Marcotuli Ilaria, Houston Kelly, Schwerdt Julian G, Waugh Robbie, Fincher Geoffrey B, Burton Rachel A, Blanco Antonio, Gadaleta Agata
Department of Soil, Plant and Food Sciences, Section of Genetics and Plant Breeding, University of Bari 'Aldo Moro', Via G. Amendola 165/A, 70126, Bari, Italy.
The James Hutton Institute, Invergowrie, Dundee, DD2 5DA, Scotland.
PLoS One. 2016 Apr 5;11(4):e0152590. doi: 10.1371/journal.pone.0152590. eCollection 2016.
Non-starch polysaccharides (NSPs) have many health benefits, including immunomodulatory activity, lowering serum cholesterol, a faecal bulking effect, enhanced absorption of certain minerals, prebiotic effects and the amelioration of type II diabetes. The principal components of the NSP in cereal grains are (1,3;1,4)-β-glucans and arabinoxylans. Although (1,3;1,4)-β-glucan (hereafter called β-glucan) is not the most representative component of wheat cell walls, it is one of the most important types of soluble fibre in terms of its proven beneficial effects on human health. In the present work we explored the genetic variability of β-glucan content in grains from a tetraploid wheat collection that had been genotyped with a 90k-iSelect array, and combined this data to carry out an association analysis. The β-glucan content, expressed as a percentage w/w of grain dry weight, ranged from 0.18% to 0.89% across the collection. Our analysis identified seven genomic regions associated with β-glucan, located on chromosomes 1A, 2A (two), 2B, 5B and 7A (two), confirming the quantitative nature of this trait. Analysis of marker trait associations (MTAs) in syntenic regions of several grass species revealed putative candidate genes that might influence β-glucan levels in the endosperm, possibly via their participation in carbon partitioning. These include the glycosyl hydrolases endo-β-(1,4)-glucanase (cellulase), β-amylase, (1,4)-β-xylan endohydrolase, xylanase inhibitor protein I, isoamylase and the glycosyl transferase starch synthase II.
非淀粉多糖（NSPs）具有多种健康益处，包括免疫调节活性、降低血清胆固醇、增加粪便体积、增强某些矿物质的吸收、益生元效应以及改善II型糖尿病。谷物中NSP的主要成分是（1,3；1,4）-β-葡聚糖和阿拉伯木聚糖。尽管（1,3；1,4）-β-葡聚糖（以下简称β-葡聚糖）并非小麦细胞壁最具代表性的成分，但就其对人体健康已证实的有益作用而言，它是最重要的可溶性纤维类型之一。在本研究中，我们探究了一个四倍体小麦群体籽粒中β-葡聚糖含量的遗传变异，该群体已用90k-iSelect芯片进行了基因分型，并结合这些数据进行关联分析。整个群体中，以籽粒干重的重量百分比表示的β-葡聚糖含量在0.18%至0.89%之间。我们的分析确定了七个与β-葡聚糖相关的基因组区域，分别位于1A、2A（两个）、2B、5B和7A（两个）染色体上，证实了该性状的数量性质。对几种禾本科物种同源区域的标记-性状关联（MTA）分析揭示了可能影响胚乳中β-葡聚糖水平的假定候选基因，可能是通过它们参与碳分配来实现的。这些基因包括糖基水解酶内切-β-（1,4）-葡聚糖酶（纤维素酶）、β-淀粉酶、（1,4）-β-木聚糖内切水解酶、木聚糖酶抑制蛋白I、异淀粉酶以及糖基转移酶淀粉合酶II。
