不同来源泡菜中乳酸菌的16S-23S rDNA间隔序列扩增及种群多样性分析

对不同来源的三种泡菜进行乳酸菌分离,并应用16S-23SrDNA间隔序列扩增指纹图谱结合16SrDNA测序对分离株进行种群多样性分析。结果显示在368株革兰氏阳性、接触酶阴性的产酸细菌中存在7个不同的分子指纹图谱(A～G型),其中杆菌指纹图谱为A、B和D型,球菌的指纹图谱为C、E、F和G型,不同来源的泡菜样品中乳酸菌谱型构成具有明显差异,其中52.3%(193/368)菌株扩增指纹图谱属于E型,显示了E型菌株是泡菜中的优势菌。从不同指纹图谱的菌株中随机挑取25株分离株进行16SrDNA扩增和测序分析,比对结果表明A型指纹图谱菌株属于Lactobacillus acidophilus;B和D型指纹图谱菌株属于Lactobacillus casei;E和G型指纹图谱菌株属于Lactococcus lactis;C和F型指纹图谱菌株属于Enterococcus sp.。在三种泡菜样品(a、b、c)中存在不同的乳酸菌种群构成,其中样品a和b菌群构成较为接近,而样品c中的菌群与a和b在构成上具有显著差异。本研究结果为泡菜发酵剂研究提供了基础数据及分析方法。

Species diversity and 16S-23S rDNA spacer sequence amplicon polymorphism of lactic acid bacteria isolated from different pickles

A total of 368 strains of gram - positive,catalase negative and acid producing bacteria were isolated from 3 pickles which were collected from different sources. The RS - PCR molecular fingerprints and 16S rDNA sequencing were applied for identification of isolates and analysis of species diversity. As a result,seven fingerprinting patterns(genotype A to G)were distributed among 368 isolates,in which rod - shaped bacteria included genotype A,B and D,and coccoid bacteria included genotype type C,E,F and G. The composition of isolates belonged to each type had obvious differences among pickles,in which genotype E was found to be common present and the dominant species in three pickles(52. 3%,193/368). Twenty - five representative strains were randomly selected for 16S rDNA amplification and sequencing analysis,and the result showed that strains of genotype A belonged to Lactobacillus acidophilus,strains of genotype B and D belonged to Lactobacillus casei,strains genotype E and G belonged to Lactococcus lactis,and strains of genotype C and F belonged to Enterococcus sp. The lactic acid bacteria species compositions were different among pickle samples,in which sample a and b were relatively similar,however,sample c was significant different from that of a and b in species composition. The result of this study showed that the RS - PCR combined with 16S rDNA sequencing technique was an effective method to research the diversity of lactic acid bacteria communities in pickles.