Phylogeny and taxonomy of Pseudoidium pedaliacearum

Abstract

Collections of Pseudoidium pedaliacearum on Sesamum indicum from Japan, Korea, and Nepal have been morphologically examined and subjected to molecular sequence analyses in order to clarify the taxonomic status and phylogenetic affinity of this powdery mildew. Pseudoidium pedaliacearum pertains to the Erysiphe aquilegiae clade, which encompasses several closely allied, morphologically similar powdery mildew species. The close affinity to Erysiphe sedi, Pseudoidium hortensiae ( Oidium hortensiae), P. neolycopersici ( Oidium neolycopersici), and some other taxa involved in the Erysiphe aquilegiae complex is discussed. The reexamination of P. pedaliacearum and the results of phylogenetic analyses [5-end of the 28S rRNA gene (including the domains D1 and D2) and internal transcribed spacer (ITS) regions] led to a reassessment of this species and its reallocation to Erysiphe on the basis of the provisions of ICN Art. F.8.