Phylogeny and taxonomy of the genera of Erysiphaceae, part 8: Podosphaera sect. Tridactyla.

Abstract

The eighth part of a series devoted to the phylogeny and taxonomy of powdery mildews is presented. In this part, the general phylogeny and taxonomy of the genus Podosphaera are treated, including a new division of this genus into sections: Podosphaera sect. Podosphaera, Podosphaera sect. Magnicellulatae, comb. nov. and the reintroduced Podosphaera sect. Tridactyla. Sect. Podosphaera consists of two morphologically deviating subsections (Podosphaera and Sphaerotheca). Subsect. Podosphaera consists of species that have apically dichotomously branched chasmothecial appendages, whereas subsect. Sphaerotheca consists of species with unbranched, mycelioid chasmothecial appendages. These subsections are not monophyletic and thus are based solely on morphology. The phylogeny and taxonomy of species of sect. Tridactyla are treated based on ITS+28S data. New primers for the protein-coding genes glutamine synthetase (GS), RNA polymerase II subunit B (RPB2), and β-tubulin (TUB2) are generated for the genus Podosphaera and provided as a resource for future research. A representative multilocus tree for the entire genus, including all sections, is presented. Additionally, the new combination Podosphaera brayana is introduced. This name has priority over Po. ampla. Erysiphe brayana is lecto- and epitypified, and a lectotype is designated for Sphaerotheca phytoptophila. The present analyses aim to provide resources for future research evaluating powdery mildews of the genus Podosphaera and, in particular, Podosphaera sect. Tridactyla.