Correspondence of high levels of beta-exotoxin I and the presence of cry1B in Bacillus thuringiensis.
Examination of 640 natural isolates of Bacillus thuringiensis showed that the 58 strains (9%) whose supernatants were toxic to Anthonomus grandis (Coleoptera: Curculionidae) produced between 10 and 175 micro g of beta-exotoxin I per ml. We also found that 55 (46%) of a sample of 118 strains whose culture supernatants were not toxic to A. grandis nevertheless produced between 2 and 5 micro g/ml. However, these amounts of beta-exotoxin I were below the threshold for detectable toxicity against this insect species. Secretion of large amounts of beta-exotoxin I was strongly associated with the presence of cry1B and vip2 genes in the 640 natural B. thuringiensis isolates studied. We concluded that strains carrying cry1B and vip2 genes also possess, on the same plasmid, genetic determinants necessary to promote high levels of production of beta-exotoxin I.
Unité de Recherches de Lutte Biologique, INRA La Minière, 78285 Guyancourt, France.
Sylvain
S
Espinasse
Michel
M
Gohar
Josette
J
Chaufaux
Christophe
C
Buisson
Stéphane
S
Perchat
Vincent
V
Sanchis
D000241:Adenosine / Q000031:analogs & derivatives* / Q000378:metabolism*; D001413:Bacillus thuringiensis / Q000235:genetics / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism*; D001427:Bacterial Toxins; D004731:Endotoxins / Q000378:metabolism*; D005838:Genotype; D006460:Hemolysin Proteins; D008970:Molecular Weight; D013400:Sugar Acids / Q000378:metabolism*
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D013400:Sugar Acids; C030956:insecticidal crystal protein, Bacillus Thuringiensis; C068295:thuringiensin; D000241:Adenosine