Search

ABSTRACTThis is the sixth contribution in a series devoted to the phylogeny and taxonomy of powdery mildews. This part includes our third treatment of the species of the genus Erysiphe. It continues the previous contribution on the phylogenetic-taxonomic assessment of the species belonging to the “Microsphaeralineage.” Since this is a large lineage, we have split the treatment of the “Microsphaeralineage” into two parts. Phylogenetic trees based on rDNA are supplemented by sequences of additional markers (CAM, GAPDH, GS, RPB2, and TUB). The “Erysiphe trifoliorumcomplex” is a challenging group that belongs to the “Microsphaeralineage.” Adequate clarification of this complex will be possible when additional worldwide multilocus sequence analyses are performed. The new species Erysiphe acetosae, E. acmisponis, E. lathyrina, E. salmoniana, and E. santalicolaare described, and the new combinations E. biuncinataand E. pavoniaeare introduced. Specimens of several species have been sequenced for the first time, particularly North American species, such as Erysiphe caryae, E. ceanothi, E. juglandis-nigrae, and E. ravenelii. Erysiphe syringaeis lectotypified and 15 species names are epitypified in order to provide ex-epitype reference sequences. For other species, non-ex-type reference sequences are proposed for phylogenetic-taxonomic purposes. Ex-type sequences for Erysiphe baptisiicola, E. sesbaniae, Microsphaera sydowiana, M. umbilici, and Oidium pavoniaehave been retrieved.

ABSTRACTPowdery mildews on oaks, caused by Erysiphespecies, have serious ecological consequences on a range of Quercushosts. In addition to Erysiphe quercicola, E. alphitoidesis one of the most common and widespread species of Erysiphehaving a wide host range among oak species, and a clear economic significance in applied ecology, forestry, and forest pathology. There are many publications addressing these important tree pathogens. Previous phylogenetic examinations have shown that E. alphitoidesrefers to a complicated species assemblage with insufficient taxonomic resolution in ITS + 28S analyses; the associated sequences form an insufficiently resolved species complex. The majority of species within the E. alphitoidescomplex cannot be unequivocally identified based solely on ITS + 28S analyses. Most of the additional species of the E. alphitoidescomplex are distributed in Asia, with a concentration in Japan. The question posed is whether there is a single widespread powdery mildew species, E. alphitoides,or an assemblage of closely allied species. To answer this question, specimens of related recognized species, particularly those from Japan, have been subjected to phylogenetic multilocus examinations, including CAM, GAPDH, GS, ITS + 28S, RPB2, and TUBsequences. An analysis of the concatenated sequences resulted in the confirmation of several distinct species. These species form highly supported clades that include E. alphitoides, E. aucubae, E. euonymicola, E. ipomoeae, E. menispermivar. dahurica, E. orixae, E. pseudolonicerae, E. sinomeniiand E. wallrothii. Erysiphe akebiaeas well as the relationship between Japanese and North American collections requires further examinations.