Ophiosphaerella agrostis sp. nov. and its relationship to other species of Ophiosphaerella

Polydomus karssenii gen. nov. sp. nov. is a dark septate endophyte with a bifunctional lifestyle parasitising eggs of plant parasitic cyst nematodes (Heterodera spp.)

In this study fungal strains were investigated, which had been isolated from eggs of the cereal cyst nematode Heterodera filipjevi, and roots of Microthlaspi perfoliatum (Brassicaceae). The morphology, the interaction with nematodes and plants and the phylogenetic relationships of these strains originating from a broad geographic range covering Western Europe to Asia Minor were studied. Phylogenetic analyses using five genomic loci including ITSrDNA, LSUrDNA, SSUrDNA, rpb2 and tef1-α were carried out. The strains were found to represent a distinct phylogenetic lineage most closely related to Equiseticola and Ophiosphaerella, and Polydomus karssenii (Phaeosphaeriaceae, Pleosporales) is introduced here as a new species representing a monotypic genus. The pathogenicity tests against nematode eggs fulfilled Koch's postulates using in vitro nematode bioassays and showed that the fungus could parasitise its original nematode host H. filipjevi as well as the sugar beet cyst nematode H. schachtii, and colonise cysts and eggs of its hosts by forming highly melanised moniliform hyphae. Light microscopic observations on fungus-root interactions in an axenic system revealed the capacity of the same fungal strain to colonise the roots of wheat and produce melanised hyphae and microsclerotia-like structure typical for dark septate endophytes. Confocal laser scanning microscopy further demonstrated that the fungus colonised the root cells by predominant intercellular growth of hyphae, and frequent formation of appressorium-like as well as penetration peg-like structures through internal cell walls surrounded by callosic papilla-like structures. Different strains of the new fungus produced a nearly identical set of secondary metabolites with various biological activities including nematicidal effects irrespective of their origin from plants or nematodes.

Additions to Phaeosphaeriaceae (Pleosporales): Elongaticollum gen. nov., Ophiosphaerella taiwanensis sp. nov., Phaeosphaeriopsis beaucarneae sp. nov. and a new host record of Neosetophoma poaceicola from Musaceae

A novel ascomycetous genus, Elongaticollum, occurring on leaf litter of Hedychium coronarium (Zingiberaceae) in Taiwan, is described and illustrated. Elongaticollum is characterized by dark brown to black, superficial, obpyriform, pycnidial conidiomata with a distinct elongate neck, and oval to oblong, hyaline, aseptate conidia. Phylogenetic analyses (maximum likelihood, maximum parsimony and Bayesian) of combined ITS, LSU, SSU and tef1-α sequence data revealed Elongaticollum as a distinct genus within the family Phaeosphaeriaceae with high statistical support. In addition, Ophiosphaerella taiwanensis and Phaeosphaeriopsis beaucarneae are described as new species from dead leaves of Agave tequilana and Beaucarnea recurvata (Asparagaceae), respectively. Neosetophoma poaceicola is reported as a new host record from dead leaves of Musa acuminata (Musaceae). Newly described taxa are compared with other similar species and comprehensive descriptions and micrographs are provided.

Detection and phylogenetic analysis of mating type genes ofOphiosphaerella korrae

Portions of the mating type genes from Ophiosphaerella korrae (J. Walker & A.M. Smith) R.A. Shoemaker (=Leptosphaeria korrae J. Walker & A.M. Smith), a pathogenic fungus of grasses, were examined by PCR (polymerase chain reaction). For nine isolates of O. korrae from North America, both mating type genes were amplified, demonstrating that both MAT idiomorphs are detectable in this homothallic ascomycete. Amplified fragments from three isolates were sequenced, and parsimony analyses of MAT1 nucleotide and protein sequences placed O. korrae in the basal position of a clade of Phaeosphaeriaceae and Pleosporaceae, whereas the MAT2 nucleotide and protein data placed O. korrae in a clade with Pleosporaceae. The internal transcribed spacer (ITS) and 18S ribosomal DNA of O. korrae were also sequenced. The 18S sequences had insufficient variability to resolve the placement of O. korrae, whereas the ITS data placed it in Phaeosphaeriaceae. A total evidence analysis of Dothideomycetes with 18S, ITS, and MAT data placed O. korrae alongside Phaeosphaeria species, with moderate bootstrap support. However, the Kishino–Hasegawa test did not demonstrate this topology to be significantly different from one where O. korrae was placed with Pleosporales. Although O. korrae does not belong in Leptosphaeria based on ITS data, MAT data do not strongly support its placement in Phaeosphaeriaceae.Key words: ascomycetes, mating type genes, ribosomal genes, taxonomy.