Submitted to: Mycologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/8/2003
Publication Date: 2/6/2004
Citation: Chaverri, P., Castlebury, L.A., Overton, B., Samuels, G.J. Hypocrea/trichoderma: species with conidiophore elongations and green conidia. Mycologia. Vol. 95(6)pp.1100-1140,2003.
Interpretive Summary: Fungi in the genus Hypocrea, often in their Trichoderma asexual states, are useful in the biological control of plant diseases. Species of Trichoderma are difficult to define because of their lack of distinctive microscopic structures. Thus it is necessary to examine them carefully and to analyze characteristics of the DNA of these fungi. By combining these approaches, it is possible to define species and determine relationships among isolates. In this paper 19 species of Trichoderma are described and illustrated based on their microscopic structures as well as the characteristics of their DNA. Five new species of Trichoderma are described. A key to species of Hypocrea/Trichoderma with green conidia and conidiophore elongations is included. This research will be used by plant pathologists and ecologists to identify the species of Trichoderma that they encountered in their research on biological control of plant diseases.
Technical Abstract: The species of Trichoderma and Hypocrea that have green conidia and sterile or fertile elongations of their conidiophores are described or redescribed and their phylogenetic position is explored. Five new species of Hypocrea are described, viz. H. cremea, H. cuneispora, H. estonica, H. strictipilis, and H. surrotunda. The phylogenetic relationships of these species were inferred based on partial RPB2 and EF-1a DNA sequence data and phenotypic characteristics, including teleomorph, anamorph, colony and growth rates. Trichoderma crassum was found to be a sister species to T. virens, based on molecular sequences and phenotypic data. Hypocrea surrotunda and H. cremea, H. cuneispora and T. longipile, T. fertile and T. oblongisporum, T. tomentosum and H. atrogelatinosa, and T. hamatum and T. pubescens, respectively, were found to be phylogenetically closely related, based on RPB2 and EF-1a gene genealogies. Anamorph and teleomorph phenotype, including conidiophore elongations, phialide morphology, conidial morphology, stroma anatomy and ascospore morphology are not useful predictors of relationships. Despite shared phenotypic characters of these Trichoderma and Hypocrea species, they are distributed between two major clades of Trichoderma/Hypocrea. Redescriptions and a key to species of Hypocrea/Trichoderma with green conidia and conidiophore elongations are presented.