Morphology and RAPD analysis of potential cyanobacterial isolates of Loktak Lake, the only largest freshwater lake in the North-East India

In the present study, ten (10) cyanobacterial strains belonging to (04) genera from different geographical habitats of Loktak Lake were morphologically identified upto genus/ species level and RAPD-PCR analysis using six (06) sets of random primers was also carried out to reveal their phylogenetic relationship and genetic diversity. The electrophoretic patterns for 10 cyanobacterial strains (03 Phormidium strains, 05 Nostoc strains, 01 Anabaena strain and 01 Calothrix strain) were used for molecular analysis using the RAPD technique. Unique banding patterns were observed from all tested cyanobacterial species and their molecular weights of each band were used to calculate their genetic distance among them. The bands generated through RAPD techniques were subjected to similarity matrix and similarity co-efficient ranged from 0.08 to 0.67. The cluster for Phormidium sp. (BTA-52) and Phormidium sp. (BTA-75) showed 66.7% similarity. Anabaena sp. (BTA-964) and Phormidium sp. (BTA-75) which belongs to different branches of the same cluster showed 21.1% similarity co-efficient. Nostoc sp. (BTA-61) and Phormidium sp. (BTA-1048) belongs to same cluster showed similarity co-efficient of 36.4%. The cluster containing Calothrix sp. (BTA-73) and Nostoc sp. (BTA-80) of different genus showed 33.3% similarity co-efficient. Nostoc sp. (BTA-60) and Nostoc muscorum (BTA-950) of the same cluster showed 9.50% co-efficient similarity. The RAPD data was further analysed by phylogenetic analysis for genetic relatedness. The morphological diversity of isolates was assured by microscopy whereas PCR based RAPD fingerprint profile was used for molecular characterization. Keywords: Cyanobacteria, Loktak Lake, Morphology, RAPD, Phylogenetic analysis