Genetic Diversity of Venturia inaequalis Across Europe

Abstract

The genetic diversity of eleven populations of Venturia inaequalis from five European countries was calculated based on the allele frequencies of 18 random amplified polymorphic DNA markers and the internal transcribed spacer region of the ribosomal DNA. Diversity within each population (H_S) was high with values ranging from 0.26 to 0.33. Average differentiation among populations (G_ST) was 0.11 and populations were isolated by distance (r²=0.50, P<0.01). This indicates that extensive short-distance gene flow occurs in Europe and that dispersal over longer distances also appears to occur frequently enough to prevent differentiation due to genetic drift. We had expected more pronounced differentiation between populations north and south of the Alps, because V. inaequalis is primarily dispersed by rain splashing and wind distribution of leaf litter, and because the Alps might form a barrier to dispersal. However, our results indicate that human-mediated gene flow due to transport of spores or infected plant material has probably occurred.