The sunflower transcription factor HaWRKY76 confers drought and flood tolerance to Arabidopsis thaliana plants without yield penalty

RAINERI J; RIBICHICH KF; CHAN RL

PLANT CELL REPORTS

SPRINGER

Lugar: Berlin; Año: 2015 vol. 34 p. 2065 - 2080

0721-7714

Waterdeficit and water excess are abiotic stress factors that seriously affect cropsworldwide. To increase the tolerance to such stresses without causing yieldpenalty, constitutes a major goal for biotechnologists. In this survey, wereport that HaWRKY76, a divergent sunflower WRKY transcription factor, is ableto confer both dehydration and submergence tolerance to Arabidopsis transgenic plantswithout yield penalty. The expression pattern of HaWRKY76 was analyzed in plants grown in standard conditions andunder different watering regimes indicating a regulation by water availability.The corresponding cDNA was isolated and cloned under the control of aconstitutive promoter and Arabidopsis plants were transformed with thisconstruct. These transgenic plants presented higher biomass, seed production andsucrose content than controls in standard growth conditions. Moreover, they exhibitedtolerance to mild drought or flood (complete submergence/waterlogging) stressesas well as the same or increased yield, depending on the stress severity andplant developmental stage, compared with controls. Drought tolerance occurredvia an ABA-independent mechanism and induction of stomatal closure. Submergencetolerance can be explained by the carbohydrate (sucrose and starch) preservationachieved through the repression of fermentation pathways. Higher cell membranestability and chlorenchyma maintenance could be the nexus between tolerance responsesin front of both stresses. Altogether, the obtained results indicated that HaWRKY76can be a potential biotechnological tool to improve crops yield as well as droughtand flood tolerances.