Anoxygenic phototroph of the Chloroflexota uses a type I reaction centre

• 成果类型: Article
• 署名作者: Tsuji, J. M.; Shaw, N. A.; Nagashima, S.; Venkiteswaran, J. J.; Schiff, S. L.; Watanabe, T.; Fukui, M.; Hanada, S.; Tank, M.; Neufeld, J. D.
• 署名单位: University of Waterloo; Hokkaido University; Japan Agency for Marine-Earth Science & Technology (JAMSTEC); Tokyo Metropolitan University; Wilfrid Laurier University; Leibniz Association; Leibniz Institut fur Deutsche Sammlung von Mikroorganismen und Zellkulturen (DSMZ); Kanagawa University; National Institute of Advanced Industrial Science & Technology (AIST)
• 刊物名称: Nature
• ISSN/ISSBN: 0028-3740
• DOI: 10.1038/s41586-024-07180-y
• 发表日期: 2024-03-28
• 关键词: experimental lakes area; gen. nov.; photosynthetic bacterium; sequence; EVOLUTION; chlorosomes; database; complex; terrestrial; aurantiacus

摘要

Scientific exploration of phototrophic bacteria over nearly 200 years has revealed large phylogenetic gaps between known phototrophic groups that limit understanding of how phototrophy evolved and diversified1,2. Here, through Boreal Shield lake water incubations, we cultivated an anoxygenic phototrophic bacterium from a previously unknown order within the Chloroflexota phylum that represents a highly novel transition form in the evolution of photosynthesis. Unlike all other known phototrophs, this bacterium uses a type I reaction centre (RCI) for light energy conversion yet belongs to the same bacterial phylum as organisms that use a type II reaction centre (RCII) for phototrophy. Using physiological, phylogenomic and environmental metatranscriptomic data, we demonstrate active RCI-utilizing metabolism by the strain alongside usage of chlorosomes3 and bacteriochlorophylls4 related to those of RCII-utilizing Chloroflexota members. Despite using different reaction centres, our phylogenomic data provide strong evidence that RCI-utilizing and RCII-utilizing Chloroflexia members inherited phototrophy from a most recent common phototrophic ancestor. The Chloroflexota phylum preserves an evolutionary record of the use of contrasting phototrophic modes among genetically related bacteria, giving new context for exploring the diversification of phototrophy on Earth. Cultivation of a new anoxygenic phototrophic bacterium from Boreal Shield lake water-representing a transition form in the evolution of photosynthesis-offers insights into how the major modes of phototrophy diversified.