OsAE7 Interacts With ZFP36 to Mediate Antioxidant Defense in Rice

Abscisic acid (ABA) plays a crucial role in plants' adaptation to drought and salinity. This study used Y2H (Yeast two-hybrid system), GST pull-down, and LCI (Firefly luciferase complementation imaging assay) approaches to reveal the role of the interaction between OsAE7 (asymmetric leaves1/2 enhancer 7) and ZFP36 (zinc finger protein 36) in rice. Subcellular localization analysis revealed that OsAE7 is localized in the nucleus. After treatment with ABA, H₂O₂, osmotic stress (polyethylene glycol, PEG), and NaCl, the expression level of OsAE7 genes in leaves has increased. Experiments with H₂O₂ scavenger (DMTU) and NADPH oxidase inhibitor (DPI) indicated that ABA induces the up-regulation of OsAE7 expression through increased ROS production. The OsAE7 gene knockout mutant osae7-KO was constructed using the CRISPR/Cas9 system and Agrobacterium-mediated method, and T₁ generation homozygous lines osae7-1 and osae7-2 were obtained. Under simulated stress with PEG and NaCl, the antioxidant defense enzyme activity, relative water content, and proline content of the osae7-KO mutant were significantly lower than those of the wild type, while the malondialdehyde content and relative plasma membrane permeability were significantly higher, indicating that the osae7-KO mutant has lower stress resistance. osae7-KO plants were also much less sensitive to ABA than the wild type. qRT-PCR analysis showed that the interaction with ZFP36 affects the induction of OsAE7 by ABA. In conclusion, OsAE7 is involved in the ABA signaling pathway and plays a role in the plant's response to drought and salt stresses.