Complete genome sequence of Pseudolactococcus raffinolactis strain GCULR from a spotted seal (Phoca largha) in Korea

Pseudolactococcus raffinolactis-a lactic acid-producing bacterium recently reclassified from Lactococcus-demonstrates emerging potential for probiotics and food applications. We report the complete genome of strain GCULR isolated from a stranded spotted seal (Phoca largha) in Korea, to provide genomic data for understanding beneficial bacteria in marine mammals.

P. raffinolactis strain GCULR was isolated from a stranded spotted seal in Korea, and its whole genome was sequenced using PacBio and Illumina X-10 platforms. Its complete genome comprises a single circular chromosome of 2,270,555 bp with 39.9% GC content and no plasmids. Annotation revealed 2,260 genes, including 2,145 protein-coding sequences, 56 transfer RNAs, 13 ribosomal RNAs, 3 non-coding RNAs, and 43 pseudogenes. Comparative analysis showed an average nucleotide identity of 99.3% with strain WiKim0068, confirming its close relationship with a food-derived isolate. Genome-based screening revealed the presence of several potential virulence- and antimicrobial resistance-associated genes and two intact prophage regions. AntiSMASH analysis predicted a conserved bacteriocin biosynthetic cluster, indicating its functional potential. These findings offer novel insights into the beneficial bacteria in endangered marine mammals and expand our understanding of the ecological and functional diversity of P. raffinolactis.