The cyanobacterium Prochlorococcus has divergent light-harvesting antennae and may have evolved in a low-oxygen ocean
| Autor: | Carlos Henríquez-Castillo, Salvador Ramírez-Flandes, Alejandro A. Murillo, Ramunas Stepanauskas, Alvaro M Plominsky, Connor Morgan-Lang, Steven J. Hallam, Osvaldo Ulloa |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Proceedings of the National Academy of Sciences. 118 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.2025638118 |
| Popis: | Marine picocyanobacteria of the genus Prochlorococcus are the most abundant photosynthetic organisms in the modern ocean, where they exert a profound influence on elemental cycling and energy flow. The use of transmembrane chlorophyll complexes instead of phycobilisomes as light-harvesting antennae is considered a defining attribute of Prochlorococcus Its ecology and evolution are understood in terms of light, temperature, and nutrients. Here, we report single-cell genomic information on previously uncharacterized phylogenetic lineages of this genus from nutrient-rich anoxic waters of the eastern tropical North and South Pacific Ocean. The most basal lineages exhibit optical and genotypic properties of phycobilisome-containing cyanobacteria, indicating that the characteristic light-harvesting antenna of the group is not an ancestral attribute. Additionally, we found that all the indigenous lineages analyzed encode genes for pigment biosynthesis under oxygen-limited conditions, a trait shared with other freshwater and coastal marine cyanobacteria. Our findings thus suggest that Prochlorococcus diverged from other cyanobacteria under low-oxygen conditions before transitioning from phycobilisomes to transmembrane chlorophyll complexes and may have contributed to the oxidation of the ancient ocean. |
| Databáze: | OpenAIRE |
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