中文摘要：

为了探究马铃薯表面附着乳酸菌的多样性,收集青海不同地区的10份马铃薯样品,对分离到的乳酸菌进行生理生化特征检测,结合16Sr RNA基因序列分析对已分离到的乳酸菌进行基因分型和菌种鉴定,结果表明马铃薯样品表面存在丰富的乳酸菌,基本分为3个属Leuconostoc（60%）、Lactococcus（14.3%）和Enterococcus（25.7%）,分属于7个种或者亚种,分别为Ln.mesenteroides subsp.dextranicum、Ln.mesenteroides subsp.mesenteroides、Ln.lactis、L.lactis subsp.lactis、L.lactis subsp.hordniae、E.mundtii和E.gallinarum.

英文摘要：

To study the biodiversity of Lactic acid bacteria （LAB）from potato, in this study, 10 samples of potato from different sources of Qinghai were collected,the strains obtained from potato were identified with physiological and biochemical characteristics including catalase test,fermentation of glucose,carbon source fermentation test and 16S rRNA gene sequencing. The result showed that lactic acid bacteria were successfully isolated from the 10 samples;types of LAB isolated from roots were more than that of the stem and leaf. According to morphological, physiological and biochemical characteristics, the isolated LAB could be divided into 5 groups： PA,PB,PC,PD,PE. Strains of＇lactic acid bacteria in PA and PB group were hetero-fermentative strains which could ferment glucose, while strains in PC, PD and PE group were homo-fermentative strains which could not ferment glucose. Carbon source fermentation indicated that all strains could not utilize erythritol, D-arabinose, L-xylose, ribitol ,fl-methyl xyloside, sorbin, dulcitol, inositol, inulin, xylitol, D-lyxose, D-trehalose, L- trehalose and L-arabitol as carbon sources but they could ferment glucose as a carbon source. 16S rRNA gene sequencing indicated that strains in PA and PB belonged to Leuconostoc genus, and PA was mesenteroides species ; PC belonged to Lactococcus genus ; PD and PE belonged to Enterococcus genus of LAB, PD and PE were identified as E.mundtii and E. gallinarum respectively. Phylogenetic tree analysis showed that the LAB isolates from potato belonged to 3 genera namely Leuconostoc （60%）,Lactococcus （ 14.3）and Enterococcus （25.7%）;7 species or subspecies,Ln, mesenteroides subsp, dextranicum , Ln. mesenteroides subsp, mesenteroides , Ln. lactis , L. lactis subsp, lactis, L. lactis subsp, hordniae, E. Mundtii and E. gallinarum. This study has certain significance for utilization of Lactic acid bacteria resources in Tibet plateau area.