Universidad de Los Andes, Bogotá, Colombia.
Universidad del Tolima, Ibagué, Colombia.
Theor Appl Genet. 2019 Jul;132(7):2003-2016. doi: 10.1007/s00122-019-03334-z. Epub 2019 Apr 11.
The Common Bean Angular Leaf Spot Resistance Gene Phg-2 was fine-mapped to a 409-Kbp region, and molecular markers for breeders were developed and validated in field experiments. Common bean (Phaseolus vulgaris L.) is an important food legume in Latin America, Asia and Africa. It is an important source of protein, carbohydrates and micro-minerals, particularly for smallholder farmers. Common bean productivity is affected by angular leaf spot (ALS) disease caused by the pathogenic fungus Pseudocercospora griseola, resulting in significant yield losses, particularly in low-input smallholder farming systems in the tropics. The ALS resistance gene Phg-2, which was found in several highly resistant common bean genotypes, was investigated in crosses between Mesoamerican pre-breeding lines and elite Andean breeding lines. Next-generation sequencing (NGS) data sets were used to design new SNP-based molecular markers. The Phg-2 locus was confirmed to be the major locus providing ALS resistance in these crosses. The locus was fine-mapped to a 409-Kbp region on chromosome 8. Two clusters of highly related LRR genes were identified in this region, which are the best candidate genes for Phg-2. Molecular markers were identified that are closely linked to the Phg-2 resistance gene and also highly specific to the donor germplasm. Marker-assisted selection (MAS) was used to introgress the Phg-2 resistance locus into Andean breeding germplasm using MAB lines. The usefulness of molecular markers in MAS was confirmed in several field evaluations in complex breeding crosses, under inoculation with different ALS pathotypes. This project demonstrates that NGS data are a powerful tool for the characterization of genetic loci and can be applied in the development of breeding tools.
菜豆黄花叶病抗性基因 Phg-2 被精细定位到 409-Kbp 区域，并且在田间试验中开发和验证了用于育种者的分子标记。菜豆（Phaseolus vulgaris L.）是拉丁美洲、亚洲和非洲的一种重要食用豆类。它是蛋白质、碳水化合物和微量元素的重要来源，特别是对小农户而言。菜豆的生产力受到由病原菌 Pseudocercospora griseola 引起的黄花叶病（ALS）的影响，导致产量显著下降，尤其是在热带地区低投入的小农作系统中。在中美洲预育种系和安第斯育种种系之间的杂交中，研究了几种高抗菜豆基因型中发现的 ALS 抗性基因 Phg-2。使用下一代测序（NGS）数据集设计了新的基于 SNP 的分子标记。证实 Phg-2 基因座是这些杂交中提供 ALS 抗性的主要基因座。该基因座被精细定位到 8 号染色体上的 409-Kbp 区域。在该区域中鉴定出两个高度相关的 LRR 基因簇，它们是 Phg-2 的最佳候选基因。鉴定出与 Phg-2 抗性基因紧密连锁且对供体种质高度特异的分子标记。使用 MAB 系通过 MAS 将 Phg-2 抗性基因座导入安第斯育种种质中。在不同 ALS 病原型的接种下，在复杂的杂交育种中，对几个田间评估证实了分子标记在 MAS 中的有用性。该项目表明，NGS 数据是表征遗传基因座的有力工具，并可应用于育种工具的开发。
