Genomic and physiological characterization of Aliivibrio sp. REG001485: A specialized functional ecotype for long-term bioluminescent signaling

Bioluminescence is a valuable tool for industrial applications, yet the rapid signal instability of many marine strains limits its broader implementation. This study characterized the genomic and physiological profile of Aliivibrio sp. (REG001485), an isolate from the Southern Blue Amazon (Brazilian Exclusive Economic Zone). Phylogenomic (ANI and dDDH) and pangenomic analyses (anvi’o) were performed for taxonomic placement and to evaluate genomic variability against 41 high-quality reference genomes. Physiological assays assessed the effects of temperature (4–37 °C), salinity (1–5%), pH (5.0–9.0), and carbon sources (Biolog EcoPlate) on biomass and bioluminescence. Genomic metrics (ANI 96.0%; dDDH 67.9%) placed the isolate at the threshold of the A. fischeri species complex. The strain exhibited a significant thermal decoupling between growth (optimal at 20–30 °C) and bioluminescence (optimal at 4–10 °C). N-Acetyl-D-Glucosamine (NAG) and Tween 80 were identified as specific metabolic triggers that enhance light emission without proportional biomass increase. Under static conditions at pH 6.5 in an optimized medium (BO1485), the strain maintained detectable bioluminescence for over 100 days without nutrient supplementation. Pangenomic profiling revealed a unique accessory genome of 160 singleton gene clusters, including specialized machinery for acid resistance (GadA), cold adaptation (CspC), and long-term survival (HigB system). These results demonstrate that REG001485 represents a distinct functional ecotype with high environmental plasticity. While its position at the genomic detection limit suggests a potential novel species, this study establishes the lineage as a resilient biological component for long-term monitoring and autonomous signaling applications in fluctuating marine environments.