Vitamin A deficiency is one of the most prevalent nutritional deficiencies worldwide. Sorghum [Sorghum bicolor L. (Moench)] is a major cereal crop consumed by millions of people in regions with high vitamin A deficiency. We quantified carotenoid concentrations in a diverse sorghum panel using high‐performance liquid chromatography and conducted a genome‐wide association study (GWAS) of grain carotenoids to identify genes underlying carotenoid variation. There was moderate variation for β‐carotene (00.8 μg g⁻¹), lutein (0.3–9.4 μg g⁻¹), and zeaxanthin (0.2–9.1 μg g⁻¹), but β‐cryptoxanthin and α‐carotene were nearly undetectable. Genotype had the largest effect size, at 81% for zeaxanthin, 62% for β‐carotene, and 53% for lutein. Using multiple models, GWAS identified several significant associations between carotenoids and single nucleotide polymorphisms (SNPs), some of which colocalized with known carotenoid genes that have not been previously implicated in carotenoid variation. Several of the candidate genes identified have also been identified in maize (Zea mays L.) and Arabidopsis (Arabidopsis thaliana) carotenoid GWAS studies. Notably, an SNP inside the putative ortholog of maize zeaxanthin epoxidase (ZEP) had the most significant association with zeaxanthin and with the ratio between lutein and zeaxanthin, suggesting that ZEP is a major gene controlling sorghum carotenoid variation. Overall findings suggest there is oligogenic inheritance for sorghum carotenoids and suitable variation for marker‐assisted selection. The high carotenoid germplasm and significant associations identified in this study can be used in biofortification efforts to improve the nutritional quality of sorghum.

中文翻译：

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推进高粱中维生素原A的生物强化：全球种质中谷物类胡萝卜素的全基因组关联研究

维生素A缺乏症是世界上最普遍的营养缺乏症之一。高粱[高粱（Moench）]是维生素A缺乏症高发地区数百万人食用的一种主要谷物。我们使用高效液相色谱法对不同高粱中的类胡萝卜素浓度进行了定量，并进行了谷物类胡萝卜素的全基因组关联研究（GWAS），以识别类胡萝卜素变异的基因。β-胡萝卜素（00.8μgg ^-1），叶黄素（0.3–9.4μgg ^-1）和玉米黄质（0.2–9.1μgg ^-1），但几乎检测不到β-隐黄质和α-胡萝卜素。基因型的影响最大，玉米黄质为81％，β-胡萝卜素为62％，叶黄素为53％。GWAS使用多种模型，确定了类胡萝卜素和单核苷酸多态性（SNP）之间的几个重要关联，其中一些与已知的类胡萝卜素基因共定位，而这些基因先前并未涉及类胡萝卜素的变异。在玉米（Zea mays L.）和拟南芥（Arabidopsis thaliana）类胡萝卜素GWAS研究中也鉴定出了一些候选基因。值得注意的是，玉米玉米黄质环氧化酶（ZEP）的直系同源物中有一个SNP）与玉米黄质以及叶黄素和玉米黄质之间的比例具有最显着的关联，这表明ZEP是控制高粱类胡萝卜素变异的主要基因。总体研究结果表明，高粱类胡萝卜素具有寡聚遗传性，而标记辅助选择具有适当的变异性。本研究中确定的高类胡萝卜素种质和重要的关联可用于生物强化工作，以提高高粱的营养质量。