title: A group of grapevine MYBA transcription factors located in chromosome 14 control anthocyanin synthesis in vegetative organs with different specificities compared with the berry color locus.
abstract: Grapevine organs accumulate anthocyanins in a cultivar-specific and environmentally induced manner. The MYBA1-A2 genes within the berry color locus in chromosome 2 represent the major genetic determinants of fruit color. The simultaneous occurrence of transposon insertions and point mutations in these genes is responsible for most white-skinned phenotypes; however, the red pigmentation found in vegetative organs suggests the presence of additional regulators. This work describes a genomic region of chromosome 14 containing three closely related R2R3-MYB genes, named MYBA5, MYBA6 and MYBA7. Ectopic expression of the latter two genes in grapevine hairy roots promoted anthocyanin accumulation without affecting other phenylpropanoids. Transcriptomic profiling of hairy roots expressing MYBA1, MYBA6 and MYBA7 showed that these regulators share the activation of late biosynthetic and modification/transport-related genes, but differ in the activation of the FLAVONOID-3'5'-HYDROXYLASE (F3'5'H) family. An alternatively spliced MYBA6 variant was incapable of activating anthocyanin synthesis, however, because of the lack of an MYC1 interaction domain. MYBA1, MYBA6.1 and MYBA7 activated the promoters of UDP-GLUCOSE:FLAVONOID 3-O-GLUCOSYLTRANSFERASE (UFGT) and ANTHOCYANIN 3-O-GLUCOSIDE-6″-O-ACYLTRANSFERASE (3AT), but only MYBA1 induced F3'5'H in concordance with the low proportion of tri-hydroxylated anthocyanins found in MYBA6-A7 hairy roots. This putative new color locus is related to the red/cyanidic pigmentation of vegetative organs in black- and white-skinned cultivars, and forms part of the UV-B radiation response pathway orchestrated by ELONGATED HYPOCOTYL 5 (HY5). These results demonstrate the involvement of additional anthocyanin regulators in grapevine and suggest an evolutionary divergence between the two grape color loci for controlling additional targets of the flavonoid pathway.
authors.affiliation: Center for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Barcelona, Spain.
authors.forename: José Tomás
authors.identifier: http://orcid.org/0000-0002-9196-1813
authors.initials: JT
authors.lastname: Matus
authors.affiliation: Department of Biotechnology, University of Verona, Verona, Italy.
authors.forename: Erika
authors.initials: E
authors.lastname: Cavallini
authors.affiliation: Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Santiago, Chile.|Departamento de Fruticultura y Enología, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Loyola
authors.affiliation: Centre for Organismal Studies Heidelberg (COS Heidelberg), Im Neuenheimer Feld 360, Heidelberg, 69120, Germany.
authors.forename: Janine
authors.initials: J
authors.lastname: Höll
authors.affiliation: Department of Biotechnology, University of Verona, Verona, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Finezzo
authors.affiliation: Department of Biotechnology, University of Verona, Verona, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Dal Santo
authors.affiliation: INRA, UMR1083 SPO, 2 place Viala, Montpellier, F-34060, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Vialet
authors.affiliation: Department of Biotechnology, University of Verona, Verona, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Commisso
authors.affiliation: Department of Agricultural, Forestry and Food Sciences, University of Turin, Largo Braccini 2, Grugliasco, 10095, Italy.
authors.forename: Federica
authors.initials: F
authors.lastname: Roman
authors.affiliation: Department of Agricultural, Forestry and Food Sciences, University of Turin, Largo Braccini 2, Grugliasco, 10095, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Schubert
authors.affiliation: Departamento de Fruticultura y Enología, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: José Antonio
authors.initials: JA
authors.lastname: Alcalde
authors.affiliation: Centre for Organismal Studies Heidelberg (COS Heidelberg), Im Neuenheimer Feld 360, Heidelberg, 69120, Germany.|Dienstleistungszentrum Ländlicher Raum (DLR) Rheinpfalz, Breitenweg 71, Viticulture and Enology group, Neustadt/W, D-67435, Germany.|Fachhochschule Bingen, Berlinstr. 109, Bingen am Rhein, D-55411, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Bogs
authors.affiliation: INRA, UMR1083 SPO, 2 place Viala, Montpellier, F-34060, France.
authors.forename: Agnès
authors.initials: A
authors.lastname: Ageorges
authors.affiliation: Department of Biotechnology, University of Verona, Verona, Italy.
authors.forename: Giovanni Battista
authors.initials: GB
authors.lastname: Tornielli
authors.affiliation: Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Patricio
authors.initials: P
authors.lastname: Arce-Johnson
mesh_terms: D000872:Anthocyanins / Q000096:biosynthesis* / Q000235:genetics; D032461:Chromosomes, Plant; D019143:Evolution, Molecular; D018506:Gene Expression Regulation, Plant; D010858:Pigmentation; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D027843:Vitis / Q000235:genetics / Q000378:metabolism*
chemical_list: D000872:Anthocyanins; D010940:Plant Proteins; D014157:Transcription Factors
keywords: 
  Vitis vinifera
  ; HY5; UV-B; flavonoids; light; tri-hydroxylated anthocyanins