OsADR3 increases drought stress tolerance by inducing antioxidant defense mechanisms and regulating OsGPX1 in rice (Oryza sativa L.)

The C (Cys) 2H (His) 2-type transcription factor is one of the most important transcription factors in plants and plays a regulatory role in the physiological responses of rice to abiotic stresses. A novel rice C2H2-type zinc finger protein, abscisic acid (ABA)-drought-reactive oxygen species (ROS) 3 (OsADR3), was found to confer drought stress tolerance by enhancing antioxidant defense and regulating OsGPX1. Overexpression of OsADR3 in rice increased tolerance to drought stress by increasing ROS scavenging ability and ABA sensitivity. In contrast, CRISPR/Cas9-mediated knockout of osadr3 increased the sensitivity of rice to drought and oxidative stress. An exogenous ROS-scavenging reagent restored the drought-stress tolerance of osadr3-CRISPR plants. Global transcriptome analysis suggested that OsADR3 increased the expression of OsGPX1 under drought stress. Electrophoretic mobility shift, yeast one-hybrid, and dual-luciferase reporter assays revealed that OsADR3 modified the expression of OsGPX1 by directly binding to its promoter. Knockdown of OsGPX1 repressed ROS scavenging ability under drought stress in OsADR3-overexpression plants. These findings suggest that OsADR3 plays a positive regulatory role in drought-stress tolerance by inducing antioxidant defense and associated with the ABA signaling pathway in rice.