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Title: Molecular markers to determine ecological fate of Bacillus thuringiensis subsp. kurstaki

Author
item SHRINVAS, KSHAMA - VA. COMMONWEALTH UNIV.
item KESTER, KAREN - VA. COMMONWEALTH UNIV.
item BROWN, BONNIE - VA. COMMONWEALTH UNIV.
item Martin, Phyllis

Submitted to: Molecular Ecology Notes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/12/2008
Publication Date: 5/16/2008
Citation: Shrinvas, K., Kester, K., Martin, P.A.W, Brown, B., 2008. Molecular markers to determine the ecological of bacillus thuringiensis subsp. kurstaki. Molecular Ecology Research. 8:1145-1158.

Interpretive Summary: Using bacteria specifically pathogenic to insects to control pests is a good alternative to chemical control. In order to be able to determine efficacy as well as environmental effects of applying such bacteria, it is necessary to be able to differentiate the particular bacteria applied from other related bacteria that naturally occur in the same environment. One way to identify organisms is by their DNA sequence. We developed 3 DNA sequences, or primers, that specifically identified a Bacillus thuringiensis (Bt) strain that was applied for the control of caterpillar pests from two locations near Champaign, IL. The primers were able to specifically detect the caterpillar-active Bt where it has been applied and did not detect it where there was no record of an application. These primers did not identify other Bt strains such as one used for mosquito control or other strains of Bt that had been isolated from similar environments. These primers can be used by scientists and regulatory agencies to detect applications of caterpillar active Bt.

Technical Abstract: Bacillus thuringiensis (“Bt”) is a ubiquitous soil bacterium with entomopathogenic properties. One strain, Bt subsp. kurstaki (“Btk”), is highly toxic to lepidopteran larvae and used in many commercial products for biological pest control. We designed a set of DNA markers that successfully identified Btk when screened against other Bacillus species and subspecies. These subspecies-specific primer sets allowed detection and characterization of Btk within an environmental background that contained many Bacillus species. Because Btk is used as an active ingredient in many commercial formulations, yet is not widely distributed in North America or Europe, these markers will prove useful in investigations on the environmental persistence and ecological fate of Btk.