RT Journal Article
SR Electronic
T1 Evolutionary recent dual obligatory symbiosis among adelgids indicates a transition between fungus and insect associated lifestyles
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.10.16.342642
DO 10.1101/2020.10.16.342642
A1 Gitta Szabó
A1 Frederik Schulz
A1 Alejandro Manzano-Marín
A1 Elena Rebecca Toenshoff
A1 Matthias Horn
YR 2020
UL http://biorxiv.org/content/early/2020/10/16/2020.10.16.342642.abstract
AB Adelgids (Insecta: Hemiptera: Adelgidae) form a small group of insects but harbor a surprisingly diverse set of bacteriocyte-associated endosymbionts, which suggest multiple replacement and acquisition of symbionts over evolutionary time. Specific pairs of symbionts have been associated with adelgid lineages specialized on different secondary host conifers. Using a metagenomic approach, we investigated the symbiosis of the Adelges laricis/tardus species complex containing betaproteobacterial (‘ Candidatus Vallotia tarda’) and gammaproteobacterial (‘Candidatus Profftia tarda’) symbionts. Genomic characteristics and metabolic pathway reconstructions revealed that Vallotia and Profftia are evolutionary young endosymbionts, which complement each other’s role in essential amino acid production. Phylogenomic analyses and a high level of genomic synteny indicate an origin of the betaproteobacterial symbiont from endosymbionts of Rhizopus fungi. This evolutionary transition was accompanied with substantial loss of functions related to transcription regulation, secondary metabolite production, bacterial defense mechanisms, host infection and manipulation. The transition from fungus to insect endosymbionts extends our current framework about evolutionary trajectories of host-associated microbes.Competing Interest StatementThe authors have declared no competing interest.