ISOLATION OF A NON-INSECTICIDAL BACILLUS-THURINGIENSIS STRAIN BELONGING TO SEROTYPE H8A8B

Bacillus thuringiensis strains non-toxic to Lepidoptera, Bombyx mori a nd Diptera, Culex pipiens pallens larvae were isolated from Korean soi l samples during an investigation of B. thuringiensis isolates highly toxic to insect pests. One of these isolates, NTB-88, produces paraspo ral inclusions about 138 kDa in size and is non-toxic to 19 insect spe cies of three orders, Lepidoptera, Diptera and Coleoptera, even though it is highly susceptible to tryptic cleavage. Study of flagellar (H) antibodies of 33 B. thuringiensis strains revealed that NTB-88 has an H antigen identical with that of subsp. morrisoni (serotype 8a8b). Com parison of parasporal inclusion proteins and plasmid DNA patterns of s train NTB-88 with B. thuringiensis subsp. morrisoni HD-12 and B. thuri ngiensis subsp. morrisoni PG-14 showed that the isolate is a novel non -insecticidal B. thuringiensis strain belonging to serotype 8a8b.