All that glitters is not Ramularia

Ramularia is a species-rich genus that harbours plant pathogens responsible for yield losses to many important crops, including barley, sugar beet and strawberry. Species of Ramularia are hyphomycetes with hyaline conidiophores and conidia with distinct, thickened, darkened, refractive conidiogenous loci and conidial hila, and Mycosphaerella sexual morphs. Because of its simple morphology and general lack of DNA data in public databases, several allied genera are frequently confused with Ramularia. In order to improve the delimitation of Ramularia from allied genera and the circumscription of species within the genus Ramularia, a polyphasic approach based on multilocus DNA sequences, morphological and cultural data were used in this study. A total of 420 isolates belonging to Ramularia and allied genera were targeted for the amplification and sequencing of six partial genes. Although Ramularia and Ramulariopsis proved to be monophyletic, Cercosporella and Pseudocercosporella were polyphyletic. Phacellium isolates clustered within the Ramularia clade and the genus is thus tentatively reduced to synonymy under Ramularia. Cercosporella and Pseudocercosporella isolates that were not congeneric with the ex-type strains of the type species of those genera were assigned to existing genera or to the newly introduced genera Teratoramularia and Xenoramularia, respectively. Teratoramularia is a genus with ramularia-like morphology belonging to the Teratosphaeriaceae, and Xenoramularia was introduced to accommodate hyphomycetous species closely related to Zymoseptoria. The genera Apseudocercosporella, Epicoleosporium, Filiella, Fusidiella, Neopseudocercosporella, and Mycosphaerelloides were also newly introduced to accommodate species non-congeneric with their purported types. A total of nine new combinations and 24 new species were introduced in this study

Phylogenetic reassessment of the Chaetomium globosum species complex

Chaetomium globosum, the type species of the genus, is ubiquitous, occurring on a wide variety of substrates, in air and in marine environments. This species is recognised as a cellulolytic and/or endophytic fungus. It is also known as a source of secondary metabolites with various biological activities, having great potential in the agricultural, medicinal and industrial fields. On the negative side, C. globosum has been reported as an air contaminant causing adverse health effects and as causal agent of human fungal infections. However, the taxonomic status of C. globosum is still poorly understood. The contemporary species concept for this fungus includes a broadly defined morphological diversity as well as a large number of synonymies with limited phylogenetic evidence. The aim of this study is, therefore, to resolve the phylogenetic limits of C. globosum s.str. and related species. Screening of isolates in the collections of the CBS-KNAW Fungal Biodiversity Centre (The Netherlands) and the China General Microbiological Culture Collection Centre (China) resulted in recognising 80 representative isolates of the C. globosum species complex. Thirty-six species are identified based on phylogenetic inference of six loci, supported by typical morphological characters, mainly ascospore shape. Of these, 12 species are newly described here. Additionally, C. cruentum, C. mollipilium, C. rectum, C. subterraneum and two varieties of C. globosum are synonymised under C. globosum s.str., and six species are resurrected, i.e. C. angustispirale, C. coarctatum, C. cochliodes, C. olivaceum, C. spiculipilium and C. subglobosum. Chaetomium ascotrichoides is segregated from C. madrasense and the genus name Chaetomidium is rejected. Five species, including C. globosum s.str., are typified here to stabilise their taxonomic status. A further evaluation of the six loci used in this study as potential barcodes indicated that the 28S large subunit (LSU) nrDNA and the internal transcribed spacer regions and intervening 5.8S nrRNA (ITS) gene regions were unreliable to resolve species, whereas β-tubulin (tub2) and RNA polymerase II second largest subunit (rpb2) showed the greatest promise as DNA barcodes for differentiating Chaetomium species. This study provides a starting point to establish a more robust classification system for Chaetomium and for the Chaetomiaceae