Seaweed-associated bacteria from the Gulf of Mannar show prey-lytic and predator-like activity

Prey-predator interactions are crucial for maintaining the diversity and stability of the ecosystem. In contrast to the extensively studied macropredators, the diversity and ecological significance of the micro-predators remain understudied. The aim of this study was to understand the diversity of bacterial predators and to isolate the predators associated with algal samples collected from the Gulf of Mannar. Sixteen out of twenty-eight algal samples showed prey-lawn lesion formation. Newly isolated strains of Pseudomonas paraeruginosa , Nitratireductor aquimarinus , Shewanella algae, and Alcaligenes phenolicus were identified with previously unknown predatory-like traits, and showed a broad spectrum of prey range. The scanning electron microscopy images showed candidate predator–prey contact consistent with epibiotic interaction. Further, in vitro enrichment followed by metagenomics suggested the presence of candidate epiphytic prey-lytic bacteria associated with Caulerpa sp., highlighting algal-associated candidate predatory bacteria.