Induction, modification, and transduction of the salicylic acid signal in plant defense responses

Salicylic acid signaling appears to activate plant defense responses against pathogens and play an important role in binding catalase and impeding its enzymatic activity. Increased salicylic acid levels correlate with infection of tobacco with tobacco mosaic virus and induction of defense-related genes such as that which encodes pathogenesis-related protein 1 (PR-1). The PR gene expression and disease resistance inhibit catalytic activity. The results indicate that catalase can also act as receptor for salicylic acid.