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Apple MPK4 mediates phosphorylation of MYB1 to enhance light-induced anthocyanin accumulation |
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| Authors: | Tuo Yang Huaying Ma Yu Li Yan Zhang Jie Zhang Ting Wu Tingting Song Yuncong Yao Ji Tian |
| Affiliation: | 1. Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing, China Plant Science and Technology College, Beijing University of Agriculture, Beijing, China These authors contributed equally to this work.;2. Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing, China Plant Science and Technology College, Beijing University of Agriculture, Beijing, China;3. College of Horticulture, China Agricultural University, Beijing, China;4. Plant Science and Technology College, Beijing University of Agriculture, Beijing, China;5. Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing University of Agriculture, Beijing, China |
| Abstract: | Anthocyanins are plant pigments with diverse biological functions that contribute to fruit quality and are beneficial to human health. Anthocyanin accumulation can be influenced by environmental signals, such as light, and plants have developed sophisticated systems to receive and transduce these signals. However, the associated molecular mechanisms are not well understood. In this study, we investigated the potential function of mitogen-activated protein kinases, which are members of the light signaling pathway, during light-induced anthocyanin accumulation in apple (Malus domestica) fruit peels. An antibody array and yeast two-hybrid screen indicated that proteins encoded by two MdMPK4 genes are light-activated and interact with the transcription factor and anthocyanin biosynthesis regulator MdMYB1. A phosphorylation assay showed that the MdMPK4 proteins phosphorylate MdMYB1, thereby increasing its stability under light conditions. Transient MdMPK4 and MdMYB1 overexpression assays further revealed that light-induced anthocyanin accumulation relies on MdMPK4 kinase activity, which is required for maximum MdMYB1 activity. Based on the expression of the chromosome 6 allele MdMPK4-06G under light conditions and the presence of light response elements in the MdMPK4-06G promoter, we concluded that it is more responsive to light than the chromosome 14 allele MdMPK4-14G. These results suggest a potential biotechnological strategy for increasing fruit anthocyanin content via light induction. |
| Keywords: | light Malus domestica anthocyanin MPK4 protein phosphorylation |