Characterization of root Medicago truncatula transcription factors involved in salt stress response

ARIEL, FD; GRUBER, V; MANAVELLA, PA; CRESPI, M; CHAN, RL

Rosario

Congreso; SAIB; 2006

SAIB

The root architecture of the model legume Medicago truncatula is determined by the action of environmental stresses on specific genes, which adapt root development to this constraint. In this work, we isolated and characterised Transcription Factors (TFs) expressed in Medicago roots in response to salt stress. TFs were identified using genomic approaches and massive quantitative RT-PCR. Among a collection of 39 TFs, we chose 4 from the HD-ZIP, NAC, RR and WRKY families, respectively, to analyse their regulation and expression in detail. Full-length cDNA clones corresponding to these TFs were obtained by retrotranscription followed by PCR and cloned in both an appropriate vector to transform Arabidopsis plants and Medicago roots. Fusions of these cDNAs with GST from Schistosoma japonicum served to express the encoded proteins. Such proteins were purified by affinity chromatography andin vitro analysis, consisting of EMSA and PCR assisted binding site selection (SELEX), were carried out. This analysis enabled us to characterise protein-DNA interactions for these TFs. Our aim is to dissect the regulatory pathways involved in the response to salt stress in legume roots and eventually identify genes able to confer plant tolerance to such adverse environmental conditions.