Gibberellins Modulate Abiotic Stress Tolerance in Plants

Abstract

Gibberellins (GAs) are important plant hormones that regulate diverse aspects of plant growth and development. Recent studies suggest that GAs are also actively involved in biotic and abiotic stress responses. However, the genetic evidence and underlying mechanism for the roles of GAs in the response to abiotic stress are still not well dissected. Our previous study has demonstrated that the rice EUI1 P450 epoxidizes the active gibberellins in a novel deactivation reaction and is involved in basal disease resistance in rice. Here, we further found that the eui1 loss-of-function mutant decreased salt tolerance compared to the wild-type control, while overexpression of EUI1 both in rice and Arabidopsis dramatically increased salt tolerance. Consistent with the finding, the eui1 mutant with higher level of GA was less sensitive to abscisic acid (ABA), and the transgenic Arabidopsis and rice plants which constitutively express EUI1 and result in GA deficiency were hypersensitive to ABA. We proposed that GAs play a role in abiotic stress response probably through modulating the ABA signaling pathway.