First comprehensive phylogenetic analysis of the genus Erysiphe (Erysiphales, Erysiphaceae) I. The Microsphaera lineage.
The genus Erysiphe (including powdery mildew fungi only known as anamorph, Pseudoidium) is the largest genus in the Erysiphaceae and contains more than 50% of all species in this family. Little is known about the phylogenetic structure of this genus. We conducted a comprehensive phylogenetic analysis of the Microsphaera-lineage, a monophyletic group including species of sects. Microsphaera and Erysiphe, using 401 sequences of nuc ITS1-5.8S-ITS2 and the 28S rDNA regions. This analysis gave many small clades delimited by the host plant genus or family. We identified two deep branches, albeit with moderate bootstrap supports, that divided the 401 sequences into three large groups. In addition, we identified four large clades consisting of homogeneous sequences of powdery mildews from a wide range of host plants beyond family level, namely, the E. aquilegiae clade, the E. alphitoides clade, the E. quercicola clade, and the E. trifoliorum s. lat. clade. Isolates from herbaceous plants were mostly situated in the E. aquilegiae clade and in Group III that was located at the most derived position of the Microsphaera-lineage. On the other hand, the basal part of the Microsphaera-lineage was occupied by isolates from woody plants except for E. glycines that was used as an outgroup taxon. This supports our previous hypothesis that tree-parasitic powdery mildews are phylogenetically primitive in the Erysiphaceae in general, and host-shift from trees to herbs occurred many times independently during the evolution of powdery mildews. Molecular clock analyses suggested that the divergence of the Microsphaera-lineage began ca. 20 million years ago in the Miocene Epoch of the Neogene Period.
Graduate School of Bioresources, Mie University, 1577 Kurima-Machiya, Tsu 514-8507, Japan takamatu@bio.mie-u.ac.jp.
Susumu
S
Takamatsu
Graduate School of Bioresources, Mie University, 1577 Kurima-Machiya, Tsu 514-8507, Japan.
Hanako
H
Ito Arakawa
Graduate School of Bioresources, Mie University, 1577 Kurima-Machiya, Tsu 514-8507, Japan.
Yoshiaki
Y
Shiroya
Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences (MTA), 1525 Budapest, P.O. Box 102, Hungary.
Levente
L
Kiss
M.G. Kholodny Institute of Botany of the National Academy of Sciences of Ukraine, 2 Tereshchenkivska Street, Kiev, 01601, Ukraine.
Vasyl
V
Heluta
D001203:Ascomycota / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D004271:DNA, Fungal / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D019143:Evolution, Molecular; D008969:Molecular Sequence Data; D016533:Mycological Typing Techniques; D010802:Phylogeny; D010935:Plant Diseases / Q000382:microbiology*; D010944:Plants / Q000382:microbiology
D004271:DNA, Fungal; D004275:DNA, Ribosomal
28S rDNA; ITS; Pseudoidium; host relationship; powdery mildew