title: Development of PCR markers for Tamyb10 related to R-1, red grain color gene in wheat.
abstract: The grain color of wheat affects not only the brightness of flour, but also tolerance to preharvest sprouting. Grain color is controlled by dominant R-1 genes located on the long arm of hexaploid wheat chromosomes 3A, 3B, and 3D (R-A1, R-B1, and R-D1, respectively). The red pigment of the grain coat is composed of catechin and proanthocyanidin (PA), which are synthesized via the flavonoid biosynthetic pathway. We isolated the Tamyb10-A1, Tamyb10-B1, and Tamyb10-D1 genes, located on chromosomes 3A, 3B, and 3D, respectively. These genes encode R2R3-type MYB domain proteins, similar to TT2 of Arabidopsis, which controls PA synthesis in testa. In recessive R-A1 lines, two types of Tamyb10-A1 genes: (1) deletion of the first half of the R2-repeat of the MYB region and (2) insertion of a 2.2-kb transposon belonging to the hAT family. The Tamyb10-B1 genes of recessive R-B1 lines had 19-bp deletion, which caused a frame shift in the middle part of the open reading frame. With a transient assay using wheat coleoptiles, we revealed that the Tamyb10 gene in the dominant R-1 allele activated the flavonoid biosynthetic genes. We developed PCR-based markers to detect the dominant/recessive alleles of R-A1, R-B1, and R-D1. These markers proved to be correlated to known R-1 genotypes of 33 varieties except for a mutant with a single nucleotide substitution. Furthermore, double-haploid (DH) lines derived from the cross between red- and white-grained lines were found to necessarily carry functional Tamyb10 gene(s). Thus, PCR-based markers for Tamyb10 genes are very useful to detect R-1 alleles.
authors.affiliation: Institute of Plant Science and Resources, Okayama University, 2-20-1 Chuo, Kurashiki, Okayama, Japan. eikohimi@server.rib.okayama-u.ac.jp
authors.forename: Eiko
authors.initials: E
authors.lastname: Himi
authors.forename: Masahiko
authors.initials: M
authors.lastname: Maekawa
authors.forename: Hideho
authors.initials: H
authors.lastname: Miura
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Noda
mesh_terms: D002392:Catechin / Q000096:biosynthesis / Q000378:metabolism; D003433:Crosses, Genetic; D017931:DNA Primers / Q000235:genetics; D002523:Edible Grain / Q000502:physiology*; D016368:Frameshift Mutation / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics*; D005819:Genetic Markers / Q000235:genetics*; D005838:Genotype; D010858:Pigmentation / Q000235:genetics* / Q000502:physiology; D044945:Proanthocyanidins / Q000096:biosynthesis / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014908:Triticum / Q000235:genetics* / Q000502:physiology
chemical_list: D017931:DNA Primers; D005819:Genetic Markers; D044945:Proanthocyanidins; C013221:proanthocyanidin; D002392:Catechin