Association mapping and meta-analysis: two complementary approaches for the detection of reliable Septoria tritici blotch quantitative resistance in bread wheat (Triticum aestivum L.)

• Published in: Molecular breeding 2013-10, Vol.32 (3), p.563-584
• Main Authors: Goudemand, Ellen, Laurent, Valérie, Duchalais, Laure, Tabib Ghaffary, Seyed Mahmod, Kema, Gert H. J, Lonnet, Philippe, Margalé, Eric, Robert, Olivier
• Format: Article
• Language: English
• Subjects: Ascomycetes; azole fungicides; Biomedical and Life Sciences; Biotechnology; Bread; breeding; dwarfing; dwarfing genes; early development; Gene mapping; Genetic analysis; genetic background; genetic techniques and protocols; genome-wide association; hexaploid wheat; Life Sciences; Linkage analysis; loci; Mapping; Markers; Meta-analysis; Molecular biology; Mycosphaerella graminicola; pathogens; Plant biology; Plant Genetics and Genomics; plant height; Plant Pathology; Plant Physiology; Plant Sciences; population-structure; Populations; qtl metaanalysis; Quantitative trait loci; Septoria tritici; Septoria tritici blotch; Signs and symptoms; trait loci; Triticum aestivum; Wheat; winter-wheat
• ISSN: 1380-3743; 1572-9788
• DOI: 10.1007/s11032-013-9890-4

Septoria tritici blotch (STB), caused by the ascomycete Mycosphaerella graminicola, is one of the most ubiquitous and important diseases of bread wheat worldwide. The aim of this study was to identify markers linked to loci conferring resistance to STB from seven biparental populations. Linkage analysis, meta-analysis and association mapping were combined to identify robust quantitative trait loci (QTLs) for resistance. Linkage analysis led to the detection of 115 QTLs for resistance to STB and 66 QTLs linked to plant height and/or earliness. Meta-analysis clustered these 115 QTLs into 27 Meta-QTLs (MQTLs) of pathogen resistance, of which 14 were found to be linked to plant height and/or earliness. Both the relationship between dwarfing and susceptibility to STB and the significant negative correlation between earliness and STB symptoms were confirmed. Eleven loci were linked to STB resistance by association mapping using a general linear model and/or a mixed linear model, of which eight co-located with STB MQTLs and two co-located with individual QTLs. Associated markers located in MQTL regions enhanced the relevance of the results and validated the potential of an association mapping approach. With several biparental populations, meta-analysis is the most relevant form of genetic analysis study, but association mapping can be used as a validation method. Regions linked to resistance in both methods should be relevant for use in breeding programs for improving resistance to STB in wheat varieties. The main interest in comparing both approaches is to detect robust loci that will be functional in many genetic backgrounds rather than just in one or a few specific backgrounds.