Recombinant larvicidal bacteria with markedly improved efficacy against culex vectors of west nile virus.
An urgent need exists for new agents to control mosquito vectors of disease. Mosquito larvicides based on the bacteria Bacillus thuringiensis subsp. israelensis (Bti) or B. sphaericus (Bs) are effective in many habitats, but use is limited by their high cost. Moreover, mosquito resistance evolves rapidly to Bs where it is used intensively. The efficacy of these bacteria is due to a binary protein (BsB) in Bs and four proteins (Cry4A, Cry4B, Cry11A, and Cyt1A) in Bti. Here we report the use of cyt1A promoters and a 5' mRNA stabilizing sequence to synthesize high levels of Bs2362 binary toxin in Bti strains. The recombinant BtiIPS-82/BsB showed high potency against fourth instars of Culex quinquefasciatus, a vector of West Nile virus, being 21-fold as potent as BtiIPS-82, and 32-fold as potent as Bs2362. Similar improved efficacy was obtained against larvae of Cx. tarsalis. Moreover, BtiIPS-82/BsB suppressed resistance to Bs2362 in Cx. quinquefasciatus.
Park
Hyun-Woo
HW
Department of Entomology, Interdepartmental Graduate Programs in Microbiology, and Genetics, Genomics and Bioinformatics, University of California, Riverside, California 92521, USA.
Bideshi
Dennis K
DK
Wirth
Margaret C
MC
Johnson
Jeffrey J
JJ
Walton
William E
WE
Federici
Brian A
BA
D000818:Animals; D001407:Bacillus / Q000235:genetics / Q000472:pathogenicity*; D001483:Base Sequence; D003465:Culex / Q000145:classification / Q000821:virology*; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D007303:Insect Vectors; D010572:Pest Control, Biological; D011995:Recombination, Genetic; D013045:Species Specificity; D014901:West Nile Fever / Q000635:transmission*; D014902:West Nile virus / Q000302:isolation & purification*
D017931:DNA Primers