P-007 - Analysis of nematode surface proteins

Many surface molecules and secretions of nematodes are known to modulate plant immunity and therefore play an important role in the early interaction between plant and nematodes. Enolase (2-phospho-D-glycerate hydrolase, EC 4.2.1.11), a conserved glycolytic enzyme, was identified in a proteomic analysis of the extracellular fluid of the plant-parasitic cyst nematode Heterodera schachtii. Enolase is thought to have a variety of functions. In animal- and insect-pathogenic nematodes, it has been identified as a surface molecule and shown to activate the host's immune system. Since plants lack an adaptive immune system, we wanted to investigate whether H. schachtii enolase can affect plant immunity, growth and development. Therefore, we cloned and expressed the nematode enolase in E. coli. Exposure of A. thaliana seedlings to recombinant enolase resulted in a significant effect at high concentrations (425–850 μg/ml), but showed no effect at lower concentrations (10–100 μg/ml). Furthermore, we did not observe any production of reactive oxygen species, one of the first reactions of the plant to a pathogen-associated molecular pattern. We conclude that the enolase released by nematodes does not trigger canonical pattern-triggered immunity, but may potentially affect plant cell growth and development.