Luckew Alexander S, Swaminathan Sivakumar, Leandro Leonor F, Orf James H, Cianzio Silvia R
Department of Agronomy, Iowa State University, Ames, IA, 50011, USA.
Department of Plant Pathology, Iowa State University, Ames, IA, 50011, USA.
Theor Appl Genet. 2017 Oct;130(10):2139-2149. doi: 10.1007/s00122-017-2947-8. Epub 2017 Jul 26.
Four novel QTL and interactions among QTL were identified in this research, using as a parent line the most SDS-resistant genotype within soybean cultivars of the US early maturity groups. Soybean sudden death syndrome (SDS) reduces soybean yield in most of the growing areas of the world. The causal agent of SDS, soilborne fungus Fusarium virguliforme (Fv), releases phytotoxins taken up by the plant to produce chlorosis and necrosis in the leaves. Planting resistant cultivars is the most successful management practice to control the disease. The objective of this study was to identify quantitative trait loci (QTL) associated with the resistance response of MN1606SP to SDS. A mapping population of F lines created by crossing the highly resistant cultivar 'MN1606SP' and the susceptible cultivar 'Spencer' was phenotyped in the greenhouse at three different planting times, each with three replications. Plants were artificially inoculated using SDS infested sorghum homogeneously mixed with the soil. Data were collected on three disease criteria, foliar disease incidence (DI), foliar leaf scorch disease severity (DS), and root rot severity. Disease index (DX) was calculated as DI × DS. Ten QTL were identified for the different disease assessment criteria, three for DI, four for DX, and three for root rot severity. Three QTL identified for root rot severity and one QTL for disease incidence are considered novel, since no previous reports related to these QTL are available. Among QTL, two interactions were detected between four different QTL. The interactions suggest that resistance to SDS is not only dependent on additive gene effects. The novel QTL and the interactions observed in this study will be useful to soybean breeders for improvement of SDS resistance in soybean germplasm.
本研究利用美国早熟组大豆品种中对大豆猝死综合症（SDS）抗性最强的基因型作为亲本系，鉴定出了4个新的数量性状基因座（QTL）以及QTL之间的互作。大豆猝死综合症会降低世界上大部分种植区的大豆产量。SDS的病原体，土壤传播的真菌镰刀菌（Fv），释放出植物吸收的毒素，导致叶片出现黄化和坏死。种植抗性品种是控制该病最成功的管理措施。本研究的目的是鉴定与MN1606SP对SDS的抗性反应相关的数量性状基因座（QTL）。通过将高抗品种“MN1606SP”与感病品种“Spencer”杂交创建的F 家系定位群体，在温室中于三个不同的种植时间进行表型分析，每个时间重复三次。使用与土壤均匀混合的经SDS侵染的高粱对植株进行人工接种。收集了关于三个病害标准的数据，即叶部病害发病率（DI）、叶部叶焦病严重程度（DS）和根腐病严重程度。病害指数（DX）计算为DI×DS。针对不同的病害评估标准鉴定出了10个QTL，其中3个与DI相关，4个与DX相关，3个与根腐病严重程度相关。鉴定出的3个与根腐病严重程度相关的QTL和1个与病害发病率相关的QTL被认为是新的，因为之前没有关于这些QTL的报道。在QTL之间，检测到四个不同QTL之间存在两个互作。这些互作表明对SDS的抗性不仅依赖于加性基因效应。本研究中观察到的新QTL和互作对大豆育种者改良大豆种质对SDS的抗性将是有用的。
