Distribution and Genomic Variation of Thermophilic Cyanobacteria in Diverse Microbial Mats at the Upper Temperature Limits of Photosynthesis

Eric D Kees, Senthil Murugapiran, Annastacia C Bennett, Trinity L. Hamilton

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Thermophilic cyanobacteria have been extensively studied in Yellowstone National Park (YNP) hot springs, particularly during decades of work on the thick laminated mats of Octopus and Mushroom springs. However, focused studies of cyanobacteria outside these two hot springs have been lacking, especially regarding how physical and chemical parameters along with community morphology influence the genomic makeup of these organisms. Here, we used a metagenomic approach to examine cyanobacteria existing at the upper temperature limit of photosynthesis. We examined 15 alkaline hot spring samples across six geographic areas of YNP, all with various physical and chemical parameters and community morphology. We recovered 22 metagenomeassembled genomes (MAGs) belonging to thermophilic cyanobacteria, notably an uncultured Synechococcus-like taxon recovered from a setting at the upper temperature limit of photosynthesis, 73°C, in addition to thermophilic Gloeomargarita. Furthermore, we found that three distinct groups of Synechococcus-like MAGs recovered from different temperature ranges vary in their genomic makeup. MAGs from the uncultured veryhigh- temperature (up to 73°C) Synechococcus-like taxon lack key nitrogen metabolism genes and have genes implicated in cellular stress responses that diverge from other Synechococcus-like MAGs. Across all parameters measured, temperature was the primary determinant of taxonomic makeup of recovered cyanobacterial MAGs. However, total Fe, community morphology, and biogeography played an additional role in the distribution and abundance of upper-temperature-limit-adapted Synechococcus-like MAGs. These findings expand our understanding of cyanobacterial diversity in YNP and provide a basis for interrogation of understudied thermophilic cyanobacteria.

Original languageEnglish (US)
Issue number5
StatePublished - Sep 2022

Bibliographical note

Funding Information:
We acknowledge that the research conducted for this work was done in Yellowstone National Park, which was created from land stolen from multiple Native American Nations, especially the Tukudeka (as well as other Shoshone-Bannock and Eastern Shoshone peoples) and Apsáalooke (Crow). These acts were done in part through the guise of Article 2 of the 1868 Fort Bridger Treaty and Article 2 of the 1868 Fort Laramie Treaty. We support efforts to give the lands encompassing YNP back to the native peoples who call it home. This research was supported by NASA Exobiology award number 80NSSC20K0614.

Publisher Copyright:
© 2022 Kees et al.


  • cyanobacteria
  • ecotypes
  • hot springs
  • MAGs
  • metagenome assembled genomes
  • metagenomes
  • microbial mats
  • nitrogen fixation
  • photosynthesis
  • Synechococcus

PubMed: MeSH publication types

  • Journal Article
  • Research Support, U.S. Gov't, Non-P.H.S.


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