摘要
分析莓实假单胞菌环境适应及腐败相关基因,为后续研究其致腐机制提供理论依据。从腐败的冷藏金枪鱼中分离腐败菌,利用根癌农杆菌KYC55筛选具有群体感应的分离株并用气相色谱-质谱联用技术(GC-MS)检测其分泌的N-酰基高丝氨酸内酯(AHLs),利用16S rRNA比对及平均核苷酸一致性(ANI)分析确定菌株类型;通过全基因组测序,确定菌株的基因功能及注释信息;利用嗜铁素检测(CASAD)平板法和紫外法检测不同温度下菌株分泌的嗜铁素量;检测接种MS-10的冷藏金枪鱼中菌落总数及挥发性盐基氮变化,结合腐败代谢物产量因子(YTVB-N/CFU)分析MS-10的致腐能力。结果表明:分离株为莓实假单胞菌(MS-10),能够分泌群体感应信号分子C8-HSL和C10-HSL,其基因组大小为5.25 Mb,GC占比为58.2%。比对多个数据库发现,MS-10的功能基因主要集中在生物代谢、信号转导以及环境应激等方面,包含群体感应调控基因traI/R及大量致腐相关基因。低温条件更有利于MS-10分泌嗜铁素。接种MS-10的金枪鱼块在冷藏期间菌落总数和TVB-N值相比于空白组明显增加,其YTVB-N/CFU值为2.77×10-7 mg/CFU。结论:莓实假单胞菌MS-10具有群体感应系统,为耐冷致腐菌,从基因水平上证明其具有较强的致腐潜力及环境适应性。研究结果为进一步探究MS-10群体感应调控机制,开展其致腐性研究提供数据支撑。
To analyze the environmental adaptation and spoilage-related genes of Pseudomonas fragi,and to provide a theoretical basis for the subsequent study of its spoilage-causing mechanism,spoilage bacteria were isolated from spoiled frozen tuna,and the isolates with quorum sensing were screened using Agrobacterium tumefaciens KYC55 and then their secreted AHLs were detected by GC-MS.The strain type was determined using 16S rRNA comparison and ANI analysis.Gene function and annotation were determined by sequencing the whole genome.The content of siderophore secreted by the strain at different temperatures was measured by CASAD plate and UV detection.The changes of total viable count and total volatile basic nitrogen in frozen tuna inoculated with MS-10 were detected,and the putrefactive ability of MS-10 was analyzed in combination with the spoilage metabolite yield factor YTVB-N/CFU.Results:The isolated strain was P.fragi,named MS-10,secreting quorum sensing signals,mainly C8-HSL and C10-HSL.Its genome size was 5.25 Mb,with 58.2%GC.Comparison of multiple databases revealed that the gene functions of MS-10 were mainly focused on biometabolism,signal transduction and environmental stress,including quorum sensing regulatory genes traI/R and a large number of spoilage-related genes.Low temperature conditions were more favorable for strain MS-10 to secrete siderophore.Tuna blocks inoculated with MS-10 showed a significant increase in total viable count and TVB-N values during refrigeration compared to the blank group,with YTVB-N/CFU values measuring 2.77×10-7 mg/CFU.Conclusion:P.fragi MS-10 possessed a quorum sensing system and was a cold-tolerant putrefactive bacterium.It was demonstrated that it had strong putrefactive potential and environmental adaptability at the genetic level,which could help to further investigate the regulatory mechanism of MS-10 quorum sensing and to provide data support for future research on its putrefactive properties.
作者
崔方超
王芸婷
刘佳宜
王当丰
檀茜倩
李秋莹
励建荣
李婷婷
Cui Fangchao;Wang Yunting;Liu Jiayi;Wang Dangfeng;Tan Xiqian;Li Qiuying;Li Jianrong;Li Tingting(College of Food Science and Technology,Bohai University,National&Local Joint Engineering Research Center of Storage,Processing and Safety Control Technology for Fresh Agricultural and Aquatic Products,China Light Industry Key Laboratory of Marine Fish Processing,Jinzhou 121013,Liaoning;College of Life Science,Dalian Minzu University,Dalian 116600,Liaoning)
出处
《中国食品学报》
EI
CAS
CSCD
北大核心
2024年第8期457-472,共16页
Journal of Chinese Institute Of Food Science and Technology
基金
国家自然科学基金重点项目(U20A2067)
辽宁省自然科学基金博士科研启动基金计划项目(2022-BS-301)。
关键词
金枪鱼
莓实假单胞菌
全基因组测序
群体感应
嗜铁素
Thunnus obesus
Pseudomonas fragi
whole genome sequencing
quorum sensing
siderophore
