cDNA-AFLP reveals a striking overlap in race-specific resistance and woundresponse gene expression profiles

The tomato Cf-9 gene confers resistance to races of the fungal pathogen Cla dosporium fulvum expressing the Avr9 gene. cDNA amplified fragment length p olymorphism analysis was used to display transcripts whose expression is ra pidly altered during the Avr9- and Cf-9-mediated defense response in tobacc o cell cultures. Diphenyleneiodonium was used to abolish the production of active oxygen species during gene induction. Of 30,000 fragments inspected, 290 showed altered abundance, of which 263 were induced independently of a ctive oxygen species. cDNA clones were obtained for 13 ACRE (for Avr9/Cf-9 rapidly elicited) genes. ACRE gene induction occurred in the presence of cy cloheximide. Avr9 induced ACRE gene expression in leaves. Surprisingly, ACR E genes were also rapidly but transiently induced in leaves in response to other stresses. The amino acid sequences of some ACRE proteins are homologo us to sequences of known proteins such as ethylene response element binding protein transcription factors, the N resistance protein, a calcium binding protein, 13-lipoxygenase, and a RING-HP zinc finger protein. Rapid inducti on of ACRE genes suggests that they play a pivotal role during plant defens e responses.