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.

Cloning and Characterization of a Critical Regulator for Preharvest Sprouting in Wheat

“…recently (Himi et al 2011). In this study, both parents of the mapping populations are white wheat, suggesting that major differences in PHS resistance are independent of grain color.…”

“…Red color pericarp/testa has been used as a genetic marker for selecting PHS resistance (Gale and Lenton 1987;Groos et al 2002;Himi et al 2002). Several other DNA markers for grain color genes have been developed recently (Himi et al 2011). In this study, both parents of the mapping populations are white wheat, suggesting that major differences in PHS resistance are independent of grain color.…”

TaMYB3, encoding a functional MYB transcriptor, isolated from the purple pericarp of Triticum aestivum

“…R and Rc occur on chromosomes 3 and 7, respectively (Himi et al 2011;Himi and Taketa 2015;Wang et al 2016), and Pp1 and Pp3, which control the purple grain trait, are located on chromosomes 7B and 2A, respectively (Khlestkina et al 2010). Therefore, the chromosomal site of TaMYB3 is clearly inconsistent with the chromosomal locations of the two complementary genes responsible for the purple grain trait of wheat.…”

“…Similar functional MYB regulators also exist in Arabidopsis (AtMYB75 [PAP1]) and AtMYB90 [PAP2]) (Borevitz et al 2000), petunia (AN2) (Quattrocchio et al 1999), sweet potato (MYB1) (Mano et al 2007), legumes (LAP1) (Peel et al 2009), and Epimedium sagitta tum (EsMYBA1) (Huang et al 2013). Among the genes associated with anthocyanin biosynthesis in Triticum aestivum, the red grain (R) and red coleoptile (Rc) genes have been shown to encode R2R3-MYB transcription factors that regulate proanthocyanidin and anthocyanin biosynthesis in grains and coleoptiles, respectively (Himi et al 2011;Himi and Taketa 2015;Wang et al 2016). The candidate gene for the purple pericarp trait in common wheat, Pp3, is the basic helix-loop-helix (bHLH) transcriptor TaMYC1 (Shoeva et al 2014;Liu et al 2016), and the Pp1 genes are thought to be orthologues of maize C1 and rice OsC1, which encode MYB-like transcription factors responsible for the activation of the structural genes encoding various enzymes that participate in anthocyanin synthesis (Saitoh et al 2004;Khlestkina 2013).…”

Approaches to improve wheat grain quality: breeding for falling number

“…Краснозерность контролируют доминантные аллели, а белозерность -рецессивные аллели R-генов, локали-зованные на длинных плечах хромосом третьей группы: (Mc��ntosh et al, 2008). Доминантные R-аллели представляют собой Myb-подобные факторы транскрипции, регулирующие экспрессию генов биосин-теза флавоноидов Сhs, Chi, F3h и Dfr (Himi et al, 2005(Himi et al, , 2011Хлесткина, 2012). Положительная роль окраски зерна в УкПП подтверждается исследованиями на почти изогенных линиях, мутантах (Warner et al, 2000;Himi et al, 2002), трансгенных растениях (Liu et al, 2013), однако молекулярные механизмы этого явления не ясны.…”