A key question in plant nematology is understanding the mechanism behind plant parasitism. The phylogenetic analysis of the 1200 SSU rDNA sequences has shown that plant parasitism has occurred at least three times independently, most likely from fungul feeders. A major step forward was the discovery that, unlike most other animals, plants parasitic nematodes are able to synthesize a wealth of cell wall degrading and modifying enzymes. For many years it was believed that animals are dependent on symbiontic micro-organisms to degrade plant cel walls. However, in recent period it has been shown that nematodes do not only produce cellulases, polygalacturonases, pectate lyasesm, but also expansis, until recent only thought to be present in plants. Another remarkable finding was that plant parasitic nematodes secrete a suite of proteins that consist only of a B30.2/SPRY domain and signal peptide for secretion (SPRYSEC family). A member of this SPRYSEC family was found to suppress not only the defence reaction to the potato cyst nematode, but also to a fungus, a virus and an oomycete.
The ultimate goal is to obtain a complete understanding of the interactions between plants and pathogens. The outcome of plant-microbe interactions is governed by various biotic and abiotic factors, like temperature, nutrients, pH and soil type. As a first step towards this goal we set out a research program that takes advantage of the model organism Caenorhabditis elegans and performed genetical genomics on a recombinant inbred population in different abiotic environments and treated the expression level of each gene as a singel quantitative trait.