Comparative Transcriptome Profiling Reveals Defense-Related Genes against Meloidogyne incognita Invasion in Tobacco

Root-knot nematodes Meloidogyne incognita are one of the most destructive pathogens, causing severe losses to tobacco productivity and quality. However, the underlying resistance mechanism of tobacco to M. incognita is not clear. In this study, two tobacco genotypes, K326 and Changbohuang, which are resistant and susceptible to M. incognita, respectively, were used for RNA-sequencing analysis. An average of 35 million clean reads were obtained. Compared with their expression levels in non-infected plants of the same genotype, 4354 and 545 differentially expressed genes (DEGs) were detected in the resistant and susceptible genotype, respectively, after M. incognita invasion. Overall, 291 DEGs, involved in diverse biological processes, were common between the two genotypes. Genes encoding toxic compound synthesis, cell wall modification, reactive oxygen species and the oxidative burst, salicylic acid signal transduction, and production of some other metabolites were putatively associated with tobacco resistance to M. incognita. In particular, the complex resistance response needed to overcome M. incognita invasion may be regulated by several transcription factors, such as the ethylene response factor, MYB, basic helix⁻loop⁻helix transcription factor, and indole acetic acid⁻leucine-resistant transcription factor. These results may aid in the identification of potential genes of resistance to M. incognita for tobacco cultivar improvement.