Institute for Advanced Marine Research, China University of Geosciences, Guangzhou, China.
State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, China.
Commun Biol. 2023 Feb 6;6(1):151. doi: 10.1038/s42003-023-04524-8.
Despite an increase in ocean warming and acidification that is expected to increase the number of harmful algal species worldwide, the population of the raphidophyte Heterosigma akashiwo has been reported to be reduced. However, how this species physically and metabolically modifies transitional C:N:P ratio and macromolecule accumulation is unknown. Considering 1st, 10th, and 20th culture generations under present (low-temperature; low-carbon-dioxide [LTLC] 21 °C; pCO 400 ppm) and future (high-temperature; high-carbon-dioxide [HTHC] 25 °C; pCO 1000 ppm) ocean conditions, we examined transitional C:N:P ratio and macromolecule level changes and performed transcriptome sequencing. The results showed that compared to 1st generation cells, 20th generation cells under HTHC conditions showed a large decrease in carbon quota (Q: 34%), nitrogen quota (Q: 36%), and phosphorus quota (Q: 32%), which were reflected in an overall reduction in DNA and RNA quantity. Decreased activation of photosynthetic, carbon fixation and lipid metabolic pathways coincided with changes in photosynthetic efficiency, carbon concentration, and lipid accumulation after long-term (20th generation) exposure to HTHC conditions. We observed that these variations in internal metabolic pathways were caused by external changes in temperature, which activated the (Ca) signaling pathway, and external changes in pCO, which altered proton exchange pathways. Our results suggest that H. akashiwo in a temperate environment will undergo profound changes in C:N:P ratio and macromolecular properties, leading to programmed cell death, in the future.
尽管预计全球海洋变暖酸化的增加会导致有害藻类物种的数量增加,但已报道拟甲藻 Heterosigma akashiwo 的种群数量减少。然而,该物种如何在物理和代谢上改变过渡 C:N:P 比和大分子积累仍不清楚。考虑到在当前(低温;低碳二氧化碳 [LTLC] 21°C;pCO 400 ppm)和未来(高温;高二氧化碳 [HTHC] 25°C;pCO 1000 ppm)海洋条件下的第 1、10 和 20 代培养,我们检查了过渡 C:N:P 比和大分子水平的变化,并进行了转录组测序。结果表明,与第 1 代细胞相比,HTHC 条件下的第 20 代细胞的碳配额(Q:34%)、氮配额(Q:36%)和磷配额(Q:32%)大幅下降,这反映在 DNA 和 RNA 数量的整体减少。长期(第 20 代)暴露于 HTHC 条件下,光合作用、碳固定和脂质代谢途径的活性降低,与光合效率、碳浓度和脂质积累的变化一致。我们观察到这些内部代谢途径的变化是由温度的外部变化引起的,这些变化激活了(Ca)信号通路,以及 pCO 的外部变化,改变了质子交换途径。我们的结果表明,在未来,温带环境中的 H. akashiwo 将经历 C:N:P 比和大分子性质的深刻变化,导致程序性细胞死亡。