Detección de genes cry1 y cry2 en cepas venezolanas de Bacillus thuringiensis y sus posibles aplicaciones en el campo de la biotecnología agrícola

Abstract

Bacillus thuringiensis (Bt) is a valuable biopesticide that is being used for the control of agricultural plagues of economic importance. Their insecticide properties are attributed to the presence of δ-endotoxins, Cry toxins, which are synthesized during the phase of sporulation of the bacterium. These toxins, when ingested by the larvae of the target insect, generate a set of physiological reactions that cause their death. The objective of the present work was the isolation and characterization of Bt strains from soils of the Guayana Region (Venezuela). Soils of different locations of Guayana were collected, dried and processed until the isolation of colonies with Bacillus spp. morphology. These colonies were grown in agar-water until sporulation and observed under the microscope for the verification of the presence of crystals, having identified 94 strains with Bacillus morphology. These strains were characterized for the presence of genes cry by the use of the PCR technique and the use of general primers for cry1 and cry 2. Of the total of analyzed strains, 75% presents the genetic profile cry1/cry2, which is toxic against Lepidoptera and Diptera and may have important applications in the agricultural and health fields. © Springer-Verlag Berlin Heidelberg 2007.