Quantitative Trait Loci Associated with the Tocochromanol (Vitamin E) Pathway in Barley

The Genome-Wide Association Studies approach was used to detect Quantitative Trait Loci associated with tocochromanol concentrations using a panel of 1,466 barley accessions. All major tocochromanol types- α-, β-, δ-, γ-tocopherol and tocotrienol- were assayed. We found 13 single nucleotide polymorphisms associated with the concentration of one or more of these tocochromanol forms in barley, seven of which were within 2 cM of sequences homologous to cloned genes associated with tocochromanol production in barley and/or other plants. These associations confirmed a prior report based on bi-parental QTL mapping. This knowledge will aid future efforts to better understand the role of tocochromanols in barley, with specific reference to abiotic stress resistance. It will also be useful in developing barley varieties with higher tocochromanol concentrations, although at current recommended daily consumption amounts, barley would not be an effective sole source of vitamin E. However, it could be an important contributor in the context of whole grains in a balanced diet.

本研究采用全基因组关联研究（Genome-Wide Association Studies）方法，以1466份大麦种质资源为研究群体，检测与生育烷醇类化合物浓度相关的数量性状位点（Quantitative Trait Loci, QTL）。本研究对所有主流生育烷醇类亚型——α-、β-、δ-、γ-生育酚及生育三烯酚——均完成了含量测定。本研究共鉴定得到13个与大麦中一种或多种该类生育烷醇亚型浓度显著相关的单核苷酸多态性（Single Nucleotide Polymorphism, SNP），其中7个位点与已克隆的、参与大麦及/或其他植物生育烷醇类生物合成的基因的同源序列遗传距离在2厘摩（cM）以内。上述关联位点验证了此前基于双亲群体QTL定位得到的研究结论。该研究成果将助力后续研究，以更清晰地阐明生育烷醇类化合物在大麦中的生物学功能，特别是其在非生物胁迫抗性中的调控作用；同时也可应用于高生育烷醇含量大麦品种的选育工作。尽管按照当前推荐的每日摄入量标准，大麦无法作为单一有效的维生素E来源，但在均衡膳食的全谷物摄入场景中，大麦可成为重要的维生素E膳食贡献来源。