Lophodermium pini-mugonis sp. nov. on needles of Pinus mugo from the Alps based on morphological and molecular data

Three new species and a new combination of Triblidium

Triblidiaceae (Rhytismatales) currently consists of two genera: Triblidium and Huangshania. Triblidium is the type genus and is characterised by melanized apothecia that occur scattered or in small clusters on the substratum, cleistohymenial (opening in the mesohymenial phase), inamyloid thin-walled asci and hyaline muriform ascospores. Before this study, only the type species, Triblidium caliciiforme, had DNA sequences in the NCBI GenBank. In this study, six specimens of Triblidium were collected from China and France and new ITS, mtSSU, LSU and RPB2 sequences were generated. Our molecular phylogenetic analysis and morphological study demonstrated three new species of Triblidium, which are formally described here: T. hubeiense, T. rostriforme and T. yunnanense. Additionally, our results indicated that Huangshania that was considered to be distinct from Triblidium because of its elongated, transversely-septate ascospores, is congeneric with Triblidium. Therefore, we have placed Huangshania in synonymy under Triblidium, rendering Triblidiaceae a monotypic family.

Multigene phylogenetic analysis detects cryptic species of Tryblidiopsis in China

Tryblidiopsis pinastri (Rhytismatales) has been recognized as being distributed throughout northern temperate regions. In the present study, comparative studies showed that species of Tryblidiopsis from China were distinct from the European type species. They are shown to belong to two new Tryblidiopsis species, T sichuanensis and T. sinensis, with a third known to be present in China but not described because the reference material is immature. Combined LSU rDNA, ITS rDNA and mtSSU rDNA sequences analyses revealed that Chinese species and European species formed a monophyletic clade. Collections of Tryblidiopsis from North America need to be re-examined and sequenced; they are probably not conspecific with T. pinastri. Tryblidiopsis species appear to be highly host specific and are probably restricted to the host genus Picea.

Molecular phylogeny reveals a core clade of Rhytismatales

Rhytismatales (Leotiomycetes, Pezizomycotina, Ascomycota) are an order of mostly plant-associated ascomycetes with a global distribution. Well known taxa include the Rhytisma tar spots on Acer spp. and several needle-cast pathogens in genera Lophodermium and Meloderma. Critical studies are lacking at all taxonomic ranks from order to species, and in particular the genus taxonomy in the order has been criticized for being unnatural. We used nuclear LSU and mitochondrial SSU sequences in Bayesian phylogenetic analyses to define a core clade of Rhytismatales sensu stricto. Some of the genera traditionally placed within the Rhytismatales, Ascodichaena, Marthamyces, Mellitiosporium, Potebniamyces, Propolis and Pseudophacidium, are shown to be phylogenetically distinct, all related to various other taxa at present placed in the polyphyletic Helotiales. Within the core clade only Cudonia, Spathularia and Terriera are supported as monophyletic. The large genera Coccomyces, Hypoderma and Lophodermium all are polyphyletic as are a few smaller genera. The traditionally used characters of ascoma and spore shape are shown to be unreliable for the delimitation of monophyletic genera but in some cases can be useful when combined with other characters. In this study we provide 72 new nrLSU and 64 new mtSSU sequences. Together with publicly available sequences data for 103 specimens representing 91 species of Rhytismatales are now available. Despite this taxon sampling intensity is still too low to propose an alternative generic taxonomy.