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Elimination of Gut Microbes with Antibiotics Confers Resistance to Bacillus thuringiensis Toxin Proteins in Helicoverpa armigera (Hubner).
Appl Biochem Biotechnol. 2015 Dec; 177(8):1621-37.AB

Abstract

Helicoverpa armigera is one of the most important pests worldwide. Transgenic crops with toxin genes from Bacillus thuringiensis (Bt) have been deployed on a large scale to control this pest. The insecticidal activity of Bt is probably influenced by the insect midgut microbes, which vary across crop hosts and locations. Therefore, we examined the role of gut microbes in pathogenicity of Bt toxins in the H. armigera. Antibiotic cocktail was used for the complete elimination of the H. armigera gut microbes. Activated Cry1Ac, Bt formulation, and transgenic cotton resulted in larval weight loss and increase in mortality, but pretreatment of larvae with antibiotic cocktail significantly decreased larval mortality and increased the larval weight gain. Activated Cry1Ac and Bt formulation inhibited the activity of proteases in midgut of H. armigera larvae but showed no such effect in the larvae pretreated with antibiotic cocktail. Five protease bands in activated Cry1Ac and two in Bt formulation-treated larvae were inhibited but no such effect in the larvae pretreated with antibiotic cocktail. Cry1Ac protein was detected in Bt/Cry1Ac protoxin-fed larval gut extract in the absence of antibiotic cocktail, but fewer in larvae pretreated with antibiotic cocktail. The activity of antioxidant enzymes and aminopeptidases increased in larvae fed on Bt toxin, but there was no significant increase in antioxidant enzymes in larvae reared on toxin protein in combination with antibiotic cocktail. The results suggest that gut microbes exercise a significant influence on the toxicity of Cry1Ac and Bt formulation in H. armigera larvae. The implications of these results have been discussed in relation to development of insect resistance to Bt transgenic crops deployed for pest management.

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Publisher Full Text (DOI)

Authors+Show Affiliations

Visweshwar R
Department of Biochemistry, Gulbarga University, Kalaburagi, Karnataka, 585 106, India. Department of Entomology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Telangana, 502324, India.
Sharma HC
Department of Entomology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Telangana, 502324, India.
Akbar SM
Department of Entomology, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Patancheru, Telangana, 502324, India.
Sreeramulu K
Department of Biochemistry, Gulbarga University, Kalaburagi, Karnataka, 585 106, India. ksramu@rediffmail.com.

MeSH

AnimalsBacillus thuringiensisBacillus thuringiensis ToxinsBacterial ProteinsDrug Resistance, MicrobialEndotoxinsGastrointestinal MicrobiomeHemolysin ProteinsLarvaMoths

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

26384494

Citation

Visweshwar, R, et al. "Elimination of Gut Microbes With Antibiotics Confers Resistance to Bacillus Thuringiensis Toxin Proteins in Helicoverpa Armigera (Hubner)." Applied Biochemistry and Biotechnology, vol. 177, no. 8, 2015, pp. 1621-37.
Visweshwar R, Sharma HC, Akbar SM, et al. Elimination of Gut Microbes with Antibiotics Confers Resistance to Bacillus thuringiensis Toxin Proteins in Helicoverpa armigera (Hubner). Appl Biochem Biotechnol. 2015;177(8):1621-37.
Visweshwar, R., Sharma, H. C., Akbar, S. M., & Sreeramulu, K. (2015). Elimination of Gut Microbes with Antibiotics Confers Resistance to Bacillus thuringiensis Toxin Proteins in Helicoverpa armigera (Hubner). Applied Biochemistry and Biotechnology, 177(8), 1621-37. https://doi.org/10.1007/s12010-015-1841-6
Visweshwar R, et al. Elimination of Gut Microbes With Antibiotics Confers Resistance to Bacillus Thuringiensis Toxin Proteins in Helicoverpa Armigera (Hubner). Appl Biochem Biotechnol. 2015;177(8):1621-37. PubMed PMID: 26384494.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Elimination of Gut Microbes with Antibiotics Confers Resistance to Bacillus thuringiensis Toxin Proteins in Helicoverpa armigera (Hubner). AU - Visweshwar,R, AU - Sharma,H C, AU - Akbar,S M D, AU - Sreeramulu,K, Y1 - 2015/09/18/ PY - 2015/05/12/received PY - 2015/09/08/accepted PY - 2015/9/20/entrez PY - 2015/9/20/pubmed PY - 2016/10/7/medline KW - Aminopeptidase KW - Antioxidant enzyme KW - Bacillus thuringiensis toxin protein KW - Gut microbes KW - Helicoverpa armigera KW - Protease KW - Resistance development SP - 1621 EP - 37 JF - Applied biochemistry and biotechnology JO - Appl Biochem Biotechnol VL - 177 IS - 8 N2 - Helicoverpa armigera is one of the most important pests worldwide. Transgenic crops with toxin genes from Bacillus thuringiensis (Bt) have been deployed on a large scale to control this pest. The insecticidal activity of Bt is probably influenced by the insect midgut microbes, which vary across crop hosts and locations. Therefore, we examined the role of gut microbes in pathogenicity of Bt toxins in the H. armigera. Antibiotic cocktail was used for the complete elimination of the H. armigera gut microbes. Activated Cry1Ac, Bt formulation, and transgenic cotton resulted in larval weight loss and increase in mortality, but pretreatment of larvae with antibiotic cocktail significantly decreased larval mortality and increased the larval weight gain. Activated Cry1Ac and Bt formulation inhibited the activity of proteases in midgut of H. armigera larvae but showed no such effect in the larvae pretreated with antibiotic cocktail. Five protease bands in activated Cry1Ac and two in Bt formulation-treated larvae were inhibited but no such effect in the larvae pretreated with antibiotic cocktail. Cry1Ac protein was detected in Bt/Cry1Ac protoxin-fed larval gut extract in the absence of antibiotic cocktail, but fewer in larvae pretreated with antibiotic cocktail. The activity of antioxidant enzymes and aminopeptidases increased in larvae fed on Bt toxin, but there was no significant increase in antioxidant enzymes in larvae reared on toxin protein in combination with antibiotic cocktail. The results suggest that gut microbes exercise a significant influence on the toxicity of Cry1Ac and Bt formulation in H. armigera larvae. The implications of these results have been discussed in relation to development of insect resistance to Bt transgenic crops deployed for pest management. SN - 1559-0291 UR - https://www.unboundmedicine.com/medline/citation/26384494/Elimination_of_Gut_Microbes_with_Antibiotics_Confers_Resistance_to_Bacillus_thuringiensis_Toxin_Proteins_in_Helicoverpa_armigera__Hubner__ DB - PRIME DP - Unbound Medicine ER -