乳酸乳球菌乳酸亚种IMAU11823全基因组测序及胞外多糖基因簇分析  

Complete Genome Sequence of Lactococcus lactis subsp.lactis IMAU11823 and Analysis of the Exopolysaccharide Biosynthesis Gene Cluster

作　　者：李敏[1] 李伟程 刘亚华 尤利军 马腾[1] 赵洁[1] 孙志宏[1] Li Min;Li Weicheng;Liu Yahua;You Lijun;Ma Teng;Zhao Jie;Sun Zhihong(Key Laboratory of Dairy Products Processing,Ministry of Agriculture,Key Laboratory of Dairy Biotechnology and Engineering,Ministry of Education,Inner Mongolia Agricultural University,Hohhot 010018)

机构地区：[1]内蒙古农业大学,乳品生物技术与工程教育部重点实验室,农业农村部奶制品加工重点实验室,呼和浩特010018

出　　处：《中国食品学报》2021年第4期256-266,共11页Journal of Chinese Institute Of Food Science and Technology

基　　金：国家自然科学基金项目(31622043);内蒙古自然科学基金项目(2016JQ04)。

摘　　要：目的:乳酸乳球菌乳酸亚种IMAU11823是从内蒙古锡林郭勒盟自然发酵乳制品嚼口中分离得到的1株具有优良发酵特性且高产胞外多糖的乳酸菌。为探究其产胞外多糖的作用机制,对其进行全基因组测序并解析基因组序列信息。方法:使用PacBio SMRT三代测序技术对该菌株进行全基因组测序,采用生物信息学方法对其进行序列组装、基因预测和功能注释,并深入挖掘可能参与胞外多糖生物合成相关的基因信息。结果:乳酸乳球菌乳酸亚种IMAU11823包含1条染色体DNA(基因组大小为2 458 520 bp,GC含量为35.2%)和3个环状质粒(pIMAU11823A、pIMAU11823B、pIMAU11823C,基因组大小和GC含量分别为127 965,24 554,7 734 bp和35.7%,39.5%,32.7%),同时发现该菌株基因组内具有乳糖、纤维二糖、蔗糖、果糖、甘露糖、半乳糖转运系统和7种糖核苷酸合成相关基因以及1个胞外多糖合成基因簇epsRXCDBEF(GTF1)H(GTF2)JKM。结论:本研究揭示了乳酸乳球菌乳酸亚种IMAU11823的基因组特征,并预测了其胞外多糖的合成机制,为研究其产生的胞外多糖结构特征提供了理论依据,同时为该菌株在工业生产中的应用奠定理论基础。Objective:A strain of Lactococcus lactis subsp.lactis,named as IMAU11823,was isolated from natural fermented dairy products Jiaokou in Xilin Gol League of Inner Mongolia,which expressed excellent fermentation characteristics and capacity of exopolysaccharide(EPS)production.In this present study,whole genome sequencing of this strain was performed to analyze the mechanisms of EPS production.Methods:The genome of this strain was generated by the PacBio SMRT sequencing technique,then the assembly,prediction and annotation of the genome were carried out in a series of bioinformatics methods.The genes related to the EPS biosynthesis were furtherly explored.Results:In the strain L.lactis subsp.lactis IMAU11823,a single circular chromosome(2458520 bp)and three circular plasmids(127965,24554,7734 bp)were detected.The GC content of the genome and plasmids were 35.2%,35.7%,39.5%and 32.7%,respectively.Furtherly,genes associated with the transport system of lactose,cellobiose,sucrose,fructose,mannose and galactose,as well as biosynthesis of seven sugar nucleotides were annotated in IMAU11823 genome.Besides,an eps gene cluster epsRXCDBEF(GTF1)H(GTF2)JKM involved in EPS biosynthesis was also predicted.Conclusion:The present study revealed the genomic characteristics and the potential mechanisms for the EPS synthesis of L.lactis subsp.lactis IMAU11823,which could provide a theoretical basis for the structural characteristics of EPS and laying a theoretical foundation for the strain in the industrial application.

关 键 词：乳酸乳球菌乳酸亚种 全基因组测序 胞外多糖 基因簇 

分 类 号：TS201.3[轻工技术与工程—食品科学]