Interaction and signalling between a cosmopolitan phytoplankton and associated bacteria
Interaction and signalling between a cosmopolitan phytoplankton and associated bacteria
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DOI：
10.1038/nature14488
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发表时间：
2015-06-04
期刊：
影响因子：
64.8
通讯作者：
Armbrust, E. V.
中科院分区：
文献类型：
--
作者：
Amin, S. A.;Hmelo, L. R.;Armbrust, E. V.
初级生产者和细菌之间的相互作用影响双方的生理，改变其环境的化学成分，并形成生态系统的多样性（1,2）。在海洋生态系统中，这些相互作用很难研究，部分原因是主要的光合生物是微观的单细胞浮游植物(3)。沿海浮游植物群落以硅藻为主，硅藻约占海洋初级产量的40%，并构成许多海洋食物网的基础(4)。硅藻与特定的细菌类群共存(3)，但潜在相互作用的机制大多未知。在这里，我们分离了一个与全球分布的硅藻相关的细菌联合体，发现亚硫酸盐杆菌通过分泌激素吲哚-3-乙酸来促进硅藻细胞分裂，这种激素是由细菌利用硅藻分泌的色氨酸和内源性色氨酸合成的。吲哚-3-乙酸和色氨酸作为信号分子，是营养物质复杂交换的一部分，包括硅藻分泌的有机硫分子和细菌分泌的氨。代谢物和亚转录组分析证实了这种信号传导模式在海洋中的潜在普遍性，这些分析表明，亚硫酸盐杆菌相关细菌广泛产生吲哚-3-乙酸，特别是在沿海环境中。我们的研究扩展了新兴的认识，即海洋微生物群落是紧密连接网络的一部分，通过提供证据证明这些相互作用是通过信息化学物质的生产和交换来调节的。
Interactions between primary producers and bacteria impact the physiology of both partners, alter the chemistry of their environment, and shape ecosystem diversity(1,2). In marine ecosystems, these interactions are difficult to study partly because the major photosynthetic organisms are microscopic, unicellular phytoplankton(3). Coastal phytoplankton communities are dominated by diatoms, which generate approximately 40% of marine primary production and form the base of many marine food webs(4). Diatoms co-occur with specific bacterial taxa(3), but the mechanisms of potential interactions are mostly unknown. Here we tease apart a bacterial consortium associated with a globally distributed diatom and find that a Sulfitobacter species promotes diatom cell division via secretion of the hormone indole-3-acetic acid, synthesized by the bacterium using both diatom-secreted and endogenous tryptophan. Indole-3-acetic acid and tryptophan serve as signalling molecules that are part of a complex exchange of nutrients, including diatom-excreted organosulfur molecules and bacterial-excreted ammonia. The potential prevalence of this mode of signalling in the oceans is corroborated by metabolite and metatranscriptome analyses that show widespread indole-3-acetic acid production by Sulfitobacter-related bacteria, particularly in coastal environments. Our study expands on the emerging recognition that marine microbial communities are part of tightly connected networks by providing evidence that these interactions are mediated through production and exchange of infochemicals.