Paratritirachium curvibasidium, a new heat-resistant basidiomycete from flare pit soils in Alberta, Canada.

Nguyen, H.D.T., Tanney, J.B., Chabot, D., Nickerson, N.L., and Seifert, K.A. (2014). "Paratritirachium curvibasidium, a new heat-resistant basidiomycete from flare pit soils in Alberta, Canada.", Mycological Progress, 13(3), pp. 575-587. doi : 10.1007/s11557-013-0941-3  Access to full text


Paratritirachium is a recently described, monotypic, basidiomycete genus in the Pucciniomycotina with one described asexual species, P. cylindroconium. Three strains of an undescribed species of Paratritirachium were isolated from flare pit soils from Alberta, Canada, using a heat treatment method. Both asexual and sexual propagules were produced in culture. Asexual reproduction was characterized by unbranched or sparingly branched conidiophores and sympodial, slightly vesicular conidiogenous cells producing aseptate conidia. Distinctive curved basidia were commonly produced in culture, yielding two pale brown, thick-walled and oval basidiospores. The basidiospores were heat-resistant and germinated only when exposed to heat. Phylogenetic analyses using the internal transcribed spacer (ITS) region and the combined small and large ribosomal subunits confirmed that these isolates are a new species of Paratritirachium, described in this study as P. curvibasidium, and that Paratritirachium should be classified in the class Tritirachiomycetes, order Tritirachiales, and family Tritirachiaceae. Transmission electron microscopy revealed simple, uniperforate septa, similar to those of a Tritirachium species, supporting the placement of Paratritirachium in the class Tritirachiomycetes. This study provides the first description of sexual reproduction in the Tritirachiomycetes and the first report of basidiospore germination after heat treatment at a high temperature (75 °C).

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