一株具有氢自养能力的固氮粘质沙雷氏菌的分离鉴定、代谢特征与功能基因检测  

Isolation,identification,metabolic characteristics,and functional gene detection of a nitrogen-fixing strain with hydrogen autotrophic ability of Serratia marcescens

作　　者：王浩然 张礼霞[2,3] 高平 李大平[2,3] WANG Haoran;ZHANG Lixia;GAO Ping;LI Daping(College of Life Science,Sichuan University,Chengdu 610065,China;Chengdu Institute of Biology,Chinese Academy of Sciences,Chengdu 610213,China;Environmental Microbiology Key Laboratory of Sichuan Province,Chengdu 610213,China)

机构地区：[1]四川大学生命科学学院,成都610065 [2]中国科学院成都生物研究所,成都610213 [3]环境微生物四川省重点实验室,成都610213

出　　处：《应用与环境生物学报》2024年第1期158-166,共9页Chinese Journal of Applied and Environmental Biology

基　　金：国家自然科学基金项目(31970106)资助。

摘　　要：氢氧化细菌(HOB)是能利用氧气氧化氢气供能以固定二氧化碳进行自养生长的一类细菌,但是目前对能够固氮的HOB研究甚少.在自然界中部分HOB常作为植物根际促生细菌(PGPR)存在,而固氮是可能的促生机制,有望从功能菌群中得到更多的固氮HOB,是否存在氢自养且可固氮的沙雷氏菌未知.从固氮氢氧化混合菌群中分离出一株产色素的固氮菌NF-HOB1,经16S rRNA基因测序鉴定为粘质沙雷氏菌(Serratia marcescens)(GenBank:OQ625884),通过碳源或氮源限制培养实验验证其具有异养固氮生长、氢自养固碳生长能力,氢气氧化速率为0.1875 mmol/d.聚合酶链式反应(PCR)扩增发现其质粒DNA编码固氮酶铁蛋白结构基因nifH,基因组编码种特异性的核酮糖-1,5-二磷酸羧化酶(Rubisco)和氢化酶3的结构基因.基因组框架图测序进一步揭示了菌株的基因组特征,基因组长4919531 bp,蛋白编码基因4778个.注释到氢化酶2、碳酸酐酶、GlnK型PII蛋白等,提示存在二氧化碳浓缩机制和以NtrB-GlnK-amtB/nifA为特征的全局氮调控机制.基因本体论(GO)和京都基因与基因组百科全书(KEGG)数据库分别注释到81.26%和48.13%的基因,结合数据库分析推测菌株可能具有多种植物促生功能.本研究表明沙雷氏菌NF-HOB1是氢氧化细菌,其丰富的代谢特性将拓展其作为菌种资源的应用前景.(图6表1参70)Hydrogen-oxidizing bacteria(HOB)is a group of bacteria that can utilize oxygen to oxidize hydrogen to provide energy to fix carbon dioxide and autotrophic growth.Still,there is little research on HOB that can fix nitrogen meanwhile.Because some HOB often acts as plant growth-promoting rhizobacteria(PGPR)in nature,and nitrogen fixation is a possible growth-promoting mechanism,it is expected to obtain more nitrogenfixing HOB from several functional communities.It is unknown whether there are both hydrogen-autotrophic and nitrogen-fixing Serratia.In this research,a pigment-producing nitrogen-fixing bacterial strain,NF-HOB1,was isolated from a nitrogen-fixing and hydrogen-oxidizing microbial community,which then was identified as Serratia marcescens b y 16S r RNA g ene sequencing(GenBank:O Q625884).T he s train c an grow by heterotrophic nitrogen fixation or hydrogen-autotrophic carbon fixation,verified through carbon/nitrogen source limited culture experiments,with a hydrogen oxidation rate of 0.1875 mmol/d.Polymerase chain reaction(PCR)amplification revealed that its plasmid DNA encodes the nitrogenase Fe-protein structural gene nifH,and the genome encodes species-specific ribose-1,5-diphosphate carboxylase(Rubisco)and hydrogenase 3 structural genes.The genome frame map sequencing further revealed the genomic characteristics of the strain,with a gene length of 4919531 bp and 4778 protein-coding genes.It was annotated to find hydrogenase 2,carbonic anhydrase,and GlnK-type PII protein,suggesting a carbon dioxide concentration mechanism and a potential global nitrogen regulation pathway characterized by NtrB-GlnK-amtB/nifA.Gene Ontology(GO)and the Kyoto Encyclopedia of Genes and Genomes(KEGG)annotated 81.26%and 48.13%of genes,respectively.Combined with database analysis,it is speculated that the strain may have multiple plant growth-promoting functions.To conclude,Serratia is a potential hydrogen-oxidizing bacteria,and its rich metabolic characteristics will broaden its application prospects as a bacterial resource.

关 键 词：粘质沙雷氏菌 氢氧化 固氮 功能基因 基因组 

分 类 号：Q939.113[生物学—微生物学]