cDNA-AFLP Reveals a Striking Overlap in Race-Specific Resistance and Wound Response Gene Expression Profiles

Abstract

The tomato Cf-9 gene confers resistance to races of the fungal pathogen Cladosporium fulvum expressing the Avr9 gene. cDNA amplified fragment length polymorphism analysis was used to display transcripts whose expression is rapidly altered during the Avr9- and Cf-9-mediated defense response in tobacco 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 active oxygen species. cDNA clones were obtained for 13 ACRE (for Avr9/Cf-9 rapidly elicited) genes. ACRE gene induction occurred in the presence of cycloheximide. Avr9 induced ACRE gene expression in leaves. Surprisingly, ACRE genes were also rapidly but transiently induced in leaves in response to other stresses. The amino acid sequences of some ACRE proteins are homologous 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-H2 zinc finger protein. Rapid induction of ACRE genes suggests that they play a pivotal role during plant defense responses.

The Transcriptional Innate Immune Response to flg22. Interplay and Overlap with Avr Gene-Dependent Defense Responses and Bacterial Pathogenesis

“…This result is consistent with the transcriptional activation of a large set of ACRE genes in Cf-9-tobacco cell culture challenged with CHX for 30 min (Durrant et al, 2000) and suggests that FLARE and ACRE genes are negatively regulated by rapidly turned over repressor proteins. It also confirms the key role played by protein turnover in the initiation of the plant defense response and suggests that relief of negative regulation is important to activate plant defense.…”

“…Both FLARE genes and ACRE (Durrant et al, 2000) genes comprise approximately 1% of expressed genes after 30-min treatment with flg22 in Arabidopsis and Avr9 in tobacco cell cultures. Moreover, in both systems we observed that more transcripts are induced than repressed (data not shown).…”

“…To more precisely compare the rapid transcript alterations, we concentrated on flg22-induced expression changes of probable Arabidopsis orthologs of ACRE genes (AtACRE genes). Twenty full-length ACRE cDNA sequences were used to search for Arabidopsis orthologs, of which 10 ACRE genes were derived from cDNA library screening (Durrant et al, 2000) and the remainder from 3# and 5# RACE amplification (O. Rowland, A.A. Ludwig, C. Merrick, F. Baillieul, F. Tracy, W. Durrant, H. Yoshioka, and J.D.G. Jones, unpublished data).…”

“…In addition, Avr9-treated Cf9 tobacco cell cultures show rapid production of ROS and activation of MAP kinases and calcium-dependent protein kinases (CDPKs; Romeis et al, 1999Romeis et al, , 2000. Gene expression profiling of Avr9-treated Cf9 tobacco cells revealed a set of Avr9/ Cf-9 rapidly elicited (ACRE) genes induced within 15 to 30 min after elicitation (Durrant et al, 2000).…”

Arabidopsis ubiquitin ligase MIEL1 mediates degradation of the transcription factor MYB30 weakening plant defence

“…Interestingly, the intermediate resistance response displayed by miel1/myb30 plants, as compared with myb30 and miel1 plants, suggest the existence of additional defence-related MIEL1 targets that are functionally redundant with MYB30 during the regulation of Arabidopsis defence to pathogens. Although modulation of the expression of several RING genes in plants after treatment with different elicitors has been described [22][23][24][25] , only a few RING proteins have been involved in the regulation of plant immunity and, in most cases, their targets remain unknown. Moreover, the regulation by ubiquitination of the transcriptional activation related to disease resistance is yet poorly documented in plants.…”