MdCOP1 Ubiquitin E3 Ligases Interact with MdMYB1 to Regulate Light-Induced Anthocyanin Biosynthesis and Red Fruit Coloration in Apple

• Published in: Plant physiology (Bethesda) 2012-10, Vol.160 (2), p.1011-1022
• Main Authors: Li, Yuan-Yuan, Mao, Ke, Zhao, Cheng, Zhao, Xian-Yan, Zhang, Hua-Lei, Shu, Huai-Rui, Hao, Yu-Jin
• Format: Article
• Language: English
• Subjects: Anthocyanins - biosynthesis; Antibodies; Arabidopsis - enzymology; Arabidopsis - genetics; Biological and medical sciences; Biosynthesis; Callus; Cloning, Molecular - methods; Color; Colors; Darkness; DNA, Complementary - genetics; DNA, Complementary - metabolism; Enzyme Activation; Enzyme Assays; Fruit - enzymology; Fundamental and applied biological sciences. Psychology; Gene expression regulation; Gene Expression Regulation, Plant; Genes; Genes, Plant; Genetic Vectors - genetics; Genetic Vectors - metabolism; Immunoprecipitation; Malus - enzymology; Malus - genetics; Malus - radiation effects; Monoclonal antibodies; Pigmentation; Plant cells; Plant physiology and development; Plants; Plants, Genetically Modified - enzymology; Plants, Genetically Modified - genetics; Proteasome Endopeptidase Complex - genetics; Proteasome Endopeptidase Complex - metabolism; Protein Interaction Mapping; Protein Stability; Proteolysis; SYSTEMS BIOLOGY, MOLECULAR BIOLOGY, AND GENE REGULATION; Transcription Factors - genetics; Transcription Factors - metabolism; Transgenic plants; Two-Hybrid System Techniques; Ubiquitin-Protein Ligases - genetics; Ubiquitin-Protein Ligases - metabolism; Ubiquitination
• ISSN: 0032-0889; 1532-2548; 1532-2548
• DOI: 10.1104/pp.112.199703

MdMYB1 is a crucial regulator of light-induced anthocyanin biosynthesis and fruit coloration in apple (Malus domestica). In this study, it was found that MdMYB1 protein accumulated in the light but degraded via a ubiquitin-dependent pathway in the dark. Subsequently, the MdCOP1-1 and MdCOP1-2 genes were isolated from apple fruit peel and were functionally characterized in the Arabidopsis (Arabidopsis thaliana) cop1-4 mutant. Yeast (Saccharomyces cerevisiae) two-hybrid, bimolecular fluorescence complementation, and coimmunoprecipitation assays showed that MdMYBl interacts with the MdCOP1 proteins. Furthermore, in vitro and in vivo experiments indicated that MdCOP1s are necessary for the ubiquitination and degradation of MdMYB1 protein in the dark and are therefore involved in the light-controlled stability of the MdMYB1 protein. Finally, a viral vectorbased transformation approach demonstrated that MdCOP1s negatively regulate the peel coloration of apple fruits by modulating the degradation of the MdMYB1 protein. Our findings provide new insight into the mechanism by which light controls anthocyanin accumulation and red fruit coloration in apple and even other plant species.