Colour genes (R and Rc) for grain and coleoptile upregulate flavonoid biosynthesis genes in wheat.
Pigmentation of wheat grain and coleoptile is controlled by the R gene on chromosomes of the homoeologous group 3 and the Rc gene on chromosomes of the homoeologous group 7, respectively. Each of these genes is inherited monogenically. The pigment of grain has been suggested to be a derivative of catechin-tannin and that of coleoptile to be anthocyanin. These polyphenol compounds are known to be synthesized through the flavonoid biosynthesis pathway. We isolated 4 partial nucleotide sequences of the early flavonoid biosynthesis genes (CHS, CHI, F3H, and DFR) in wheat. The expression of these genes was examined in the developing grain of red-grained and white-grained wheat lines. CHS, CHI, F3H, and DFR were highly upregulated in the grain coat tissue of the red-grained lines, whereas there was no significant expression in the white-grained lines. These results indicate that the R gene is involved in the activation of the early flavonoid biosynthesis genes. As for coleoptile pigmentation, all 4 genes were expressed in the red coleoptile; however, DFR was not activated in the white coleoptile. The Rc gene appears to be involved in DFR expression. The possibility that wheat R and Rc genes might be transcription factors is discussed.
Himi
Eiko
E
Research Institute for Bioresources, Okayama University, Japan.
Nisar
Ahmed
A
Noda
Kazuhiko
K
D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism; D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism; D000595:Amino Acid Sequence; D000872:Anthocyanins / Q000096:biosynthesis; D018548:Cotyledon / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism; D005419:Flavonoids / Q000096:biosynthesis*; D018507:Gene Expression Regulation, Developmental; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D019753:Intramolecular Lyases / Q000235:genetics / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014908:Triticum / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism
D000872:Anthocyanins; D005419:Flavonoids; D009687:Nuclear Proteins; D010940:Plant Proteins; C085200:R protein, Zea mays; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; D000429:Alcohol Oxidoreductases; C056570:dihydroflavanol 4-reductase; C038888:flavonoid 3'-hydroxylase; C085313:flavonol synthase; D000217:Acyltransferases; C020141:flavanone synthetase; D019753:Intramolecular Lyases; C019865:chalcone isomerase