The production of synthetic chemodisruptive peptides in planta disrupts the establishment of cyst nematodes.

Root exudates from transgenic potato plants expressing a chemoreception-disruptive peptide inhibit acetylcholinesterase by up to 63 +/- 3%. This inhibition correlates strongly with the efficacy of the exudates as a presoak solution for infective juveniles of Heterodera glycines that leads to reduced root invasion. The establishment of developing Globodera pallida at 21 days post-infection in these transgenic plants was also suppressed in containment trials. Relative to controls, the best line showed a 47 +/- 5% reduction in developing females and had 188 +/- 25% more undeveloped infective juveniles. This suggests that disorientation of chemoreception occurs after initial root invasion. Line (e) showed the highest level of resistance with 61 +/- 4% in glasshouse trials conducted over a 9-week period. This result represents the combined effect on the number of cysts produced and the number of eggs each cyst contains. The level of control shown to saccate females was consistent in both the 21-day and 9-week post-infection studies. Another chemoreception-disruptive peptide, that binds to nematode nicotinic receptors in cholinergic neurones, provided a 52.6 +/- 1% reduction in the number of nematodes able to establish in transgenic hairy roots that expressed the peptide. This confirms that both chemoreception-disruptive peptides have efficacy in suppressing parasitism by cyst nematodes when expressed in planta at low concentrations.