Mevalonate kinase represses anthocyanin biosynthesis via sucrose transporters and gibberellin synthesis pathways in arabidopsis

KEY MESSAGE: Arabidopsis MVK negatively regulates sucrose-induced anthocyanin accumulation by modulating SUC1-mediated sucrose transport and gibberellin homeostasis. Anthocyanins are flavonoid pigments that function as crucial modulators of plant responses to environmental stressors by mitigating oxidative damage and facilitating cellular adaptation. Anthocyanin biosynthesis is tightly regulated by transcriptional networks that respond to developmental cues and external stimuli. In this study, we identify mevalonate kinase (MVK), a critical enzyme in the cytosolic isoprenoid biosynthesis pathway, as a repressor of sucrose-induced anthocyanin production in arabidopsis. Loss-of-function mvk-1 mutants show increased anthocyanin levels compared to wild-type (WT) plants under high-sucrose conditions. The expression of anthocyanin biosynthetic and regulatory genes, such as CHS, DFR, and MYB75/PAP1, increases in mvk-1 mutants grown in the presence of high sucrose, and mvk-1 mutants exhibit elevated sucrose accumulation through the upregulation of sucrose transporters compared to WT under high-sucrose conditions. Furthermore, reduced gibberellic acid (GA) in mvk-1 mutants resulted in stabilization of repressors of GA signaling, known as DELLA proteins, thereby facilitating sucrose-induced anthocyanin accumulation. Our findings suggest that MVK negatively regulates sucrose-induced anthocyanin biosynthesis by modulating sucrose transport and GA homeostasis in arabidopsis.