Diversity, Phylogeny, and Host-Specialization of Species in Korea.

The genus (Peronosporaceae; Oomycota) is an obligate biotrophic group that causes downy mildew disease on the Brassicaceae and allied families of Brassicales, including many economically relevant crops, such as broccoli, cabbage, radish, rape, and wasabi. To investigate the diversity of species in northeast Asia, we performed a morphological analysis for the dried herbarium specimens collected in Korea, along with molecular phylogenetic inferences based on internal transcribed spacer rDNA and 2 mtDNA sequences. It was confirmed that 14 species of exist in Korea. Of these, three species, previously classified under the genus , were combined to : comb. nov. (ex ), comb. nov. (ex ), and comb. nov. (ex ). In addition, finding two potentially new species specific to northeast Asian plants is noteworthy in support of the view that the species abundance of has been underestimated hitherto.