Department of Functional and Evolutionary Ecology, Bio-Oceanography and Marine Biology Unit, University of Vienna, Djerassiplatz 1, A-1030 Vienna, Austria.
Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA 98195, USA.
Sci Adv. 2024 May 17;10(20):eadn5143. doi: 10.1126/sciadv.adn5143. Epub 2024 May 15.
Marine heterotrophic prokaryotes primarily take up ambient substrates using transporters. The patterns of transporters targeting particular substrates shape the ecological role of heterotrophic prokaryotes in marine organic matter cycles. Here, we report a size-fractionated pattern in the expression of prokaryotic transporters throughout the oceanic water column due to taxonomic variations, revealed by a multi-"omics" approach targeting ATP-binding cassette (ABC) transporters and TonB-dependent transporters (TBDTs). Substrate specificity analyses showed that marine SAR11, Rhodobacterales, and Oceanospirillales use ABC transporters to take up organic nitrogenous compounds in the free-living fraction, while Alteromonadales, Bacteroidetes, and Sphingomonadales use TBDTs for carbon-rich organic matter and metal chelates on particles. The expression of transporter proteins also supports distinct lifestyles of deep-sea prokaryotes. Our results suggest that transporter divergency in organic matter assimilation reflects a pronounced niche separation in the prokaryote-mediated organic matter cycles.
海洋异养原核生物主要通过转运蛋白摄取环境基质。靶向特定基质的转运蛋白模式决定了异养原核生物在海洋有机质循环中的生态作用。本研究通过针对三磷酸腺苷结合盒（ABC）转运蛋白和 TonB 依赖性转运蛋白（TBDT）的多组学方法，揭示了由于分类学差异，海洋水柱中整个水柱中存在着原核转运蛋白表达的大小分级模式。底物特异性分析表明，海洋 SAR11、红杆菌和海洋螺旋菌使用 ABC 转运蛋白从自由生活部分中摄取含氮有机化合物，而交替单胞菌、拟杆菌和鞘氨醇单胞菌使用 TBDT 从富含碳的有机物和颗粒上的金属螯合物中摄取。转运蛋白蛋白的表达也支持深海原核生物的不同生活方式。研究结果表明，有机质同化中的转运蛋白多样性反映了原核介导的有机质循环中明显的生态位分离。
