Insect resistance to Bacillus thuringiensis (Bt) crystal protein is a major threat to the long-term use of transgenic Bt crops. Gene stacking is a readily deployable strategy to delay the development of insect resistance while it may also broaden insecticidal spectrum. Here, we report the creation of transgenic rice expressing discrete Cry1Ab and Cry2Ab simultaneously from a single expression c...

A fluorescence-based approach was developed to analyze in vivo the function of Manduca sexta cadherin (Bt-R(1)) as a Cry1 toxin receptor. We cloned a Bt-R(1a) cDNA that differs from Bt-R(1) by 37 nucleotides and two amino acids and expressed it transiently in Drosophila melanogaster Schneider 2 (S2) cells. Cells expressing Bt-R(1a) bound Cry1Aa, Cry1Ab, and Cry1Ac toxins on ligand blots, and in...

Two candidate diagnostic concentrations of the Cry1Ab and Cry1Ac toxins from Bacillus thuringiensis corresponding to the LC99 and EC99 (effective concentration that causes 99% growth inhibition) for European corn borer, Ostrinia nubilalis (Hübner), were determined based on previously obtained baseline data. Validation experiments using field-collected European corn borer populations from across...

Blended refuge for transgenic plants expressing Bacillus thuringiensis (Bt) toxins has been approved in the northern United States as a resistance management strategy alternative to a structured refuge. A three-year study (2012-2014) was conducted with 54 trials across nine states in the southern United States to evaluate plant injury from lepidopteran pests of corn and yield in a corn hybrid e...

Four subpopulations of a Plutella xylostella (L.) strain from Malaysia (F(4) to F(8)) were selected with Bacillus thuringiensis subsp. kurstaki HD-1, Bacillus thuringiensis subsp. aizawai, Cry1Ab, and Cry1Ac, respectively, while a fifth subpopulation was left as unselected (UNSEL-MEL). Bioassays at F(9) found that selection with Cry1Ac, Cry1Ab, B. thuringiensis subsp. kurstaki, and B. thuringie...

Abstract Background In 2009, Spanish farmers reported a novel weed, now identified as relative of maize’s ancestor, teosinte, in their maize fields. Introgression the insect resistance transgene cry1Ab from genetically modified (GM) into populations this weedy teosinte could endow it with additional defense mechanisms. The aims study were: (1) to test if hybridization between GM and plants Spai...

First generation of insect-protected transgenic corn (Bt-corn) was based on the expression of Cry1Ab or Cry1Fa proteins. Currently, the trend is the combination of two or more genes expressing proteins that bind to different targets. In addition to broadening the spectrum of action, this strategy helps to delay the evolution of resistance in exposed insect populations. One of such examples is t...

The increasing global adoption of genetically modified (GM) plant derivatives in animal feed has provoked a strong demand for an appropriate detection method to evaluate the existence of transgenic protein in animal tissues and animal by-products derived from GM plant fed animals. A highly specific and sensitive sandwich enzyme immunoassay for the surveillance of transgenic Cry1Ab protein from ...

Thirteen of the most common lepidopteran-specific Cry proteins of Bacillus thuringiensis have been tested for their efficacy against newly hatched larvae of two populations of the spiny bollworm, Earias insulana. At a concentration of 100 microg of toxin per milliliter of artificial diet, six Cry toxins (Cry1Ca, Cry1Ea, Cry1Fa, Cry1Ja, Cry2Aa, and Cry2Ab) were not toxic at all. Cry1Aa, Cry1Ja, ...

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...