Laboratory selection with Cry1Ab, the predominant Bacillus thuringiensis (Bt) toxin in transgenic corn, Zea mays L., produced >1000-fold resistance in two laboratory strains of European corn borer, Ostrinia nubilalis (Hübner). We tested the offspring of various crosses to determine the mode of inheritance of resistance to Cry1Ab. Patterns of inheritance of resistance were similar in the two res...

The fall webworm, Hyphantria cunea (Drury) is a major invasive pest in China. Aminopeptidase N (APN) isoforms in lepidopteran larvae midguts are known for their involvement in the mode of action of insecticidal crystal (Cry) proteins from Bacillus thuringiensis. In the present work, we identified a putative Cry1Ab toxin-binding protein, an APN isoform designated HcAPN3, in the midgut of H. cune...

The susceptibilities of 18 field populations of the sugarcane borer, Diatraea saccharalis (F.), to two sources of Bacillus thuringiensis (Bt) Cry1Ab protein were determined using laboratory bioassays. Fifteen of the 18 field populations were collected from seven locations across Louisiana and the other three populations were sampled from the Gulf Coast area of Texas during 2004–2006. Neonates o...

Insecticidal crystal proteins from Bacillus thuringiensis in sprays and transgenic crops are extremely useful for environmentally sound pest management, but their long-term efficacy is threatened by evolution of resistance by target pests. The diamondback moth (Plutella xylostella) is the first insect to evolve resistance to B. thuringiensis in open-field populations. The only known mechanism o...

Laboratory tests were conducted to establish the relative toxicity of Bacillus thuringiensis (Bt) toxins and pollen from Bt corn to monarch larvae. Toxins tested included Cry1Ab, Cry1Ac, Cry9C, and Cry1F. Three methods were used: (i) purified toxins incorporated into artificial diet, (ii) pollen collected from Bt corn hybrids applied directly to milkweed leaf discs, and (iii) Bt pollen contamin...

We developed a microarray based on 2895 unique transcripts assembled from 15,000 cDNA sequences from the European corn borer (Ostrinia nubilalis) larval gut. This microarray was used to monitor gene expression in early third-instar larvae of Bacillus thuringiensis (Bt)-susceptible O. nubilalis after 6 h feeding on diet, with or without the Bt Cry1Ab protoxin. We identified 174 transcripts, for ...

The European (Ostrinia nubilalis Hübner) and Asian corn borers (Ostrinia furnacalis Guenée) are closely related and display similar sensitivity to Cry1 toxins. In this study, we compared the binding patterns of Cry1Ab and Cry1F toxins between both Ostrinia spp., as well as the expression of putative cadherin- and aminopeptidase-N (APN)-like protein receptors. Additionally, cDNA sequences of the...

We constructed a model for Bacillus thuringiensis Cry1 toxin binding to midgut membrane vesicles from Heliothis virescens. Brush border membrane vesicle binding assays were performed with five Cry1 toxins that share homologies in domain II loops. Cry1Ab, Cry1Ac, Cry1Ja, and Cry1Fa competed with (125)I-Cry1Aa, evidence that each toxin binds to the Cry1Aa binding site in H. virescens. Cry1Ac comp...

We have investigated the immunological and metabolomic impacts of Cry1Ab administration to mice, either as a purified protein or as the Cry1Ab-expressing genetically modified (GM) MON810 maize. Humoral and cellular specific immune responses induced in BALB/cJ mice after intra-gastric (i.g.) or intra-peritoneal (i.p.) administration of purified Cry1Ab were analyzed and compared with those induce...

cotton (gossypium hirsutum l.)  is an important fiber crop in iran, cultivated on 150000-200000 ha of land.  in iran the estimated loss due to the insect pest is more than 30%. traditionally, pests are controlled by 10-12 times spraying per growing season of environmentally harmful chemical insecticides (e.g. endosulfan and/or methosystox). in order to produce transgenic cotton resistance to in...