Asgard archaea including the novel phylum Gerdarchaeota participate in organic matter degradation
Asgard archaea, proposed as a new archaeal superphylum, are currently composed of five phyla: Lokiarchaeota, Thorarchaeota, Odinarchaeota, Heimdallarchaeota, and Helarchaeota. Since Asgard archaea contain abundant eukaryotic signature proteins and form a monophyletic group with eukaryotes in a phylogenetic tree, they are regarded as the closest relatives of Eukarya and have therefore attracted increasing research interests, although the debate about the evolutionary relationship is ongoing. In the past several years, metagenome-assembled genomes (MAGs) enabled us to decipher the metabolic capabilities of Asgard archaea, and the most recent isolation and transcriptomic analysis of Lokiarchaeota provided further insights into their metabolic capabilities. However, since no comprehensive information about the in situ activity of these Asgard archaea has been compiled so far, our understanding of these phylogenetically and evolutionally important archaea is based on prediction, and thus, severely limited.