Comparative proteome analysis illustrates tobacco defense mechanisms in response to Ralstonia solanacearum infection

Background Ralstonia solanacearum causing bacterial wilt disease provokes tremendous losses in global crop production including tobacco. Transcriptional changes in response to R. solanacearum infection have already been intensively studied in various plant species. However, the genetic networks regulating defense responses of different tobacco varieties having different resistance backgrounds are quite limited. Results In this study, we performed a comparative proteome analysis of two tobacco cultivars, resistant (R) and susceptible (S), during the infection of R. solanacearum, to uncover the potential candidate genes regulating tobacco resistance to R. solanacearum. We observed huge difference in protein profiles between the two cultivars after R. solanacearum infection. The proteins involved in salicylic acid (SA), jasmonic acid (JA) and ethylene (ETH) exhibited significant changes in response to R. solanacearum. These changes thought to regulate defense responses in tobacco plants. Phenylpropanoid metabolism related proteins including PAL, 4CL, POD, and TOGT also showed differential regulation in both R and S tobacco cultivars in response to R. solanacearum infection, which may be one of the reason why the different resistance showed in these two cultivars. By using CRISPR/Cas9, we experimentally validated that knockout of NtTOGT gene has decreased tobacco resistance to R. solanacearum. Conclusion Collectively, our results provide new insights to understand tobacco defense mechanism against R. solanacearum that would benefit breeding programs in the future. It will asset to identify potential defense responsive genes to understand and improve plant resistance. In addition, we suggest that NtTOGT might be a resistant gene involved in plant defense response against R. solanacearum.