The present study proposed different techniques to differentiate some toxigenic cyanobacterial strains applying short tandemly repeated repetitive (STRR), randomly amplified polymorphic DNA (RAPD), restriction fragment length polymorphism (RFLP) and sequencing the gene produced. In this study, primers corresponding to the STRR sequence used in the PCR were STRRA1, STRRB1 and mixed STRRA1+STRRB1 showed a genetic heterogeneity among isolates from different geographic regions. STRR-PCR indicated to be useful for clustering of even closely related strains . A total of eight primers were initially chosen to generate RAPD patterns. RAPD-PCR was used to generate unique and identify DNA profiles for six strains of yanobacteria. The strain-specific randomly amplified polymorphic DNA profile made it possible to discriminate among all toxigenic cyanobacteria. . RFLP analysis and sequencing of the 16SrRNA gene have revealed a very close relationship between certain strains of cyanobacteria The PCR products corresponding to the 16SrRNA genes of the six strains were digested with MspI, Sau3A1, HaeIII, RsaI, EcoRI and HinfI. Several molecular approaches now provide powerful adjuncts to the culture-dependent techniques. One approach in particular that couples PCR and rRNA-based phylogeny has been effective in the exploration of microbial environments and the identification of uncultured organisms. PCR product for cyanoacterial identification (16SrRNA, Nitrogenase, and Phycocyanin genes and toxicity genes (Microcystin, Nodularin,Cylindrospermopsin and Saxitoxin toxins) have been sequenced, respectively. It is generally accepted for bacteria that a 16SrDNA sequence similarity of 96±97% and DNA±DNA hybridization values of 70% relative binding (RB) with a ΔTm of 5°C represent the lower boundary of a species and that a genus may be defined by species with 95% or greater sequence similarity. However, it has been suggested that values as low as 50% RB and a ΔTm of 7°C may be employedfor the delineation of species, and showed that sequence similarity is often greater than 98±99% when total DNA similarity is as low as 10±40% RB. Similar conclusions were showed that the relationship between RB and sequence similarity varies even within the same subphylum. The data was analysis by SeqMan software.

Keyword: cyanobacterial, 16SrRNA, Molecular, DNA, PCR- Based, Toxigenic

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