction between βC1 protein and GLABROUS1 enhancer binding protein (GeBP) in Solanaceae

Abstract

Abstract Transcription factors (TFs) play crucial roles in plant development and pathogen defense. However, plant viruses can exploit TFs to facilitate their infection or transmission. In this study, we confirmed the βC1 proteins, encoded by tobacco curly shoot virus (TbCSV)- and tomato yellow leaf curl China virus (TYLCCNV)-associated betasatellites, interacted with GLABROUS1 enhancer binding protein (GeBP) TFs from solanaceous plants including Nicotiana benthamiana, Solanum lycopersicum, S. tuberosum, and Capsicum annuum. Further analysis verified the nuclear localization, homodimerization, and DNA-binding ability of the GeBP TFs, along with its interaction with βC1 in the nucleus. PVX-mediated overexpression of NbGeBP showed no effect on the accumulation of viral and betasatellite DNAs in N. benthamiana plants after infection with TbCSV and its heterologous betasatellite, malvastrum yellow vein virus associated betasatellite (MaYVB), or its homologous betasatellite, TbCSB. However, both TbCSV and MaYVV caused a decrease in NbGeBP expression during the early stages of infection, regardless of the presence of homologous or heterologous betasatellites, implying that NbGeBP might play a role in virus infection. TbCSV/TbCSB and TYLCCNV/TYLCCNB infect many solanaceous plants, and solanaceous GeBP proteins interact with βC1 proteins from TbCSB and TYLCCNB. The yeast two-hybrid and bimoleccular fluorescence complementation assays showed that AtGeBP from Arabidopsis thaliana could not interact with TbCSB βC1, revealing that the GeBP-βC1 interactions might only exist in GeBP proteins from solanaceous plants. Importantly, the βC1 protein from MaYVB, which was almost not reported on natural infection in solanaceous plants, could not interact with GeBP, suggesting the potential roles of GeBP in monopartite begomovirus infection of solanaceous plants.

Keywords

• Geminivirus
• βC1 protein
• Transcription factor
• GLABROUS1 enhancer binding protein (GeBP)
• Nuclear localization
• Solanaceous plants