School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia.
Environ Microbiol. 2013 May;15(5):1318-33. doi: 10.1111/1462-2920.12035. Epub 2012 Nov 30.
We performed a metagenomic survey (6.6 Gbp of 454 sequence data) of Southern Ocean (SO) microorganisms during the austral summer of 2007-2008, examining the genomic signatures of communities across a latitudinal transect from Hobart (44°S) to the Mertz Glacier, Antarctica (67°S). Operational taxonomic units (OTUs) of the SAR11 and SAR116 clades and the cyanobacterial genera Prochlorococcus and Synechococcus were strongly overrepresented north of the Polar Front (PF). Conversely, OTUs of the Gammaproteobacterial Sulfur Oxidizer-EOSA-1 (GSO-EOSA-1) complex, the phyla Bacteroidetes and Verrucomicrobia and order Rhodobacterales were characteristic of waters south of the PF. Functions enriched south of the PF included a range of transporters, sulfur reduction and histidine degradation to glutamate, while branched-chain amino acid transport, nucleic acid biosynthesis and methionine salvage were overrepresented north of the PF. The taxonomic and functional characteristics suggested a shift of primary production from cyanobacteria in the north to eukaryotic phytoplankton in the south, and reflected the different trophic statuses of the two regions. The study provides a new level of understanding about SO microbial communities, describing the contrasting taxonomic and functional characteristics of microbial assemblages either side of the PF.
我们在 2007-2008 年的南极夏季进行了南大洋（SO）微生物的宏基因组调查（66 亿 bp 的 454 序列数据），研究了从霍巴特（44°S）到南极默茨冰川（67°S）的纬度横断面上的群落基因组特征。在极锋（PF）以北，SAR11 和 SAR116 进化枝以及蓝细菌属聚球藻和鱼腥藻的操作分类单元（OTUs）强烈过表达。相反，Gammaproteobacterial Sulfur Oxidizer-EOSA-1（GSO-EOSA-1）复合体、Bacteroidetes 和 Verrucomicrobia 门以及红螺菌目（Rhodobacterales）的 OTUs 是 PF 以南水域的特征。PF 以南富集的功能包括一系列转运蛋白、硫还原和组氨酸降解为谷氨酸，而支链氨基酸转运、核酸生物合成和蛋氨酸挽救则在 PF 以北过表达。分类和功能特征表明，初级生产力从北部的蓝细菌向北转移到南部的真核浮游植物，反映了两个区域的不同营养状态。该研究提供了对 SO 微生物群落的新的理解水平，描述了 PF 两侧微生物组合的对比分类和功能特征。
