Hypocrea/Trichoderma: species with conidiophore elongations and green conidia

Abstract

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 explored. The described species include T. crassum, T. fasciculatum, T. fertile, T. hamatum, T. longipile, T. oblongisporum, T. pubescens, T. spirale, T. strictipile, T. strigosum, T. stromaticum, T. tomentosum, Hypocrea aureoviridis f. macrospora, H. ceramica. and H. semiorbis. Trichoderma fasciculatum originally was described from cultures from ascospores of an unidentified Hypocrea specimen; it is considered to be a synonym of T. strictipile. The remaining species of Trichoderma considered here have not been linked to teleomorphs, and the Trichoderma anamorphs of H. aureoviridis f. macrospora and H. semiorbis have not been named. Five new species of Hypocrea are described, viz. H. cremea, H. cuneispora, H. estonica, H. strictipilosa and H. surrotunda. The phylogenetic relationships of these species were inferred based on partial RPB2 and EF-1α 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 closely related phylogenetically, based on RPB2 and EF-1α 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 the 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.

• Ascomycetes
• Hypocreaceae
• Hypocreales
• molecular phylogenetics
• RNA polymerase II subunit RPB2
• synanamorphs
• systematics
• teleomorph-anamorph connection
• translation elongation factor EF-1α
• Trichoderma sect. Pachybasium

We appreciate Dr. John Bissett and Ms. Carolyn Babcock (DAOM) for providing us with cultures from the DAOM collection. Dr. Steven Rehner kindly provided an EF1-α primer sequence and Andrew N. Miller gave helpful advice on the use of RPB2. We also thank Drs. Elwin L. Stewart, David M. Geiser and Amy Y. Rossman for their comments on the paper. This study was supported in part by the United States National Science Foundation (PEET) grant 9712308, “Monographic Studies of Hypocrealean Fungi: Hypocrea and Hypomyces” to Pennsylvania State University, Department of Plant Pathology. An interactive key to identification of Trichoderma species is available at http://nt.ars-grin.gov/taxadescriptions/keys/TrichodermaIndex.cfm or it can be accessed through the Systematic Botany and Mycology Lab Website, http://nt.ars-grin.gov