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 asEuprymna 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 ofLoligo 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) andPsychrobacter alimentarius(bioluminescent). Under Alkanal Monooxygenase (FMN-linked), genome annotations in theP. alimentariusgenome expose Alkanal Monooxygenase Alpha Chain bacterial bioluminescence. High similarity between the isolatedP. alimentariusstrain 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 ourP. alimentariusisolate and earlier published strains was whole-genome alignment with the Mauve tool. The findings suggest thatP. alimentariusmay be involved in the bioluminescence ofLoligo forbesiiand support current understanding of cephalopod bacteria associated withLoligo 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.