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Yuanming Zhu,
Michael R Loso,
Gerald B Watson,
Thomas C Sparks,
Richard B Rogers,
Jim X Huang,
B Clifford Gerwick,
Jonathan M Babcock,
Donald Kelley,
Vidyadhar B Hegde,
Benjamin M Nugent,
James M Renga,
Ian Denholm,
Kevin Gorman,
Gerrit J DeBoer,
James Hasler, Thomas Meade,
James D Thomas
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ABSTRACT: The discovery of sulfoxaflor [N-[methyloxido[1-[6-(trifluoromethyl)-3-pyridinyl]ethyl]-λ(4)-sulfanylidene] cyanamide] resulted from an investigation of the sulfoximine functional group as a novel bioactive scaffold for insecticidal activity and a subsequent extensive structure-activity relationship study. Sulfoxaflor, the first product from this new class (the sulfoximines) of insect control agents, exhibits broad-spectrum efficacy against many sap-feeding insect pests, including aphids, whiteflies, hoppers, and Lygus, with levels of activity that are comparable to those of other classes of insecticides targeting sap-feeding insects, including the neonicotinoids. However, no cross-resistance has been observed between sulfoxaflor and neonicotinoids such as imidacloprid, apparently the result of differences in susceptibility to oxidative metabolism. Available data are consistent with sulfoxaflor acting via the insect nicotinic receptor in a complex manner. These observations reflect the unique structure of the sulfoximines compared with neonicotinoids.
Journal of Agricultural and Food Chemistry 11/2010; 59(7):2950-7. · 2.82 Impact Factor
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ABSTRACT: Transgenic maize, Zea mays L., event TC1507 produces the Cry1F protein to provide protection from feeding by several important lepidopteran pests, including Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae). Reports of reduced field performance against this species in Puerto Rico were investigated, and laboratory bioassays showed that S. frugiperda collected from the affected area exhibited lower sensitivity to the Cry1F protein compared with typical colonies from other regions. The resistance was shown to be autosomally inherited and highly recessive. The Puerto Rico colony was shown to be moderately less sensitive than susceptible laboratory strains to Cry1Ab and Cry1Ac, but the differences in sensitivity were dramatically smaller than for Cry1F. Potential contributory factors to the emergence of resistance to Cry1F in Puerto Rico populations of S. frugiperda include the tropical island geography, unusually large population sizes in 2006, and drought conditions reducing the availability of alternative hosts. In response to this resistance incident, the technology providers have stopped commercial sales of TC1507 maize in Puerto Rico pending potential reversion to susceptibility.
Journal of Economic Entomology 08/2010; 103(4):1031-8. · 1.70 Impact Factor
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ABSTRACT: The tcdA gene of Photorhabdus luminescens encodes a 283-kDa protein, toxin A, that is highly toxic to a variety of insects, including some agriculturally important pests. We tested the efficacy of transgenic toxin A in Arabidopsis thaliana for control of feeding insects. Plants with toxin A expression above about 700 ng/mg of extractable protein were highly toxic to tobacco hornworm (Manduca sexta). Toxin A isolated from transgenic plants also strongly inhibited growth of the southern corn rootworm (Diabrotica undecimpunctata howardi). Addition of 5' and 3' untranslated regions of a tobacco osmotin gene (osm) increased toxin A production 10-fold and recovery of insect-resistant lines 12-fold. In the best line, high toxin A expression and insect resistance were maintained for at least five generations in all progeny. The intact tcdA mRNA represents the largest effective transgenic transcript produced in plants to date. These results may open a new route to transgenic pest control in agriculture.
Nature Biotechnology 11/2003; 21(10):1222-8. · 23.27 Impact Factor
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ABSTRACT: A family of novel binary insecticidal crystal proteins, with activity against western corn rootworm, Diabrotica virgifera virgifera LeConte, was identified from Bacillus thuringiensis Berliner. A binary insecticidal crystal protein (bICP) from B. thuringiensis strain PS149B1 is composed of a 14-kDa protein (Cry34Abl) and a 44-kDaprotein (Cry35Ab1). These proteins have been co-expressed in transgenic maize plants, Zea mays L., and effectively control western corn rootworm larvae under field conditions. Laboratory experiments were conducted to better understand the contribution of each component protein to the in vivo activity of the bICP. The 14-kDa protein is active alone against southern corn rootworm, Diabrotica undecimpunctata howardi Barber, and was synergized by the 44-kDa protein. In mixtures, the concentration of the 14-kDa protein had a greater impact on efficacy than the 44-kDa component. Although both proteins are clearly required for maximal insecticidal activity, laboratory results did not support the formation of a stable, fixed-ratio complex of the two component proteins.
Journal of Economic Entomology 07/2002; 95(3):635-9. · 1.70 Impact Factor
