title: Identification of a Genetic Factor Required for High γ-Isoform Concentration in Rice Vitamin E.
abstract: The γ-isoforms of tocopherols (Tc) and tocotrienols (T3) possess high biological activities in comparison to the α-isoforms. The concentrations of Tc and T3 isoforms in rice (Oriza sativa) was cultivar-dependent. Using chromosome segment substitution lines (CSSLs) and near isogenic lines (NILs) of indica cultivar "Kasalath" in a japonica cultivar "Koshihikari" genetic background, the Kasalath genomic segment on chromosome 2 was determined to be responsible for the high γ-isoform concentration: γ-tocopherol methyltransferase (γ-TMT) was identified as a candidate gene. An amino acid substitution in the coding region and several nucleotide polymorphisms, including an insertion of 10 base pairs in the promoter region, were identified. Gene expression analysis revealed that low expression levels of the γ-TMT gene in Kasalath were not associated with the γ-isoform concentration. Genetic variations in the coding region of the γ-TMT gene may play a major role in determining the γ-isoform concentration. This information could be used to breed rice with a high γ-isoform content.
authors.affiliation: Agricultural Experiment Station, Toyama Agricultural Research Center , Toyama, Toyama 939-8153, Japan.|Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University , Kanazawa, Ishikawa 920-1192, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Sekine
authors.affiliation: Agricultural Experiment Station, Toyama Agricultural Research Center , Toyama, Toyama 939-8153, Japan.
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Murata
authors.affiliation: Food Research Institute, National Agriculture and Food Research Organization (NARO) , Tsukuba, Ibaraki 305-8642, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Kimura
authors.affiliation: Food and Biodynamic Chemistry Laboratory, Graduate School of Agricultural Science, Tohoku University , Sendai, Miyagi 981-8555, Japan.
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Nakagawa
authors.affiliation: Food and Biotechnology Innovation Project, New Industry Creation Science Hatchery Center (NICHe), Tohoku University , Sendai, Miyagi 980-8579, Japan.|Food and Health Science Research Unit, Graduate School of Agricultural Science, Tohoku University , Sendai, Miyagi 981-8555, Japan.
authors.forename: Teruo
authors.initials: T
authors.lastname: Miyazawa
mesh_terms: D032461:Chromosomes, Plant / Q000235:genetics / Q000378:metabolism; D008780:Methyltransferases / Q000235:genetics / Q000378:metabolism; D012275:Oryza / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D024505:Tocopherols / Q000737:chemistry* / Q000378:metabolism; D024508:Tocotrienols / Q000737:chemistry* / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D024508:Tocotrienols; D008780:Methyltransferases; C047259:gamma-tocopherol methyltransferase; D024505:Tocopherols
keywords: breeding; isoform biosynthesis; rice; tocotrienols; γ-tocopherol methyltransferase