Transgenic Arabidopsis plants bearing PromoterHaHB11::HaHB11 exhibit significantly enhanced biomass

GIACOMELLI, JORGE; MORA, CELESTE; CABELLO, JULIETA; CHAN, RAQUEL

Rosario

Congreso; L Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2014

HD-Zips are plant specific transcription factors (TFs) combining a Homeobox Domain (HD) and a Leucine Zipper (Zip). HaHB11 is a sunflower divergent HD-Zip I TF. It was previously reported that the ectopic and overexpression of this gene in Arabidopsis driven by the 35S constitutive promoter conferred to transgenic plants relevant traits: tolerance to both drought and flooding stresses, larger rosettes and improved yield compared with controls. However, this constitutive expression also caused a developmental delay when the expression levels are very high. In order to avoid this penalty, the HaHB11 promoter was isolated from a BAC genomic library. Transgenic plants in which this promoter drives either the HaHB11 cDNA or the reporter GUS expression were generated and analyzed. GUS expression was clearly detected in roots, hypocotyls and petioles of plants grown in standard conditions. ProH11::HAHB11 plants exhibited larger rosettes than controls either in control and mild stress conditions, significantly improved seed yield, larger roots and did not display developmental delays or penalties. However, these plants did not show enhanced stress tolerance. In conclusion, the construct ProH11::HAHB11 resulted in an interesting and relevant biotechnological tool to improve biomass and yield. Further studies with enhancers or other crops would give a complete comparative scenario.