The molecular basis of how cyst nematodes coordinate their life cycle with their host

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This project will determine the molecular basis by which this protein links hatch of PCN to the presence of host root diffusates. Our preliminary data have allowed the identification of an eggshell localised annexin, which contains a unique (to this specific annexin in PCN) an insertion in one of the predicted calcium binding sites of the protein. We have confirmed that this annexin binds lipids in a calcium-dependent manner and that it undergoes a conformational change in the presence of calcium that is lost in the presence of host root diffusates. Silencing of the gene encoding this annexin disrupts the ability of the nematode to control the permeability of the eggshell. Collectively these data suggest a critical role for the annexin in linking activation of the nematode life cycle to the presence of host derived chemical cues. In this project we will determine the structural and biochemical basis by which the annexin responds to compounds present in root diffusates and changes the permeability of the nematode eggshell.

Cyst nematodes cause major losses to many important crops across the world. In the UK, the potato cyst nematodes cause yield losses valued at over £50 million each year. New infestations into previously clean land threatens the future of the seed industry in Scotland. In addition, PCN has been reported in several sub-Sharan African countries where potato is a major food and cash crop for smallholder farmers and is causing huge yield losses in this region. New control strategies for PCN therefore offer the potential for major societal impact.
The proposed work described here offers the potential for scientific advances in terms of our understanding of the interaction between plants and pathogens as well as the development of new knowledge that could underpin development of new control strategies for these devastating pathogens. The proposed work will provide the starting point for new chemical control agents that specifically target the function of this protein. This protein represents an attractive control target as it is specific to pest species of nematode and can be targeted in the dormant stage of the nematode. These features contrast with current chemical control strategies which have broad off-target effects and are effective only against the juvenile stage which is active for a very short time in the soil. The unique opportunity for development of new cyst nematode control tools presented by this protein is recognised by Syngenta, who have provided a letter of support confirming their willingness to further exploit the findings derived from this project.