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Diversity of Bacillus thuringiensis strains from Colombia with insecticidal activity against Spodoptera frugiperda (Lepidoptera:Noctuidae)
Author(s) -
Arango J.A.,
Romero M.,
Orduz S.
Publication year - 2002
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.2002.01545.x
Subject(s) - lepidoptera genitalia , bacillus thuringiensis , noctuidae , spodoptera , biology , biological pest control , botany , microbiology and biotechnology , library science , humanities , philosophy , bacteria , genetics , computer science , gene , recombinant dna
Aims: To identify and characterize Bacillus thuringiensis strains highly toxic to Spodoptera frugiperda , and to explore the genetic diversity of such strains. Methods and Results: The insecticidal activity of 1100 strains of B. thuringiensis from Colombian soil samples was assayed against first instar S. frugiperda larvae, and 32 active strains were found. After a second bioassay evaluation, the eight most potent strains were selected for further characterization, which included crystal protein profiles determined by polyacrylamide gel electrophoresis, plasmid profile, plasmid restriction patterns, cry gene composition, qualitative determination of β‐exotoxin production, random amplified polymorphic DNA, serotyping, and toxicity to S. frugiperda . All Colombian strains contained cry1Aa , cry1Ab , cry1Ac , cry1B , cry1C and cry1D genes. However, PCR profiles of the Colombian strains suggested the presence of variants of the cry 1 genes. Serotyping indicated that these strains belong to the kurstaki , thuringiensis , canadiensis and indiana subspecies. Interestingly, three strains belonging to different serotypes and subspecies were found in the same soil sample, and toxicity ranged between 11 and 976 ng cm –2 of diet. Conclusions: It has been shown that B. thuringiensis strains belonging to different serotypes and displaying variable potency to S. frugiperda larvae can be found in the same soil sample. Significance and Impact of the Study: The results obtained indicate that some of the B. thuringiensis strains studied could be of interest for further development for S. frugiperda control programmes.