Distribution and diversity of rhodopsin-producing microbes in the Chesapeake Bay.

Distribution and diversity of rhodopsin-producing microbes in the Chesapeake Bay. Appl Environ Microbiol. 2018 Apr 27;: Authors: Maresca JA, Miller KJ, Keffer JL, Sabanayagam CR, Campbell BJ Abstract Although sunlight is an abundant source of energy in surface environments, less than 0.5% of the available photons are captured by (bacterio)chlorophyll dependent photosynthesis in plants and bacteria. Metagenomic data indicate that 30-60% of the bacterial genomes in some environments encode rhodopsins, retinal-based photosystems found in heterotrophs, suggesting that sunlight may provide energy for more life than previously suspected. However, quantitative data on the number of cells that produce rhodopsins in environmental systems is limited. Here, we use total internal reflection fluorescence microscopy to show that the number of free-living microbes that produce rhodopsins increases along the salinity gradient in the Chesapeake Bay. We correlate this functional data with environmental data to show that rhodopsin abundance is positively correlated with salinity and with indicators of active heterotrophy during the day. Metagenomic and metatranscriptomic data suggest that the microbial rhodopsins in the low-salinity samples are primarily found in Actinobacteria and Bacteroidetes, while those in the high-salinity samples are associated with SAR-11 type Alphaproteobacteria.ImportanceMicrobial rhodopsins are common light-activated ion pum...
Source: Applied and Environmental Microbiology - Category: Microbiology Authors: Tags: Appl Environ Microbiol Source Type: research