HE Miao, ZHAO Yuqing, LI Juxing, GE Jiaqi, CHEN Panting, YING Xin, ZHANG Lianhui, WANG Changlu, LI Zhenjing, GUO Qingbin, LIU Huanhuan
In this study, the genomes of 19 Latilactobacillus curvatus and 40 L. sakei strains were comparatively analyzed. Average nucleic acid identity (ANI) and genome-wide colinearity indicated that the genomes of L. curvatus and L. sakei had weak nucleotide sequence homology, allowing them to be used as indicators to distinguish the two species. Pangenomes for these species were constructed, whose core gene functions were annotated. The results showed that the core genomes of L. curvatus and L. sakei were mainly involved in their basic metabolism. Analysis of individual genomes of the strains revealed that 1) both L. curvatus and L. sakei contained a wide range of genes encoding glycoside hydrolases, which are abundant genetic resources for catabolizing and metabolizing dietary fiber such as polysaccharides, lactose utilization, and lignocellulose; 2) antibiotic resistance genes were annotated in the genomes of three strains, which originate from horizontal gene transfer; 3) the unique arginine deiminase pathway of L. sakei, the serine dehydratase and guanine deaminase pathways of L. curvatus, and the glutamate decarboxylase pathway of several strains were identified, revealing that the acid tolerance mechanisms of these two species are different; and 4) genes encoding cold stress proteins were discovered, which endow the two species with good cold processing properties. Moreover, the genomes of some L. sakei strains contained gene clusters related to the biosynthesis of lactocin S and condensin. In conclusion, this study established taxonomic criteria for the two species and information on individual differences between their strains, which will provide a basis for the study of the physiological, biochemical, molecular genetic mechanisms of L. curvatus and L. sakei and their industrial applications.