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ARS Home » Research » Publications at this Location » Publication #93839


item Samuels, Gary

Submitted to: Mycota
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/17/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: The fungi are a diverse group of organisms classified into a number of major groups one of which is the Pyrenomycetes or ascomycetous fungi bearing their reproductive structures in perithecia. Pyrenomycetes include fungi that function as plant and human pathogens, serve as sources of toxins, and are useful in the biological control of plant pathogens and insects. A comprehensive, abbreviated account of this group of fungi is needed in order to communicate about them to non-specialists. This chapter provides a synopsis of the characteristics of these fungi including the major uses of Pyrenomycetes, their life histories, and their classification at the ordinal level. The morphological characteristics of each order in the Pyrenomycetes are outlined and the relationships between them presented based on the most recent findings using molecular data. This chapter will be used by all persons interested in an overview of the latest information and recent references related to the biology and classification of the Pyrenomycetes.

Technical Abstract: Pyrenomycetes are fungi united by two features: (1) perithecial, or less frequently cleiostothecial, ascomata within which (2) unitunicate, or in some cases evanescent asci, are formed. Ascomata may be solitary, superficial, and not associated with stromata or they may be densely gregarious and seated on or immersed within stromata or tissue of the substratum. They may be manifested only in their asexual form, that is formed independently of the sexual form, separated from it by season, geography, or genetic compatibility. This group of organisms includes many industrially beneficial fungi as well as agents of some of the most devastating plant and animal diseases and toxicoses. Pyrenomycetes primarily are terrestrial organisms that occur in a wide variety of habitats. They are known from virtually all ecosystems, including tundra, forests, grasslands, and deserts, where they are important as decomposer organisms. Within these habitat many pyrenomycete are biotropic, forming parasitic and endophytic associations with plants, animals, and other fungi. The extralimital pyrenomycetes include the Laboulbeniales and several unclassified genera, all of which have evanescent asci and are closely associated with arthropods for dispersal; most of the thousands of species of Laboulbeniales are obligate parasites of arthropods. A few pyrenomycetes are associated with photobionts to form lichens, but none has been reported as mycorrhizal. Some pyrenomycetes have invaded freshwater and marine aquatic habitats.