National Key Laboratory of Crop Genetics and Germplasm Enhancement, National Center for Soybean Improvement, Key Laboratory for Biology and Genetic Improvement of Soybean (General, Ministry of Agriculture), Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing Agricultural University, Nanjing, China.
Division of Plant Sciences and National Center for Soybean Biotechnology, University of Missouri, Columbia, MO, USA.
J Exp Bot. 2021 Jun 22;72(13):4993-5009. doi: 10.1093/jxb/erab168.
Aluminium (Al) toxicity inhibits soybean root growth, leading to insufficient water and nutrient uptake. Two soybean lines ('Magellan' and PI 567731) were identified differing in Al tolerance, as determined by primary root length ratio, total root length ratio, and root tip number ratio under Al stress. Serious root necrosis was observed in PI 567731, but not in Magellan under Al stress. An F8 recombinant inbred line population derived from a cross between Magellan and PI 567731 was used to map the quantitative trait loci (QTL) for Al tolerance. Three QTL on chromosomes 3, 13, and 20, with tolerant alleles from Magellan, were identified. qAl_Gm13 and qAl_Gm20 explained large phenotypic variations (13-27%) and helped maintain root elongation and initiation under Al stress. In addition, qAl_Gm13 and qAl_Gm20 were confirmed in near-isogenic backgrounds and were identified to epistatically regulate Al tolerance via internal detoxification instead of Al3+ exclusion. Phylogenetic and pedigree analysis identified the tolerant alleles of both loci derived from the US ancestral line, A.K.[FC30761], originally from China. Our results provide novel genetic resources for breeding Al-tolerant soybean and suggest that internal detoxification contributes to soybean tolerance to excessive soil Al.
铝（Al）毒性抑制大豆根系生长，导致水分和养分吸收不足。通过在铝胁迫下的主根长比、总根长比和根尖数比，确定了两个大豆品系（'Magellan'和 PI 567731）在耐铝性方面存在差异。在铝胁迫下，PI 567731 观察到严重的根坏死，但 Magellan 没有。利用来自 Magellan 和 PI 567731 杂交的 F8 重组自交系群体，对耐铝性的数量性状位点（QTL）进行了作图。在第 3、13 和 20 号染色体上鉴定到三个 QTL，其耐铝性等位基因来自 Magellan。qAl_Gm13 和 qAl_Gm20 解释了较大的表型变异（13-27%），有助于在铝胁迫下维持根系伸长和起始。此外，在近等基因背景下证实了 qAl_Gm13 和 qAl_Gm20，并通过内部解毒而不是 Al3+排斥来调控耐铝性的上位性。系统发生和系谱分析确定了两个位点的耐铝等位基因均来自美国祖先系 A.K.[FC30761]，最初来自中国。我们的结果为培育耐铝大豆提供了新的遗传资源，并表明内部解毒有助于大豆耐受过量的土壤铝。
