Large-scale comparative transcriptome analysis of Nicotiana tabacum response to Ralstonia solanacearum infection

Tobacco bacterial wilt caused by Ralstonia solanacearum invades tobacco plants during the whole growth period affecting yield and quality. However, the transcriptome profiling of tobacco plant in response to bacterial wilt has not been well studied. In this study, we identified the transcriptional profiles of bacterial wilt-resistant (ac Yanyan97) and -susceptible (ac Honghuadajinyuan) tobacco cultivars infected with R. solanacearum at six time points by RNA sequencing. Gene expression analysis showed that the resistant cultivar manifested a faster change in the expression of defense-related genes than the susceptible cultivar during R. solanacearum infection, by which more differentially expressed genes (DEGs) were up-regulated rather than down-regulated at all time points. Functional analysis indicated that DEGs were involved in plant hormones, glutathione and secondary metabolic pathways associated with tobacco resistance to bacterial wilt induced by R. solanacearum. Through subsequent Short Time-series Expression Miner (STEM) and weighted correlation network (WGCNA) analyses, the phenylpropanoid metabolic pathway was identified as a key pathway for tobacco defense against R. solanacearum infestation. In summary, our results provide transcriptomic profiles of tobacco response to R. solanacearum infestation.