Department of Biology, Stanford University, Stanford, CA, 94305, USA.
Carnegie Institution for Science, Department of Plant Biology, Stanford, CA, 94305, USA.
Nat Commun. 2024 Jul 16;15(1):5988. doi: 10.1038/s41467-024-49844-3.
Maintenance of water homeostasis is a fundamental cellular process required by all living organisms. Here, we use the single-celled green alga Chlamydomonas reinhardtii to establish a foundational understanding of osmotic-stress signaling pathways through transcriptomics, phosphoproteomics, and functional genomics approaches. Comparison of pathways identified through these analyses with yeast and Arabidopsis allows us to infer their evolutionary conservation and divergence across these lineages. 76 genes, acting across diverse cellular compartments, were found to be important for osmotic-stress tolerance in Chlamydomonas through their functions in cytoskeletal organization, potassium transport, vesicle trafficking, mitogen-activated protein kinase and chloroplast signaling. We show that homologs for five of these genes have conserved functions in stress tolerance in Arabidopsis and reveal a novel PROFILIN-dependent stage of acclimation affecting the actin cytoskeleton that ensures tissue integrity upon osmotic stress. This study highlights the conservation of the stress response in algae and land plants, and establishes Chlamydomonas as a unicellular plant model system to dissect the osmotic stress signaling pathway.
水稳态的维持是所有生物都需要的基本细胞过程。在这里，我们使用单细胞绿藻莱茵衣藻通过转录组学、磷酸化蛋白质组学和功能基因组学方法来建立对渗透胁迫信号通路的基本认识。通过这些分析鉴定的途径与酵母和拟南芥的比较，使我们能够推断它们在这些谱系中的进化保守性和分化。通过它们在细胞骨架组织、钾转运、囊泡运输、丝裂原激活蛋白激酶和叶绿体信号传导中的功能，发现 76 个基因在不同的细胞区室中发挥作用，对于莱茵衣藻的渗透胁迫耐受是重要的。我们表明，这五个基因的同源物在拟南芥的胁迫耐受中具有保守功能，并揭示了一个新的、依赖于丝状肌动蛋白的适应阶段，影响着肌动蛋白细胞骨架，从而确保组织在渗透胁迫下的完整性。这项研究强调了藻类和陆地植物应激反应的保守性，并确立了莱茵衣藻作为一种单细胞植物模型系统，用于剖析渗透胁迫信号通路。
