Phylogeny of the Erysiphales (powdery mildews) inferred from internal transcribed spacer ribosomal DNA sequences

Phylogenetic relationships were inferred for 45 powdery mildews plus two outgroup species from internal transcribed spacer sequence data. Phylogenetic analyses revealed that the powdery mildews formed six evolutionary lineages, which corresponded well to recently revised mitosporic taxa. Clade 1 consisted of Erysiphe, Microsphaera, and Uncinula, all of which have an Oidium subgenus Pseudoidium mitosporic state. Clade 2 consisted of Erysiphe galeopsidis and Erysiphe cumminsiana, which have an Oidium subgenus Striatoidium mitosporic state. Clade 3 consisted of Erysiphe species with an Oidium subgenus Reticuloidium mitosporic state. Clade 4 consisted of Leveillula and Phyllactinia, which have Oidiopsis and Ovulariopsis mitosporic states, respectively. Clade 5 consisted of Sphaerotheca, Podosphaera, and Cystotheca, which have Oidium subgenera Fibroidium and Setoidium mitosporic states. Clade 6 consisted of Blumeria graminis, which has an Oidium subgenus Oidium mitosporic state. Seventeen morphological characters were analysed and found not to conflict with the molecular data, so the morphological and molecular data were combined. The combined data increased the overall support for the six clades.Key words: Ascomycete, Blumeria, Erysiphe, fungi, molecular evolution, plant pathogen.