This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplemental material
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Google Scholar
Right arrow Articles by Johnston, P. R.
Right arrow Articles by Crickmore, N.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Johnston, P. R.
Right arrow Articles by Crickmore, N.
Agricola
Right arrow Articles by Johnston, P. R.
Right arrow Articles by Crickmore, N.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, August 2009, p. 5094-5099, Vol. 75, No. 15
0099-2240/09/$08.00+0     doi:10.1128/AEM.00966-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Gut Bacteria Are Not Required for the Insecticidal Activity of Bacillus thuringiensis toward the Tobacco Hornworm, Manduca sexta{triangledown} ,{dagger}

Paul R. Johnston* and Neil Crickmore

Department of Biochemistry, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, United Kingdom

Received 28 April 2009/ Accepted 3 June 2009

It was recently proposed that gut bacteria are required for the insecticidal activity of the Bacillus thuringiensis-based insecticide, DiPel, toward the lepidopterans Manduca sexta, Pieris rapae, Vanessa cardui, and Lymantria dispar. Using a similar methodology, it was found that gut bacteria were not required for the toxicity of DiPel or Cry1Ac or for the synergism of an otherwise sublethal concentration of Cry1Ac toward M. sexta. The toxicities of DiPel and of B. thuringiensis HD73 Cry– spore/Cry1Ac synergism were attenuated by continuously exposing larvae to antibiotics before bioassays. Attenuation could be eliminated by exposing larvae to antibiotics only during the first instar without altering larval sterility. Prior antibiotic exposure did not attenuate Cry1Ac toxicity. The presence of enterococci in larval guts slowed mortality resulting from DiPel exposure and halved Cry1Ac toxicity but had little effect on B. thuringiensis HD73 Cry– spore/Cry1Ac synergism. B. thuringiensis Cry– cells killed larvae after intrahemocoelic inoculation of M. sexta, Galleria mellonella, and Spodoptera litura and grew rapidly in plasma from M. sexta, S. litura, and Tenebrio molitor. These findings suggest that gut bacteria are not required for B. thuringiensis insecticidal activity toward M. sexta but that B. thuringiensis lethality is reduced in larvae that are continuously exposed to antibiotics before bioassay.

* Corresponding author. Mailing address: Department of Biochemistry, School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9QG, United Kingdom. Phone: 44 1273 678694. Fax: 44 1273 678433. E-mail: P.R.Johnston{at}sussex.ac.uk

{triangledown} Published ahead of print on 12 June 2009.

{dagger} Supplemental material for this article may be found at http://aem.asm.org/.

Applied and Environmental Microbiology, August 2009, p. 5094-5099, Vol. 75, No. 15
0099-2240/09/$08.00+0     doi:10.1128/AEM.00966-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»