Polyphasic characterization of 15 heterocytous cyanobacterial isolates from different habitats of India and description of 9 novel species belonging to the genera Desikacharya, Aliinostoc, and Desmonostoc

A total of 15 cyanobacterial strains from India exhibiting the typical Nostoc-like morphology were characterized using a polyphasic approach. The strains were collected from the states of Tripura, Nagaland, Assam, and Madhya Pradesh in climatic conditions that ranged from tropical to sub-tropical. Despite prior studies on tropical cyanobacteria, many regions remain unexplored, requiring extensive research studies to discover novel cyanobacterial diversity. The molecular and phylogenetic analysis using the 16S rRNA gene indicated that out of the fifteen strains under study, eight clustered within the genus Desikacharya, six represented the genus Desmonostoc, and one of the strains belonged to the genus Aliinostoc. Upon further analysis, based on the 16S rRNA gene, 16S23S ITS p-distance values, and 16S23S ITS secondary structure analysis to enhance the resolution at the species level, nine out of the fifteen new strains were found to be representatives of novel taxa belonging to the genera Desikacharya, Aliinostoc, and Desmonostoc. Thus, in the present study, we have described herein nine novel species of cyanobacteria, namely Desikacharya nitens, Desikacharya fasciculatum, Desikacharya caementicola, Desikacharya pachmarhiensis, Desikacharya globata, Desikacharya brahmaputrae, Desikacharya grandispora, Aliinostoc fuscum, and Desmonostoc guwahatiense, in accordance with the International Code of Nomenclature for algae, fungi and plants (ICN). The study highlights the potential to discover new cyanobacterial lineages in underexplored regions, emphasizing the need for further research in tropical and sub-tropical regions. Moreover, the study also sheds light on the geographical distribution of Desmonostoc salinum and its vast ecological adaptation. [Display omitted] •Polyphasic characterization of 15 cyanobacterial strains from the tropical and sub-tropical regions of India.•16S rRNA gene analysis indicated the strains to be members of the genera Desikacharya, Aliinostoc, and Desmonostoc.•Morphological, ecological, and 16S rRNA gene analysis along with 16S23S ITS region analysis of the 15 strains, indicated that 9 strains are novel cyanobacterial lineages.•The vast ecological distribution of Desmonostoc salinum was observed.