Global abundance of microbial rhodopsins.
Photochemical reaction centers and rhodopsins are the only phototrophic mechanisms known to have evolved on Earth. The minimal cost of bearing a rhodopsin-based phototrophic mechanism in comparison to maintaining a photochemical reaction center suggests that rhodopsin is the more abundant of the two. We tested this hypothesis by conducting a global abundance calculation of phototrophic mechanisms from 116 marine and terrestrial microbial metagenomes. On average, 48% of the cells from which these metagenomes were generated harbored a rhodopsin gene, exceeding the reaction center abundance by threefold. Evidence from metatranscriptomic data suggests that this genomic potential is realized to a substantial extent, at least for the small-sized (>0.8 μm) of microbial fractions.
Department of Plant and Environmental Sciences, Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, Israel.
Omri M
OM
Finkel
Oded
O
Béjà
Shimshon
S
Belkin
D000595:Amino Acid Sequence; D054892:Metagenome; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics; D025604:Rhodopsins, Microbial / Q000235:genetics*; D059467:Transcriptome
D045322:Photosynthetic Reaction Center Complex Proteins; D025604:Rhodopsins, Microbial