Molecular Characterization OF cry1, cry2, cry3 y cry4 Genes In Bacillus thuringiensis Isolates and Determination of its Bioinsecticide Activity in Aedes aegypti Larvae

• Published in: Interciencia Vol. 38; no. 2; p. 128
• Main Author: Serrano, Fabian Galvis
• Format: Journal Article
• Language: English; Spanish
• Published: 01.02.2013
• Subjects: Aedes aegypti; Bacillus thuringiensis
• ISSN: 0378-1844

Chemical insecticides can be toxic and cause environmental degradation. Therefore, biological control of insects represents an alternative of low ecological impact. Bacillus thuringiensis is a spore-forming Gram-positive bacterium that produces parasporal crystals of a proteic nature, formed by delta endotoxins that are toxic to a large number of insects and are biodegradable and innocuous to other species. In the present work 13 native strains of B. thuringiensis were isolated from soil samples and identified by selective methods and the BBL CRYSTAL method. In the molecular characterization utilizing specific primers for the identification of cry1, cry2, cry3 y cry4 genes, eight isolates presented the cry3 gene and two presented the cry2 gene. These two latter isolates were used in a bioassay on Aedes aegypti larvae to determine their toxic effect, showing that the preliminary toxicity essay of the BtUDES2 isolate presented a lethality of 56.67%. When determining the lethal concentration of this same isolate, an average lethal concentration of 11.4333ng.ml-1 and a total lethal concentration of 17.1542ng.ml-1 were found.