Interactions between nematodes and microorganisms: Bridging ecological and molecular approaches

This chapter focuses on particular aspects of the biotic interactions between nematodes and other microorganisms. The behavior of any particular nematode is governed by an interaction between its internal physiological state, as determined by its genetic makeup and biochemistry, and the external environment in which it finds itself. Molecular approaches, and in particular using rDNA, have been hugely important in understanding the phylogenetic relationships between different organisms and assessing their biodiversity. However, more recently, multilocus approaches are being pursued with both bacteria and nematodes. Although these approaches are hugely important for the scientist endeavoring to use one organism to control another, where each of these organisms have been locked into an arms race—one against the other, rapid generation of genetic diversity among a small set of genes can probably be the norm. Identifying those genes that are predictive of host range on the part of the pathogen or parasite, and resistance on the part of the host, and understanding their diversity will become a starting point for the selection of control agents and the development of robust biological control strategies.