A tale of two lineages: how the strains of the earliest divergent symbiotic Frankia clade spread over the world
Journal
BMC genomics
Journal Volume
23
Journal Issue
1
Date Issued
2022-08-19
Author(s)
Berckx, Fede
Nguyen, Thanh Van
Bandong, Cyndi Mae
Lin, Hsiao-Han
Yamanaka, Takashi
Katayama, Sae
Wibberg, Daniel
Blom, Jochen
Kalinowski, Jörn
Tateno, Masaki
Simbahan, Jessica
Brachmann, Andreas
Pawlowski, Katharina
Abstract
It is currently assumed that around 100 million years ago, the common ancestor to the Fabales, Fagales, Rosales and Cucurbitales in Gondwana, developed a root nodule symbiosis with a nitrogen-fixing bacterium. The symbiotic trait evolved first in Frankia cluster-2; thus, strains belonging to this cluster are the best extant representatives of this original symbiont. Most cluster-2 strains could not be cultured to date, except for Frankia coriariae, and therefore many aspects of the symbiosis are still elusive. Based on phylogenetics of cluster-2 metagenome-assembled genomes (MAGs), it has been shown that the genomes of strains originating in Eurasia are highly conserved. These MAGs are more closely related to Frankia cluster-2 in North America than to the single genome available thus far from the southern hemisphere, i.e., from Papua New Guinea.To unravel more biodiversity within Frankia cluster-2 and predict routes of dispersal from Gondwana, we sequenced and analysed the MAGs of Frankia cluster-2 from Coriaria japonica and Coriaria intermedia growing in Japan, Taiwan and the Philippines. Phylogenetic analyses indicate there is a clear split within Frankia cluster-2, separating a continental from an island lineage. Presumably, these lineages already diverged in Gondwana.Based on fossil data on the host plants, we propose that these two lineages dispersed via at least two routes. While the continental lineage reached Eurasia together with their host plants via the Indian subcontinent, the island lineage spread towards Japan with an unknown host plant.
Subjects
Actinorhizal symbiosis; Biogeography; Coriaria; Frankia; Root nodules
SDGs
Publisher
BMC
Type
journal article