Congratulations to Krzysztof Jurdzinski and his co-authors on their recently published research, "Large-scale phylogenomics of aquatic bacteria reveal molecular mechanisms for adaptation to salinity", Science Advances!
Says Krzysztof,
In this work, we revealed species-level separation between aquatic biomes (freshwater, brackish, and marine). While species were separated by salinity barriers, geography had stronger effects than salinity on brackish intraspecies diversity.
Furthermore, we identified cross-biome transition events across the whole bacterial tree of life. Thes events were rare, ancient, disconnected from major geological events (formation of the Baltic and the Caspian Seas), and occurred more often into than out of the brackish waters. The changes of the inhabited biome led to convergent proteome-scale reorganizations of protein properties and amino acid composition, occurring over long evolutionary timespan. We also identified gene functions gained or lost across multiple transitions of diverse bacteria between the same biomes.
The work systematically tracks the separation of freshwater, brackish, and marine bacterial communities. The results suggest that after the local changes in salinity lead to a biome change, the niches are filled rather by migration than local adaptation, which has important implications for conservation efforts. Finally, we connect the rareness of cross-biome transitions to adaptation barriers. The selective pressure for large-scale proteome reorganization and for specific changes in gene repertoire prevent frequent changes of habitat across the biome barriers.
Krzysztof was given the opportunity to work with his collaborators during an AMRI Exchange program in spring of 2022.
Co-authors Krzysztof T Jurdzinski1†, Maliheh Mehrshad2†, Luis Fernando Delgado1, Ziling Deng1, Stefan Bertilsson2, Anders F Andersson1*