ubes containing 7 ml sterile tap water. Plantlets were kept in a growth chamber for 14 days during which time the volume of water in each tube was maintained at 7 ml. The water was removed and used in an assay to measure the inhibition of alkaline phosphatase. For each reaction, 20 ml root exudate and 0.2 units alkaline phosphatase were preincubated for 30 min at room temperature prior to the addition of 100 ml p-nitrophenyl phosphate. The absorbance at 405 nm was measured immediately and at subsequent 5 min intervals for one hour and the resultant regression lines used to determine enzyme activity. Four replicates were tested for each root exudate sample. Appropriate controls were included that lacked enzyme, MedChemExpress BIX02189 substrate or exudate and a standard curve was derived from non-transgenic root exudate spiked with known concentrations of synthetic peptide. Transgenic Potatoes for Cyst Nematode Control Containment trials The potato plants for resistance trial were grown as before in a sand/loam mix containing cysts of G. pallida to provide an initial population of 10 viable eggs/g soil. There were 10 replicate pots for untransformed Desiree and each of three transgenic lines harbouring the MDK-peptide construct. G. pallida final population estimates were made for two dry soil samples of 100 g taken post harvest from each pot. Cysts were recovered from each 100 g sample using a Fenwick can, disrupted in 10 ml water and the released eggs in 
three replicate 1 ml aliquots counted using standard methods. For nematode faunal analysis in containment, all plants were trialled in 25 cm pots containing approximately 9 kg soil taken from the future field trial site. A single potato plant or six oil seed rape plants were grown in each pot. Two GMNR lines studied previously that express the engineered rice cystatin OcIDD86 either constitutively or under control of a root specific promoter were included in this trial. Immediately prior to planting the soil was thoroughly mixed and triplicate 150 g samples removed for nematode faunal analysis. Rooted potato plantlets taken from liquid media were transferred to a compost/Perlite mix in 7 cm pots and established for 42 days prior to transfer into the field soil. OSR was similarly pre-grown for 42 days. There were three replicate pots each for OSR, untransformed Desiree and Sante potato cultivars, two cystatin-expressing transgenic lines and three MDK-peptide transgenic lines. Plants were grown at 2062uC on 16 h: 8 h light cycle in a containment glasshouse and a 100 g soil sample was withdrawn from the plant rhizosphere of each pot both when the untransformed cv Desiree was in flower and just before harvest. Each sample was collected from 6 positions that were 10 cm deep around a 7 cm radius from the plant stem. Soil nematodes were extracted for analysis using the Seinhorst flask method. positions and the samples combined and mixed prior to nematode extraction. Each individual nematode was assigned a tentative identification based upon morphological characteristics observed using a Leica DMRB microscope. It was then digested to release DNA and the lysate was stored at 220uC until required. PCR was carried out on 2 ml lysate using Biotaq Red DNA polymerase and primers SSU18A and PubMed ID:http://www.ncbi.nlm.nih.gov/pubmed/22182422 SSU26R designed to conserved sequences of the SSU gene. The PCR reaction conditions were as described previously. PCR products were purified then directly sequenced using a Taq Dye Deoxy Terminator Cycle Sequencing system and an automated