Hjortshøj, R L4; Ravnshøj, A R5; Nyman, M6; Orabi, J7; Backes, G7; Pinnschmidt, H1; Havis, N.6; Stougaard, Jens9; Stukenbrock, E H.8
1 Plant Pathology and Entomology, Faculty of Agricultural Sciences, Aarhus University, Aarhus University2 Department of Integrated Pest Management, Faculty of Agricultural Sciences, Aarhus University, Aarhus University3 Department of Molecular Biology and Genetics - Plant Molecular Biology, Department of Molecular Biology and Genetics, Science and Technology, Aarhus University4 Sejet Plantbreeding5 Department of Plant Biology and Biotechnology, Copenhagen University6 Crop and Soil Research Group, Scottish Rural University College7 Department of Agriculture and Ecology, Copenhagen University8 Max Planck Institute for Terrestial Micropbiology9 Department of Molecular Biology and Genetics - Plant Molecular Biology, Department of Molecular Biology and Genetics, Science and Technology, Aarhus University
The ascomycete pathogen Ramularia collo-cygni causes Ramularia leaf spot (RLS) on barley. Although R. collo-cygni is considerd an emerging disease of barley, little is known about genetic diversity or population genetic structure of this pathogen. We applied a set of polymorphic AFLP (Amplified Fragment Length Polymorphism) markers to investigate population genetic structure in two Northern European populations of R. collo-cygni. The distribution of AFLP alleles revealed low levels of population subdivision and high levels of genetic diversity at both locations. Our analyses included 87 isolates and of these 84 showed a unique genotype pattern. The genetic structure of populations in Scotland and Denmark is highly similar and we find no evidence of population sub-division. An analysis of molecular variance was used to show that 86 % of the variance is attributable to within field genetic variance. In spite of the high levels of genetic and genotypic diversity in the R. collo-cygni populations, we find significant evidence of linkage disequilibrium among the AFLP alleles using a multilocus analysis. We propose that the high levels of genotypic diversity and the lack of population differentiation result from considerable levels of gene flow between populations most likely mediated by seed borne dispersal of inoculum.
European Journal of Plant Pathology, 2013, Vol 136, Issue 1, p. 51-60