Development of a recombinant strain of Bacillus thuringiensis subsp. kurstaki HD-73 that produces the endochitinase ChiA74.
Bacillus thuringiensis subsp. kurstaki HD-73 was transformed with the homologous endochitinase gene chiA74 of B. thuringiensis subsp. kenyae LBIT-82 under the regulation of its own promoter and Shine-Dalgarno sequence. The plasmid, pEHchiA74, which harbors chiA74, was detected by southern blot analysis and showed high segregational stability when the recombinant strain was grown in a medium without antibiotic. The recombinant bacterium transformed with pEHchiA74 showed an improvement in chitinolytic activity three times that of the wild-type strain. Expression of ChiA74 did not have any deleterious effect on the crystal morphology and size, but sporulation and Cry1Ac production in rich medium (nutrient broth with glucose) was reduced by approximately 30%. No significant increase in the toxicity of the transformant bacterium toward Plutella xylostella was detected using the same amount of total protein. However, it is possible that ChiA74 synthesis compensated for the decrease in net Cry1Ac synthesis and toxicity observed with the recombinant strain.
Casique-Arroyo
Gabriela
G
Departamento de Ingeniería en Alimentos, Instituto de Ciencias Agrícolas, Universidad de Guanajuato, Apartado postal 311, Irapuato, Guanajuato, 36500, Mexico.
Bideshi
Dennis
D
Salcedo-Hernández
Rubén
R
Barboza-Corona
José Eleazar
JE
D000818:Animals; D001413:Bacillus thuringiensis / Q000201:enzymology* / Q000235:genetics / Q000502:physiology; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism; D002688:Chitinases / Q000235:genetics / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004731:Endotoxins / Q000235:genetics / Q000378:metabolism; D006460:Hemolysin Proteins / Q000235:genetics / Q000378:metabolism; D007814:Larva / Q000382:microbiology; D008858:Microscopy, Phase-Contrast; D009036:Moths / Q000382:microbiology; D010957:Plasmids / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism; D013171:Spores, Bacterial / Q000201:enzymology / Q000235:genetics; D014170:Transformation, Genetic
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D011994:Recombinant Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D002688:Chitinases