Cloning and expression of mosquito larvicidal protein gene from a highly toxic local strain of Bacillus sphaericus.

Bacillus sphaericus strain 10 (BS10), isolated from Jiangsu Province of China, is highly toxic to the mosquito larvae. During sporulation, BS10 produces a parasporal crystalline protein which is toxic to the larvae of a number of mosquito species, and extremely toxic against the larvae of Culex pipiens. Using the Escherichia coli cloning vector pAT153, two clones which hybridized with the synthesizing 18-bases oligonucleotides probe have been obtained. One of the recombinants, TG1 (pFL37), contains a 4.0 kb HindIII DNA fragment from BS10, and produces the 43 kd larvicidal toxin protein. Western blotting analysis and biological assay of mosquito larvicidal activity confirm that larvicidal toxin gene of BS10 is expressed in E. coli.