Transgenic corn expressing the insecticidal toxin from Bacillus thuringiensis Berliner is gaining support as an effective control technology for use against lepidopteran pests, particularly European corn borer, Ostrinia nubilalis Hübner (Lepidoptera: Crambidae). However, there is concern that widespread adoption of transgenic plants will rapidly lead to B. thuringiensis toxin resistance. Thus, long-term selection of O. nubilalis populations with the Cry1Ab B. thuringiensis toxin has been undertaken in several laboratories in the United States and in Europe. We present results from two independent selection experiments performed in laboratories at the University of Nebraska and at the Institut National de la Recherche Agronomique in France. Although the protocols and methods used by the two laboratories were different, the results were comparable. The highest level of resistance occurred at generation 7 (14-fold), generation 9 (13-fold), and generation 9 (32-fold) for three different strains. For each strain, the level of resistance fluctuated from generation to generation, although there were consistently significant decreases in toxin susceptibility across generations for all selected strains. These results suggest that low levels of resistance are common among widely distributed O. nubilalis populations.
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http://dx.doi.org/10.1603/0022-0493-94.6.1564 | DOI Listing |
Int J Biol Macromol
January 2025
Zhengzhou Research Base, National Key Laboratory of Cotton Bio-breeding and Integrated Utilization, School of Agricultural Sciences, Zhengzhou University, Zhengzhou 450001, Henan, China; National Key Laboratory of Cotton Bio-breeding and Integrated Utilization, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, Henan, China; Western Agricultural Research Center, Chinese Academy of Agricultural Sciences, Changji 831100, China. Electronic address:
The widespread commercialization of genetically modified (GM) crops makes it important to assess the potential impact of Bacillus thuringiensis (Bt) on non-target organisms. Pardosa astrigera is an important predator in agroforestry ecosystems, and female and male spiders may react differently to Bt toxins due to their different activity habits and nutritional requirements. In this study, we found that exposure to Cry2Aa protein did not affect the survival and body weight of P.
View Article and Find Full Text PDFBiology (Basel)
December 2024
Graduate School of Science and Technology, Niigata University, 8050 Ikarashi 2 No-Cho, Nishi-ku, Niigata 950-2181, Japan.
Public acceptance of genetically modified crops engineered with (Bt) insecticidal protein genes (BT-GMCs), which confer resistance to various lepidopteran insect pests, is generally lacking. As a major concern over BT-GMCs is the allergenicity of insecticidal proteins, alleviating safety concerns should help increase public acceptance. In this study, three lepidopteran-specific Bt toxins, Cry1Aa, Cy1Ab, and Cry1Ac, were treated with simulated digestive fluids under various conditions.
View Article and Find Full Text PDFJ Econ Entomol
January 2025
Department of Entomology and Plant Pathology, North Carolina State University, the Vernon G. James Research and Extension Center, Plymouth, NC, USA.
Transgenic corn (Zea mays L.) expressing insecticidal toxins from Bacillus thuringiensis (Bt) helps to control or suppress injury from a range of target insect pests. This study summarizes the yield benefits of Bt corn from field trials in Georgia, North Carolina, and South Carolina evaluating Bt and non-Bt corn hybrids from 2009 to 2023.
View Article and Find Full Text PDFJ Econ Entomol
January 2025
Department of Entomology and Plant Pathology and the North Carolina Plant Sciences Institute, NC State University, Raleigh, NC, USA.
Debate over resistance management tactics for genetically engineered (GE) crops expressing insecticidal toxins is not new. For several decades, researchers, regulators, and agricultural industry scientists have developed strategies to limit the evolution of resistance in populations of lepidopteran and coleopteran pests. A key attribute of many of these events was insecticide resistance management (IRM) strategies designed around a presumed high-dose expression sufficient to kill 99.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Developing simple and efficient multi-gene expression systems is crucial for multi-trait improvement or bioproduction in transgenic plants. In previous research, an -based bicistronic system from the nonpathogenic fungus efficiently expressed multiple enzyme proteins in yeast and maize, and the heterologous enzymes successfully performed their catalytic activity to reconstruct the biosynthetic pathway in the host organism. Unlike enzyme proteins, some heterologous functional proteins (such as insecticidal proteins) are dose-dependent and they need to express sufficient levels to perform their biological functions.
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