title: McMYB12 Transcription Factors Co-regulate Proanthocyanidin and Anthocyanin Biosynthesis in Malus Crabapple.
abstract: The flavonoid compounds, proanthocyanidins (PAs), protect plants from biotic stresses, contribute to the taste of many fruits, and are beneficial to human health in the form of dietary antioxidants. In this study, we functionally characterized two Malus crabapple R2R3-MYB transcription factors, McMYB12a and McMYB12b, which co-regulate PAs and anthocyanin biosynthesis. McMYB12a was shown to be mainly responsible for upregulating the expression of anthocyanin biosynthetic genes by binding to their promoters, but to be only partially responsible for regulating PAs biosynthetic genes. In contrast, McMYB12b showed preferential binding to the promoters of PAs biosynthetic genes. Overexpression of McMYB12a and McMYB12b in tobacco (Nicotiana tabacum) altered the expression of flavonoid biosynthetic genes and promoted the accumulation of PAs and anthocyanins in tobacco petals. Conversely, transient silencing their expression in crabapple plants, using a conserved gene region, resulted in reduced PAs and anthocyanin production a green leaf phenotype. Meanwhile, transient overexpression of the two genes and silenced McMYB12s in apple (Malus domestica) fruit had a similar effect as overexpression in tobacco and silenced in crabapple. This study reveals a new mechanism for the coordinated regulation of PAs and anthocyanin accumulation in crabapple leaves, which depends on an auto-regulatory balance involving McMYB12a and McMYB12b expression.
authors.affiliation: Department of Plant Science and Technology, Beijing University of Agriculture, Beijing, China.|Key Laboratory of New Technology in Agricultural Application of Beijing, Beijing University of Agriculture, Beijing, China.|Beijing Collaborative innovation center or eco-environmental improvement with forestry and fruit trees, Beijing, China.
authors.forename: Ji
authors.initials: J
authors.lastname: Tian
authors.affiliation: Department of Plant Science and Technology, Beijing University of Agriculture, Beijing, China.|Key Laboratory of New Technology in Agricultural Application of Beijing, Beijing University of Agriculture, Beijing, China.|Beijing Collaborative innovation center or eco-environmental improvement with forestry and fruit trees, Beijing, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Plant Science and Technology, Beijing University of Agriculture, Beijing, China.|Key Laboratory of New Technology in Agricultural Application of Beijing, Beijing University of Agriculture, Beijing, China.|Beijing Collaborative innovation center or eco-environmental improvement with forestry and fruit trees, Beijing, China.
authors.forename: Zhen-Yun
authors.initials: ZY
authors.lastname: Han
authors.affiliation: Department of Plant Science and Technology, Beijing University of Agriculture, Beijing, China.|Key Laboratory of New Technology in Agricultural Application of Beijing, Beijing University of Agriculture, Beijing, China.|Beijing Collaborative innovation center or eco-environmental improvement with forestry and fruit trees, Beijing, China.
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Song
authors.affiliation: Department of Plant Science and Technology, Beijing University of Agriculture, Beijing, China.|Key Laboratory of New Technology in Agricultural Application of Beijing, Beijing University of Agriculture, Beijing, China.|Beijing Collaborative innovation center or eco-environmental improvement with forestry and fruit trees, Beijing, China.
authors.forename: Jin-Yan
authors.initials: JY
authors.lastname: Li
authors.affiliation: Department of Plant Science and Technology, Beijing University of Agriculture, Beijing, China.|Key Laboratory of New Technology in Agricultural Application of Beijing, Beijing University of Agriculture, Beijing, China.|Beijing Collaborative innovation center or eco-environmental improvement with forestry and fruit trees, Beijing, China.
authors.forename: Ya-Ru
authors.initials: YR
authors.lastname: Wang
authors.affiliation: Department of Plant Science and Technology, Beijing University of Agriculture, Beijing, China.|Key Laboratory of New Technology in Agricultural Application of Beijing, Beijing University of Agriculture, Beijing, China.|Beijing Collaborative innovation center or eco-environmental improvement with forestry and fruit trees, Beijing, China.
authors.forename: Yun-Cong
authors.initials: YC
authors.lastname: Yao
mesh_terms: D000595:Amino Acid Sequence; D000872:Anthocyanins / Q000096:biosynthesis*; D001665:Binding Sites; D053898:Biosynthetic Pathways; D005419:Flavonoids / Q000096:biosynthesis; D018506:Gene Expression Regulation, Plant; D020868:Gene Silencing; D027845:Malus / Q000145:classification / Q000502:physiology*; D010641:Phenotype; D018515:Plant Leaves / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D044945:Proanthocyanidins / Q000096:biosynthesis*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D014157:Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D000872:Anthocyanins; D005419:Flavonoids; D010940:Plant Proteins; D044945:Proanthocyanidins; D014157:Transcription Factors; C013221:proanthocyanidin