The Experts below are selected from a list of 32829 Experts worldwide ranked by ideXlab platform
William H. Mcgaughey - One of the best experts on this subject based on the ideXlab platform.
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PROTEINASE-MEDIATED Insect Resistance TO BACILLUS THURINGIENSIS TOXINS
The Journal of biological chemistry, 1997Co-Authors: Brenda Oppert, Karl J. Kramer, Richard W. Beeman, D.e. Johnson, William H. McgaugheyAbstract:Two Bacillus thuringiensis (Bt)-resistant strains of the Indianmeal moth, Plodia interpunctella, lack a major gut proteinase that activates Bt protoxins. The absence of this enzyme is genetically linked to larval survival on Bt-treated diets. When considered with previous data supporting the existence of receptor-mediated Insect Resistance to Bt, these results provide evidence that Insect adaptation to these toxins occurs through multiple physiological mechanisms, which complicate efforts to prevent or manage Resistance to Bt toxins in Insect control programs.
Bert Visser - One of the best experts on this subject based on the ideXlab platform.
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Insect Resistance of transgenic plants that express modified Bacillus thuringiensis cryIA(b) and cryIC genes: a Resistance management strategy.
Plant molecular biology, 1994Co-Authors: T. Van Der Salm, Dirk Bosch, G. Honée, Lanxiang Feng, E. Munsterman, P. Bakker, Willem J. Stiekema, Bert VisserAbstract:Tobacco and tomato plants were generated exhibiting Insect Resistance due to the introduction of modified cryIA(b) and cryIC genes of Bacillus thuringiensis. Limited modifications at selected regions of the coding sequences of both genes are sufficient to obtain Resistance against Spodoptera exigua, Heliothis virescens and Manduca sexta. The criteria used to modify both genes demonstrate that the removal of sequence motifs potentially resulting in premature polyadenylation and transcript instability causes increased Insect Resistance. The expression of a cryIC-cryIA(b) fusion resulting in protection against S. exigua, H. virescens and M. sexta demonstrates the potential of expressing translational fusions, not only to broaden the Insect Resistance of transgenic plants, but also to simultaneously employ different gene classes in Resistance management strategies.
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Insect Resistance of Transgenic Plants that Simultaneously Express Modified Bacillus thuringiensis cryIA(B) and cryIC Genes: A Resistance Management Strategy
Biocontrol Science and Technology, 1994Co-Authors: T. Van Der Salm, Dirk Bosch, G. Honée, Lanxiang Feng, E. Munsterman, P. Bakker, Willem J. Stiekema, Bert VisserAbstract:Tobacco and tomato plants were generated exhibiting Insect Resistance due to the introduction of modified cryIA(b) and cryIC genes of Bacillus thuringiensis. Limited modifications at selected regions of the coding sequences of both genes are sufficient to obtain plants resistant against Spodoptera exigua, Heliothis virescens and Manduca sexta. The criteria used to modify both genes demonstrate that the removal of sequence motifs potentially resulting in premature polyadenylation and transcript instability causes increased Insect Resistance of plants. The expression of a cryIC‐cryIA(b) fusion resulting in protection against S. exigua, H. virescens and M. sexta demonstrates the potential of expressing translational fusions, not only to broaden the Insect Resistance of transgenic plants, but also simultaneously to employ different gene classes in Resistance management strategies.
Brian M Leckie - One of the best experts on this subject based on the ideXlab platform.
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agroinfiltration as a technique for rapid assays for evaluating candidate Insect Resistance transgenes in plants
Plant Cell Reports, 2011Co-Authors: Brian M Leckie, Neal C StewartAbstract:Functional analysis of candidate transgenes for Insect Resistance in stably transformed plants is a time-consuming task that can take months to achieve in even the fastest of plant models. In this study, a rapid screening technique is described, which employs candidate transgene transient expression using agroinfiltration in Nicotiana benthamiana combined with a simple Insect bioassay. Using this system the known Insecticidal protein Cry1Ac is demonstrated to effectively control Helicoverpa zea. Insects fed tissue with synthesized GFP (green fluorescent protein) as a positive control were shown to have enhanced growth and development. Additionally, a Brassica oleracea proteinase inhibitor (BoPI), a less characterized Insect Resistance candidate, demonstrated effectiveness to decrease the growth and development of H. zea at high levels of transient expression. Bioassays performed on stable transformants showed that BoPI had a low level of Insect Resistance at the more typical levels of gene transcription found in stably transformed plants. This agroinfiltration-Insect bioassay procedure can give a rapid assessment of Insect Resistance significantly decreasing the time needed for evaluation of candidate genes.
Monique Royer - One of the best experts on this subject based on the ideXlab platform.
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managing Insect Resistance to plants producing bacillus thuringiensis toxins
Critical Reviews in Biotechnology, 1999Co-Authors: Roger Frutos, Cecile Rang, Monique RoyerAbstract:ABSTRACT: Insect-resistant transgenic plants have become an important tool for the protection of crops against Insect pests. The acreage of Insecticidal transgenic plants is expected to increase significantly in the near future. The bacterium Bacillus thuringiensis is currently the source of Insecticidal proteins in commercial Insect-resistant transgenic plants and will remain the most important source during the next decade. Insect Resistance to B. thuringiensis Cry toxins is the main problem. Only one species, the diamondback moth, has evolved a Resistance to B. thuringiensis-based formulations under field conditions. However, many other Insect species were selected for Resistance under laboratory conditions, indicating that there is a potential for evolution of Resistance in most major pests. Many studies were conducted to elucidate the mode of action of the Cry toxins, the mechanisms and genetics of Resistance, and the various factors influencing its development. This article reviews Insect Resistance...
Mario Soberon - One of the best experts on this subject based on the ideXlab platform.
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How to cope with Insect Resistance to Bt toxins
Trends in biotechnology, 2008Co-Authors: Alejandra Bravo, Mario SoberonAbstract:Transgenic Bt crops producing Insecticidal crystalline proteins from Bacillus thuringiensis, so-called Cry toxins, have proved useful in controlling Insect pests. However, the future of Bt crops is threatened by the evolution of Insect Resistance. Understanding how Bt toxins work and how Insects become resistant will provide the basis for taking measures to counter Resistance. Here we review possible mechanisms of Resistance and different strategies to cope with Resistance, such as expression of several toxins with different modes of action in the same plant, modified Cry toxins active against resistant Insects, and the potential use of Cyt toxins or a fragment of cadherin receptor. These approaches should provide the means to assure the successful use of Bt crops for an extended period of time.
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engineering modified bt toxins to counter Insect Resistance
Science, 2007Co-Authors: Mario Soberon, Bruce E. Tabashnik, Liliana Pardolopez, Idalia Lopez, Isabel Gomez, Alejandra BravoAbstract:The evolution of Insect Resistance threatens the effectiveness of Bacillus thuringiensis (Bt) toxins that are widely used in sprays and transgenic crops. Resistance to Bt toxins in some Insects is linked with mutations that disrupt a toxin-binding cadherin protein. We show that susceptibility to the Bt toxin Cry1Ab was reduced by cadherin gene silencing with RNA interference in Manduca sexta, confirming cadherin's role in Bt toxicity. Native Cry1A toxins required cadherin to form oligomers, but modified Cry1A toxins lacking one alpha-helix did not. The modified toxins killed cadherin-silenced M. sexta and Bt-resistant Pectinophora gossypiella that had cadherin deletion mutations. Our findings suggest that cadherin promotes Bt toxicity by facilitating toxin oligomerization and demonstrate that the modified Bt toxins may be useful against pests resistant to standard Bt toxins.