Twelve expressed sequence tags-derived markers were isolated from Plasmopara halstedii (Oomycetes), the causal agent of sunflower downy mildew. A total of 25 single nucleotide polymorphisms and five indels were detected by single-strand conformation polymorphism analysis and developed for high-throughput genotyping of 32 isolates. There was a high level of genetic diversity (HE = 0.484). Observed heterozygosity ranged from 0 to 0.143 indicating that P. halstedii is probably a selfing species. These markers were also useful in detecting significant genetic variations among French populations (FST = 0.193) and between French and Russian populations (FST = 0.23). Cross-amplification tests on three closely related species indicated that no loci amplified in other Oomycete species.
Twelve polymorphic expressed sequence tags-derived markers for Plasmopara halstedii, the causal agent of sunflower downy mildew