A 1.1-kilobase region downstream of the bin operon in Bacillus sphaericus strain 2362 decreases bin yield and crystal size in strain 2297.
The 2297 strain of Bacillus sphaericus produces a crystal of the Bin (binary) toxin that is approximately fourfold larger than that of strain 2362, the strain currently used in VectoLex, a commercial mosquito larvicide. Comparison of the regions downstream from the bin operon in these two strains showed that strain 2362 contained a 1.6-kb region with four orf genes not found in strain 2297. Insertion of a 1.1-kb portion of this region from strain 2362 by homologous recombination downstream from the bin operon in strain 2297 reduced Bin toxin production by 50 to 70% and toxicity to fourth-instar larvae of Culex quinquefasciatus by 68%. These results suggest that the 1.6-kb region downstream from the bin operon in B. sphaericus 2362 is responsible for the lower Bin yield and smaller crystal size characteristic of this strain.
Park
Hyun-Woo
HW
Public Health Entomology Center, Florida A&M University, Panama City, FL 32405, USA. hyun-woo.park@famu.edu
Tang
Mujin
M
Sakano
Yuko
Y
Federici
Brian A
BA
D000818:Animals; D001407:Bacillus / Q000166:cytology / Q000235:genetics* / Q000378:metabolism* / Q000472:pathogenicity; D001427:Bacterial Toxins / Q000096:biosynthesis*; D003465:Culex / Q000382:microbiology; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005798:Genes, Bacterial; D007814:Larva / Q000382:microbiology; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D016366:Open Reading Frames; D017422:Sequence Analysis, DNA; D016019:Survival Analysis; D014774:Virulence
D001427:Bacterial Toxins; D004269:DNA, Bacterial; C046134:binB protein, Bacillus sphaericus