Revealing CO ₂ -Fixing SAR11 Bacteria in the Ocean by Raman-Based Single-Cell Metabolic Profiling and Genomics

The majority of marine microbes remain uncultured, which hinders the identification and mining CO 2 -fixing genes, pathways, chassis from oceans. Here, we investigated in seawater euphotic zone Yellow Sea China by detecting tracking their 13 C-bicarbonate ( C-HCO 3 - ) intake via single-cell Raman spectra (SCRS) analysis. target cells were then isolated Raman-activated Gravity-driven Encapsulation (RAGE), genomes amplified sequenced at one-cell resolution. metabolism, phenotype genome are consistent. We identified a not-yet-cultured Pelagibacter spp., actively assimilates , also possesses most genes encoding enzymes Calvin-Benson cycle for fixation, complete gene set rhodopsin-based light-harvesting system, full necessary carotenoid synthesis. four proteorhodopsin (PR) spp. confirmed heterologous expression E. coli . These results suggest that hitherto uncultured uses light-powered metabolism to contribute global carbon cycling.