Abstract
We analyzed the DNA sequences of four gene regions, 28S and 18S rDNA, the ITS region and rpb2, to obtain a high resolution phylogenetic tree of Dacrymycetes. In addition, we comparatively studied micro- and macromorphological characteristics of representative species. The traditional generic classification based on morphological characteristics was not reflected by our molecular phylogenies. Ancestral state reconstructions indicated that the morphology of basidia and clamp connections are evolutionarily stable. In contrast, basidiocarps and basidiospore septation patterns appear variable. Dacrymyces unisporus shares the dolipores with non-perforate parenthesomes typical of other dacrymycetous taxa but is a unique species having predominantly non-bifurcate basidia and subglobose to ovoid basidiospores with transverse and longitudinal septa. In molecular phylogenies this species is a member of Dacrymycetes but always occupies a sister position in relation to the rest of the Dacrymycetes. Based on our results we propose a new genus, Unilacryma, for D. unisporus. For proper accommodation of this taxon, we introduce the family Unilacrymaceae and the order Unilacrymales.
Acknowledgments
We are grateful for the help of the Fungal Biodiversity Centre of the Centraalbureau voor Schimmelcultures (CBS), International Collection of Microorganisms from Plants (ICMP), Culture collection of National Institute of Agrobiological Science (MAFF) and Forest Products Laboratory in U.S. Department of Agriculture for sending us cultures of dacrymycetous strains.
This research was supported by the grant from Global COE program “Advanced utilization of fungus/mushroom resources for sustainable society in harmony with nature” of Tottori University.