Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems/College of the Environment & Ecology, Xiamen University, Xiamen 361102, China.
Environ Sci Technol. 2022 Apr 19;56(8):5247-5255. doi: 10.1021/acs.est.1c08584. Epub 2022 Mar 30.
Diatoms, accounting for 40% of the marine primary production and 20% of global carbon dioxide fixation, are threatened by the ongoing ocean warming (OW). However, whether and how these ecologically important phytoplankton adapt to OW remains poorly unknown. Here, we experimentally examined the metabolic adaptation of a globally important diatom species () to OW at two elevated temperatures (24 and 28 °C compared with 20 °C) under short-term (∼300 generations) and long-term (∼700 generations) selection. Both warming levels significantly increased the cell growth rate but decreased the chlorophyll content. The contents of particulate organic carbon (POC) and particulate organic nitrogen (PON) decreased significantly initially (i.e., until 300 generations) at two temperature treatments but completely recovered after 700 generations of selection, suggesting that ultimately developed thermal adaptation. Proteomic analysis demonstrated that elevated temperatures upregulated energy metabolism via glycolysis, tricarboxylic acid cycle, and fatty acid oxidation as well as nitrogen acquisition and utilization, which in turn reduced substance storage because of trade-off in the 300th generation, thus decreasing POC and PON. Interestingly, populations at both elevated temperatures exhibited significant proteome plasticity in the 700th generation, as primarily demonstrated by the increased lipid catabolism and glucose accumulation, accounting for the recovery of POC and PON. Changes occurring in cells at the 300th and 700th generations demonstrate that can adapt to the projected OW, and readjusting the energy metabolism is an important adaptive strategy.
硅藻占海洋初级生产力的 40%，全球二氧化碳固定量的 20%，它们受到持续海洋变暖（OW）的威胁。然而，这些生态上重要的浮游植物是否以及如何适应 OW 仍然知之甚少。在这里，我们在短期（约 300 代）和长期（约 700 代）选择下，实验性地研究了一种全球重要的硅藻物种（）对 OW 的代谢适应。与 20°C 相比，两个升温水平（24°C 和 28°C）均显著提高了细胞生长速率，但降低了叶绿素含量。在两种温度处理下，颗粒有机碳（POC）和颗粒有机氮（PON）的含量最初（即在 300 代之前）显著下降，但在 700 代选择后完全恢复，表明最终发展出了热适应。蛋白质组学分析表明，高温通过糖酵解、三羧酸循环和脂肪酸氧化以及氮的获取和利用来上调能量代谢，从而减少物质储存，因为在第 300 代发生了权衡，因此减少了 POC 和 PON。有趣的是，在第 700 代，两个高温种群的蛋白质组表现出显著的可塑性，主要表现为脂类分解代谢和葡萄糖积累增加，这解释了 POC 和 PON 的恢复。在第 300 代和第 700 代的细胞中发生的变化表明，能够适应预测的 OW，并且重新调整能量代谢是一种重要的适应策略。
