Genetic Diversity of Indigenous Bacillus thuringiensis Strains by RAPD-PCR to Combat Pest Resistance
Department of Microbiology, University of Dhaka, Dhaka- 1000, Bangladesh
Bt Research, 2015, Vol. 6, No. 8 doi: 10.5376/bt.2015.06.0008
Received: 08 Sep., 2015 Accepted: 15 Oct., 2015 Published: 27 Nov., 2015
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Preferred citation for this article:
Shishir M.A., Pervin S., Sultana M., Khan S.N., and Md Hoq M., 2015, Genetic Diversity of Indigenous Bacillus thuringiensis Strains by RAPD-PCR to Combat Pest Resistance, Bt Research, 6(8): 1-16 (doi: 10.5376/bt.2015.06.0008 )
Genetic diversity is highly relevant and significant in discovering novel insecticidal genes in Bacillus thuringiensis (Bt) strains and to deal with the problems of emerging insect resistance towards Bt biopesticides. In view of this, Random Amplified Polymorphic DNA (RAPD)-PCR analysis was performed with a decamer AGCTCAGCCA for molecular typing of 177 Bt strains of Bangladesh to determine their genetic diversity. These Bt strains were allocated into 15 genomic types with their binary matrices as determined from the dendrogram based on a standardized distance in scale bar. Genotype 9 and 11 were the largest among others, each containing more than 25% of the Bt strains. The average diversity index, as deduced for each group by cluster: isolate ratio at a specific distance, was higher for locations (0.27 ± 0.098) than that for biotypes (0.23 ± 0.046) which indicates an unmingled and vertical transfer of biochemical properties among the strains. Prevalence of agriculturally important subgroups of cry1 gene in indigenous Bt strains was also determined where cry1Aa and cry1Ca gene were found to be the most prevalent (21.74%). While analyzing the distribution pattern of cry genes, they were observed to be present in all RAPD- genotypes but genotype 10 and were most prevalent in genotypes 1, 6 and 9. The phylogeny reconstruction among the strains was performed by neighbor-joining method with the 16S rRNA gene sequences and the correlation among the phylogeny, RAPD genotypes, Biotypes and presence of cry genes were analyzed.
Bacillus thuringiensis; cry genes; Genotyping; resistance; RAPD-PCR