The Potential of Metagenomic Approaches for Understanding Soil Microbial Processes

Technological advances in sequencing technologies and bioinformatics analysis tools now enable the generation of a metagenome from soil, although the ultimate goal of obtaining the entire complement of all genes of all organisms in a given sample of soil still lies in the future. The rich information obtained from a soil metagenome will undoubtedly provide new insights into the taxonomic and functional diversity of soil microorganisms; the question is whether it will also yield greater understanding of how C, N, and other nutrients cycle in soil. The purpose of this review is to describe the steps involved in producing a soil metagenome, including some of the potential pitfalls associated with its production and annotation. Possible solutions to some of these challenges are presented. Selected examples from published soil metagenomic studies are discussed, with an emphasis on clues that they have provided about biogeochemical cycling.