International Symposium on Cereal Leaf Blights 2019 | University College Dublin, Ireland | 22-24 May 2019

QTL mapping in a wheat MAGIC population reveals a consistent locus on chromosome 2A across locations and inoculation methods for leaf reactions to Parastagonospora nodorum

Min Lin*
Department of Plant Sciences, Norwegian University of Life Sciences, Post Box 5003, NO-1432 Ås, Norway

Andrea Ficke
Norwegian Institute of Bioeconomy Research, Fr. A. Dahlsvei 20, NO-1430 Ås, Norway

Beatrice Corsi
NIAB, Huntingdon Road, Cambridge, CB3 0LE, UK

James Cockram
NIAB, Huntingdon Road, Cambridge, CB3 0LE, UK

Morten Lillemo
Department of Plant Sciences, Norwegian University of Life Sciences, Post Box 5003, NO-1432 Ås, Norway

Oral Presentation
Host Genetics and Resistance Breeding

Moore Auditorium, UCD O'Brien centre for Science
24 May 2019, 10:00

View this abstract online by visting

The necrotrophic pathogen Parastagonospora nodorum is the causal agent of Septoria nodorum blotch (SNB). Compared to the other diseases in the wheat leaf blotch complex, Septoria tritici blotch and Tan spot, SNB is the most important wheat leaf blotch disease in Norway. The pathogen causes symptoms not only on leaves but also on glumes, which reduce both grain yield and grain quality. Former studies reported that the inheritance of resistance to leaf blotch and glume blotch is genetically different. Previous leaf blotch studies proved that P. nodorum interacts with host sensitivity loci via necrotrophic effectors (NEs) based on an inverse-gene-for-gene mechanism. However, the genetics underlying sensitivity to glume blotch still remains unknown. An interaction on wheat head partially regulated by gene involved in leaf blotch pathogenicity is one of the hypothesis suggested. In this study, an eight-parent winter wheat multiparent advanced generation intercross (MAGIC) population from the UK (‘NIAB Elite MAGIC’) was tested in field trials over four years for leaf blotch (4 trials in Norway, 2 trials in the UK) and two years for glume blotch (2 trials in Norway). Naturally infected straw was used as inoculum in Norway, while in the UK a spore suspension (106 *10-1) was applied twice during the growing season to inoculate wheat plants. Ten quantitative trait loci (QTLs) were identified across chromosomes 2A, 2D, 3A, 3B, 4A, 5D, 6A and 7D. Among these, a QTL on chromosome 2A was detected for both leaf and glume blotch. Haplotype analysis confirmed the consistency of this QTL across countries and inoculation methods for leaf blotch. However, the most susceptible haplotype for leaf blotch turned out to be the most resistant for glume blotch. Further investigation will be needed to disentangle the mechanism behind leaf and glume blotch reactions caused by this QTL.