Isolation And Identification Of Bacillus Thuringiensis

In the globe,the damage from insects is one of the most important factors for loss of agricaltual productions.Bacillus thuringiensis has been widely used as a microbial insecticide because of plenty advantages including specific insecticidal activity,safety to human and mammal,harmony to the environment. Primarily insecticidal activity is closely related with its carried coding ICPs(Insecticidal Crystal Proteins,ICPs)of Bacillus thuringiensis cry genes.Therefore,cry genetic engineering research has became very popular in recent years.So far,the international community has 476 species of rodent protein cloning of genes, but with Bt applications have been expanding and Bt ICPs genes bring the insect resistance differently,finding new strains and genes is one of the effective ways of resolving insect resistance.In this study, 144 Bt strains were isolated from 276 soil samples collected from 19 provinces by temperature selection and fuchsin staining. 91 strains were identified the subspecies by physiological and biochemical identification. 10 pairs of universal prime were designed for characterization of insectieidal crystal protein genes.66 strains containing cry / cyt genes. On this basis polyacrylamide gel electrophoresis method was used to identify the cry / cyt gene. 17 cry7/cry8 genes were divided into four categories, 13 cry11 genes were divided into two categories.This study also analyzed the distribution and diversity of cry genes, as well as the relationship between genotype and insecticidal activity, which are important to the discovery of new genotypes, insecticidal activity forecasts, and the development and utilization of Bt resources.