Microbial Genome Sequencing: Coupling Diversity with Function: Metagenomics of Boreal Forest Fungi

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Fungi play dominant roles in decomposition and plant nutrient acquisition, and thus influence net primary productivity, carbon sequestration in soil, and the biogeochemical cycling of key elements such as nitrogen and phosphorus. Little is known about the roles of particular fungal species in these processes, in part because many species cannot easily be isolated in pure culture. Metagenomic methods offer solutions to this isolation-bias problem. The boreal forest plays a central role in global biogeochemical cycling due to its abundance and because it stores approximately 30% of the earth's reactive carbon. Hence, fungal diversity and function in the boreal forest are compelling subjects for metagenomic scrutiny. This project will undertake the most detailed examination to date of fungal diversity, genetic relationships and substrate specificity within a single geographic region. In the first step, 32,000 clones from PCR libraries of fungal ribosomal gene-regions amplified from soil DNA extracts will be sequenced. The DNAs will be extracted from key soil substrates (e.g. leaf litter, humus, wood, roots) within each of three forest types that are important components of the northern boreal forest. Discovery of novel fungi and their substrate preferences are anticipated. In the second step, the same ribosomal region will be sequenced in 4000 dried fruitbodies (e.g. mushrooms) maintained within the UAF Mycological Herbarium. The herbarium specimen sequences will permit below-ground and above-ground views of diversity to be compared, will help identify unknown fungi, and will provide a powerful database for identification of the constituent fungi observed in 'community fingerprints' from a variety of related ecological studies.