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PEET: Lasiosphaeriaceae

Systematic Study of Chaetosphaeria and Lasiosphaeria

To explore the Lasiosphaeriaceae project in full go to the micro-site: click here.

The Sordariales (Fungi, Ascomycetes) contains 99 genera, divided among eight families. It includes many economically and ecologically important species including species of Ceratocystis and Chaetomium as well as the model taxa Neurospora crassa and Sordaria fimicola. However, recent phylogenetic analyses of DNA sequence data that included single representatives of four of the families of Sordariales suggest that the order is not monophyletic. A detailed assessment of the relationship among Sordarialean families is necessary to address this issue but before a meaningful sampling strategy can be devised, revisions of several key genera must be undertaken. The Lasiosphaeriaceae, 51 genera and about 1000 species, is the largest and most morphologically diverse family in the order, and in particular several of the species-rich genera in the family remain unstudied. Relationships among the genera are also unknown.

In this study, we propose to prepare monographs of two of the largest genera in the Lasiosphaeriaceae, Chaetosphaeria and Lasiosphaeria, which have never been treated systematically and are key to understanding phylogenetic relationships in the family and the order. Species in the two genera are ecologically and economically important and although they have been described primarily from north temperate regions previous work by the PI suggests that they are a dominant part of the neotropical mycota involved with litter decomposition. Fieldwork will be undertaken in several sites in the U.S.A., Puerto Rico, Panama, and Ecuador to assess their ecological significance in more detail. These sites were chosen to sample areas with known high species diversity and to test several recent hypotheses on fungal biodiversity and biogeography.

Based on the results of the monographic work, an assessment of phylogenetic relationships of Chaetosphaeria and Lasiosphaeria with the other genera currently included in the Lasiosphaeriaceae will be undertaken, this will facilitate critical analysis of relationships among the eight families of Sordariales. Both the monographic and the family level phylogenetic studies will be based on morphological and molecular data obtained from type and other herbarium specimens, newly collected specimens, and cultures. This program directly addresses several of the major challenges currently facing ascomycete systematics including: a) rigorously examining patterns of variation in some of the key morphological characters currently used in ascomycete taxonomy, b) integrating sexual and asexual taxa into a unified phylogeny and classification, c) stabilizing generic, familial and ordinal concepts using a phylogenetic approach, d) determining taxonomic diversity in tropical countries, e) integrating these data into monographic treatments, and f) training students to become well versed in traditional as well as modern tools and analyses. Modern monographic treatments of ascomycetes are rare, and comprehensive treatments for species-rich genera currently are lacking. Thus, another important goal of this project is to publish monographs that will be used as models for future systematic work on ascomycetes.