The Novel Halotolerant, Filamentous Cyanobacterium <i>Krienitziella sambharensis</i> gen. et sp. nov. (Nodosilineales, Cyanobacteriophyta) Isolated from an Indian Wetland (Sambhar Salt Lake, India)

Soda lakes are ecologically significant habitats characterized by high salinity, alkaline pH, and intense evaporation. These milieus are hostile to most life, though these lakes could be a rich source for discovering novel halotolerant and halophilic cyanobacterial taxa. The Indian subcontinent is endowed with shallow saline–alkaline lakes whose cyanobacterial diversity has been little explored. The present study was undertaken to explore the cyanobacterial diversity in an inland saline–alkaline lake (Sambhar Lake) in India using a polyphasic approach. Two thin, filamentous strains encapsulated within thick sheaths and capable of nodule formation under normal light conditions were recovered. Both isolates exhibited growth at up to 4% salinity, indicating their halotolerant nature. The studied strains exhibited <95% 16S rRNA gene similarity with closely related taxa from the genera <i>Thainema</i> and <i>Insularia</i> and formed a distinct evolutionary lineage in phylogenetic tree supported by a high bootstrap value. Additionally, the secondary structures of the 16S-23S Internal Transcribed Spacer (ITS) regions (D1-D1′ and BoxB) of the studied strains showed remarkable differences from phylogenetically closely related taxa, indicating these strains represent a new genus in the Nodosilineales: <i>Krienitziella sambharensis</i> gen. et sp. nov., in accordance with the International Code of Nomenclature for Algae, Fungi, and Plants (ICN).