Multilocus Sequence Typing Of Lactobacillus Plantarum From Naturally Fermented Foods

Lactobacillus plantarum (L.plantarum), a common species in fermented food and human intestine, is essential for food flavor as well as the health of host. The accurate and rapid identification and typing at strain level is a crucial prerequisite for applications of L.plantarum. Multilocus sequencing typing (MLST) is a powerful technique for bacterial typing. In present study, the population structure of 164 strains of L.plantarum from paocai, fermented dairy food, sour dough, sour congee and reference strains (were 69, 54,17,17 and 7 strains respectively) were analyzed using MLST with 8 housekeeping genes, clpX, groEL, murC, murE, pheS, pyrQ recA and uvrC.Then the genetic relationship and evolutionary process among all of isolates were deduced. The results showed that the 157 L. plantarum isolates and 7 reference strains could be assigned into 68 different STs, which could be further divided into 9 clonal complexes (CCs).41 STs (accounting for 25% of strains) were represented by a single strain. It was proved that recombination was the main reason for the genetic diversity of L.plantarum via IA and IAS and split decomposition analysis, and five ancestral lineages possibly existed among all isolates of L.plantarum by structure and split decomposition analysis. Our results also revealed that the isolates from sour dough in Mongolia were closer to ancestral lineages of L.plantarum. The population structure of most tested strains were correlated with the isolates source. This study, provided a reference for the selection of starter culture and accurate identification of L.plantarum at gene level by developing a MLST scheme.