An effective basis for control of potato cyst-nematodes and assessment of the impact on soil health

Plant parasitic nematodes cause losses to global agriculture of 100b dollars annually. Potato cyst nematode costs the UK potato industry an estimated 43 m pounds sterling/year. Control often depends on nematicides that are both harmful to the environment and possibly human health but often essential for economic potato cropping in the UK. We have developed novel resistance that controls many nematodes including potato cyst-nematodes. This antifeedant approach has been shown to be effective, completely safe in food and benign to the environment. It has been highlighted uniquely by two government reports for its importance to UK agriculture. This work will develop the approach and achieve 90 per cent resistance by stacking antifeedants with peptides that prevent nematode attraction to host roots. The number and diversity of other nematode species will be used as an indication of soil health. We will determine whether or not using the peptides has any effect on non-target nematode species. We will develop methods that will allow nematode diversity to be assessed in a large number of field samples.This will add a further appropriate basis to those we have already deployed. We wish to assess any environmental impact of our technology on soil organisms in the field and allow its comparison with the pesticide use it would replace.

Plant parasitic nematodes cause losses to global agriculture of 100b Dollars annually. Potato cyst nematode costs the UK potato industry an estimated 43m pounds sterling/year. Control often depends on nematicides that are both harmful to the environment and possibly human health but often essential for economic potato cropping in the UK. We have developed genetically modified, nematode resistant (GMNR) potatoes that have been shown to have no substantial adverse effect on either invertebrate associates of potato above ground or on soil communities. The approach relies on a cysteine proteinase inhibitor already in food, which prevents nematodes from utilising their dietary protein. Toxicological studies establish that a margin of exposure is more than 2000 fold when root specific promoters are used to deliver the cystatin to where nematodes feed while providing low expression of a safe novel protein in food. Work by others has established that the protein is not an allergen. The proposed work will stack that approach with novel peptides that disrupt nematode chemosensory-mediated invasion of host roots. This will involve restricted expression of peptide at sites of invasion and in the rhizosphere. All the components of the stacked defence will be delivered behind promoters that optimise expression at site of invasion and feeding where it is required and limit expression elsewhere i.e. in tubers. New GMNR lines harbouring stacked defences will be challenged in containment and later, the best lines will be tested in the field. In this work we will extend our completed, comprehensive environmental impact studies from our GMNR-cystatin plants to those that disrupt nematode orientation to roots. Non-target nematodes form a dominant group of soil meiofauna, occur in all soil types, with both high abundance and biodiversity. Nematodes play an important role in soil functioning, e.g. in food webs and have been judged as the most promising indicators of soil quality. We will establish base lines that can be applied later to GMNR and other plants in a range of field soils. A recent, promising approach for nematode species identification and comparison between different populations is the use of molecular barcodes derived from PCR amplification, sequencing and analysis of the small subunit ribosomal RNA gene. We will use this approach in parallel with morphological recognition of changes in nematode abundance or prevalence in our soils. The aim of the work is to establish the potential of a fully biosafe GM replacement for current UK use of environmentally damaging pesticides. One novel variant of this technology depends on nematode control via GM allelopathic plants without production of tubers from GM potato plants.