The systematics of reduced, soil-inhabiting ascomycetes

点击翻译按钮获取中文摘要

Lack of information concerning the phylogenetic relationships and diversity of fungi is acute, particularly within the Ascomycota, a group that includes the majority of economically important fungi. Ascomycetes have been enumerated and identified in many habitats, but studies documenting their diversity are limited by the selective nature of isolation methods and the difficulty of identifying these fungi. Many ascomycetes do not form sexual states and are defined on the basis of their asexual spore forms (anamorphs). Anamorphic ascomycetes are typically simple anatomically and thus challenging to identify. Ascomycetes that form no spore stages in pure culture cannot be identified using microscopy-based methods. Fortunately, the problem of accurately identifying anamorphic and non-sporulating ascomycetes has been solved largely through the PCR (polymerase chain reaction)-amplification of target gene regions and the comparison of DNA sequences of the resulting amplicons. Sequence data are also valuable for inferring phylogenies that permit the recognition of monophyletic groups and the assessment of hypotheses based on ecological and morphological characters.The proposed research will focus on the systematics and diversity of structurally simple, soil-inhabiting, cellulose- and keratin-degrading members of the Chaetomiaceae and Onygenales using culture-based and molecular methods. Investigation of the Chaetomiaceae will test the hypothesis that morphology reflects phylogenetic relationships within this genus. Study of soil-inhabiting Onygenales will determine if keratin-degrading members of this order dominate the mycota of soil near the hibernacula of red-sided garter snakes. Documenting this community will improve our understanding of the diversity and distribution of keratin-degrading ascomycetes and may assist in identifying of emerging infectious diseases of reptiles caused by fungi. Both studies will result in the description of new species and the construction of phylogenies that will ultimately facilitate the discovery of the Chaetomiaceae and Onygenales in natural communities.