MESSENGER HARPIN SEED TREATMENT AND HARPINEA GENE TRANSGENIC COTTON REDUCE REPRODUCTION BY ROOT KNOT AND RENIFORM NEMATODES

摘要

Messenger is the first commercialized product from a new class of chemistry called harpin proteins. Harpin, the active ingredient in Messenger , activates natural stress-defense responses in plants that increase plant vigor and result in better overall plant health. Root-knot nematodes (RKN), Meloidogyne incognita, and reniform nematodes (RN), Rotylenchulus reniformis, are important nematode pests of rgany crop species including cotton. The effects of harpin, as a seed treatment (N-Hibit ), foliar spray (Messenger ), and transgenic gene were studied on cotton in growth chamber experiments. Plant height, the number of nodes per plant, and total plant biomass were increased with certain timings of topical treatments (seed or foliar treatment). With both RKN and RN, treated plants averaged lower numbers of nematodes than untreated plants, and in all cases the fecundity of females was decreased. All eight of the transgenically-expressed harpin constructs of PE58 averaged less RKN eggs per root weight compared with the Coker control. Although results were variable, these studies suggest that harpin may be useful in mitigating damage to cotton due to nematodes, particularly the combination of seed treatment followed by foliar spray and perhaps as a transgenic gene within the plant.