Functional characterization of the Arabidopsis AtHB12, an HD-Zip type I transcription factor.

RÉ DELFINA A., BONAVENTURE GUSTAVO, CHAN RAQUEL L.

Puerto Madryn

Congreso; XLVI Reunión Anual de la SAIB; 2010

AtHB12 belongs to the plant HD-Zip I family of transcription factors (TFs). In order to analyze the function of this TF and the putative regulation role of its C-terminus domain (CT), several Arabidopsis transgenic plants were generated: overexpressors of AtHB12 (AT12), overexpressors of a truncated version lacking the CT (AT12wct) and knock-out plants (iAT12). Developmental parameters were measured in these plants and the observations indicated that AT12 and WT plants initiated flowering at the same time whereas AT12wct plants had a delayed flowering. In addition, AT12wct plants exhibited shorter shoots and shorter roots than AT12 and WT plants. Besides, iAT12 plants showed longer roots than WT and AT12 plants. Finally, upon abiotic and biotic stresses, the genotypes presented different phenotypes. Transcript levels of AtHB7, a close homologue of AtHB12, seemed to be affected by the overexpression and by the knock out of the latter one, indicating that AtHB12 might regulate the expression of AtHB7. Moreover, the results indicated that the CT of AtHB12 is playing a crucial role in this gene function, probably by interacting with other proteins. Future assays including a yeast two hybrid screening for the identification of interacting partners will be performed in order to corroborate this hypothesis.