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Insecticidal evaluation of Beauveria bassiana engineered to express a scorpion neurotoxin and a cuticle degrading protease

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Abstract

To improve the insecticidal efficacy of the entomopathogen Beauveria bassiana, the fungus was genetically modified with an insect-specific scorpion neurotoxin AAIT and an insect cuticle degrading protease PR1A from another insect pathogen (Metarhizium anisopliae). The wild-type and the transformants were bioassayed against the larvae of Masson’s pine caterpillar Dendrolimus punctatus and the wax moth Galleria mellonella. In comparison to the wild-type strain, engineered isolates took fewer spores to kill 50% of pine caterpillars, 15-fold less for the aaIT single transformant Bb13T and eightfold less for the double transformant Bb13TPR1A, respectively. The median lethal times for Bb13T and Bb13TPR1A were reduced by 40% and 36.7%, respectively against D. punctatus and 24.4% and 20.9%, respectively against G. mellonella. Our data showed that the cotransformation of these two genes produced no synergistic effects on virulence improvement. It is evident from this study that AAIT could be degraded by the protease PR1A when they are expressed together, emphasizing that protein interactions need to be evaluated when working with multiple genes, particularly if they include proteases.

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Acknowledgments

This work was supported by the National Hi-Tech Research and Development Program of China (2006AA10A119, 2006AA10A212) and the program from Science and Technology Commission of Shanghai Municipality (07PJ14101). Monica Pava_Ripoll was supported by a grant from CENICAFE. The authors also highly appreciate Dr. Yuxian Xia for the antibodies and Prof. Raymond J. St. Leger for critical reading of this paper.

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Correspondence to Chengshu Wang.

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Lu, D., Pava-Ripoll, M., Li, Z. et al. Insecticidal evaluation of Beauveria bassiana engineered to express a scorpion neurotoxin and a cuticle degrading protease. Appl Microbiol Biotechnol 81, 515–522 (2008). https://doi.org/10.1007/s00253-008-1695-8

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Keywords

  • Beauveria bassiana
  • Genetic engineering
  • Scorpion neurotoxin
  • Protease
  • Virulence