Biology Department, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA.
Biology and Paleo Environment Division, Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, 10964, USA.
Environ Microbiol. 2020 May;22(5):1847-1860. doi: 10.1111/1462-2920.14942. Epub 2020 Feb 28.
The widespread coccolithophore Emiliania huxleyi is an abundant oceanic phytoplankton, impacting the global cycling of carbon through both photosynthesis and calcification. Here, we examined the transcriptional responses of populations of E. huxleyi in the North Pacific Subtropical Gyre to shifts in the nutrient environment. Using a metatranscriptomic approach, nutrient-amended microcosm studies were used to track the global metabolism of E. huxleyi. The addition of nitrate led to significant changes in transcript abundance for gene pathways involved in nitrogen and phosphorus metabolism, with a decrease in the abundance of genes involved in the acquisition of nitrogen (e.g. N-transporters) and an increase in the abundance of genes associated with phosphate acquisition (e.g. phosphatases). Simultaneously, after the addition of nitrate, genes associated with calcification and genes unique to the diploid life stages of E. huxleyi significantly increased. These results suggest that nitrogen is a major driver of the physiological ecology of E. huxleyi in this system and further suggest that the addition of nitrate drives shifts in the dominant life-stage of the population. Together, these results underscore the importance of phenotypic plasticity to the success of E. huxleyi, a characteristic that likely underpins its ability to thrive across a variety of marine environments.
广泛分布的颗石藻 Emiliania huxleyi 是一种丰富的海洋浮游植物，通过光合作用和钙化作用影响着全球碳循环。在这里，我们研究了北太平洋亚热带环流中 E. huxleyi 种群对营养环境变化的转录反应。我们使用宏转录组学方法，通过营养添加微宇宙研究来追踪 E. huxleyi 的全球代谢。添加硝酸盐导致参与氮磷代谢的基因途径的转录丰度发生显著变化，与氮获取（例如 N 转运蛋白）相关的基因丰度降低，与磷酸盐获取（例如磷酸酶）相关的基因丰度增加。同时，添加硝酸盐后，钙化相关基因和 E. huxleyi 二倍体生活阶段特有的基因显著增加。这些结果表明，氮是该系统中 E. huxleyi 生理生态学的主要驱动因素，并进一步表明，添加硝酸盐会导致种群主要生活阶段的转变。这些结果强调了表型可塑性对 E. huxleyi 成功的重要性，这种特性可能是其在各种海洋环境中茁壮成长的基础。
