Mapping resistance to powdery mildew in barley reveals a large-effect nonhost resistance QTL

• Published in: Theoretical and applied genetics 2018-05, Vol.131 (5), p.1031-1045
• Main Authors: Romero, Cynara C. T., Vermeulen, Jasper P., Vels, Anton, Himmelbach, Axel, Mascher, Martin, Niks, Rients E.
• Format: Article
• Language: English
• Subjects: Agriculture; Ascomycota; Barley; Biochemistry; Biomedical and Life Sciences; Biotechnology; Blumeria graminis; Chromosome Mapping; Disease resistance (Plants); Disease Resistance - genetics; Diseases and pests; durability; EPS; Gene loci; Gene mapping; Genetic aspects; Genetic factors; haustoria; Health aspects; histology; Hordeum - genetics; Hordeum - microbiology; Hordeum vulgare; Laboratorium voor Plantenveredeling; Laboratory of Plant Breeding; Life Sciences; Mildew; mildews; molecular cloning; Original; Original Article; Papillae; PBR Non host and insect resistance; PBR Non host en Insectenresistentie; Phenotype; Plant Biochemistry; Plant Breeding; Plant Breeding/Biotechnology; Plant Diseases - genetics; Plant Diseases - microbiology; Plant Genetics and Genomics; Polygenic inheritance; Powdery mildew; Prevention; PW Unifarm Serre Zuid; Quantitative Trait Loci; resistance genes; Unifarm Serre Zuid; wheat
• ISSN: 0040-5752; 1432-2242
• DOI: 10.1007/s00122-018-3055-0

Key message Resistance factors against non-adapted powdery mildews were mapped in barley. Some QTLs seem effective only to non-adapted mildews, while others also play a role in defense against the adapted form. The durability and effectiveness of nonhost resistance suggests promising practical applications for crop breeding, relying upon elucidation of key aspects of this type of resistance. We investigated which genetic factors determine the nonhost status of barley ( Hordeum vulgare L.) to powdery mildews ( Blumeria graminis ). We set out to verify whether genes involved in nonhost resistance have a wide effectiveness spectrum, and whether nonhost resistance genes confer resistance to the barley adapted powdery mildew. Two barley lines, SusBgt SC and SusBgt DC , with some susceptibility to the wheat powdery mildew B. graminis f.sp. tritici ( Bgt ) were crossed with cv Vada to generate two mapping populations. Each population was assessed for level of infection against four B. graminis ff.spp, and QTL mapping analyses were performed. Our results demonstrate polygenic inheritance for nonhost resistance, with some QTLs effective only to non-adapted mildews, while others play a role against adapted and non-adapted forms. Histology analyses of nonhost interaction show that most penetration attempts are stopped in association with papillae, and also suggest independent layers of defence at haustorium establishment and conidiophore formation. Nonhost resistance of barley to powdery mildew relies mostly on non-hypersensitive mechanisms. A large-effect nonhost resistance QTL mapped to a 1.4 cM interval is suitable for map-based cloning.