Diversity And Phylogeny Of Lactic Acid Bacteria Isolated From Traditional Fermented Pickles In Sichuan

Pickled vegetables are products by fermentation. The pickled vegetables have a huge amount lactobacillus, which is a major system in balance of micro-ecology of human gastro intestine. Therefore, they are functional foods and benefit to healthy. Pickled vegetables origin mainly in Sichuan, its unique geographical environment and climatic conditions conducive to fermentation of lactic acid bacteria, which provided rich material for the production of pickled vegetables. The diversity and phylogeny of 61 lactic acid bacteria strains, which were isolated from the traditional fermented pickles samples in the Sichuan province, were investigated by the 16S rDNA PCR-RFLP, ERIC-PCR, AFLP,16S rDNA sequences. The conclusions are as following:The strains were analyzed by 16S rDNA PCR-RFLP with five kinds of restriction endonucleases including Haeâ…¢, Mspâ… , Hinfâ… , Hhaâ… and Taqâ… . Seventeen genotypes were identified,and the majority were genotype A.Among the 5 restriction enzymes used, Hha I was the most discriminating enzyme. According to the similarity of the all strains for the cluster analysis, It is showed that the similarity of 16S rDNA PCR-RFLP of the tested strains relatively high, indicating less affected by the environment in the process of the evolution of 16S rDNA.ERIC-PCR and AFLP analysis were of high sensitivity, with abundant genetic band pattern. Based on the dendrograms generated by ERIC-PCR, these strains where gathered together at the similarity of 45%, and were divided into 10 groups at the similarity of 80%. Based on the dendrograms generated by AFLP, these strains where gathered together at the similarity of 58%, and were divided into 8 groups at the similarity of 80%. The results showed that a high genetic diversity existed among these lactic acid bacteria from traditional fermented pickles in Sichuan province.Judging from the overall classification, the clustering results of 16S rDNA PCR-RFLP, ERIC-PCR, AFLP was consistent. The similar results were obtained from these three molecular markers: Some strains came from different sources were of high similarity, while the less similarity was achieved in some strains of the same sources, indicating that there was no significant correlation between the lactic acid bacteria of natural fermented pickles and geographical position in the Sichuan region. Most strains were highly similar and even reached 100%, indicating that there were obvious advantages of bacteria in the natural fermentation pickled vegetables in Sichuan.Homology analysis of 16S rDNA gene sequence indicated that there was a homology above 99% among strains 12-1-1,6-1-2,13-1-3,7-1-2 with their reference strains.6-1-2 was identified as Lactobacillus plantarum (L. plantarum),12-1-1 was identified as Lactobacillus fermented (L. fermentum),13-1-3 and 7-1-2 were identified as Enterococcus durans (E. durans). The homology of 5-2-1 with L. casei was 94.7%, which indicated there is unidentified new species in Sichuan pickles. The homology among the representative strains were from 84% to 100%. The results showed that a high genetic diversity existed among these lactic acid bacteria from traditional fermented pickles in Sichuan region.This study showed that these lactic acid bacterial mainly belong to two genus groups:Lactobacillus and Enterococcus, mainly including L. plantarum, L.fermentum and E. durans. The results indicated that L. plantarum had an extensive distribution and L. plantarum was the predominant strain in Sichuan region.The results of this research revealed genetic diversity and phylogenetic position of lactic acid bacteria in Sichuan region, and the result laid the theoretical foundation for the development and application of vegetables pickled by direct vat starter.