Polymorphism of Lactobacilli from fermented milk products in Northern Tibet
藏北地区传统发酵乳中乳杆菌的多样性分析

Abstract: Objective] In order to study the Biodiversity of Lactobacilli which were from Northern Tibet in China, ERIC-PCR (enterobacterial repetitive intergenic consensus sequence polymerase chain reaction) technique was developed. Methods] Seventy seven Lactobacillus strains were isolated from traditional fermented milk products which are made by herd man families in Northern Tibet of China. By ERIC-PCR technique method, using NTSYS-pc2.1 software, we investigated the polymorphism and types of the strains. Results]The results suggested that the amplified bands of ERIC-PCR were clear and stable with high repetition and high polymorphisms. The cluster analysis showed that at level 0.73, 77 tested strains were clustered into 4 groups: A1: strains of Lactobacillus casei (35.06% of the strains), A2: strains of Lactobacillus fermentum (61.04% of the strains), A3: strains of Lactobacillus helveticus and A4: strains of Lactobacillus plantarum. The biodiversity of isolates from A1and A2 groups was further investigated. A1 could be divided into five genotypes at the similarity value of 80.0%. A2 could be divided into six genotypes at the similarity value of 84.0%. Conclusion]Using ERIC-PCR technique, the Lactobacilli from Northen Tibet could be distinguished at specices level. Results from this study showed that there was no positive relationship between the ERIC-PCR gene types and the origin of the strains.