Pseudoscorpion Wolbachia symbionts: diversity and evidence for a new supergroup S

Abstract

Background: Wolbachia are the most widely spread endosymbiotic bacteria, present in a wide variety of insects and two families of nematodes. As of now, however, relatively little genomic data has been available. The Wolbachia symbiont can be parasitic, as described for many arthropod systems, an obligate mutualist, as in filarial nematodes or a combination of both in some organisms. They are currently classified into 16 monophyletic lineage groups ("supergroups"). Although the nature of these symbioses remains largely unknown, expanded Wolbachia genomic data will contribute to understanding their diverse symbiotic mechanisms and evolution. Results: This report focuses on Wolbachia infections in three pseudoscorpion species infected by two distinct groups of Wolbachia strains, based upon multi-locus phylogenies. Geogarypus minor harbours wGmin and Chthonius ischnocheles harbours wCisc, both closely related to supergroup H, while Atemnus politus harbours wApol, a member of a novel supergroup S along with Wolbachia from the pseudoscorpion Cordylochernes scorpioides (wCsco). Wolbachia supergroup S is most closely related to Wolbachia supergroups C and F. Using target enrichment by hybridization with Wolbachia-specific biotinylated probes to capture large fragments of Wolbachia DNA, we produced two draft genomes of wApol. Annotation of wApol highlights presence of a biotin operon, which is incomplete in many sequenced Wolbachia genomes. Conclusions: The present study highlights at least two symbiont acquisition events among pseudoscorpion species. Phylogenomic analysis indicates that the Wolbachia from Atemnus politus (wApol), forms a separate supergroup ("S") with the Wolbachia from Cordylochernes scorpioides (wCsco). Interestingly, the biotin operon, present in wApol, appears to have been horizontally transferred multiple times along Wolbachia evolutionary history.

Evolution ofWolbachiamutualism and reproductive parasitism: insight from two novel strains that co-infect cat fleas

“…1 ), it is clear that multiple independent BOOM acquisitions have occurred in wolbachiae irrespective of lineage divergences. This is supported by a previous study positing recent BOOM acquisition in w Nfla and w Nleu ( Gerth & Bleidorn, 2017 ) and a current report that detected partial BOOM loci in w Apol, a Supergroup S Wolbachia strain infecting pseudoscorpions ( Lefoulon et al, 2020 ). The nature of BOOM flanking regions in the genomes of w CfeT, w VulC, w Cle, w Str, and w Lug, which collectively lack synteny and are riddled with transposases, recombinases and phage-related elements ( Table S3 ), also attests to LGT as the origin for BOOM in these genomes.…”

“…Some of the Wolbachia strains in closely related Supergroups C, F and D are considered mutualists with their nematode or arthropod hosts, supporting the absence of RP-inducing genes in the genomes of these strains. Still, other strains not included in our analysis, namely those belonging to Supergroups S ( Lefoulon et al, 2020 ; Chafee et al, 2010 ), P ( Glowska et al, 2015 ), and J ( Lefoulon et al, 2016 ) may eventually be shown to carry RP-inducing genes, especially since some of these strains are not known as mutualists. w Fol, another basal Wolbachia lineage ( Fig.…”

“…Unlike other notable rickettsial genera that contain human pathogens (e.g., Rickettsia , Orientia , Neorickettsia , Anaplasma , and Ehrlichia ), wolbachiae do not infect vertebrates ( Gillespie et al, 2012 ). A single species, Wolbachia pipientis , is formally recognized with numerous members designated as strains within 16 reported supergroups ( Augustinos et al, 2011 ; Baldo & Werren, 2007 ; Bing et al, 2014 ; Glowska et al, 2015 ; Haegeman et al, 2009 ; Lo et al, 2002 ; Ros et al, 2009 ; Lefoulon et al, 2020 ). Genomic divergence indicates further species names are warranted ( Chung et al, 2018 ), though increasing diversity and community consensus suggest caution regarding further Wolbachia classification at the species level ( Lindsey et al, 2016 ; Ramírez-Puebla et al, 2015 ).…”

Diminutive, degraded but dissimilar: Wolbachia genomes from filarial nematodes do not conform to a single paradigm

“…Most of the molecular characterizations of Wolbachia strains have been based on either single gene or multi-locus phylogenies [53, 55–65]. The supergroups A, B, E, H, I, K, M, N, O, P, Q and S are exclusively composed of symbionts of arthropods [55, 57, 59, 63, 66–70]. In contrast, supergroups C, D and J are restricted to filarial nematodes [4, 58, 61, 71], whereas supergroup L is found only in plant-parasitic nematodes [3, 72].…”

The Evolution and Biogeography of Wolbachia in Ants (Hymenoptera: Formicidae)

“…However, it is not known whether these functions are related to a particular Wolbachia strain or host [9]. As this bacterium has been found in association with hundreds of hosts and encompasses an immense diversity, the classification of strains into supergroups has been proposed and about 17 supergroups, to date, have been reported through genotyping a single gene, several genes, or even genomic approaches [10]. These supergroups are called "A to S", with G and R no longer considered separate supergroups [11,12].…”