Diversity and Characterization of Bacillus thuringiensis Strains and Cry Gene Variability in Agro-Ecological Zones of Mali

Aims: This study aimed to identify the diversity of : Bacillus thuringiensis (Bt) strains in soils from different agro-ecological zones of Mali. Study Design: Location and duration of the study: The work was carried out in Bamako, at LaboREM-Biotech located on the Badalabougou hill. Methodology: Soil samples were collected in the different agro-ecological zones of Mali, specifically in the localities of Bougouni, Nièna, Sikasso, Koutiala, Ségou, Faya (classified forest) and Baguinéda. To properly carry out this activity, bacteria were isolated from soil samples. The different isolates obtained from the Luria Bertani (LB) agar culture medium were identified and characterized according to their macroscopic and microscopic aspects and their metabolic profile. After biochemical characterization, the different strains selected underwent molecular characterization by PCR using specific primers for the identification of Cry genes. Results: In this study, seventy-two bacterial strains with a characteristic appearance of Bt were isolated. Sixty-nine (69) strains were identified as Bt after biochemical characterization of the selected isolates. Results of the PCR analysis showed that: among the Bt strains analyzed, sixty-two strains contained at least of the Cry1, Cry4, Cry10, Cry11, Cry24 and Cry32 genes and form 05 large groups with high diversity. Seven Bt strains selected did not code for any of the Cry genes sought. Conclusion: Sixty-nine Bt strains were isolated in the different agroecological zones of Mali studied. These strains were used to strengthen the Bt bank already present at LaboREM-Biotech. This study shows the existence of a strong diversity of Bts in the agroecological zones studied and provides an overview of the diversity of cry genes carried by these strains and their importance in various fields.