Research Interests:
Research in the Berbee laboratory focuses on the diversity and molecular phylogenetics of fungi. Fungi and animals shared a common ancestor over a billion years ago. Since that time, animals evolved into herbivores and predators while fungi became specialized as decay agents and recyclers in the environment; as plant and animal pathogens; and as symbionts contributing as mycorrhizal partners to plant growth. Through a combination of field and laboratory work, students and postdoctoral researchers are finding and culturing fungi and fungus-like organisms, many of them new to science, and then applying microscopic and molecular phylogenetic techniques to place the origin and diversification of the fungi in a phylogenetic context.

Current research
1. Deep divergences and ancient lineages of fungi and fungus-like organisms (Taylor et al. 2006, Mycologia; Berbee et al. 2007, New Phytologist). With funding from Canada’s NSERC and from the US NSF, members of the Berbee lab are collecting new fungi and fungus-like organisms from aquatic environments, growing them in pure culture whenever possible, and combining microscopic and phylogenetic approaches to make inferences about their biology and evolutionary origins (Marshall et al. 2008, Protist; Tsui et al. 2009, Molecular Phylogenetics and Evolution). Including our newly discovered organisms as well as taxa from culture collections, they are sequencing genes that allow reconstruction of patterns of evolutionary origin of the fungus life style among evolutionarily divergent fungi and fungus-like organisms.

2. Ascomycete evolution, breeding systems and systematics. With more than 30,000 known species, the ascomycetes are diverse and ecologically important. With the support of NSERC, students in the Berbee lab are reconstructing patterns of evolution in the ascomycetes. They are concentrating on the Pleosporales, a well-defined group including many species with adaptations to specialized habitats. Like whales and seals, some fungi in this group originated on land but then returned to the water. Over 60 species in the order Pleosporales produce helicoid asexual spores many adapted for dispersal in water and colonization of aquatic habitats. Our analyses are showing extensive convergence in most morphological characters and molds forming complex, barrel-shaped helical spores to trap air bubbles for floatation arose convergently from three, primarily terrestrial lineages in the Pleosporales (Tsui et al. 2006, Molecular Phylogenetics and Evolution).
    The Pleosporales also included many serious pathogens of plants. To track the molecular evolution of changes in breeding systems among these plant pathogens, the Berbee lab is applying molecular amplification of mating type gene DNA. The two opposite mating type genes are the master regulators of sexual reproduction in these fungi. In an outcrossing species, haploid individuals with opposite mating types can mate and 50% of their haploid progeny will be of each mating type. Asexual reproduction propagates the parental mating type. In a selfing species, each haploid nucleus in an individual carries the two opposite mating type genes. Working backwards, by examining the distribution of mating type genes in a population, we can distinguish outcrossing from selfing individuals and sexual from asexual populations (Inderbitzin et al. 2005, PNAS; Inderbitzin et al.; 2006, Canadian Journal of Botany). 15,000 ascomycete species lack known sexual states and for these fungi, our molecular genetic detection of mating type genes will provide a tool to distinguish cryptic sexuality from true clonality (Berbee et al. 2003, Mycological Research).

3. Mycorrhizal fungal diversity. Forestry is of great economic importance in British Columbia (BC) and one of the goals of foresters is to develop management strategies that maintain the diversity of forest organisms including fungi. Mycorrhizae are mutually beneficial associations between fungi and roots of plants and they are required for healthy forests. Our studies have shown that BC fungi are highly diverse (Allen et al. 2003, New Phytologist; Wright et al. 2009, Mycorrhiza). Even though fungi are clearly important to tree health, which fungi are important for particular trees in particular regions of the province remains largely unknown. With funding from the BC Forest Science Program, from NSERC, and with the support of the Vancouver Mycological Society and graduate and undergraduate students conducting research projects, we are exploring the diversity of fungi in BC and contributing to a DNA sequence barcode database that will facilitate identification of our mushroom species. With these data, we will be able to correlate the occurrence of particular fungi with tree species, with geographical regions, and with tree growth rates. This research helps lay the groundwork for development of conservation management strategies for fungi and for the plant community that requires fungal partnerships.

Ascomycete evolution.

Mycorrhizal fungal diversity.