State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan, Ministry of Education Key Laboratory of Agriculture Biodiversity for Plant Disease Management, Yunnan Agricultural University, Kunming, 650201, China.
Institute of Food Crops, Yunnan Academy of Agricultural Sciences, Kunming, 650205, China.
Mol Biol Rep. 2021 Apr;48(4):3379-3392. doi: 10.1007/s11033-021-06350-9. Epub 2021 Apr 22.
Gray leaf spot (GLS) caused by Cercospora zeae-maydis or Cercospora zeina is one of the devastating maize foliar diseases worldwide. Identification of GLS-resistant quantitative trait loci (QTL)/genes plays an urgent role in improving GLS resistance in maize breeding practice. Two groups of recombinant inbred line (RIL) populations derived from CML373 × Ye107 and Chang7-2 × Ye107 were generated and subjected to genotyping-by-sequencing (GBS). A total of 1,929,222,287 reads in CML373 × Ye107 (RIL-YCML) and 2,585,728,312 reads in Chang7-2 × Ye107 (RIL-YChang), with an average of 10,961,490 (RIL-YCML) and 13,609,096 (RIL-YChang) reads per individual, were got, which was roughly equal to 0.70-fold and 0.87-fold coverage of the maize B73 RefGen_V4 genome for each F individual, respectively. 6418 and 5139 SNP markers were extracted to construct two high-density genetic maps. Comparative analysis using these physically mapped marker loci demonstrated a satisfactory colinear relationship with the reference genome. 11 GLS-resistant QTL have been detected. The individual QTL accounted for 1.53-24.00% of the phenotypic variance explained (PVE). The new consensus QTL (qYCM-DS3-3/qYCM-LT3-1/qYCM-LT3-2) with the largest effect was located in chromosome bin 3.05, with an interval of 2.7 Mb, representing 13.08 to 24.00% of the PVE. Further gene annotation indicated that there were four candidate genes (GRMZM2G032384, GRMZM2G041415, GRMZM2G041544, and GRMZM2G035992) for qYCM-LT3-1, which may be related to GLS resistance. Combining RIL populations and GBS-based high-density genetic maps, a new larger effect QTL was delimited to a narrow genomic interval, which will provide a new resistance source for maize breeding programs.
叶斑病（GLS）由玉米尾孢菌或玉米叶点霉菌引起，是世界范围内玉米叶片毁灭性病害之一。鉴定抗 GLS 的数量性状位点（QTL）/基因对于提高玉米育种实践中的 GLS 抗性具有重要意义。本研究以 CML373×Ye107 和 Chang7-2×Ye107 衍生的两组重组自交系（RIL）群体为材料，进行基因分型测序（GBS）。在 CML373×Ye107（RIL-YCML）和 Chang7-2×Ye107（RIL-YChang）中，分别获得了 1929222287 条和 2585728312 条reads，每个个体的平均reads 数约为 10961490（RIL-YCML）和 13609096（RIL-YChang），分别相当于玉米 B73 RefGen_V4 基因组的 0.70 倍和 0.87 倍。分别提取 6418 和 5139 个 SNP 标记，构建了两个高密度遗传图谱。使用这些物理图谱标记位点进行的比较分析显示，与参考基因组具有令人满意的共线性关系。共检测到 11 个抗 GLS 数量性状位点（QTL）。单个 QTL 解释的表型变异为 1.53-24.00%。具有最大效应的新共识 QTL（qYCM-DS3-3/qYCM-LT3-1/qYCM-LT3-2）位于 3.05 号染色体 bin 内，区间为 2.7 Mb，占 PVE 的 13.08-24.00%。进一步的基因注释表明，qYCM-LT3-1 可能与 GLS 抗性相关，包含四个候选基因（GRMZM2G032384、GRMZM2G041415、GRMZM2G041544 和 GRMZM2G035992）。结合 RIL 群体和基于 GBS 的高密度遗传图谱，将一个新的、更大效应的 QTL 限定在一个狭窄的基因组区间内，这将为玉米育种计划提供新的抗性来源。
