Analysis of the Defence Responses to Tomato Spotted Wilt Orthotospovirus (TSWV) and Hippeastrum Chlorotic Ringspot Orthotospovirus (HCRV) Infection in Capsicum Annuum Based on Transcriptome

Background: Orthotospovirus has a wide range of hosts, widely distributed in southwestern China and have serious harm to crop production. Tomato spotted wilt orthotospovirus (TSWV) and Hippeastrum chlorotic ringspot orthotospovirus (HCRV) are seriously harms the quality of pepper ( Capsicum annuum L.). However, the detailed molecular mechanism of pepper disease caused by TSWV and HCRV remains obscure. Method: Transcriptome analysis (RNA-seq) based on high-throughput sequencing, with TSVV, HCRV and mock-inoculated plants as controls, to investigate and compare the gene expression changes in pepper leaves, and analyze the plants invaded by orthotospoviruses defensive response. Results: : The RNA-Seq results of pepper 1 day after inoculation (1 dpi) showed that the number of differentially expressed genes(DEG) after HCRV infection was greater than that after TSWV infection. Gene Ontology enrichment and KEGG pathway analyses were performed on the two viruses, and the KEGG results showed that DEG were mainly enriched in plant-pathogen interactions, plant hormone signal transduction, and defence processes. Conclusion: The conclusion of this study is that after orthotospovirus infects pepper, the DEG changes in the processes of plant-pathogen interaction, plant hormone and phenylpropanoid synthesis. In addition, transcription factors such as WRKY and MYB changed significantly. These factors comprehensively affect the plant's defence response and ultimately enhance the plant's resistance to viruses. Findings of present study will significantly help enhance our understanding of the complicated defense process of plant responses to orthotospoviruses infection.