Diversity and distribution of Asgard Archaea including new genomes of Thor- and Lokiarchaeota from a salt lagoon

Lokeshwaran Manoharan, Jessica Kozlowski, Maria Filipa Baltazar de Lima de Sousa, Christa Schleper

The current wealth of publicly available sequencing data, as well as advances in sequencing technology, have allowed for the discovery of diverse new Archaeal groups. These new lineages are of interest for the ever-changing phylogenetic tree of Archaea as well as their potential as important players in global Biogeochemical cycles. One such group of interest is the Asgard archaea, a new superphylum defined as a sister group to the TACK superphylum. While studies have so far focused mostly on the evolutionary implications of the Asgard archaea placement in the tree of life, the environmental distribution of the members within this superphylum is not well understood. Also, given the ever-increasing publicly available genomes of the Asgard archaea, their phylogeny as a superphylum is not clear. Here we provide a meta-analysis of the environmental distribution of the Asgard archaea, based on more than 4,400 Asgard 16S rRNA sequences available in the Silva (version-132) database. We also provide an improved phylogeny by filtering for chimeras and renaming the wrongly annotated sequences from the Silva database. Also, we report on a new Thorarchaeota genome and 3 new Lokiarchaeota genomes obtained from a salt-crusted lagoon near Puertecitos on the Baja California Peninsula of Mexico. These new genomes are the first reported from a salt-lagoon and provide the most complete Thor genome (93% complete) publicly available. We used our genomes to further assess the Asgard phylogeny as a whole. Also, we compared our genomes to those publicly available for a more complete understanding of the specific functional niches they may have in global biogeochemical cycles and how environmental placement may affect these roles.

Department für Ökogenomik und Systembiologie
ÖFOS 2012
Link zum Portal