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

Abstract

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, 16S-23S ITS p-distance values, and 16S-23S ITS secondary structure analysis to enhance the resolution at the species level, 9 out of the 15 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. © 2024 Elsevier B.V.