A polyphasic contribution to the knowledge of Auxarthron (Onygenaceae)

In a survey of coprophilous fungi in Italy, two interesting ascomycetes were recovered from hedgehog dung. These fungi showed a sexual morph characterized by gymnothecia, globose reticulate ascospores, a Malbranchea asexual state, and a keratinolytic ability, and were identified morphologically and molecularly as Auxarthron umbrinum and A. concentricum of the Onygenaceae. The history, ecology, and morphology of the genus Auxarthron as a whole, and of A. umbrinum and A. concentricum in particular, are revised. A preliminary evaluation of the antagonistic properties of A. umbrinum and A. concentricum against phytopathogenic fungi has been performed in dual cultures. Growth inhibition of some plant pathogenic fungi was recorded, and the effects were growth medium dependent. When solid-state fermentation (SSF) substrate of both Auxarthron isolates has been submitted to extraction, both the organic extract residues (n-hexane and CH2Cl2) and the lyophilized aqueous phases were used for the antibiotic test against plant pathogenic fungi. Significant antifungal activity was obtained by organic fractions and aqueous residue of A. concentricum against Alternaria brassicicola and Botrytis cinerea, whereas A. umbrinum appeared to be less effective. The analysis of ITS nrDNA sequences suggests that an extensive phylogenetic revision of the genus Auxarthron is necessary.