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 sometimes support bioluminescence. Though these interactions in cephalopods have been well studied in species such as Euprymna scolopes , not much is known about other cephalopods, most especially those of 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 Egypt’s 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 comparative genomic study including ANI calculations tool and phylogenetic tree building. Moreover quite highly sequence conserved in GenBank between our P. alimentarius isolate and earlier published strains was whole-genome alignment with the Mauve tool. The findings suggest that P. alimentarius may be involved in the bioluminescence of Loligo forbesii and support current understanding of cephalopod bacteria associated with Loligo 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.