Correlation between serovars of Bacillus thuringiensis and type I β-exotoxin production

• Published in: Journal of invertebrate pathology Vol. 82; no. 1; pp. 57 - 62
• Main Authors: Sara Hernández, Carmen, Martı́nez, Clara, Porcar, Manuel, Caballero, Primitivo, Ferré, Juan
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 2003; Elsevier
• Subjects: Adenosine - analogs & derivatives; Adenosine - biosynthesis; Bacillus thuringiensis; Bacillus thuringiensis - immunology; Bacillus thuringiensis - metabolism; Bacterial toxins; Bacteriology; Biological and medical sciences; Flagellar (H) antigen; Fundamental and applied biological sciences. Psychology; HPLC; Microbiology; Pathogenicity, virulence, toxins, bacteriocins, pyrogens, host-bacteria relations, miscellaneous strains; Serotype; Serotyping; Serovar; Sugar Acids; β-Exotoxin; Bacterial toxins; Serovar; Flagellar (H) antigen; Bacillus thuringiensis; β-Exotoxin; Serotype; HPLC; HPLC chromatography; Artificial selection; Biosynthesis; Bacillaceae; Strain; Toxin; Bacillales; Bacteria; Exotoxin; H antigen
• ISSN: 0022-2011; 1096-0805
• DOI: 10.1016/S0022-2011(02)00199-4

β-Exotoxin is a thermostable metabolite produced by some strains of Bacillus thuringiensis. Because of vertebrate toxicity, most commercial preparations of B. thuringiensis are prepared from isolates that do not produce β-exotoxin. The aim of the present study was to find out the possible relationship between serovars of B. thuringiensis and β-exotoxin production. A specific HPLC assay for type I β-exotoxin has been used to detect this exotoxin in supernatants from final whole cultures of 100 strains belonging to four serovars of B. thuringiensis: thuringiensis, kurstaki, aizawai, and morrisoni. For each serovar, 25 strains randomly chosen from two Spanish collections were analyzed. Frequency of β-exotoxin production was higher in B. thuringiensis serovar thuringiensis, whereas only two strains from serovar kurstaki showed β-exotoxin production. None of the 25 strains belonging to serovars aizawai and morrisoni was found to produce this compound. Along with data from other studies, serovars can be classified as “common,” “seldom,” or “rare” β-exotoxin producers. The serovar-dependent β-exotoxin production is discussed in relation to the evolutionary process of serovar differentiation, the plasmid compatibility and limited plasmid exchange between serovars, and with the serovar-dependent regulation of plasmid-encoded genes.