Genetic background and functional genome of Limosilactobacillus fermentum F-6

Abstract:

[Objective] Enhancing immunity and producing exopolysaccharide (EPS),Limosilactobacillus fermentum is widely used in food industry and is of huge economic value.Based on population genetics,this paper aims to analyze the genetic background and functional gene characteristics of L. fermentum F-6,which is expected to lay a genetic basis for the development and utilization of the strain.[Methods] Comparative genomics was used to analyze the whole-genome sequences of 23 L. fermentum strains and 1 model strain ATCC 14931^T from NCBI,Roary to identify core-pan genes,and rapid annotation using subsystem technology (RAST) to annotate the genomes.[Results] A phylogenetic tree was constructed based on the yielded 997 core genes and the analysis showed that the clustering had nothing to do with the source.However,strain F-6 was in the same clade with 3 food-derived strains.Genome annotation results revealed that only strain F-6 contained genes involved in branched chain amino acid synthesis pathway (ilvD,leuA,etc.) and thus can provide essential amino acids for the body.Strain F-6 harbored a large number of genes encoding glycosyltransferases and UDP-glucose 4-epimerase,and contained a complete eps cluster.Compared with other L. fermentum strains,strain F-6 had the unique functional gene gadC which is associated to acid resistance.In addition,potential probiotic genes such as genes related to the synthesis of glutathione,antimicrobial peptide,and adhesion molecules were also identified in the genome.[Conclusion] According to the genomic background and functional genome,F-6 is a potential probiotic strain with acid resistance genes,branched chain amino acid synthesis genes,and a complete eps gene cluster,which will contribute to our understanding of the genetic basis of L. fermentum F-6.

Key words:Limosilactobacillus fermentum F-6;comparative genomics;genetic background;functional genes;eps cluster