Exploring bacterial diversity in seagrass meadow of Thalassia hemprichii and Syringodium isoetifolium from Tanzania’s coast

Seagrasses are highly productive coastal ecosystems that harbor diverse bacterial communities, including both culturable and unculturable taxa. These bacteria play vital roles in ecological, biogeochemical, and biotechnological processes. In this study, a metagenomic approach using Pacific Biosciences next-generation sequencing was employed to investigate bacterial diversity associated with Thalassia hemprichii and Syringodium isoetifolium collected from the Mjimwema coast, Dar es Salaam, Tanzania. Results revealed that T. hemprichii supported greater bacterial species diversity (117 OTUs) compared to S. isoetifolium (109 OTUs). Among plant compartments, roots harbored the highest diversity, followed by rhizosphere sediment and leaves. The phylum Proteobacteria dominated across all samples (24.85–99.23%), with Gammaproteobacteria (20.58–99.11%), Vibrionales (7.86–98.91%), Vibrionaceae (7.88–98.91%), and the genus Vibrio (4.79–91.99%) as the most abundant taxa. Although this study did not establish the functional roles of the identified bacteria, it provides the first comprehensive insight into the bacterial diversity associated with T. hemprichii and S. isoetifolium in the Western Indian Ocean. The findings offer a valuable baseline for future research aimed at functional characterization of seagrass- associated microbiomes, particularly their ecological roles and potential biotechnological applications.