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Title: Reconsideration of Protocrea (Hypocreales, Hypocreaceae)

item Samuels, Gary

Submitted to: Mycologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/29/2008
Publication Date: 12/20/2008
Citation: Jaklitsch, W.M., Poldmaa, K., Samuels, G.J. 2008. Reconsideration of Protocrea (Hypocreales, Hypocreaceae). Mycologia. 100:962-984.

Interpretive Summary: Plant diseases can be controlled using biological agents such as fungi in the genus Trichoderma and the closely related genus Gliocladium. The use of these fungi to control diseases is hindered by lack of accurate characterization of potentially useful species. In this research species of Gliocladium that have a sexual state in Protocrea are described and illustrated. The type species, that is, the single species that defines this group, is redescribed and illustrated based on fresh specimens while the five other species in this genus are also reevaluated, redescribed and illustrated. Because these fungi are so small, they must be defined using characters such as the shape of their spores and how they grow as well as using DNA sequences. This research will be used by plant pathologists working to develop biological agents to control plant diseases.

Technical Abstract: The genus Protocrea is re-defined, based on holotype and fresh specimens of its type species P. farinosa, using morphology of teleomorph and anamorph and phylogenetic analyses of rpb2 sequences. Data based on currently available specimens suggest the existence of six species. Apart from the type, P. farinosa, none of the species originally included are accepted in the genus. Species of Protocrea are characterized by perithecia formed in or on a subiculum, bicellular ascospores that disarticulate at the septum while still in the ascus and by anamorphs belonging to Gliocladium s. stricto. For Hypocrea farinosa sensu auct. the new species H. decipiens is introduced. Hypocrea pallida is recognized as a species of Protocrea. It is closely related to P. farinosa, morphologically, phylogenetically, and by habit. Protocrea illinoensis is described here as the sister taxon of P. farinosa found in the USA. All species are polyporicolous, with the principal hosts Skeletocutis nivea for P. farinosa and P. illinoensis, and species of Oligoporus/ Tyromyces for P. pallida. In addition to hosts, the main differences among these species is a stronger (orange) pigmentation of perithecia and subiculum in P. pallida and a violaceous KOH reaction in P. pallida and P. illinoensis. P. farinosa is only known from Europe with certainty and P. illinoensis only from the USA, while P. pallida is probably cosmopolitan. Putative synonymy of some similar species is discussed.