Multilocus sequence data reveal extensive phylogenetic species diversity within the Neurospora discreta complex

Abstract

Previous observations of morphological, reproductive and genetic variation have suggested that Neurospora discreta, as presently circumscribed, might represent a diverse complex of multiple species. To investigate this hypothesis we examined the phylogenetic relationships among 73 fungal strains traditionally identified as N. discreta. Strains were chosen from across the morphological, ecological and geographical ranges of the species. Sequence data were obtained from three unlinked nuclear loci, and phylogenetic species recognition was applied to the dataset using protocols that have been shown to be reliable for identifying independent lineages and delineating species of Neurospora. The results demonstrate that the present circumscription of N. discreta includes at least eight separate phylogenetic species. This research also reveals an abundance of previously unrecognized genetic diversity within the genus, characterizes the interspecific evolutionary relationships and contributes to a fuller understanding of species diversity in Neurospora.