Anthocyanins play diverse roles in plant physiology and stress adaptation.In Arabidopsis,the MYB–bHLH–WD40(MBW)complex has a crucial role in the regulation of anthocyanin synthesis.Here,we report that the R2R3-MYB t...Anthocyanins play diverse roles in plant physiology and stress adaptation.In Arabidopsis,the MYB–bHLH–WD40(MBW)complex has a crucial role in the regulation of anthocyanin synthesis.Here,we report that the R2R3-MYB transcription factor MYB30 and the ubiquitin E3 ligase RHA2b participate in anthocyanin biosynthesis through regulation of the MBW complex.MYB30 was found to negatively regulate sucrose-induced anthocyanin biosynthesis in Arabidopsis seedlings.Expression of multiple genes involved inflavo-noid or anthocyanin biosynthesis was affected in the myb30 mutant,and MYB30 directly repressed the expression of MYB75,which encodes a core component of the MBW complex,by binding to its promoter.Moreover,MYB30 physically interacted with MYB75 to inhibit its activity by repressing MBW complex as-sembly.In addition,sucrose treatment signicantly promoted MYB30 degradation via the action of RHA2b.The ubiquitination and degradation of MYB30 were signicantly attenuated in the rha2b mutant un-der high-sucrose treatment,and further analysis showed that MYB75 directly promoted RHA2b expression in response to high sucrose.Our work thus reveals an anthocyanin biosynthetic regulatory module,RHA2b–MYB30,that controls the function of the MBW complex via MYB75.The repression of MYB75 by MYB30 is released by MYB75-induced RHA2b expression,thus ensuring the self-activation of MYB75 when anthocy-anin synthesis is needed.展开更多
基金supported by the National Natural Science Foundation of China (grants 32170295 and 31870241 to H.Z.)the China Postdoctoral Science Foundation (grant 2023M730776 to J.H.)the Institutional Research Fund of Sichuan University (grant 2020SCUNL212 to H.L.).
文摘Anthocyanins play diverse roles in plant physiology and stress adaptation.In Arabidopsis,the MYB–bHLH–WD40(MBW)complex has a crucial role in the regulation of anthocyanin synthesis.Here,we report that the R2R3-MYB transcription factor MYB30 and the ubiquitin E3 ligase RHA2b participate in anthocyanin biosynthesis through regulation of the MBW complex.MYB30 was found to negatively regulate sucrose-induced anthocyanin biosynthesis in Arabidopsis seedlings.Expression of multiple genes involved inflavo-noid or anthocyanin biosynthesis was affected in the myb30 mutant,and MYB30 directly repressed the expression of MYB75,which encodes a core component of the MBW complex,by binding to its promoter.Moreover,MYB30 physically interacted with MYB75 to inhibit its activity by repressing MBW complex as-sembly.In addition,sucrose treatment signicantly promoted MYB30 degradation via the action of RHA2b.The ubiquitination and degradation of MYB30 were signicantly attenuated in the rha2b mutant un-der high-sucrose treatment,and further analysis showed that MYB75 directly promoted RHA2b expression in response to high sucrose.Our work thus reveals an anthocyanin biosynthetic regulatory module,RHA2b–MYB30,that controls the function of the MBW complex via MYB75.The repression of MYB75 by MYB30 is released by MYB75-induced RHA2b expression,thus ensuring the self-activation of MYB75 when anthocy-anin synthesis is needed.
