Transcript profiling for Avr4/Cf-4- and Avr9/Cf-9-dependent defence gene expression

Abstract

Tomato Cf genes confer resistance to the leaf mold pathogen Cladosporium fulvum. The Avr4/Cf-4- and Avr9/Cf-9-dependent hypersensitive responses (HRs) are distinct in cell death pattern, intensity, and sensitivity to environmental conditions. To understand the mechanism resulting in these differences, comparative transcript profiling for Avr4/Cf-4- and Avr9/Cf-9-dependent defence gene expression by cDNA-AFLP was performed previously. 367 ACE (Avr/Cf-elicited) transcript-derived fragments (TDFs) were identified, among which 189 were cloned and sequenced. In this study, we report another 89 ACE fragments. These ACE genes were associated with: defence, signal transduction, HR and cell death, transcriptional regulation, metabolism, protein synthesis, photosynthesis, membrane fusion, secretion and trafficking, miscellaneous biological processes, and genes with unknown function or with no significant similarity to known sequences. Among these sequences 43 (potentially encoding 36 types of proteins) were identified for the first time as genes differentially expressed during the development of Avr/Cf-dependent HR. Sequence and expression data from this study further support that transcription is reprogrammed to promote defence response and HR and repress photosynthesis in the Avr/Cf HR+ seedlings. © 2008 KNPV.