A Novel Ah-miR2916-AhERF13-AhSUC3 Module Regulates Al Tolerance via Ethylene-Mediated Signaling in Peanut (Arachnis hypogea L).

Abstract

Aluminum (Al) toxicity in acidic soils leads to a considerable reduction in crop yields. MicroRNAs play essential roles in abiotic stress responses, but little is known of their role in the response of peanut (Arachnis hypogea L.) to Al stress. In this study, a novel Ah-miR2916 (miR2916)-AhERF13-AhSUC3 module was found to be involved in the Al-stress response via ethylene-mediated signaling in peanut. Overexpression of miR2916 in Arabidopsis resulted in reduced Al tolerance by downregulating ethylene biosynthesis, while knockdown miR2916 in peanut enhanced Al tolerance. Notably, the APETALA2/ethylene-responsive factor (ERF), AhERF13, was identified as a potential target of miR2916. AhERF13 expression was increased in miR2916 knockdown peanut lines and displayed an opposing pattern to that of miR2916 under Al stress. Consistently, knockdown AhERF13 peanut lines indicated that AhERF13 positively regulates Al tolerance by upregulating ethylene biosynthesis. AhERF13 was shown capable of binding to an ERF motif in the promoter region of sucrose transport protein 3 (AhSUC3) and positively regulate its expression. Consequently, AhSUC3 improved Al tolerance by upregulating ethylene biosynthesis. These results provide further insights into the molecular mechanisms operating during peanut response to Al stress, and suggests targets for manipulation in breeding programs for improved Al tolerance.