Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ, USA.
Dauphin Island Sea Lab, Dauphin Island, AL, USA.
Nat Microbiol. 2019 Nov;4(11):1790-1797. doi: 10.1038/s41564-019-0502-x. Epub 2019 Jul 15.
Diatoms are among the most globally distributed and ecologically successful organisms in the modern ocean, contributing upwards of 40% of total marine primary productivity. By converting dissolved silicon into biogenic silica, and photosynthetically fixing carbon dioxide into particulate organic carbon, diatoms effectively couple the silicon (Si) and carbon cycles and ballast substantial vertical flux of carbon out of the euphotic zone into the mesopelagic and deep ocean. Viruses are key players in ocean biogeochemical cycles, yet little is known about how viral infection specifically impacts diatom populations. Here, we show that Si limitation facilitates virus infection and mortality in diatoms in the highly productive coastal waters of the California Current Ecosystem. Using metatranscriptomic analysis of cell-associated diatom viruses and targeted quantification of extracellular viruses, we found a link between Si stress and the early, active and lytic stages of viral infection. This relationship was also observed in cultures of the bloom-forming diatom Chaetoceros tenuissimus, where Si stress accelerated virus-induced mortality. Together, these findings contextualize viruses within the ecophysiological framework of Si availability and diatom-mediated biogeochemical cycling.
硅藻是现代海洋中分布最广、生态最成功的生物之一，对海洋初级生产力的贡献率超过 40%。通过将溶解硅转化为生物硅，并将光合作用固定的二氧化碳转化为颗粒有机碳，硅藻有效地将硅（Si）和碳循环联系起来，并将大量的碳从透光带垂直输送到中层带和深海。病毒是海洋生物地球化学循环的关键参与者，但人们对病毒感染如何具体影响硅藻种群知之甚少。在这里，我们表明硅限制促进了加利福尼亚洋流生态系统高生产力沿海水域中硅藻的病毒感染和死亡率。通过对细胞相关硅藻病毒的宏转录组分析和对细胞外病毒的靶向定量，我们发现硅胁迫与病毒感染的早期、活跃和裂解阶段之间存在联系。在形成水华的硅藻 Chaetoceros tenuissimus 的培养物中也观察到了这种关系，其中硅胁迫加速了病毒诱导的死亡率。总的来说，这些发现将病毒置于硅供应和硅藻介导的生物地球化学循环的生态生理框架内。
