Greenhouse and Processing Crops Research Centre, Agriculture and Agri-Food Canada, 2585 County Road 20, Harrow, Ontario, Canada.
Theor Appl Genet. 2010 Jul;121(2):283-94. doi: 10.1007/s00122-010-1309-6. Epub 2010 Mar 12.
Daily consumption of cadmium (Cd) contaminated foods poses a risk to human health. Cultivar selection is an important method to limit Cd uptake and accumulation; however, analyzing grain Cd concentration is costly and time-consuming. Developing markers for low Cd accumulation will facilitate marker assisted selection (MAS). Inheritance studies using a threshold value of 0.2 mg kg(-1) for low and high and an F(2:3) population showed that low Cd accumulation in soybean seed is under the control of a major gene (Cda1, proposed name) with the allele for low accumulation being dominant. A recombinant inbred line (RIL) population (F(6:8)) derived from the cross AC Hime (high Cd accumulation) and Westag-97 (low Cd accumulation) was used to identify the DNA markers linked to Cda gene(s) or quantitative trait loci (QTLs) controlling low Cd accumulation. We screened 171 simple sequence repeat (SSR) primers that showed polymorphism between parents on the 166 RILs. Of these, 40 primers were newly developed from the soybean genomic DNA sequence. Seven SSR markers, SatK138, SatK139, SatK140 (0.5 cM), SatK147, SacK149, SaatK150 and SattK152 (0.3 cM), were linked to Cda1 in soybean seed. All the linked markers were mapped to the same linkage group (LG) K. The closest flanking SSR markers linked to Cda1 were validated using a parallel population (RILs) involving Leo x Westag-97. Linked markers were also validated with diverse soybean genotypes differing in their seed Cd concentration and showed that SSR markers SatK147, SacK149, and SattK152 clearly differentiated the high and low Cd accumulating genotypes tested. To treat Cd uptake as a quantitative trait, QTL analysis using a linkage map constructed with 161 markers identified a major QTL associated with low Cd concentration in the seeds. The QTL was also mapped to the same location as Cda1 on LG-K. This QTL accounted for 57.3% of the phenotypic variation. Potential candidate genes (genes with known or predicted function that could influence the seed Cd concentration) like protein kinase, putative Adagio-like protein, and plasma membrane H(+)-ATPase were found to be located in the locus of interest. Of the four SSR markers located in the region, SattK152 was localized in the plasma membrane H(+)-ATPase gene. SSR markers closely linked to Cda1 in seeds of soybean were identified and have potential to be used for MAS to develop low Cd accumulating cultivars in a breeding program.
日常食用镉（Cd）污染的食物会对人类健康造成危害。品种选择是限制镉吸收和积累的重要方法；然而，分析谷物中的镉浓度既昂贵又耗时。开发用于低镉积累的标记物将有助于标记辅助选择（MAS）。使用 0.2mgkg(-1) 的低和高阈值值以及 F(2:3) 群体进行的遗传研究表明，大豆种子中的低镉积累受一个主基因（Cda1，建议名称）的控制，该基因的低积累等位基因是显性的。来自 AC Hime（高 Cd 积累）和 Westag-97（低 Cd 积累）杂交的重组自交系（RIL）群体（F(6:8)）用于鉴定与 Cda 基因或控制低 Cd 积累的数量性状位点（QTLs）相关的 DNA 标记。我们在 166 个 RIL 上筛选了在亲本之间表现出多态性的 171 个简单重复序列（SSR）引物。其中，40 个引物是从大豆基因组 DNA 序列中新开发的。在大豆种子中，7 个 SSR 标记 SatK138、SatK139、SatK140（0.5cM）、SatK147、SacK149、SaatK150 和 SattK152（0.3cM）与 Cda1 连锁。所有连锁标记均映射到相同的连锁群（LG）K 上。与 Cda1 连锁的最近侧翼 SSR 标记使用涉及 Leo x Westag-97 的平行群体（RILs）进行了验证。连锁标记还与不同的大豆基因型进行了验证，这些基因型在种子的 Cd 浓度上存在差异，结果表明 SSR 标记 SatK147、SacK149 和 SattK152 可以清楚地区分测试的高 Cd 积累和低 Cd 积累基因型。为了将 Cd 吸收视为数量性状，使用基于 161 个标记构建的连锁图谱进行 QTL 分析，鉴定出与种子中低 Cd 浓度相关的主要 QTL。该 QTL也映射到 LG-K 上与 Cda1 相同的位置。该 QTL解释了 57.3%的表型变异。在感兴趣的区域中发现了与蛋白激酶、假定的 Adagio 样蛋白和质膜 H(+)-ATPase 等具有已知或预测功能的候选基因（可能影响种子 Cd 浓度的基因）。在位于该区域的四个 SSR 标记中，SattK152 定位于质膜 H(+)-ATPase 基因中。在大豆种子中与 Cda1 紧密连锁的 SSR 标记已被鉴定出来，有望用于 MAS，以在育种计划中开发低 Cd 积累品种。
