Acremonium phylogenetic overview and revision of Gliomastix, Sarocladium, and Trichothecium
Published: March 22nd, 2011
Revised: July 21st, 2014
Abstract
Over 200 new sequences are generated for members of the genus Acremonium and related taxa including ribosomal small subunit sequences (SSU) for phylogenetic analysis and large subunit (LSU) sequences for phylogeny and DNA-based identification. Phylogenetic analysis reveals that within the Hypocreales, there are two major clusters containing multiple Acremonium species. One clade contains Acremonium sclerotigenum, the genus Emericellopsis, and the genus Geosmithia as prominent elements. The second clade contains the genera Gliomastix sensu stricto and Bionectria. In addition, there are numerous smaller clades plus two multi-species clades, one containing Acremonium strictum and the type species of the genus Sarocladium, and, as seen in the combined SSU/LSU analysis, one associated subclade containing Acremonium breve and related species plus Acremonium curvulum and related species. This sequence information allows the revision of three genera. Gliomastix is revived for five species, G. murorum, G. polychroma, G. tumulicola, G. roseogrisea, and G. masseei. Sarocladium is extended to include all members of the phylogenetically distinct A. strictum clade including the medically important A. kiliense and the protective maize endophyte A. zeae. Also included in Sarocladium are members of the phylogenetically delimited Acremonium bacillisporum clade, closely linked to the A. strictum clade. The genus Trichothecium is revised following the principles of unitary nomenclature based on the oldest valid anamorph or teleomorph name, and new combinations are made in Trichothecium for the tightly interrelated Acremonium crotocinigenum, Spicellum roseum, and teleomorph Leucosphaerina indica. Outside the Hypocreales, numerous Acremonium-like species fall into the Plectosphaerellaceae, and A. atrogriseum falls into the Cephalothecaceae.
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Identification and molecular characterization of the phytoplasma associated with peach rosette-like disease at the Canadian Clonal Genebank based on the 16S rRNA gene analysis
Published: March 11th, 2011
Revised: July 21st, 2014
Abstract
Peach trees exhibiting peach rosette-like disease symptoms and infected by a phytoplasma of group 16SrI ‘Candidatus Phytoplasma asteris’ at the Canadian Clonal Genebank were further tested for the pathogen characterization based on the 16S rRNA gene. Nested PCR with phytoplasma universal primers R16mF2/R1 and R16F2n/R2 resulted in amplification of products of approximately 1.25 kb from all four symptomatic trees tested. Virtual RFLP of the R16F2n/R2 sequenced amplicons with selected restriction endonucleases showed unique RFLP patterns when compared to the described 16SrI phytoplasma subgroups; these data were confirmed by phylogenetic analyses. The phytoplasma was therefore assigned as a member of a new 16SrI subgroup (16SrI-W). Results represent the first report of a new phytoplasma 16SrI subgroup infecting peach in Canada, and provide a valuable tool for further epidemiological studies on this phytoplasma in peach.
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