Characterization of a novel Bacillus thuringiensis toxin active against Aedes aegypti larvae.

• A novel mosquitocidal toxin named Xpp81Aa1 with a thioredoxin domain was identified from Bt strain HSY204. • The xpp81Aa1 gene was successfully expressed in E. coli cells. • The Xpp81Aa toxin has synergism with the Cry2Aa and Cry4Aa toxins against Aedes aegypti larvae. • Xpp81Aa1 is an effective moquitocidal protein that could be used in combination with other toxins. Some Bacillus thuringiensis (Bt) strains produce dipteran-active toxins and can control larval mosquitoes. We identified a novel mosquitocidal toxin named Xpp81Aa1 with the thioredoxin domain from Bt strain HSY204. This toxin has very little sequence similarity to the three-domain Cry toxin and Cyt toxins and has significant toxicity to Aedes aegypti larvae. A safety assessment indicated that the Xpp81Aa1 toxin has no cytocidal activity against red blood cells and did not induce allergic reactions. The Xpp81Aa1 toxin exhibited a synergistic effect in combination with Cry2Aa and Cry4Aa protein toxins. Thus, the Xpp81Aa1 toxin could be a good candidate for mosquito control applications to reduce the mosquito-borne disease. [Display omitted] [ABSTRACT FROM AUTHOR]