5株北极微藻藻际环境的细菌多样性  

Analysis of bacterial diversity in the phycosphere of five Arctic microalgae

作　　者：苗祯[1,2] 杜宗军[1] 李会荣[2] 楼妍颖 罗玮[2] 

机构地区：[1]山东大学(威海)海洋学院,威海264209 [2]中国极地研究中心、国家海洋局极地科学重点实验室,上海200136

出　　处：《生态学报》2015年第5期1587-1600,共14页Acta Ecologica Sinica

基　　金：国家863计划项目(2012AA021706,2013AA065805);南北极环境综合考察与评估专项(CHINARE2012-02-01)

摘　　要：对5株北极微藻,如脆杆藻(Fragilariopsis sp.)、微单胞藻(Micromonas sp.)、四棘藻(Attheya septentrionalis)、海链藻(Thalassiosira sp.)和小球藻(Chlorella sp.)的不同生长时期的粘附细菌和游离细菌的16S rRNA基因进行PCR-DGGE分析,研究藻际环境的细菌多样性。结果表明,5株微藻具有不同的藻际微生物群落结构组成,其中微单胞藻、脆杆藻、四棘藻和海链藻的藻际细菌主要由Cyanobacteria(藻蓝细菌)、α-Proteobacteria(α-变形菌纲)和γ-Proteobacteria(γ-变形菌纲)组成,仅微单胞藻和脆杆藻检测出CFB(Cytophaga-Flexibacter-Bacteroides,噬纤维菌-屈挠杆菌-拟杆菌)。小球藻由Cyanobacteria、CFB、α-Proteobacteria和β-Proteobacteria(β-变形菌纲)组成。微单胞藻的藻际菌群结构稳定,不同生长时期的游离细菌和粘附细菌组成差异不明显。3株硅藻-脆杆藻、四棘藻和海链藻的游离细菌主要由γ-Proteobacteria组成,小球藻的游离细菌主要为β-Proteobacteria,而5株微藻的粘附细菌主要由Cyanobacteria组成。从DGGE图谱来看,在脆杆藻生长的延滞期、指数期和稳定期,其藻际游离细菌和粘附细菌的16S rRNA基因扩增条带数量和位置均有明显差异,但优势扩增条带较稳定;其他4株藻粘附细菌和游离细菌的扩增条带比较稳定,说明藻际关联菌群结构较稳定。藻菌种间特异性关系为不同微藻藻株提供了重要的线索,同时也带来更多的隐藏在藻际环境中的信息。As an important primary producer in the marine ecosystem,phytoplankton cells excrete organic compounds.These include high proportions of carbohydrates,amino acids and organic acids,including glycolic acid which forms the base of the marine microbial food web,and affects bacterial growth. Bacteria can live free in the phycosphere and also attached to the surface of algal cells,consuming extracellular products and consequently participate in biogeochemical cycling. Phytoplankton-bacteria interactions range from symbiotic to parasitic interactions,which play an important part in the microbial loop. However,research into phytoplankton-bacterium interactions is limited and yet to be published. The object of this study was to determine the specific associations between dominant algae and associated bacteria in the North Polar Region. We analyzed bacterial diversity in the phycosphere of four Arctic marine microalgae isolates（ Micromonas sp.,Fragilariopsis sp.,Attheya septentrionalis and Thalassiosira sp.） and one glacial isolate,Chlorella sp.. Fragilariopsis sp.,Attheya septentrionalis,and Thalassiosira sp. belong to Bacillariophyta,while Chlorella sp. and Micromonas sp. belong toChlorophyta. The 16 S rRNA gene of the attached and free bacteria related to these five microalgae during different growth phases was analyzed by polymerase chain reaction-denaturing gradient gel electrophoresis. The associated bacterial diversity based on DGGE profiles was rich. These bacteria were clustered into Cyanobacteria, CFB, α-Proteobacteria, β-Proteobacteria,and γ-Proteobacteria. Bacteria in the phycosphere of marine isolates Micromonas sp.,Fragilariopsis sp.,Attheya septentrionalis and Thalassiosira sp. mainly belonged to cyanobacteria,α-Proteobacteria and γ-Proteobacteria. CFB was detected only in the phycosphere of Micromonas sp. and Fragilariopsis sp. With regard to the only glacial isolate Chlorella sp.,cyanobacteria,CFB,α-Proteobacteria,and β-Proteobacteria were detected in the majority. Differences in the dominant b

关 键 词：北极微藻 藻际环境 关联菌群 16S RRNA DGGE 

分 类 号：Q949.2[生物学—植物学] Q938