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United States Department of Agriculture

Agricultural Research Service

Title: Molecular Systematics of the Hypocreales: a Teleomorph Gene Phylogeny and the Status of Their Anamorphs

Authors
item Rehner, Stephen
item Samuels, Gary

Submitted to: Canadian Journal of Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 1, 1995
Publication Date: N/A

Interpretive Summary: The development of management strategies to control crop diseases are hindered by lack of knowledge about the relationships between fungi in the Hypocreales. Fungi belonging to this order are important to agricultural as both plant pathogens and as agents of biological control. Phylogenetic relationships among species in the Hypocreales were determined based on an analysis of sequences of the ribosomal DNA. This study demonstrates that the hypocrealean fungi known to cause diseases of plants are only distantly related to those that are useful in biological control. These results will be useful to plant breeders who need to distinguish these fungi and scientists working to develop these strains as agents of biological control.

Technical Abstract: Phylogenetic relationships among 40 species in the Hypocreales and Clavicipitales were inferred from sequence data obtained from the nuclear large-subunit ribosomal DNA. Cladistic analysis of these data support the monophyly of the Hypocreales with the Clavicipitales derived from within the Hypocreales. Four groupings were resolved and are informally designated as the Hypocrea, Claviceps, Bionectria and Nectria groups. Phylogenetic placement of teleomorphs including Melanospora and cleistothecial taxa, such as Heleococcum, Mycoarachis and Roumegueriella, demonstrate the facility of molecular phylogenies to accommodate taxa with highly modified morphologies. Similarly, the hypocrealean origins of the anamorph species Verticillium lecanii and Acremonium chrysogenum illustrate the potential of the molecular phylogenetic approach to accommodate anamorph isolated within the context of a teleomorph phylogeny. Together these results suggest that a comprehensive classification of the Hypocreales, inclusive of teleomorph and anamorph states, is attainable through a molecular phylogenetic approach.

Last Modified: 7/23/2014
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