Nitrogen-fixing organelle in a marine alga

• 成果类型: Article
• 署名作者: Coale, Tyler H.; Loconte, Valentina; Turk-Kubo, Kendra A.; Vanslembrouck, Bieke; Mak, Wing Kwan Esther; Cheung, Shunyan; Ekman, Axel; Chen, Jian-Hua; Hagino, Kyoko; Takano, Yoshihito; Nishimura, Tomohiro; Adachi, Masao; Le Gros, Mark; Larabell, Carolyn; Zehr, Jonathan P.
• 署名单位: University of California System; University of California Santa Cruz; University of California System; University of California San Francisco; United States Department of Energy (DOE); Lawrence Berkeley National Laboratory; National Taiwan Ocean University; National Taiwan Ocean University; Kochi University; Japan Fisheries Research & Education Agency (FRA); Kochi University
• 刊物名称: SCIENCE
• ISSN/ISSBN: 0036-11835
• DOI: 10.1126/science.adk1075
• 发表日期: 2024-04-12
• 页码: 217-222
• 关键词: x-ray tomography; ucyn-a; genome; cyanobacterium; EVOLUTION; annotation; eukaryotes; diversity; reduction; sequence

摘要

Symbiotic interactions were key to the evolution of chloroplast and mitochondria organelles, which mediate carbon and energy metabolism in eukaryotes. Biological nitrogen fixation, the reduction of abundant atmospheric nitrogen gas (N-2) to biologically available ammonia, is a key metabolic process performed exclusively by prokaryotes. Candidatus Atelocyanobacterium thalassa, or UCYN-A, is a metabolically streamlined N-2-fixing cyanobacterium previously reported to be an endosymbiont of a marine unicellular alga. Here we show that UCYN-A has been tightly integrated into algal cell architecture and organellar division and that it imports proteins encoded by the algal genome. These are characteristics of organelles and show that UCYN-A has evolved beyond endosymbiosis and functions as an early evolutionary stage N-2-fixing organelle, or nitroplast.