Molecular phylogeny of fungi in the genus Thelonectria (Hypocreales, Nectriaceae): Are they really monophyletic?
C. SALGADO-SALAZAR (1), A. Y. Rossman (2), P. Chaverri (3). (1) University of Maryland, College Park, MD, U.S.A.; (2) USDA-ARS, Beltsville, MD, U.S.A.; (3) Department of Plant Science and Landscape Architecture, University of Maryland, College Park, MD, U.S.A.
<i>Thelonectria</i> is an emblematic genus of nectriaceous fungi adapted to a wide range of woody hosts and found in many tropical and temperate environments. About 20 species have been described to date, involving morphologically similar species formerly assigned to <i>Neonectria</i>. In general, species in this group have a perithecial wall comprised of thick walled cells, a knobby or prominent perithecial apex, spinulose or tuberculate ascospores, microconidia only produced in some species, and chlamydospores absent. Although <i>Thelonectria</i> sensu lato species share morphological characters, they seem to be symplesiomorphic, shared by an assemblage of genetically very divergent species, as previous studies have found that the majority of species in this genus comprise species complexes. Based on the results obtained from multilocus phylogenetic analyses using six nuclear markers, a polyphyletic nature for <i>Thelonectria</i> species is revealed. Here it is proposed that in order to preserve monophyly, species relationships in the genus <i>Thelonectria</i> should be reconsidered. Based on these results, the generic limits of <i>Thelonectria</i> should be reduced, and new genera erected. However, as many generic limits can be applied, i.e. more that one genus can be created, segregated genera should be based on the relationship among morphological, molecular and geographical characters.
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