Expanding the Egbenema Horizon: Novel Species Discovery in India and First Complete Genome Assembly of the Genus

Abstract

The recognition of Egbenema bharatensis, a novel species of cyanobacteria from the Northern Western Ghats, extends the phylogenetic and ecological understanding of the genus Egbenema and highlights terrestrial microbial diversity. Morphological characterization revealed resemblance with other Egbenema species but was inconclusive for definitive classification. Initial 16S rRNA sequencing indicated relationship at the genus level, yet sequence similarity less than 98% and observed morphological differences suggested taxonomic novelty. Whole-genome sequencing provided full resolution, with low similarity to known cyanobacterial taxa, and confirmed the isolate as a novel species. Further 16S-ITS region analyses corroborated its novelty and revealed characteristic structural features. Functional genome annotation revealed nitrogen fixation, cobalamin biosynthesis, and stress tolerance pathways, suggesting its metabolic versatility and potential biotechnological applications. The presence of multiple toxin-antitoxin systems and bioenergy-producing genes also reflects its adaptability to environmental fluctuation. This study also presents the first complete genome of the genus Egbenema, filling a significant gap in cyanobacterial genomic resources. These findings encourage integrative taxonomic practices and affirm the significance of exploring biodiversity hotspots for uncovering cryptic microbial diversity with ecological and industrial potential.