Department of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY14853, USA.
Theor Appl Genet. 2011 Jul;123(2):307-26. doi: 10.1007/s00122-011-1585-9. Epub 2011 Apr 28.
To capture diverse alleles at a set of loci associated with disease resistance in maize, heterogeneous inbred family (HIF) analysis was applied for targeted QTL mapping and near-isogenic line (NIL) development. Tropical maize lines CML52 and DK888 were chosen as donors of alleles based on their known resistance to multiple diseases. Chromosomal regions ("bins"; n = 39) associated with multiple disease resistance (MDR) were targeted based on a consensus map of disease QTLs in maize. We generated HIFs segregating for the targeted loci but isogenic at ~97% of the genome. To test the hypothesis that CML52 and DK888 alleles at MDR hotspots condition broad-spectrum resistance, HIFs and derived NILs were tested for resistance to northern leaf blight (NLB), southern leaf blight (SLB), gray leaf spot (GLS), anthracnose leaf blight (ALB), anthracnose stalk rot (ASR), common rust, common smut, and Stewart's wilt. Four NLB QTLs, two ASR QTLs, and one Stewart's wilt QTL were identified. In parallel, a population of 196 recombinant inbred lines (RILs) derived from B73 × CML52 was evaluated for resistance to NLB, GLS, SLB, and ASR. The QTLs mapped (four for NLB, five for SLB, two for GLS, and two for ASR) mostly corresponded to those found using the NILs. Combining HIF- and RIL-based analyses, we discovered two disease QTLs at which CML52 alleles were favorable for more than one disease. A QTL in bin 1.06-1.07 conferred resistance to NLB and Stewart's wilt, and a QTL in 6.05 conferred resistance to NLB and ASR.
为了在玉米中捕获与疾病抗性相关的一组基因座的不同等位基因，应用了异质自交系（HIF）分析进行靶向 QTL 作图和近等基因系（NIL）的开发。选择热带玉米品系 CML52 和 DK888 作为等位基因的供体，因为它们已知对多种疾病具有抗性。根据玉米中疾病 QTL 的共识图谱，靶向与多种疾病抗性（MDR）相关的染色体区域（“箱”；n=39）。我们生成了针对靶向基因座的 HIF ，但在基因组的约 97%上是同基因的。为了检验 CML52 和 DK888 等位基因在 MDR 热点条件下产生广谱抗性的假设，对 HIF 和衍生的 NIL 进行了北方叶斑病（NLB）、南方叶斑病（SLB）、灰斑病（GLS）、炭疽病叶斑病（ALB）、炭疽病茎腐病（ASR）、普通锈病、普通黑粉病和 Stewart's 萎蔫病的抗性测试。鉴定了四个 NLB QTL、两个 ASR QTL 和一个 Stewart's 萎蔫病 QTL。同时，还评估了源自 B73×CML52 的 196 个重组自交系（RIL）群体对 NLB、GLS、SLB 和 ASR 的抗性。所映射的 QTL（四个用于 NLB、五个用于 SLB、两个用于 GLS 和两个用于 ASR）大多与使用 NIL 发现的 QTL 相对应。通过 HIF 和 RIL 分析相结合，我们发现了两个 CML52 等位基因有利于多种疾病的疾病 QTL。第 1.06-1.07 箱中的一个 QTL 赋予对 NLB 和 Stewart's 萎蔫病的抗性，第 6.05 箱中的一个 QTL 赋予对 NLB 和 ASR 的抗性。
