Molecular Identification of Nematode Gut Contents 

Quinn D. Martin, Byron J. Adams

Species-specific food web relationships involving free-living microbivorous nematodes are not well established, yet critical to our understanding of their involvement in nutrient cycling and ecosystem function.  Antarctic soil ecosystems are the simplest on earth and serve as a model system for exploring the role of biodiversity in ecosystem functioning.  To establish which bacteria are involved in trophic relationships with nematodes, we surface-sterilized nematodes and extracted their DNA, including bacterial DNA from the gut contents of the nematodes.  From this bacterial DNA we PCR amplified the 16S gene and sequenced the product in order to determine the identity of the gut contents of the nematode.  We successfully amplified and sequenced the 16s rRNA of Photorhabdus from the gut of the nematode genus Heterorhabditis.  We are currently continuing these experiments with Plectus nematodes from the MCM.  Given a broader sampling regimen, success with this approach could be used to establish food web relationships in more complex ecosystems.