Discovery of the parnafungins, antifungal metabolites that inhibit mRNA polyadenylation, from the Fusarium larvarum complex and other Hypocrealean fungi.

Evaluation of fungal fermentation extracts with whole cell Candida albicans activity resulted in the identification of a novel class of isoxazolidinone-containing metabolites named parnafungins. Chemical-genetic profiling with the C. albicans fitness test identified the biochemical target as inhibition of polyadenosine polymerase, a component of the mRNA cleavage and polyadenylation complex. Parnafungins were discovered from fermentation extracts of fungi resembling F. larvarum isolated from plants, plant litter and lichens. Furthermore authentic strains of F. larvarum var. larvarum and F. larvarum var. rubrum could be induced to produce parnafungins and their degradation products in low titers. Relationships among strains of the F. larvarum complex (FLC), including parnafungin-producing strains, were examined by cladistic analyses of rDNA, mitochondrial rDNA, and two protein-coding genes, comparisons of antifungal activity and antifungal metabolite profiles, and morphological phenotypes. Integrated analyses of these data led to the conclusion that the diversity within the FLC exceeded the one-to-one correspondence between F. larvarum and its teleomorph Cosmospora aurantiicola. Based on multiple gene sequence analyses, strains of the FLC formed a monophyletic clade inclusive of the parnafungin-producing strains. The FLC, including newly discovered parnafungin-producing strains, could be resolved into at least six different lineages, possibly representing cryptic' species, of which one was not fully resolved from F. larvarum var. rubrum. Fusarium larvarum var. rubrum represents a species distinct from var. larvarum. Finally we report that two other species from the Hypocreales, Trichonectria rectipila and Cladobotryum pinarense, are able to produce parnafungins and their open-ring forms.

Studies on Morinia: recognition of Morinia longiappendiculata sp. nov. as a new endophytic fungus, and a new circumscription of Morinia pestalozzioides.

A new coelomycete, Morinia longiappendiculata sp. nov., isolated from living stems of four plant species in central Spain, is described. The distinctive morphological characteristics of this fungus are the production of conidia with long basal and apical appendages on filiform conidiogenous cells that contrasts with the short-appendaged conidia and cylindrical conidiogenic cells of the type species, M. pestalozzioides. Comparative sequence analysis of the ITS rDNA region and fragments of the translation elongation factor 1alpha, actin and chitin synthase 1 genes and the study of the HPLC profiles of the M. longiappendiculata and M. pestalozzioides isolates supported the recognition of the new species. Comparison of the ITS rDNA sequences of the Morinia isolates with GenBank sequences indicated that the genus belongs to the Amphisphaeriaceae with the highest similarity to Bartalinia and Truncatella. Bresadola's original definition of M. pestalozzioides is updated by adding information on conidiogenesis and molecular data. A lectotype and epitype are designated for the species. A study of bioactive metabolites revealed that M. pestalozzioides cultures produced moriniafungin, a novel sordarin analog with potent antifungal activity.