Background: Bt cotton has been widely planted in China for over a decade to control H. armigera, but field surveys indicate increasing resistance in the pest. It has been speculated that accumulating plant secondary compounds in mature cotton may interact with Bt toxins and affect the toxicity of Bt to H. armigera.
Results: Both quercetin, one of the main flavonoids in cotton, and the Bt toxin Cry1Ac protein had significant negative effects on the growth, development and survival of H. armigera when added singly to artificial diet, but their effects were inhibited when added in combination. Quercetin was antagonistic to Cry1Ac toxicity at all tested concentrations.
Conclusion: The accumulation of quercetin might be one factor contributing to the reduced toxicity of mature Bt cotton plants to H. armigera, and could partially explain the reduced efficacy of Cry1Ac in controlling this pest in the field. © 2015 Society of Chemical Industry.
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http://dx.doi.org/10.1002/ps.4160 | DOI Listing |
J Agric Food Chem
January 2025
State Key Laboratory of Vegetable Biobreeding, Department of Plant Protection, Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
Understanding the molecular mechanisms underlying insect resistance to (Bt) pesticidal proteins is crucial for sustainable pest management. Here, we found that downregulation of the ecdysone oxidase gene () in the normal feeding stages contributes to increased 20-hydroxyecdysone (20E) titer and mediates resistance to the Bt Cry1Ac toxin. The gene was cloned and its expression was significantly downregulated in the midgut of Bt-resistant and Cry1Ac-selected .
View Article and Find Full Text PDFMikrochim Acta
December 2024
Key Laboratory of Agricultural Genetically Modified Organisms Traceability of the Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China.
A multi-chromatic and multi-component lateral flow immunoassay (MCMC-LFIA) was developed for simultaneous detection of CP4 EPSPS, Bt-Cry1Ab, Bt-Cry1Ac, and PAT/bar proteins in genetically modified (GM) crops. Captured antibodies specific to these exogenous proteins were separately immobilized on a nitrocellulose membrane as test zones. Multi-colored microspheres, used as visible multi-probes, were conjugated with corresponding antibodies and sprayed on the conjugate pad.
View Article and Find Full Text PDFPest Manag Sci
December 2024
Department of Plant Protection, Federal University of Santa Maria, Santa Maria, Brazil.
Background: The sunflower looper, Rachiplusia nu (Guenée), evolved resistance to the insecticidal protein Cry1Ac expressed in soybean and emerged as an important soybean pest in Brazil, requiring the application of insecticides for their control. Here, we characterized the susceptibility of Brazilian populations of R. nu to several insecticides and developed diagnostic concentrations for a proactive insect resistance management (IRM) program.
View Article and Find Full Text PDFInt J Biol Macromol
December 2024
State Key Laboratory of Cotton Bio-breeding and Integrated Utilization, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China; Western Agricultural Research Center, Chinese Academy of Agricultural Sciences, Changji 831100, China.
Hoverflies, capable of abilities providing dual ecosystem services including pest control and pollination, are exposed to insecticidal proteins from transgenic plants via pollen and prey aphids. However, the effects of such exposures on hoverflies have never been adequately assessed. Here, we investigated impacts of the most widely used biotoxin Cry1Ac on a representative hoverfly species Episyrphus balteatus through food chain transmission and active toxin exposure.
View Article and Find Full Text PDFJ Invertebr Pathol
February 2025
Department of Entomology, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
Cry2Ab2 is a Bacillus thuringiensis (Bt) protein that has been pyramided with Cry1A.105 in transgenic maize and Cry1Ac in cotton to control some major lepidopteran pests including the corn earworm/bollworm, Helicoverpa zea (Boddie). However, the widespread occurrence of resistance of this pest to the pyramided Cry1A/Cry2A crops in the southern region of the United State has become a threat to the sustainability of the technology.
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