StABF1, a b-ZIP transcription factor involved in abiotic stress response and tuberization

MARÍA NOELIA MUÑIZ GARCÍA ; LUCIANA MAZZOCCHI; MARIA T TELLEZ IÑON; DANIELA A CAPIATI

Potrero de los Funes-San Luis

Congreso; - XLVII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2011

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular

ABF/AREB bZIP transcription factors mediate plant abiotic stress responses by regulating the expression of stress-related genes. These proteins bind to the abscisic acid (ABA)-responsive element (ABRE), which is the major cis-acting regulatory sequence in ABAdependent gene expression. We have already cloned and characterized an ABF/AREB transcription factor from potato (Solanum tuberosum L), named StABF1, which is able to bind to the ABRE in vitro. StABF1 is induced by ABA, osmotic stress and cold, suggesting that it might be a key regulator of ABA-dependent stress response in potato. Since a stimulatory effect of ABA in tuberization has been reported, we determined if StABF1 expression is regulated during the tuber formation process using a semi-quantitative RT-PCR approach. StABF1 expression increased during tuber development and then decreased in the last stage (S4), when the tuber is already formed. High sucrose:nitrogen ratio (in vitro tuber-inducing condition) increased StABF1 mRNA levels in leaves. As ABF/AREB activity is regulated by phosphorylation, in-gel kinase assays were performed to determine the phosphorylation status of StABF1 under tuber-inducing or tuberization inhibitory conditions. Interestingly, changes in phosphorylation were detected. These results suggest that StABF1, besides acting in stress response, might be involved in tuber development.