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

Giardini Naxos, Italy - 18/21 September, 2002

ISBN 88-900622-3-1

Poster Abstract - 5.09

CHARACTERIZATION OF A NOVEL ARABIDOPSIS THALIANA PROTEIN THAT INTERACTS WITH A METHYL-JASMONATE INDUCIBLE NAC TRANSCRIPTION FACTOR

DI GIACOMO E., FRUGIS G., MELE G., MARIOTTI D.

Istituto di Biologia Agroambientale e Forestale (IBAF), CNR, Area della Ricerca di Roma, Via Salaria Km. 29,300, 00016 Monterotondo Scalo (Roma), Italy

Arabidopsis thaliana, methyl jasmonate, NAC, signal transduction

Jasmonates (JAs), including jasmonic acid (JA) and its methyl-ester methyl jasmonate (MeJa), are synthesized from linolenic acid via an inducible octadecanoic pathway. They act as plant hormones by regulating developmental processes and responses to environmental cues that include root growth, pollen development, abscission, senescence and responses to wounding and pathogens infection.

NACs are a family of genes specific to plants that play a role in a diverse set of developmental processes. The encoded proteins are characterized by highly conserved domains in the N-terminal region, whereas their C-terminal sequences are divergent in both length and amino acid composition. As a family, NACs show no definitive sequence homology to any other proteins and do not present any known functional motif.

Previous studies suggested an involvment of some Arabidopsis thaliana NAC genes in different hormone signal transduction pathway. As a matter of fact at least two NAC genes (NAC4 and NAC5) have been shown to be upregulated in response to MeJa treatment.

Two-hybrid assays using NAC5 protein as a bait, identified two putative NAC5 interacting proteins (NAC5-ip).

Here we present the characterization of ProtX, a NAC5-ip, that showed no homology with any other known protein. The full length cDNA of ProtX was isolated and placed either in sense or antisense direction, under the control of both 35S promoter and XVE glucocorticoid inducible system. These constructs were used to obtain Arabidopsis thaliana transgenic plants. We will present the phenotypical and molecular characterization of plants that misexpress ProtX gene in response to methyl jasmonate as well as other stress-related hormones.