Molecular characterization of marine Cyanobacteria from the Indian subcontinent deduced from sequence analysis of the phycocyanin operon (cpcb-IGS-cpcA) and 16S-23S ITS region.
Molecular characterization of ten marine cyanobacterial isolates belonging to the order Oscillatoriales was carried out using the phycocyanin locus (cpcBA-IGS) and the 16S-23S internally transcribed spacer region. DNA sequences from the phycocyanin operon discriminated ten genotypes, which corresponded to seven morphotypes identified by traditional microscopic analysis. The cpcB coding region revealed 17 % nucleotide variation, while cpcA exhibited 29 % variation across the studied species. Phylogenetic analyses support the conclusion that the Phormidium and Leptolyngbya genera are not monophyletic. The nucleotide variations were heterogeneously distributed with no or minimal informative nucleotides. Our results suggest that the discriminatory power of the phycocyanin region varies across the cyanobacterial species and strains. The DNA sequence analysis of the 16S-23S internally transcribed spacer region also supports the polyphyletic nature of the studied oscillatorian cyanobacteria. This study demonstrated that morphologically very similar strains might differ genotypically. Thus, molecular approaches comprising different gene regions in combination with morphological criteria may provide better taxonomical resolution of the order Oscillatoriales.
Premanandh
Jagadeesan
J
National Facility for Marine Cyanobacteria, Bharathidasan University, Palkalaiperur, Tiruchirapalli, 620024 India. jpanandh@yahoo.com
Priya
Balakrishnan
B
Teneva
Ivanka
I
Dzhambazov
Balik
B
Prabaharan
Dharmar
D
Uma
Lakshmanan
L
D015373:Bacterial Typing Techniques; D000458:Cyanobacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification / Q000648:ultrastructure; D021903:DNA, Ribosomal Spacer / Q000032:analysis*; D014644:Genetic Variation; D007194:India; D008858:Microscopy, Phase-Contrast; D008969:Molecular Sequence Data; D009876:Operon; D010798:Phycocyanin / Q000235:genetics*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012338:RNA, Ribosomal, 23S / Q000235:genetics; D012623:Seawater / Q000382:microbiology*; D017422:Sequence Analysis, DNA
D021903:DNA, Ribosomal Spacer; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S; D010798:Phycocyanin