The genome of a novel isolate of Prochlorococcus from the Red Sea contains transcribed genes for compatible solute biosynthesis.

Abstract
Marine microbes possess genomic and physiological adaptations to cope with varying environmental conditions. So far, the effects of high salinity on the most abundant marine photoautotrophic organism, Prochlorococcus, in marine oligotrophic environments are mostly unknown. Here, we report the isolation of a new Prochlorococcus strain (RSP50) belonging to high-light (HL) clade II from the Red Sea, one of the warmest and most saline bodies of water in the global ocean. A comparative genomic analysis identified a set of 59 genes that were exclusive to RSP50 relative to currently available Prochlorococcus genomes, the majority of which (70%) encode for hypothetical proteins of unknown function. However, three of the unique genes encode for a complete pathway for the biosynthesis of the compatible solute glucosylglycerol, and are homologous to enzymes found in the sister lineage Synechococcus. Metatranscriptomic analyses of this metabolic pathway in the water-column of the Red Sea revealed that the corresponding genes were constitutively transcribed, independent of depth and light, suggesting that osmoregulation using glucosylglycerol is a general feature of HL II Prochlorococcus in the Red Sea.

Citation
Shibl AA, Ngugi DK, Talarmin A, Thompson LR, Blom J, et al. (2018) The genome of a novel isolate of Prochlorococcus from the Red Sea contains transcribed genes for compatible solute biosynthesis. FEMS Microbiology Ecology. Available: http://dx.doi.org/10.1093/femsec/fiy182.

Acknowledgements
We thank AbdulAziz Al-Suwailem from the Coastal and Marine Resources Core Lab (CMRC) and the scientists, captain and crew of the R/V Aegaeo from the KAUST Red Sea Expedition 2013 for their logistical and technical support. We also thank Rachid Sougrat from the Imaging Core Lab as well as Manal Andijani, Hicham Mansour, Alaguraj Dharmarajnadar and Hatim Talal Almansouri from the Biosciences Core Laboratory (BCL) at KAUST for their help with sample analysis.

Publisher
Oxford University Press (OUP)

Journal
FEMS Microbiology Ecology

DOI
10.1093/femsec/fiy182

Additional Links
https://academic.oup.com/femsec/advance-article/doi/10.1093/femsec/fiy182/5090968

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