Korarchaeota

Korarchaeota is a phylum within the domain Archaea. It comprises lineages that have been detected mainly through environmental DNA and genome-resolved metagenomics rather than from cultivated organisms. Phylogenetically, Korarchaeota are considered among the deepest-branching lineages within Archaea, and their precise placement relative to other archaeal phyla remains debated.

Habitat and discovery: Members have been recovered from a range of high-temperature environments, including hot springs and geothermally heated sediments worldwide. The lineage was first identified from environmental 16S rRNA gene sequences, and subsequent genome-scale analyses have expanded understanding of its diversity while formal cultivation remains scarce.

Physiology and metabolism: Because cultured representatives are scarce, physiology is inferred from genomes and from comparative analyses with related lineages. Korarchaeota are thought to be thermophilic and largely anaerobic, utilizing organic substrates such as peptides and simple carbohydrates. Some metabolic pathways appear incomplete, suggesting possible dependencies on community members for certain nutrients or cofactors.

Genomics and significance: Genome-resolved studies indicate variable genome sizes and a set of core genes that distinguish Korarchaeota from other Archaea. The phylum is of particular interest for evolutionary biology because its apparent early divergence among Archaea can inform interpretations of ancient metabolic traits and archaeal diversification. Ongoing efforts aim to obtain more complete genomes and, if possible, cultivated representatives to clarify physiology and ecological roles.