Bacillus thuringiensis subsp. tenebrionis, strain BI 256–82: a third pathotype within the H-serotype 8a8b

Abstract

With regard to their host range, the Bacillus thuringiensis strains belonging to H-serotype 8a8b can be assigned to three different pathotypes: strains G 2 and Morrison to pathotype A (pathogenic only for larvae of Lepidoptera), strain PG 14 to pathotype B (pathogenic only for larvae of Nematocera, Diptera), and strain BI 256–82 to pathotype C (pathogenic only for Chrysomelidae, Coleoptera). The parasporal toxin crystals of the three pathotypes differ in morphology, protein pattern, and serology. The crystal of BI 256–82 is plate-like, whereas others are bipyramidal (G-2 and Morrison) or sphaerical (PG-14). The protein pattern (SDS-PAGE) of BI 256–82 comprises two protein bands with molecular weights of about 74 × 103 and 68 × 103. No serological cross-reaction was found between crystal antigens of BI 256–82 and those of the two other pathotypes. Furthermore, strain BI 256–82 does not produce β-exotoxin (in contrast to G-2 and Morrison) and belongs to O-serotype IX (in contrast to PG-14).