Midgut bacteria required for Bacillus thuringiensis insecticidal activity
- PMID: 17005725
- PMCID: PMC1622799
- DOI: 10.1073/pnas.0604865103
Midgut bacteria required for Bacillus thuringiensis insecticidal activity
Abstract
Bacillus thuringiensis is the most widely applied biological insecticide and is used to manage insects that affect forestry and agriculture and transmit human and animal pathogens. This ubiquitous spore-forming bacterium kills insect larvae largely through the action of insecticidal crystal proteins and is commonly deployed as a direct bacterial spray. Moreover, plants engineered with the cry genes encoding the B. thuringiensis crystal proteins are the most widely cultivated transgenic crops. For decades, the mechanism of insect killing has been assumed to be toxin-mediated lysis of the gut epithelial cells, which leads to starvation, or B. thuringiensis septicemia. Here, we report that B. thuringiensis does not kill larvae of the gypsy moth in the absence of indigenous midgut bacteria. Elimination of the gut microbial community by oral administration of antibiotics abolished B. thuringiensis insecticidal activity, and reestablishment of an Enterobacter sp. that normally resides in the midgut microbial community restored B. thuringiensis-mediated killing. Escherichia coli engineered to produce the B. thuringiensis insecticidal toxin killed gypsy moth larvae irrespective of the presence of other bacteria in the midgut. However, when the engineered E. coli was heat-killed and then fed to the larvae, the larvae did not die in the absence of the indigenous midgut bacteria. E. coli and the Enterobacter sp. achieved high populations in hemolymph, in contrast to B. thuringiensis, which appeared to die in hemolymph. Our results demonstrate that B. thuringiensis-induced mortality depends on enteric bacteria.
Conflict of interest statement
The authors declare no conflict of interest.
Figures
Similar articles
-
Interactions between Bacillus thuringiensis subsp. kurstaki HD-1 and midgut bacteria in larvae of gypsy moth and spruce budworm.J Invertebr Pathol. 2010 Feb;103(2):124-31. doi: 10.1016/j.jip.2009.12.008. Epub 2009 Dec 24. J Invertebr Pathol. 2010. PMID: 20035766
-
A mid-gut microbiota is not required for the pathogenicity of Bacillus thuringiensis to diamondback moth larvae.Environ Microbiol. 2009 Oct;11(10):2556-63. doi: 10.1111/j.1462-2920.2009.01980.x. Epub 2009 Jun 25. Environ Microbiol. 2009. PMID: 19555371
-
Identification and characterization of a novel cytotoxic protein, parasporin-4, produced by Bacillus thuringiensis A1470 strain.Biotechnol Annu Rev. 2008;14:225-52. doi: 10.1016/S1387-2656(08)00009-4. Biotechnol Annu Rev. 2008. PMID: 18606366 Review.
-
Ecological consequences of ingestion of Bacillus cereus on Bacillus thuringiensis infections and on the gut flora of a lepidopteran host.J Invertebr Pathol. 2008 Sep;99(1):103-11. doi: 10.1016/j.jip.2008.04.007. Epub 2008 Apr 27. J Invertebr Pathol. 2008. PMID: 18533180
-
Bacillus thuringiensis as a specific, safe, and effective tool for insect pest control.J Microbiol Biotechnol. 2007 Apr;17(4):547-59. J Microbiol Biotechnol. 2007. PMID: 18051264 Review.
Cited by
-
Metagenomic Analyses Reveal Gut Microbial Profiles of Cnaphalocrocis medinalis Driven by the Infection of Baculovirus CnmeGV.Microorganisms. 2024 Apr 9;12(4):757. doi: 10.3390/microorganisms12040757. Microorganisms. 2024. PMID: 38674701 Free PMC article.
-
Antibiotic alters host's gut microbiota, fertility, and antimicrobial peptide gene expression vis-à-vis ampicillin treatment on model organism Drosophila melanogaster.Int Microbiol. 2024 Mar 19. doi: 10.1007/s10123-024-00507-9. Online ahead of print. Int Microbiol. 2024. PMID: 38502456
-
The immunostimulatory role of an Enterococcus-dominated gut microbiota in host protection against bacterial and fungal pathogens in Galleria mellonella larvae.Front Insect Sci. 2023 Oct 26;3:1260333. doi: 10.3389/finsc.2023.1260333. eCollection 2023. Front Insect Sci. 2023. PMID: 38469511 Free PMC article.
-
Cry1Ac Mixed with Gentamicin Influences the Intestinal Microbial Diversity and Community Composition of Pink Bollworms.Life (Basel). 2023 Dec 28;14(1):58. doi: 10.3390/life14010058. Life (Basel). 2023. PMID: 38255673 Free PMC article.
-
The intricate triangular interaction between protective microbe, pathogen and host determines fitness of the metaorganism.Proc Biol Sci. 2023 Dec 6;290(2012):20232193. doi: 10.1098/rspb.2023.2193. Epub 2023 Dec 6. Proc Biol Sci. 2023. PMID: 38052248
References
-
- Gill SS, Cowles EA, Pietrantonio PV. Annu Rev Entomol. 1992;37:615–636. - PubMed
-
- Knowles BH. Adv Insect Physiol. 1994;24:275–308.
-
- Entwistle PF, Cory JS, Bailey MJ, Higgs S. Bacillus thuringiensis, an Environmental Biopesticide: Theory and Practice. New York: Wiley Interscience; 1993.
-
- Bulla LA, Jr, Rhodes RA, St Julian G. Annu Rev Microbiol. 1975;29:163–190. - PubMed
Publication types
MeSH terms
Substances
LinkOut - more resources
Full Text Sources
Other Literature Sources