Susceptible response

Many plant parasitic nematodes, including the potato cyst nematodes, are biotrophic and induce complex feeding structures (syncytia) in the roots of their hosts. The syncytium is a large, multinucleate, metabolically active structure and its formation requires massive reprogramming of plant gene expression. Understanding how nematodes induce these structures in plants is an important goal of our work.

In our previous work we showed that plant parasitic nematodes, like animal parasitic nematodes, are coated in proteins that protect them from the defence responses of their hosts (Robertson et al., 2000). More recently we have identified proteins that may be involved in induction or maintenance of feeding structures and have developed systems for functional analysis of such proteins. More about this work can be found in Chen et al., (2005) and Jones et al., (2003)

Nematode avirulence

During a biotrophic interaction, such as that between nematodes and plants, a battle goes on between host and pathogen. The host will aim to detect the pathogen while the pathogen will aim either to mask itself from the host or down-regulate any defence response that the host induces. Identification of nematode proteins that may manipulate the host response is a goal of our work.

Plants detect pathogens using Resistance (R) genes. These proteins recognise corresponding pathogen proteins called avirulence (Avr) genes in a gene-for-gene manner. The interaction between R and Avr protein may also involve another host molecule that the R gene is protecting (the guard hypothesis). We aim to identify nematode Avr genes using genomics tools. Recent work has shown that polymorphisms in one nematode secreted protein, chorismate mutase, are correlated with virulence against a resistance source from Solanum vernei.

References

Chen, Q. Rehman, S., Smant, G. Jones J.T. 2005. Functional analysis of pathogenicity proteins of the potato cyst nematode Globodera rostochiensis using RNAi. MPMI 18, 621-625

Jones, J.T., Furlanetto, C., Bakker, E., Banks, B., Blok, V.C., Chen, Q. and Prior, A. 2003. Characterisation of a chorismate mutase from the potato cyst nematode Globodera pallida. Molecular Plant Pathology 4, 43-50.

Robertson, L., Robertson, W.M., Sobczak, M., Bakker, J., Tetaud, E., Arinagayayam, M.R., Ferguson, M.A.J., Fairlamb, A.H. and Jones, J.T. 2000. Cloning, expression and functional characterisation of a thioredoxin peroxidase from the potato cyst nematode Globodera rostochiensis. Molecular and Biochemical Parasitology 111, 41-49.