XVI International Botanical Congess
Contribution of ethylene to formation of necrotic lesions and subsequent induction of basic pathogenesis-related (PR) protein genes were tested. Induction of ACC oxidase (ACO) gene expression as well as ethylene production obviously preceded the lesion appearance and ion leakage in N-gene dependent synchronous lesion formation system in tobacco. Inhibitors of ethylene biosynthesis or action suppressed both lesion formation and basic PR gene induction. Enhanced basic PR gene induction by ACC treatment was observed in ACO-overproducing transgenic tobacco plants. These results indicate that ethylene is an indispensable factor for hypersensitive reaction (HR) and basic PR gene induction.