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United States Department of Agriculture

Agricultural Research Service

Title: Phylogenetic Placement of the Genera Sagenoma and Dichotomomyces in the Trichocomaceae

Author
item Peterson, Stephen

Submitted to: Mycological Society of America
Publication Type: Abstract Only
Publication Acceptance Date: June 16, 1998
Publication Date: N/A

Technical Abstract: Sagenoma viride asci develop from branching hyphal initials, as is found in species of Talaromyces, but the bright green cleistothecia have reticulate peridial hyphae, and the ascospores are green, as is found in some species of the Gymnoascaceae. The anamorphic state of Sagenoma is the Acremonium-like genus Sagenomella. Placement of S. viride in the Trichocomaceae is problematical because this species also has characteristics of the Gymnoascaceae. In contrast to S. viride, the cleistothecial peridium of Dichotomomyces cejpii is composed of a single layer of polygonal cells, which is similar to the ascomata of Neosartorya spp., but the conidia are aleuriospores formed on dichotomously branched hyphae rather than phialospores from an aspergillum. D. cejpii also has characteristics of both families. Molecular comparisons of the taxa were made to determine their familial placement. ITS and lsu-rDNA sequences from species of Aspergillus, Talaromyces, Penicillium, Sagenoma and Dichotomomyces were aligned, and analyzed phylogenetically using PAUP. S. viride is part of the Talaromyces clade and differs phenotypically from other Talaromyces species by its colony color and anamorphic state. D. cejpii is phylogenetically part of the Neosartorya clade. Ascoma and ascospore morphology are consistent with its placement in the Neosartorya clade, but whether the anamorphic state is a true aleuriospore must be reexamined.

Last Modified: 8/27/2014
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