Nanopore-Based Whole-Genome Sequencing Reveals a Bioluminescent and Non-Bioluminescent Bacterium Isolated from the Squid Loligo forbesi in the Red Sea.

Common in aquatic life, symbiotic interactions with luminescent bacteria to enable bioluminescence. Although interactions in cephalopods have been well investigated in species including Euprymna scolopes, little is known about other cephalopods, especially those found in the Red Sea. This work separated and identified bioluminescent and non-bioluminescent bacterial strains from the ink sacs and eyes of Loligo forbesii, a squid species taken from the Zaafarana area of the Suez Canal in Egypts Red Sea. Whole-genome sequencing based on Nanopores turned up two distinct bacterial strains: Shewanella baltica (non-bioluminescent) and Psychrobacter alimentarius (bioluminescent). Under Alkanal Monooxygenase (FMN-linked), genome annotations in the P. alimentarius genome expose Alkanal Monooxygenase Alpha Chain bacterial bioluminescence. High similarity between the isolated P. alimentarius strain and publicly archived reference genomes was confirmed by a comparative genomic study, including an ANI calculations tool and phylogenetic tree building. Moreover, a whole-genome alignment using the Mauve tool revealed a high level of sequence conservation between our P. alimentarius isolate and previously published strains in GenBank. The findings suggest that P. alimentarius may be involved in the bioluminescence of L. forbesii and support current understanding of cephalopod bacteria associated with L. forbesii. The present work provides more information on the whole genome sequence including genomes annotation of both bioluminescent and non bioluminescent strain and explores the bacterial symbiotic in cephalopod marine organisms inhabiting the Red Sea.