MOLECULAR CHARACTERIZATION OF CYANOBACTERIA USING POLYMERASE CHAIN REACTION (PCR)

Molecular characterization of cyanobacterial isolates belonging to the order of Oscillatoriales was carried out using the phycocyanin locus (cpcBA-IGS) and the 16S-23S internally transcribed spacer region. DNA sequences from the phycocynanin operon discriminated ten genotypes, which correspond to seven morphotypes identified by traditional microscopic analysis. The cyanobacterial strains, belonging to genera (Synechococcus, Merismopedia, Leptolyngbya, Limnothrix, and Nostoc), were isolated and identified by morphological and molecular analysis. Morphological identification of the isolated strains was congrudent with their phylogenetic analysis based on 16S rDNA gene sequences. Cyanobacterial genera (Synechocystis, Aphanacopsa, Merismopedia, Lyngbya, Phormidium and Pseudonabaena) were identified by direct microscopic inspection. Our results suggests that the discriminatory power of the phycocyanin region varies across the cyanobacterial species and strains. The DNA sequence analysis of the transcribed spacer region also supports the polyphyletic nature of the studied Oscillatorian cyanobacteria. Thus, molecular approaches comprising different gene regions in combination with morphological criteria may provide better taxonomical resolution of the Oscillatoria.