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Article Dans Une Revue Pathogens Année : 2020

Insecticidal Activity of Bacteria from Larvae Breeding Site with Natural Larvae Mortality: Screening of Separated Supernatant and Pellet Fractions

Résumé

Mosquitoes can transmit to humans devastating and deadly pathogens. As many chemical insecticides are banned due to environmental side effects or are of reduced efficacy due to resistance, biological control, including the use of bacterial strains with insecticidal activity, is of increasing interest and importance. The urgent actual need relies on the discovery of new compounds, preferably of a biological nature. Here, we explored the phenomenon of natural larvae mortality in larval breeding sites to identify potential novel compounds that may be used in biological control. From there, we isolated 14 bacterial strains of the phylum Firmicutes, most of the order Bacillales. Cultures were carried out under controlled conditions and were separated on supernatant and pellet fractions. The two fractions and a 1:1 mixture of the two fractions were tested on L3 and early L4Aedes albopictus. Two concentrations were tested (2 and 6 mg/L). Larvae mortality was recorded at 24, 48 and 72 h and compared to that induced by the commercializedB. thuringiensissubsp.israelensis. Of the 14 strains isolated, 11 were active against theA. albopictuslarvae: 10 of the supernatant fractions and one pellet fraction, and mortality increased with the concentration. For the insecticide activity prediction in three strains of theBacillus cereuscomplex, PCR screening of the crystal(Cry)and cytolytic(Cyt)protein families characteristic toB. thuringiensissubsp.israelensiswas performed. Most of the genes coding for these proteins' synthesis were not detected. We identified bacterial strains that exhibit higher insecticidal activity compared with a commercial product. Further studies are needed for the characterization of active compounds.
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hal-03149963 , version 1 (15-06-2023)

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Handi Dahmana, Didier Raoult, Florence Fenollar, Oleg Mediannikov. Insecticidal Activity of Bacteria from Larvae Breeding Site with Natural Larvae Mortality: Screening of Separated Supernatant and Pellet Fractions. Pathogens, 2020, 9 (6), pp.486. ⟨10.3390/pathogens9060486⟩. ⟨hal-03149963⟩
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