α-cyanobacteria possessing form IA RuBisCO globally dominate aquatic habitats

作者：Pedro J. Cabello‐Yeves, David J. Scanlan, Cristiana Callieri, Antonio Picazo, Lena Schallenberg, Paula Huber, Juan J. Roda‐Garcia, Maciej Bartosiewicz, О. И. Белых, И. В. Тихонова, Alberto Torcello-Requena, Paula Martin De Prado, Andrew Millard, Antonio Camacho, Francisco Rodríguez‐Valera, Richard J. Puxty · 发表于：The ISME Journal · 年份：2022 · DOI：10.1038/s41396-022-01282-z · 被引用次数：49 · 研究领域：Photosynthetic Processes and Mechanisms、Microbial Community Ecology and Physiology、Algal biology and biofuel production

Abstract RuBisCO (ribulose 1,5-bisphosphate carboxylase/oxygenase) is one the most abundant enzymes on Earth. Virtually all food webs depend on its activity to supply fixed carbon. In aerobic environments, RuBisCO struggles to distinguish efficiently between CO2 and O2. To compensate, organisms have evolved convergent solutions to concentrate CO2 around the active site. The genetic engineering of such inorganic carbon concentrating mechanisms (CCMs) into plants could help facilitate future global food security for humankind. In bacteria, the carboxysome represents one such CCM component, of which two independent forms exist: α and β. Cyanobacteria are important players in the planet’s carbon cycle and the vast majority of the phylum possess a β-carboxysome, including most cyanobacteria used as laboratory models. The exceptions are the exclusively marine Prochlorococcus and Synechococcus that numerically dominate open ocean systems. However, the reason why marine systems favor an α-form is currently unknown. Here, we report the genomes of 58 cyanobacteria, closely related to marine Synechococcus that were isolated from freshwater lakes across the globe. We find all these isolates possess α-carboxysomes accompanied by a form 1A RuBisCO. Moreover, we demonstrate α-cyanobacteria dominate freshwater lakes worldwide. Hence, the paradigm of a separation in carboxysome type across the salinity divide does not hold true, and instead the α-form dominates all aquatic systems. We thus qu...