Characterization of Tunisian Bacillus thuringiensis strains with abundance of kurstaki subspecies harbouring insecticidal activities against the lepidopteran insect Ephestia kuehniella.
The study of 257 crystal-producing Bacillus thuringiensis isolates from bioinsecticide free soil samples collected from different sites in Tunisia, was performed by PCR amplification, using six primer pairs specific for cry1, cry2, cry3, cry4, and vip3A genes, by the investigation of strain plasmid pattern, crystal morphology and delta-endotoxin content and by the assessment of insecticidal activities against the lepidopteran insect Ephestia kuehniella. Based on plasmid pattern study, 11 representative strains of the different classes were subjected to morphological and molecular analyses. The comparison of the PFGE fingerprints confirmed the heterogeneity of these strains. B. thuringiensis kurstaki strains, harbouring at the same time the genes cry1A, cry2, cry1Ia, and vip3A, were the most abundant (65.4%). 33.34% of the new isolates showed particular delta-endotoxin profiles but no PCR products with the used primer sets. B. thuringiensis israelensis was shown to be also very rare among the Tunisian B. thuringiensis isolates diversity. These findings could have considerable impacts for the set up of new pest control biological agents.
Saadaoui
Imen
I
Laboratory of Biopesticides, Centre of Biotechnology of Sfax, P.O. Box 1177, 3018, Sfax, Tunisia.
Al-Thani
Roda
R
Al-Saadi
Fatma
F
Belguith-Ben Hassan
Najeh
N
Abdelkefi-Mesrati
Lobna
L
Schultz
Patrick
P
Rouis
Souad
S
Jaoua
Samir
S
D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism / Q000472:pathogenicity*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism*; D015373:Bacterial Typing Techniques; D016000:Cluster Analysis; D016172:DNA Fingerprinting; D004269:DNA, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D004731:Endotoxins / Q000378:metabolism*; D006460:Hemolysin Proteins / Q000378:metabolism*; D007915:Lepidoptera / Q000382:microbiology* / Q000502:physiology*; D010957:Plasmids / Q000032:analysis; D012988:Soil Microbiology; D016019:Survival Analysis; D014416:Tunisia
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis