Genome and functional diversity of Leuconostoc mesenteroides from different habitats and geographic locations

Abstract

Leuconostoc mesenteroides is widely used in the food industry because of its excellent exopolysaccharide and bacteriocin production capacity. In this study, 178 isolates from dairy products, fermented plant material and the human gut were analyzed by comparative genomics. Firstly, from the perspective of genomic characteristics analysis, we found that the isolates from fermented plant materials have large genomes. In addition, the genomic characteristics of European starter strains are highly diverse, which indicates that gene simplification or decline has occurred in a specific environment. Secondly, the population genetic diversity of Leu. mesenteroides was analyzed based on the whole genome, and it was found that the flora structure had obvious separation source and regional correlation. Leu. mesenteroides in China, Sichuan and Gansu are closely related, and the genetic distance of starter cultures in Europe is close. The ANOVA analysis of the genomic characteristics of the strain and environmental factors showed that the genomic characteristics of the strain were significantly different in different environments, that is, Leu. mesenteroides had habitat adaptability. Finally, through functional annotation, it was found that the environment also affected the functional genome of the isolated strain. Isolates from fermented plant material had unique genes related to α-1, 3-galactosyltransferase and β-galactosidase. Dairy isolates from China had more α-1, 6-mannosyltransferase, while those from northern Europe lacked genes related to maltose phosphorylase. Furthermore, we found that 85% of isolates had bacteriocin-producing genes. This study shows that Leu. mesenteroides has great genomic plasticity and high versatility, and provides a solid genetic foundation for its subsequent development and use.