Functional diversity at the Rc (red coleoptile) gene in bread wheat

The presence of the allele Rc-A1b on chromosome 7A specified the expression profile of the F3h-1 (encoding flavanone 3-hydroxylase) genes and anthocyanin pigmentation in coleoptiles of Russian bread wheat cultivar 'Saratovskaya 29'. A quantitative RT-PCR analysis compared the temporal expression profile of F3h-A1, F3h-B1, and F3h-D1 in the coleoptiles of 'Saratovskaya 29' and the standard cytogenetic stock 'Chinese Spring' ('Hope' 7A), both of which carry Rc-A1b. There was no within-genotype variation for expression level of the F3h-1 homoeologues at any of the sampling times, but the expression profiles varied markedly between the two genotypes. This result suggested that there may be functional allelic diversity at Rc-A1, which affects the transcription of the F3h-1 genes in colored coleoptiles. Microsatellite-based genetic mapping was used to locate Rc-A1 along with the new loci Pc-A1 (purple culm), Plb-A1 (purple leaf blade), and Pls-A1 (purple leaf sheath) in a single cluster on the short arm of chromosome 7A.