CONICET | Buscador de Institutos y Recursos Humanos

HaHB11 is amember of the sunflower homeodomain-leucine zipper I subfamily of transcriptionfactors. The analysis of a sunflower microarray hybridized with RNA from HaHB11-transformed leaf-disks indicatedthe regulation of many genes encoding enzymes from glycolisis and fermentativepathways. A 1300 bp promoter sequence, fused to the GUS reporter gene, was used to transform Arabidopsis plants showingan induction of expression after flooding treatments, concurrently with HaHB11 regulation by submergence insunflower. Furthermore, Arabidopsis transgenic plants expressing HaHB11 were obtained exhibitingsignificant increases in rosette and stem biomass concomitantly with notablehigher seeds yield compared to controls. These transgenic plants also exhibitedtolerance to flooding stress, both to submergence and waterlogging. Carbohydratescontents were higher in the transgenics compared to wild type and decreasedless after submergence treatments. Finally, transcript levels of selected genesinvolved in glycolisis and fermentative pathways as well as the correspondingenzymatic activities were assessed both, in sunflower and transgenicArabidopsis plants, before and after submergence. Altogether, the present work leadsus to propose HaHB11 as a biotechnological tool to improve crops yield, biomassand flooding tolerance.