Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal.
Wageningen University & Research, Wageningen, The Netherlands.
Phytopathology. 2020 Mar;110(3):633-647. doi: 10.1094/PHYTO-06-19-0207-R. Epub 2020 Jan 28.
Common bean () is one of the most consumed legume crops in the world, and Fusarium wilt, caused by the fungus f. sp. , is one of the major diseases affecting its production. Portugal holds a very promising common bean germplasm with an admixed genetic background that may reveal novel genetic resistance combinations between the original Andean and Mesoamerican gene pools. To identify new sources of Fusarium wilt resistance and detect resistance-associated single-nucleotide polymorphisms (SNPs), we explored, for the first time, a diverse collection of the underused Portuguese common bean germplasm by using genome-wide association analyses. The collection was evaluated for Fusarium wilt resistance under growth chamber conditions, with the highly virulent f. sp. strain FOP-SP1 race 6. Fourteen of the 162 Portuguese accessions evaluated were highly resistant and 71 intermediate. The same collection was genotyped with DNA sequencing arrays, and SNP-resistance associations were tested via a mixed linear model accounting for the genetic relatedness between accessions. The results from the association mapping revealed nine SNPs associated with resistance on chromosomes Pv04, Pv05, Pv07, and Pv08, indicating that Fusarium wilt resistance is under oligogenic control. Putative candidate genes related to phytoalexin biosynthesis, hypersensitive response, and plant primary metabolism were identified. The results reported here highlight the importance of exploring underused germplasm for new sources of resistance and provide new genomic targets for the development of functional markers to support selection in future disease resistance breeding programs.
菜豆（ ）是世界上消费最多的豆科作物之一，由真菌 f. sp. 引起的枯萎病是影响其生产的主要病害之一。葡萄牙拥有一种非常有前途的混合遗传背景的普通菜豆种质资源，可能揭示了原始安第斯和中美洲基因库之间新的遗传抗性组合。为了鉴定枯萎病抗性的新来源并检测与抗性相关的单核苷酸多态性（SNP），我们首次通过全基因组关联分析探索了未充分利用的葡萄牙普通菜豆种质资源的多样性。在生长室条件下，使用高度致病的 f. sp. 菌株 FOP-SP1 系 6 对该收集品系进行了枯萎病抗性评估。在所评估的 162 个葡萄牙品系中，有 14 个高度抗性，71 个中度抗性。对同一集合进行了 DNA 测序阵列的基因型分析，并通过混合线性模型测试了 SNP-抗性关联，该模型考虑了品系之间的遗传相关性。关联图谱的结果显示，在 Pv04、Pv05、Pv07 和 Pv08 染色体上有 9 个与抗性相关的 SNP，表明枯萎病抗性受寡基因控制。鉴定出与植物抗毒素生物合成、过敏反应和植物初级代谢相关的假定候选基因。这里报道的结果强调了探索未充分利用的种质资源以寻找新的抗性来源的重要性，并为开发功能标记以支持未来抗病性育种计划中的选择提供了新的基因组靶标。
