南极普里兹湾海冰中氨氧化细菌、氨氧化古菌多样性及其生态功能分析

项目名称： 南极普里兹湾海冰中氨氧化细菌、氨氧化古菌多样性及其生态功能分析

项目编号： No.40876097

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 生物科学

项目作者： 李会荣

作者单位： 中国极地研究中心

项目金额： 44万元

中文摘要： 中国第26次南极科学考察期间，采集普里兹湾中山站附近海域海冰以及冰下海水样品，进行细菌、古菌16S rDNA以及氨单加氧酶阿尔法亚基（amoA）基因文库构建分析，结合FISH以及amoA 基因QPCR定量分析，了解海冰中氨氧化菌的数量和组成。海冰以及冰下海水样品中，氨氧化细菌16S rDNA序列属于变形杆菌门β20122;纲(βroteobacteria)中的亚硝化螺旋菌属(Nitrosospira)。AOB amoA基因克隆文库分析也证实了这点。仅海冰底层样品中检测到古菌，且全部为泉古菌（Crenarchaeota），属于Marine Group I。海冰底层以及冰下海水AOA amoA基因克隆序列都属于泉古菌，且群落结构单一。海冰底层中细菌数量较上、中层高，占细胞总数一半以上；除在海冰中层发现大量古菌外，在海冰底层、冰下海水中，古菌占总细胞数的比例差别不大（0-25%）。海冰上、中、底层中，氨氧化古菌 amoA基因拷贝数对泉古菌16S rDNA拷贝数的比值分别为0.32、7和0.54。由此推测在海冰氨氧化过程中，泉古菌起的作用较大。

中文关键词： 南极；海冰；氨氧化；16S rDNA；氨单加氧酶

英文摘要： During the 26th Chinese National Antarctic Research expeditions (CHINARE), sea ice and seawater samples were collected from the Prydz Bay, Antarctica. In this study, we examined the diversity and abundance of betaproteobacterial and crenarchaeal 16S rRNA and ammonia monooxygenase (amoA) genes in the sea ice and seawater under the ice samples to provide insight into their distribution and activities. In sea ice, bacterial phylotypes grouped within αnd γroteobacteria, the Cytophaga - Flavobacterium - Bacteroides division, and genus Pseudoalteromonas of γroteobacteria were dominant. Betaproteobacterial 16S rRNA and amoA genes clone libraries were composed exclusively of Nitrosospira-like genes in sea ice and seawater. Archaea were detected with universal 16S rDNA and amoA genes primer sets in bottom section of sea ice and seawater samples. The sequences of crenarchaeal 16S rRNA and ammonia monooxygenase (amoA) gene were affiliated with Crenarchaeota group ?. Fluorescence in situ hybridization was applied to determine the proportions of Bacteria and Archaea. The percentage of Bacteria in bottom section of sea ice was more than 56%. Crenarchaeota were approximately more abundant in middle section of sea ice. The percentage of Crenarchaeotai in bottom section of sea ice and seawater was 0-25%. The ratios of Crenarchaeota 16S rRNA to archaeal amoA genes abundance in top, middle and bottom section of sea ice were 0.32, 7 and 0.54, respectively. These results suggest ammonia-oxidizing Crenarchaeota are active contributors to the N cycle in sea ice.

英文关键词： Antarctica; sea ice; ammonia-oxidizing; 16S rDNA; ammonia monooxygenase