Up-regulation of defense genes in pepper leaves inoculated with two different Tobamoviruses

Abstract: To learn more about the mechanisms of virus resistance in pepper plants we have studied the transcriptional regulation of defense-related pepper genes following virus inoculations. Pepper leaves were inoculated with two different Tobamoviruses. Obuda pepper virus (ObPV) inoculation, which caused local necrotic lesions, led to the marked up-regulation of genes encoding pathogenesis-related (PR) proteins, a 9-lipoxygenase, and WRKY transcription factors. Pepper mild mottle virus (PMMoV) inoculation, which resulted in the systemic spreading of the virus without early visible symptoms, led to weaker inductions of gene expression than ObPV. Our results showed that the early and substantial up-regulation of these defense genes contributes to virus resistance of pepper plants.