title: Anthocyanin leaf markings are regulated by a family of R2R3-MYB genes in the genus Trifolium.
abstract: Anthocyanin pigments accumulate to form spatially restricted patterns in plants, particularly in flowers, but also occur in vegetative tissues. Spatially restricted anthocyanin leaf markings are poorly characterised in plants, but are common in forage legumes. We hypothesised that the molecular basis for anthocyanin leaf markings in Trifolium spp. is due to the activity of a family of R2R3-MYB genes. R2R3-MYB genes were identified that are associated with the two classic pigmentation loci in T. repens. The R locus patterns 'red leaf', 'red midrib' and 'red fleck' are conditioned by a single MYB gene, RED LEAF. The 'diffuse red leaf' trait is regulated by the RED LEAF DIFFUSE MYB gene. The V locus was identified through mapping two V-linked traits, 'V-broken yellow' (Vby) and 'red leaflet' (Vrl). Two highly similar R2R3-MYB genes, RED V-a and RED V-b, mapped to the V locus and co-segregated with the RED V pigmentation pattern. Functional characterisation of RED LEAF and RED V was performed, confirming their function as anthocyanin regulators and identifying a C-terminal region necessary for transactivation. The mechanisms responsible for generating anthocyanin leaf markings in T. repens provide a valuable system to compare with mechanisms that regulate complex floral pigmentation.
authors.affiliation: AgResearch Limited, Private Bag 11008, Palmerston North, 4442, New Zealand; Plant & Food Research Limited, Private Bag 11-600, Palmerston North, 4442, New Zealand.
authors.forename: Nick W
authors.initials: NW
authors.lastname: Albert
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Griffiths
authors.forename: Greig R
authors.initials: GR
authors.lastname: Cousins
authors.forename: Isabelle M
authors.initials: IM
authors.lastname: Verry
authors.forename: Warren M
authors.initials: WM
authors.lastname: Williams
mesh_terms: D000872:Anthocyanins / Q000235:genetics* / Q000378:metabolism; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D020570:Genes, myb; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D010858:Pigmentation / Q000235:genetics; D018515:Plant Leaves / Q000378:metabolism / Q000502:physiology*; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D014026:Nicotiana / Q000235:genetics; D029921:Trifolium / Q000235:genetics* / Q000378:metabolism*
chemical_list: D000872:Anthocyanins; D051792:Basic Helix-Loop-Helix Proteins; D010940:Plant Proteins
keywords: WD-repeat (WDR); WD40; basic-helix-loop-helix (bHLH); clover (Trifolium); flavonoid; legume; transcription factor