Diversity of soil fungi associated with differing monoculture forest types measured by next-generation pyrosequencing

Background/Question/Methods

It has long been understood that fungi contribute to many key ecosystem processes.  This is particularly important in forest soils, where saprotrophic fungi are the main drivers of plant organic matter decomposition and ectomycorrhizal fungi facilitate nutrient uptake for their host plants, thereby affecting plant growth and fitness.  Additionally, the presence of soil fungi shape seedling establishment and evidence suggests that ectomycorrhizal fungi may contribute to the distribution of carbohydrates from one tree to another, directly regulating the survival of nurse seedlings.  Despite their important ecological roles, there is a paucity of information regarding taxonomic diversity and abundance associated with plant host.  Largely this is due to the fact that many fungi are unculturable, lack known sexual structures, and are known only by nucleotide identification. 

Results/Conclusions

In order to understand the diversity of fungi associated with differing forest types, we have utilized next-generation sequencing techniques (454/Roche and Illumina/Solexa) to probe soil fungal diversity.  Seven mono-culture forest types (Fagus, Quercus, Pinus, Pseudotsuga, Picea plantations, an "Old-growth" native forest dominated by Fagus, and an early successional Populus bioenergy plantation) were seasonally sampled.  Next-generation sequencing showed extreme diversity in fungal taxa.  Only 24% of taxonomic sequence reads were able to be identified with existing fungal databases.  This finding agrees with recent studies employing new sequencing techniques to probe fungal diversity.  Our sequencing shows an average of more than 2000 unique fungal taxa in as little as four grams of forest soils.  This presentation will present diversity data across forest types surveyed and across seasonal sampling.