Abstract
AbstractWe describe a population genome of Eremiobacterota (KWL-0264) recovered from tundra soil metagenomes that contains the minimal set ofnifgenes needed to fix atmospheric N2. Such putative diazotroph population would link for the first time Eremiobacterota and N2fixation. The integrity of the genome and itsnifgenes are well supported by both environmental and taxonomic signals. KWL-0264 contains threenifHhomologs and the complementary set ofnifDKENBgenes that are thought needed to assemble a functional nitrogenase. The putative role in N2fixation of this Eremiobacterota population is also evidenced by the presence of other genes involved with the regulation of the N2fixation activity as well as ammonia assimilation and amino acid metabolism. Like other Eremiobacterota, KWL-0264 also encodes the potential for atmospheric chemosynthesis. Interestingly, the presence of a N2O reductase indicates that this population could also play a role as a N2O sink in tundra soils. Due to the lack of activity data, it remains uncertain if this Eremiobacterota population is able to assemble a functional nitrogenase and participate in N2fixation. Confirmation of this activity would be a testament to the great metabolic versatility of Eremiobacterota, which appears to underlie their ecological success in cold and oligotrophic environments.
Publisher
Cold Spring Harbor Laboratory