Toxins 2014, 6(4), 1222-1243; doi:10.3390/toxins6041222

Bacillus thuringiensis subsp. israelensis and Its Dipteran-Specific Toxins

Received: 28 January 2014; in revised form: 10 March 2014 / Accepted: 14 March 2014 / Published: 28 March 2014
(This article belongs to the Special Issue Bacillus thuringiensis Toxins)
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract: Bacillus thuringiensis subsp. israelensis (Bti) is the first Bacillus thuringiensis to be found and used as an effective biological control agent against larvae of many mosquito and black fly species around the world. Its larvicidal activity resides in four major (of 134, 128, 72 and 27 kDa) and at least two minor (of 78 and 29 kDa) polypeptides encoded respectively by cry4Aa, cry4Ba, cry11Aa, cyt1Aa, cry10Aa and cyt2Ba, all mapped on the 128 kb plasmid known as pBtoxis. These six δ-endotoxins form a complex parasporal crystalline body with remarkably high, specific and different toxicities to Aedes, Culex and Anopheles larvae. Cry toxins are composed of three domains (perforating domain I and receptor binding II and III) and create cation-selective channels, whereas Cyts are composed of one domain that acts as well as a detergent-like membrane perforator. Despite the low toxicities of Cyt1Aa and Cyt2Ba alone against exposed larvae, they are highly synergistic with the Cry toxins and hence their combinations prevent emergence of resistance in the targets. The lack of significant levels of resistance in field mosquito populations treated for decades with Bti-bioinsecticide suggests that this bacterium will be an effective biocontrol agent for years to come.
Keywords: biological control; mosquito-borne diseases; larvicidal crystal proteins
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MDPI and ACS Style

Ben-Dov, E. Bacillus thuringiensis subsp. israelensis and Its Dipteran-Specific Toxins. Toxins 2014, 6, 1222-1243.

AMA Style

Ben-Dov E. Bacillus thuringiensis subsp. israelensis and Its Dipteran-Specific Toxins. Toxins. 2014; 6(4):1222-1243.

Chicago/Turabian Style

Ben-Dov, Eitan. 2014. "Bacillus thuringiensis subsp. israelensis and Its Dipteran-Specific Toxins." Toxins 6, no. 4: 1222-1243.

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