Tocochromanols (tocols for short), commonly called Vitamin E, are lipid‐soluble plant antioxidants vital for regulating lipid peroxidation in chloroplasts and seeds. Barley (Hordeum vulgare L.) seeds contain all eight different isoforms of tocols; however, the extent of natural variation in their composition and their underlying genetic basis is not known. Tocol levels in barley seeds were quantified in diverse H. vulgare panels comprising 297 wild lines from a diversity panel and 160 cultivated spring‐type accessions from the mini‐core panel representing the genetic diversity of the USDA barley germplasm collection. Significant differences were observed in the concentration of tocols between the two panels. To identify the genes associated with tocols, genome‐wide association analysis was conducted with single nucleotide polymorphisms (SNPs) from Illumina arrays for the mini‐core panel and genotyping‐by‐sequencing for the wild barley panel. Forty unique SNPs in the wild barley and 27 SNPs in the mini‐core panel were significantly associated with various tocols. Marker–trait associations (MTAs) were identified on chromosomes 1, 6, and 7 for key genes in the tocol biosynthesis pathway, which have also been reported in other studies. Several novel MTAs were identified on chromosomes 2, 3, 4 and 5 and were found to be in proximity to genes involved in the generation of precursor metabolites required for tocol biosynthesis. This study provides a valuable resource for barley breeding programs targeting specific isoforms of seed tocols and for investigating the physiological roles of these metabolites in seed longevity, dormancy, and germination.

中文翻译：

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大麦种子生育酚中自然变化的全基因组关联分析

生育酚（通常称为维生素E）是脂溶性植物抗氧化剂，对于调节叶绿体和种子中的脂质过氧化至关重要。大麦（大麦L.）种子播种包含母育酚的所有八个不同同种型; 但是，其组成的自然变异程度和潜在的遗传基础尚不清楚。大麦种子中的母育酚水平在不同的H. vulgare中进行了定量样本包括来自多样性小组的297条野生品系和来自微型核心小组的160种耕作的春季型种质，代表了USDA大麦种质资源的遗传多样性。在两个面板之间观察到母育酚浓度的显着差异。为了鉴定与母育酚相关的基因，使用Illumina阵列的单核苷酸多态性（SNP）进行了迷你基因组的全基因组关联分析，并通过野生大麦面板的测序进行了基因分型。野生大麦中有40个独特的SNP，迷你核心组中有27个SNP与多种母育酚显着相关。在母育酚生物合成途径中的关键基因的染色体1、6和7上鉴定出标记-性状关联（MTA），这在其他研究中也有报道。在2号，3号，4号和5号染色体上鉴定出几种新颖的MTA，发现它们与母育酚生物合成所需的前体代谢产物的产生所涉及的基因接近。这项研究为针对大麦育种的特定同工型的大麦育种计划以及调查这些代谢物在种子寿命，休眠和发芽中的生理作用提供了宝贵的资源。