Genomic Comparison of Oxygen-Loving Bacteria from Deep Sea and Ocean Surface

Jenn Hoskins
26th November, 2024

Genomic Comparison of Oxygen-Loving Bacteria from Deep Sea and Ocean Surface

Pangenome analysis of the deep-sea strains Botrimarina sp. K2D (a), Bythopirellula sp. Pr1dT (b), and Stieleria sp. TBK1r (c) reveals unique "singleton" genes that do not indicate major adaptations for a deep-sea lifestyle, supporting the study's conclusion that these bacteria are genomically very similar to their surface-dwelling relatives.

Image adapted from: Øvreås et al. / CC BY (Source)

Key Findings

  • The study analyzed genomes of three aerobic strains from deep-sea iron-rich hydroxide deposits in the Arctic and Pacific Oceans
  • Despite extreme conditions, the deep-sea strains' genomes are similar to those of surface-inhabiting Planctomycetota
  • This suggests that these microbes have a highly adaptable and resilient genetic foundation, allowing them to thrive in diverse environments
Microbial diversity in extreme environments, such as hydrothermal vent systems on the seafloor, has long intrigued scientists. These remote areas, characterized by high pressure, steep temperature gradients, limited oxygen, and complete darkness, present unique challenges for microbial life. A recent study from the University of Bergen analyzed the genomes of three aerobic strains from the phylum Planctomycetota isolated from deep-sea iron-rich hydroxide deposits with low-temperature diffusive vents in the Arctic and Pacific Oceans[1]. The strains, named Pr1dT, K2D, and TBK1r, were collected from depths of 600 and 1,734 meters below sea level. Researchers focused on identifying genome-encoded features that facilitate phenotypical adaptations to the harsh deep-sea environment. Interestingly, the comparison with genomes of closely related surface-inhabiting Planctomycetota revealed that these deep-sea isolates do not significantly differ from their counterparts in other habitats such as macroalgae biofilms and ocean surface waters. This finding is particularly intriguing given the extreme conditions of their environment. Despite the harshness, the "deep and dark" strains exhibited a mostly non-extreme genome biology, suggesting that the genetic foundation of these microbes is highly adaptable and resilient. The study builds on previous research that utilized the 16S rRNA gene as a gold standard for determining bacterial taxonomy and phylogenetic position[2]. While the 16S rRNA gene is well-conserved and present in all bacteria, it has limitations in resolving closely related isolates. To address this, researchers have employed other molecular markers, such as the rpoB gene, which codes for the beta subunit of RNA polymerase. This gene is sufficiently conserved to act as a molecular clock and is present as a single copy in all bacteria, making it a reliable tool for phylogenetic studies[2]. In this context, the application of rpoB gene sequencing has been particularly successful in clinical microbiology and was used in the study of Planctomycetes to determine species and intraspecies relationships with high accuracy[2]. The current study's genomic analysis of deep-sea Planctomycetota strains aligns with these methodologies and expands our understanding of microbial life in extreme environments. By comparing the genomes of the deep-sea strains with those of surface-inhabiting Planctomycetota, the researchers found that the core genome of these bacteria remains largely unchanged despite the vastly different environmental conditions. This suggests a remarkable level of genetic stability and adaptability, allowing these microbes to thrive in diverse habitats. The findings underscore the importance of genomic studies in uncovering the mechanisms that enable microbial life to adapt to extreme environments. The research also highlights the potential for discovering novel microbial functions and adaptations that could have applications in biotechnology and other fields. In conclusion, the study by the University of Bergen provides valuable insights into the genomic adaptations of deep-sea Planctomycetota. By leveraging advanced genomic techniques and building on previous research, the study enhances our understanding of microbial diversity and resilience in one of Earth's most extreme environments.

GeneticsOceanographyMarine Biology

References

Main Study

1) Comparative genomic analyses of aerobic planctomycetes isolated from the deep sea and the ocean surface.

Published 25th November, 2024

https://doi.org/10.1007/s10482-024-02041-0

Related Studies

2) rpoB gene as a novel molecular marker to infer phylogeny in Planctomycetales.

https://doi.org/10.1007/s10482-013-9980-7


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