title: Occurrence and linkage between secreted insecticidal toxins in natural isolates of Bacillus thuringiensis.
abstract: Little is known about the occurrence and linkage between secreted insecticidal virulence factors in natural populations of Bacillus thuringiensis (Bt). We carried out a survey of 392 Bt strains isolated from various samples originating from 31 countries. The toxicity profile of the culture supernatants of these strains was determined individually against Anthonomus grandis (Coleoptera) and Spodoptera littoralis (Lepidoptera). We analyzed beta-exotoxin I production and searched for the genes encoding Vip1-2, Vip3, and Cry1I toxins in 125 of these strains. Our results showed that these insecticidal toxins were widespread in Bt but that their distribution was nonrandom, with significant linkage observed between vip3 and cry1I and between vip1-2 and beta-exotoxin I. Strains producing significant amounts of beta-exotoxin I were more frequently isolated from invertebrate samples than from dust, water, soil, or plant samples.
authors.affiliation: Unité de Recherches de Lutte Biologique, INRA La Minière, 78285 Guyancourt, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Espinasse
authors.forename: Josette
authors.initials: J
authors.lastname: Chaufaux
authors.forename: Christophe
authors.initials: C
authors.lastname: Buisson
authors.forename: Stéphane
authors.initials: S
authors.lastname: Perchat
authors.forename: Michel
authors.initials: M
authors.lastname: Gohar
authors.forename: Denis
authors.initials: D
authors.lastname: Bourguet
authors.forename: Vincent
authors.initials: V
authors.lastname: Sanchis
mesh_terms: D000241:Adenosine / Q000031:analogs & derivatives* / Q000032:analysis; D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics* / Q000302:isolation & purification* / Q000378:metabolism; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics*; D001427:Bacterial Toxins / Q000235:genetics* / Q000633:toxicity; D001517:Coleoptera / Q000254:growth & development; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics / Q000302:isolation & purification; D004731:Endotoxins / Q000235:genetics*; D006460:Hemolysin Proteins; D010572:Pest Control, Biological / Q000379:methods; D016133:Polymerase Chain Reaction; D018411:Spodoptera / Q000254:growth & development; D013400:Sugar Acids / Q000032:analysis; D037521:Virulence Factors / Q000032:analysis / Q000235:genetics
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004269:DNA, Bacterial; D004731:Endotoxins; D006460:Hemolysin Proteins; D013400:Sugar Acids; C447139:Vip3A protein, Bacillus thuringiensis; D037521:Virulence Factors; C030956:insecticidal crystal protein, Bacillus Thuringiensis; C068295:thuringiensin; D000241:Adenosine