title: MdMYB1 Regulates Anthocyanin and Malate Accumulation by Directly Facilitating Their Transport into Vacuoles in Apples.
abstract: Tonoplast transporters, including proton pumps and secondary transporters, are essential for plant cell function and for quality formation of fleshy fruits and ornamentals. Vacuolar transport of anthocyanins, malate, and other metabolites is directly or indirectly dependent on the H(+)-pumping activities of vacuolar H(+)-ATPase (VHA) and/or vacuolar H(+)-pyrophosphatase, but how these proton pumps are regulated in modulating vacuolar transport is largely unknown. Here, we report a transcription factor, MdMYB1, in apples that binds to the promoters of two genes encoding the B subunits of VHA, MdVHA-B1 and MdVHA-B2, to transcriptionally activate its expression, thereby enhancing VHA activity. A series of transgenic analyses in apples demonstrates that MdMYB1/10 controls cell pH and anthocyanin accumulation partially by regulating MdVHA-B1 and MdVHA-B2. Furthermore, several other direct target genes of MdMYB10 are identified, including MdVHA-E2, MdVHP1, MdMATE-LIKE1, and MdtDT, which are involved in H(+)-pumping or in the transport of anthocyanins and malates into vacuoles. Finally, we show that the mechanism by which MYB controls malate and anthocyanin accumulation in apples also operates in Arabidopsis (Arabidopsis thaliana). These findings provide novel insights into how MYB transcription factors directly modulate the vacuolar transport system in addition to anthocyanin biosynthesis, consequently controlling organ coloration and cell pH in plants.
authors.affiliation: State Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China (D.-G.H., C.-H.S., Q.-J.M., C.-X.Y., Y.-J.H.); andDepartment of Horticulture, Cornell University, Ithaca, New York 14853 (L.C.).
authors.forename: Da-Gang
authors.initials: DG
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China (D.-G.H., C.-H.S., Q.-J.M., C.-X.Y., Y.-J.H.); andDepartment of Horticulture, Cornell University, Ithaca, New York 14853 (L.C.).
authors.forename: Cui-Hui
authors.initials: CH
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China (D.-G.H., C.-H.S., Q.-J.M., C.-X.Y., Y.-J.H.); andDepartment of Horticulture, Cornell University, Ithaca, New York 14853 (L.C.).
authors.forename: Qi-Jun
authors.initials: QJ
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China (D.-G.H., C.-H.S., Q.-J.M., C.-X.Y., Y.-J.H.); andDepartment of Horticulture, Cornell University, Ithaca, New York 14853 (L.C.).
authors.forename: Chun-Xiang
authors.initials: CX
authors.lastname: You
authors.affiliation: State Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China (D.-G.H., C.-H.S., Q.-J.M., C.-X.Y., Y.-J.H.); andDepartment of Horticulture, Cornell University, Ithaca, New York 14853 (L.C.).
authors.forename: Lailiang
authors.identifier: http://orcid.org/0000-0003-1759-9761
authors.initials: L
authors.lastname: Cheng
authors.affiliation: State Key Laboratory of Crop Biology, National Research Center for Apple Engineering and Technology, College of Horticulture Science and Engineering, Shandong Agricultural University, Tai-An, Shandong 271018, China (D.-G.H., C.-H.S., Q.-J.M., C.-X.Y., Y.-J.H.); andDepartment of Horticulture, Cornell University, Ithaca, New York 14853 (L.C.) haoyujin@sdau.edu.cn.
authors.forename: Yu-Jin
authors.initials: YJ
authors.lastname: Hao
mesh_terms: D000872:Anthocyanins / Q000378:metabolism*; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites / Q000235:genetics; D001693:Biological Transport, Active; D017343:Genes, Plant; D006863:Hydrogen-Ion Concentration; D008293:Malates / Q000378:metabolism*; D027845:Malus / Q000235:genetics / Q000378:metabolism*; D008954:Models, Biological; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D021122:Protein Subunits; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D025262:Vacuolar Proton-Translocating ATPases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014617:Vacuoles / Q000378:metabolism
chemical_list: D000872:Anthocyanins; D008293:Malates; D010940:Plant Proteins; D021122:Protein Subunits; D014157:Transcription Factors; C030298:malic acid; D025262:Vacuolar Proton-Translocating ATPases