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

Giardini Naxos, Italy - 18/21 September, 2002

ISBN 88-900622-3-1

Oral Communication Abstract - S5e

NITRIC OXIDE-MEDIATED TRANSCRIPTIONAL CHANGES IN ARABIDOPSIS THALIANA

MOLESINI B.*, DELLEDONNE M.*, BUONAURIO R.**, MALACARNE G.*, MICA E.*, POLVERARI A.*

*) Dipartimento Scientifico Tecnologico, Università degli Studi di Verona, Ca’ Vignal 1, Strada Le Grazie 15, 37134 Verona

**) Dipartimento di Arboricoltura e Protezione delle Piante, Università degli Studi di Perugia, Borgo XX Giugno 74, 06121 Perugia

transcript profiling, cDNA AFLP, cell death, hypersensitive reaction

Nitric oxide (NO) production in plants has been shown to be an essential step in several processes related to development and stress response, with many important parallels with its role in animal cells. In particular, NO is the essential molecule that mediates the hypersensitive response of plants to pathogens, in synergy with reactive oxygen species (ROS). However, the molecular events downstream of NO still have largely to be elucidated. Hypersensitive cell death and related resistance responses are active phenomena, requiring de novo protein synthesis and transcriptional changes of a large array of genes are likely to have an essential role in the process. By applying a new cDNA-AFLP technique, we investigated the expression profile of Arabidopsis thaliana at different times after leaf infiltration with the NO donor sodium nitroprusside (SNP), which results in an HR-like cell death. The transcription profiles of about 3.000 genes have been examined, 120 of which showed an altered expression pattern in comparison to the control water-infiltrated plants. The large majority (about 98%) of the genes showed a transcriptional induction, often very early after the treatment (10’). Comparison of 75 selected sequences with genes reported in genomic and EST databases revealed homologies with genes involved in a wide range of functions (basic metabolism, signal transduction, disease resistance, photosynthesis, etc.), or with predicted proteins of unknown function. Functional genomic approaches are now undertaken to characterize the role of a few selected genes, which might have a regulatory role downstream of NO. Our findings indicate a wide and fast effect of NO on plant transcriptional activity, and confirm gel-based differential display techniques as an essential tool in new gene discovery.