An improved method for genomic DNA extraction from cyanobacteria

We present an improved method for genomic DNA extraction from cyanobacteria by updating the earlier method from our group (Sinha et al. 2001) that does not require lysozyme treatment or sonication to lyse the cells. This method use lysis buffer to lyse the cells and also skips the initial treatments to remove the exopolysaccharides or to break the clumps. To test the efficacy of the method DNA was extracted from the freshwater cyanobacteria Anabaena variabilis PCC 7937, Anabaena sp. PCC 7120, Synechocystis sp. PCC 6803, Synechococcus sp. PCC 6301 and Rivularia sp. HKAR-4 (Accession number: FJ939128). The spectrophotometric and gel electrophoresis analysis revealed high yield and high quality of genomic DNA extracted by this method. Furthermore, the RAPD resulted in the amplification of unidentified genomic regions of various lengths; however, rDNA amplification gave only one band of 1.5 kb in all studied cyanobacteria. Thymine dimer detection study revealed that thymine dimers are induced only by UV-B radiation in A. variabilis PCC 7937 and there is no effect of PAR and UV-A on its genome. Collectively, all these findings put forward the applicability of this method in different studies and purposes.