Proceedings of the XLVII Italian Society of Agricultural Genetics - SIGA Annual Congress

Verona, Italy - 24/27 September, 2003

ISBN 88-900622-4-X

Poster Abstract - 1.24

A NEW NAC-PROTEIN GENE OF ARABIDOPSIS INDUCED IN RESPONSE TO NITRIC OXIDE AND PATHOGENS

G. MALACARNE, E. MICA, M. PEZZOTTI, M. DELLEDONNE, A. POLVERARI

Dip.Scientifico e Tecnologico, Università degli Studi di Verona

NAC transcription factors, disease resistance, hypersensitive reaction

Transcript profiling by cDNA-AFLP of Arabidopsis thaliana following treatment with the nitric oxide (NO) donor sodium nitroprusside (SNP) allowed the identification of a homologue to the ATAF2 protein (ATAF2-like), which is induced 1 hour after the treatment. The gene product belongs to the NAC protein family of Arabidopsis, which contains a number of transcription factors unique to plants, associated with the response to various stresses. Given the well-known involvement of NO in the plant response to pathogens, we used the Real-time RT-PCR to analyse the expression level of ATAF2-like in the interactions between A. thaliana Col-0 and Pseudomonas syringae pv. tomato, both virulent and avirulent strains, and between A. thaliana and Turnip Crinkle Virus (TCV) in both compatible (ecotype Col-0) and incompatible (ecotype Dijon 17) interactions. Both the incompatibilities result in a hypersensitive reaction in Arabidopsis, that is a programmed cell death at the infection site that contributes to pathogen limitation and is often associated to an efficient race-specific resistance. Induction by NO was also confirmed.

ATAF2-like transcript abundance showed a 10-12 fold increases following nitric oxide treatment and appeared to increase in the compatible and incompatible interactions with P. s. pv. tomato, 4-fold and 8-fold respectively, 10 hours post-inoculation. TCV infection does not seem to affect ATAF2-like expression in the two ecotypes, at least within the first 24 hours.

Arabidopsis Col-0 insertional mutants carrying a single, homozygous T-DNA insertion in the coding region of ATAF2-like have been obtained and research is in progress to further characterise the functional role of this gene in the hypersensitive reaction.