Physiological dynamics of chemosynthetic symbionts in hydrothermal vent snails
Physiological dynamics of chemosynthetic symbionts in hydrothermal vent snails
复制标题
DOI：
10.1038/s41396-020-0707-2
复制
发表时间：
2020-07-02
期刊：
影响因子：
11
通讯作者：
Beinart, Roxanne A.
中科院分区：
文献类型：
--
作者：
Breusing, Corinna;Mitchell, Jessica;Beinart, Roxanne A.
无脊椎动物和化学合成细菌之间的共生构成了全世界热液喷口生态系统的基础。在劳盆地，Alviniconcha 属的深海喷口蜗牛与使用硫化物和/或氢气作为能源的 Gammaproteobacteria（A. kojimai、A. strummeri）或 Campylobacteria（A. boucheti）相关。虽然 A. boucheti 宿主-共生体组合 (holobiont) 在硫化物和氢气浓度较高的喷口占主导地位，但 A. kojimai 和 A. strummeri holobiont 在这些还原剂浓度较低的地点更为丰富。我们假设共生体生理学和基因调控的适应性差异可能会影响观察到的宿主分类群之间的生态位划分。为了检验这一假设，我们使用高压呼吸计来测量共生体代谢率，并检查暴露于原位浓度的氢气（H-2：类似于 25 μM）或硫化氢（H2S：类似于 120 μM）的全生物体中基因表达的变化。在每个实验条件下，弯曲菌共生体表现出最低的 H2S 氧化速率，但最高的 H-2 氧化速率，相对于伽马变形菌共生体，转录变化较少，碳固定也较少。这些数据揭示了共生体类型之间潜在的生理适应，这可能解释了观察到的代谢活动的净差异，并有助于观察到全生物体之间的生态位隔离。
Symbioses between invertebrate animals and chemosynthetic bacteria form the basis of hydrothermal vent ecosystems worldwide. In the Lau Basin, deep-sea vent snails of the genus Alviniconcha associate with either Gammaproteobacteria (A. kojimai, A. strummeri) or Campylobacteria (A. boucheti) that use sulfide and/or hydrogen as energy sources. While the A. boucheti host-symbiont combination (holobiont) dominates at vents with higher concentrations of sulfide and hydrogen, the A. kojimai and A. strummeri holobionts are more abundant at sites with lower concentrations of these reductants. We posit that adaptive differences in symbiont physiology and gene regulation might influence the observed niche partitioning between host taxa. To test this hypothesis, we used high-pressure respirometers to measure symbiont metabolic rates and examine changes in gene expression among holobionts exposed to in situ concentrations of hydrogen (H-2: similar to 25 mu M) or hydrogen sulfide (H2S: similar to 120 mu M). The campylobacterial symbiont exhibited the lowest rate of H2S oxidation but the highest rate of H-2 oxidation, with fewer transcriptional changes and less carbon fixation relative to the gammaproteobacterial symbionts under each experimental condition. These data reveal potential physiological adaptations among symbiont types, which may account for the observed net differences in metabolic activity and contribute to the observed niche segregation among holobionts.