luxS基因对盐胁迫下植物乳杆菌生长及细菌素合成的影响  

Effect of luxS Gene on Growth and Bacteriocin Synthesis of Lactobacillus plantarum under NaCl Stress

作　　者：孙思睿[1] 万峰[1] 赵鹏昊 侯雨佳 范小飘 梁玉[1] 孟祥晨[1] SUN Sirui;WAN Feng;ZHAO Penghao;HOU Yujia;FAN Xiaopiao;LIANG Yu;MENG Xiangchen(Key Laboratory of Dairy Science,Ministry of Education,Northeast Agricultural University,Harbin 150030,China)

机构地区：[1]东北农业大学乳品科学教育部重点实验室

出　　处：《食品科学》2019年第14期69-76,共8页Food Science

基　　金：国家自然科学基金面上项目(31671917)

摘　　要：以植物乳杆菌KLDS1.0391野生株及其luxS基因缺失突变株为研究对象,探究luxS基因对该菌盐耐受能力的影响,并测定在0%、2%、3%、4%和6%质量分数NaCl胁迫条件下,luxS基因缺失对该菌生长及细菌素合成的影响,采用实时荧光定量聚合酶链式反应(polymerase chain reaction,PCR)技术在转录水平上测定该菌细菌素合成相关基因的表达水平。结果表明:随NaCl质量分数的升高,2株菌的存活率均逐渐下降,当NaCl质量分数大于3%时,相同条件下野生株对盐的耐受能力显著强于突变株(P<0.05);除此之外,NaCl质量分数越高,菌株进入稳定期的时间越向后延迟,luxS基因缺失突变株在各NaCl质量分数下生长及细菌素合成能力均显著弱于野生株(P<0.05)。实时荧光定量PCR结果显示,当培养至稳定期24 h时,细菌素结构基因plnEF以及双组分调节基因plnD和plNC8HK均因luxS基因的缺失,表达显著下调(P<0.05)。因此,luxS基因缺失显著降低植物乳杆菌KLDS1.0391盐耐受能力,并且在NaCl胁迫条件下,该菌生长及细菌素合成能力也因luxS基因缺失而显著下降。The effect of the luxS gene on the NaCl tolerance of Lactobacillus plantarum wild-type strain KLDS1.0391 was investigated by comparing it with its luxS deletion mutant strain. Meanwhile, the influence of the luxS gene on the growth rate and bacteriocin synthesis of this strain under various concentrations of NaCl stress(0%, 2%, 3%, 4% and 6%) were measured. The expression levels of genes related to bacteriocin biosynthesis were determined by real time quantitative PCR technique at the transcriptional level. The results showed that the survival rates of the two strains decreased gradually with the increase of NaCl concentration. The tolerance to NaCl concentrations over 3% of the wild type strain was significantly stronger than that of its mutant(P < 0.05) at the same condition. Moreover, the growth rate and bacteriocin synthesis of the mutant were significantly lower than those of the wild-type strain(P < 0.05) at each NaCl concentration. Real time quantitative PCR showed that the expression of the bacteriocin structure gene plnEF and the double regulator genes plnD and plNC8 HK were all significantly down-regulated(P < 0.05) when the mutant was cultured to the stationary phase for 24 h.Therefore, luxS gene deletion significantly reduced the NaCl tolerance of L. plantarum KLDS1.0391. Meanwhile, its growth rate and bacteriocin synthesis ability under NaCl stress decreased significantly due to deletion of the luxS gene.

关 键 词：植物乳杆菌 LUXS NACL胁迫 细菌素 基因表达 

分 类 号：TS201.3[轻工技术与工程—食品科学]