title: An ancient duplication of apple MYB transcription factors is responsible for novel red fruit-flesh phenotypes.
abstract: Anthocyanin accumulation is coordinated in plants by a number of conserved transcription factors. In apple (Malus × domestica), an R2R3 MYB transcription factor has been shown to control fruit flesh and foliage anthocyanin pigmentation (MYB10) and fruit skin color (MYB1). However, the pattern of expression and allelic variation at these loci does not explain all anthocyanin-related apple phenotypes. One such example is an open-pollinated seedling of cv Sangrado that has green foliage and develops red flesh in the fruit cortex late in maturity. We used methods that combine plant breeding, molecular biology, and genomics to identify duplicated MYB transcription factors that could control this phenotype. We then demonstrated that the red-flesh cortex phenotype is associated with enhanced expression of MYB110a, a paralog of MYB10. Functional characterization of MYB110a showed that it was able to up-regulate anthocyanin biosynthesis in tobacco (Nicotiana tabacum). The chromosomal location of MYB110a is consistent with a whole-genome duplication event that occurred during the evolution of apple within the Maloideae family. Both MYB10 and MYB110a have conserved function in some cultivars, but they differ in their expression pattern and response to fruit maturity.
authors.affiliation: New Zealand Institute for Plant and Food Research Limited , Palmerston North Research Centre, Palmerston North 4442, New Zealand. david.chagne@plantandfood.co.nz
authors.forename: David
authors.initials: D
authors.lastname: Chagné
authors.forename: Kui
authors.initials: K
authors.lastname: Lin-Wang
authors.forename: Richard V
authors.initials: RV
authors.lastname: Espley
authors.forename: Richard K
authors.initials: RK
authors.lastname: Volz
authors.forename: Natalie M
authors.initials: NM
authors.lastname: How
authors.forename: Simon
authors.initials: S
authors.lastname: Rouse
authors.forename: Cyril
authors.initials: C
authors.lastname: Brendolise
authors.forename: Charmaine M
authors.initials: CM
authors.lastname: Carlisle
authors.forename: Satish
authors.initials: S
authors.lastname: Kumar
authors.forename: Nihal
authors.initials: N
authors.lastname: De Silva
authors.forename: Diego
authors.initials: D
authors.lastname: Micheletti
authors.forename: Tony
authors.initials: T
authors.lastname: McGhie
authors.forename: Ross N
authors.initials: RN
authors.lastname: Crowhurst
authors.forename: Roy D
authors.initials: RD
authors.lastname: Storey
authors.forename: Riccardo
authors.initials: R
authors.lastname: Velasco
authors.forename: Roger P
authors.initials: RP
authors.lastname: Hellens
authors.forename: Susan E
authors.initials: SE
authors.lastname: Gardiner
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Allan
mesh_terms: D000872:Anthocyanins / Q000096:biosynthesis; D001483:Base Sequence; D001947:Breeding; D002851:Chromatography, High Pressure Liquid; D002874:Chromosome Mapping; D032461:Chromosomes, Plant / Q000235:genetics / Q000378:metabolism; D019143:Evolution, Molecular; D005638:Fruit / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D020440:Gene Duplication; D018506:Gene Expression Regulation, Plant; D018745:Genome, Plant; D027845:Malus / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D008969:Molecular Sequence Data; D010641:Phenotype; D010802:Phylogeny; D010858:Pigmentation; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D040641:Quantitative Trait Loci; D016415:Sequence Alignment; D013045:Species Specificity; D014026:Nicotiana / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D000872:Anthocyanins; D010940:Plant Proteins; D014157:Transcription Factors