Cryptic carbon and sulfur cycling between surface ocean plankton
Cryptic carbon and sulfur cycling between surface ocean plankton
复制标题
表层海洋浮游生物之间的隐秘碳和硫循环
DOI：
10.1073/pnas.1413137112
复制
发表时间：
2015-01-13
影响因子：
11.1
通讯作者：
Moran, Mary Ann
中科院分区：
文献类型：
--
作者：
Durham, Bryndan P.;Sharma, Shalabh;Moran, Mary Ann
海洋中浮游植物固定的大约一半碳被海洋细菌吸收和代谢，这种转移是通过海水溶解有机碳（DOC）池介导的。海洋 DOC 的化学复杂性，以及对哪些化合物构成细菌和浮游植物之间营养相互作用基础的了解不足，阻碍了确定这一碳循环环节的关键货币的努力。在这里，我们使用基于维生素 B-12 营养缺陷的细菌-硅藻模型系统中的转录模式作为海洋浮游生物之间代谢物交换的敏感测定。当海洋玫瑰杆菌分支细菌与硅藻假微链藻共培养时，上调程度最高的基因（高达 374 倍）是那些编码 2,3-二羟基丙烷-1-磺酸盐 (DHPS) 运输和分解代谢的基因。该化合物目前在海洋微生物食物网中尚未得到公认的作用。由于 DHPS 分解代谢的基因在细菌类群中的分布有限，T.pseudonana 可以使用这种磺酸盐来有针对性地喂养有益的同伴。事实上，DHPS 既是假微藻细胞质的主要成分，也是北太平洋东部硅藻华中丰富的微生物代谢产物。此外，对北太平洋样本的转录本分析提供了玫瑰杆菌群体对 DHPS 分解代谢的证据。其他此类生物地球化学上重要的代谢物可能在海洋中常见，但很难与海水复杂的化学背景区分开来。这种硅藻衍生的磺酸盐的细菌转化代表了海洋碳和硫循环中先前未识别的且可能相当大的联系。
About half the carbon fixed by phytoplankton in the ocean is taken up and metabolized by marine bacteria, a transfer that is mediated through the seawater dissolved organic carbon (DOC) pool. The chemical complexity of marine DOC, along with a poor understanding of which compounds form the basis of trophic interactions between bacteria and phytoplankton, have impeded efforts to identify key currencies of this carbon cycle link. Here, we used transcriptional patterns in a bacterial-diatom model system based on vitamin B-12 auxotrophy as a sensitive assay for metabolite exchange between marine plankton. The most highly up-regulated genes (up to 374-fold) by a marine Roseobacter clade bacterium when cocultured with the diatom Thalassiosira pseudonana were those encoding the transport and catabolism of 2,3-dihydroxypropane-1-sulfonate (DHPS). This compound has no currently recognized role in the marine microbial food web. As the genes for DHPS catabolism have limited distribution among bacterial taxa, T. pseudonana may use this sulfonate for targeted feeding of beneficial associates. Indeed, DHPS was both a major component of the T. pseudonana cytosol and an abundant microbial metabolite in a diatom bloom in the eastern North Pacific Ocean. Moreover, transcript analysis of the North Pacific samples provided evidence of DHPS catabolism by Roseobacter populations. Other such biogeochemically important metabolites may be common in the ocean but difficult to discriminate against the complex chemical background of seawater. Bacterial transformation of this diatom-derived sulfonate represents a previously unidentified and likely sizeable link in both the marine carbon and sulfur cycles.