THE SUNFLOWER TRANSCRIPTION FACTOR HAHB11 PARTICIPATES IN THE RESPONSE TO DROUGHT

JULIETA CABELLO; ARCE AGUSTÍN LUCAS; CHAN RAQUEL LÍA

Rosario-Argentina

Congreso; Reunión de la Sociedad Argentina de Fisiología Vegetal; 2008

Sociedad Argentina de Fisiología Vegetal

Homeodomain-leucine zipper proteins constitute a family of transcription factors found only in plants. The actual knowledge about these TFs indicates that they are involved in the adaptive response to different abiotic stresses. We identified HAHB11 as a member of the Helianthus annuus subfamily I. in a public database. This protein presents an open reading frame of 175 amino acids.. In this work we present a phylogenetic analysis indicating that the more related genes are Athb-7 and Athb-12 from Arabidopsis Expression studies were performed showing that HAHB11 expression is induced by ABA, Manitol, drought stress and NaCl. Transgenic Arabidopsis thaliana plants ectopically rexpressing HAHB11 were obtained and their phenotype analyzed both in control conditions or under severe water stress. Transgenic plants present shorter stems and compact inflorescences as well as a strong tolerance to drought. A partial fragment of HAHB11 promoter was isolated from a genomic library. Using the PLACE database we were able to identify putative regulatory elements like the core motifs ABRE (Abscisic Acid Responsive Element) and DRE (Dehydration Responsive Element). We propose that HAHB11 participates in the drought adaptive response. Additional studies are being carried out in order to elucidate the mechanism of action of this sunflower gene.