Barley (Hordeum vulgare L.) seeds are a rich source of β-glucans that can help reduce blood serum cholesterol content in human diets. However, high levels of this polysaccharide in the seeds causes inefficiencies such as slow lautering during the brewing process due to the higher wort viscosity. Thus, depending on the end use, barley breeding programs have opposing goals with respect to β-glucan. Discovery of new alleles for β-glucan content in exotic barley germplasm could have significant commercial importance. We leveraged the Wild Barley Diversity Collection (WBDC; N = 314), grown at University of California-Davis experiment station, to characterize both the variation in β-glucan content found in this wild barley subspecies (Hordeum vulgare spp. spontaneum) and to reveal chromosomal regions associated with this trait. Grain β-glucan content ranged from 2.56 to 11.73% in the WBDC. Within structured subpopulations, geographical coordinates as well as annual precipitation data of original collection sites showed associations with differing levels of β-glucan content. Genome-wide association study identified a total of 13 quantitative traits loci (QTL) spread across the seven barley chromosomes that explained most of the variation in β-glucan content in the WBDC. Previously reported genes associated with β-glucan content such as β-glucan synthases and hydrolases (e.g., callose synthase) were identified within these QTL regions. Genes such as Patatin and Nudix hydrolase provide novel targets for manipulating grain β-glucan in barley. RNA-seq data from both developing and germinating barley seeds for the annotated genes in the QTL regions provide further corroboration for a functional role for these genes in modulating seed β-glucan levels.

中文翻译：

---

影响野生大麦（Hordeum vulgare ssp. spontaneum）中谷物β-葡聚糖含量的数量性状基因座揭示了与细胞壁修饰和碳水化合物代谢相关的基因

大麦 ( Hordeum vulgare L.) 种子富含 β-葡聚糖，有助于降低人类饮食中的血清胆固醇含量。然而，由于麦汁粘度较高，种子中这种多糖含量高会导致效率低下，例如在酿造过程中过滤缓慢。因此，根据最终用途，大麦育种计划在 β-葡聚糖方面具有相反的目标。在外来大麦种质中发现β-葡聚糖含量的新等位基因可能具有重要的商业意义。我们利用在加州大学戴维斯分校实验站种植的野生大麦多样性收集 (WBDC; N = 314) 来表征在这种野生大麦亚种 ( Hordeum vulgare spp . spontaneum )中发现的 β-葡聚糖含量的变化。) 并揭示与该特征相关的染色体区域。WBDC 中的谷物 β-葡聚糖含量在 2.56% 到 11.73% 之间。在结构化的亚群中，原始采集地点的地理坐标和年降水量数据显示与不同水平的 β-葡聚糖含量相关。全基因组关联研究确定了分布在七个大麦染色体上的总共 13 个数量性状基因座 (QTL)，这解释了 WBDC 中 β-葡聚糖含量的大部分变化。先前报道的与 β-葡聚糖含量相关的基因，例如 β-葡聚糖合酶和水解酶（例如，胼胝质合酶）在这些 QTL 区域内被鉴定。Patatin 和 Nudix 水解酶等基因为操纵大麦中的谷物 β-葡聚糖提供了新的靶点。