Diversity and phylogenetic analysis of heterocystous cyanobacteria using morphological, nitrogen fixation and molecular attributes

Abstract

Diversity and molecular phylogeny of 22 heterocystous cyanobacteria (Nostocales and Stigonematales), isolated from different paddy fields of Chhattisgarh, India, have been assessed on the basis of microscopic analysis, nitrogen fixing abilities,16S rRNA and <em>nif</em>H genes sequences in conjunction with phylogenetic tools. Variations in morphological attributes along with nitrogen fixing capabilities suggested that these <em>attributes</em> are strains specific. Further, it was supported by the principal component analysis (PCA) plot which showed scattered placement of these heterocystous cyanobacterial strains. The monophyletic origin of the heterocystous clade and the polyphyly of the true branching Stigonematales were observed in the constructed dendrograms based on16S rRNA and the <em>nif</em>H gene sequences. Thus, the use of morphological, physiological (nitrogen fixation) and molecular (16S rRNA and <em>nif</em>H genes sequences) parameters uncovered the better resolution of taxonomic and phylogenetic issues of heterocystous cyanobacteria.