Comparative transcriptome analysis reveals differential gene expression in resistant and susceptible tobacco cultivars in response to infection by cucumber mosaic virus

Abstract

Cucumber mosaic virus (CMV) is one of the most severe viral diseases transmitted by aphids infecting Solanum crops in China, causing great losses of crop yields and income in rural communities. The tobacco cultivars NC82 and Taiyan 8 are closely related but differ in resistance to CMV. NC82 is susceptible to infection and Taiyan 8 is resistant, but the mechanisms underlying this difference in resistance are not clear. In this study, we conducted RNA sequencing to analyze changes in gene expression induced in the leaves of Taiyan 8 and NC82 upon systemic infection with CMV, compared with gene expression in the leaves of mock-inoculated plants. Leaves were sampled at one, three, eight, and 15 days after infection. In total, 3443 and 747 differentially expressed genes were identified in Taiyan 8 and NC82, respectively. Gene ontology and pathway enrichment analyses revealed that the different responses to CMV infection between cultivars were based on microtubule-based processes, pentose and glucuronate interconversions, plant–pathogen interaction, and hormone signal transduction pathways. Genes encoding pathogenesis-related proteins, disease-resistance proteins, lipoxygenase, cellulose synthase, an auxin response factor, and an ethylene receptor showed different expression patterns. The differences in gene expression following CMV infection likely contributed to the different resistance levels of these two tobacco cultivars. The comprehensive transcriptome dataset described here, which includes candidate response genes, will serve as a resource for further studies of the molecular mechanisms associated with tobacco defense responses against CMV. Keywords: Cucumber mosaic virus, Tobacco, Resistance, Transcriptome, Differential gene expression