Univ. Grenoble Alpes, CNRS, CEA, INRAe, IRIG-LPCV, Grenoble, France.
Univ. Grenoble Alpes, CEA, IRIG-MEM, Grenoble, France.
Nat Commun. 2021 Feb 16;12(1):1049. doi: 10.1038/s41467-021-21314-0.
Eukaryotic phytoplankton have a small global biomass but play major roles in primary production and climate. Despite improved understanding of phytoplankton diversity and evolution, we largely ignore the cellular bases of their environmental plasticity. By comparative 3D morphometric analysis across seven distant phytoplankton taxa, we observe constant volume occupancy by the main organelles and preserved volumetric ratios between plastids and mitochondria. We hypothesise that phytoplankton subcellular topology is modulated by energy-management constraints. Consistent with this, shifting the diatom Phaeodactylum from low to high light enhances photosynthesis and respiration, increases cell-volume occupancy by mitochondria and the plastid CO-fixing pyrenoid, and boosts plastid-mitochondria contacts. Changes in organelle architectures and interactions also accompany Nannochloropsis acclimation to different trophic lifestyles, along with respiratory and photosynthetic responses. By revealing evolutionarily-conserved topologies of energy-managing organelles, and their role in phytoplankton acclimation, this work deciphers phytoplankton responses at subcellular scales.
真核浮游植物的全球生物量虽小，但在初级生产和气候方面发挥着重要作用。尽管人们对浮游植物多样性和进化的理解有所提高，但我们在很大程度上忽略了它们环境可塑性的细胞基础。通过对七个不同浮游植物类群的比较三维形态计量分析，我们观察到主要细胞器的恒定体积占有率和质体与线粒体之间保持不变的体积比。我们假设浮游植物亚细胞拓扑结构受到能量管理限制的调节。与此一致的是，将硅藻属的小环藻从低光照转移到高光强会增强光合作用和呼吸作用，增加线粒体和固定 CO2 的质体淀粉核的细胞体积占有率，并促进质体-线粒体接触。细胞器结构和相互作用的变化也伴随着氮营养盐对不同营养生活方式的适应，以及呼吸和光合作用的响应。通过揭示能量管理细胞器的进化保守拓扑结构及其在浮游植物适应中的作用，这项工作揭示了亚细胞尺度上的浮游植物响应。
