349V Poster Online - Virtual Posters
Wednesday April 06, 4:00 PM - 7:00 PM

Authors:
Bruna Roman ¹; Carolina Prediger ^1,2; Amir Yassin ²; Lilian Madi-Ravazzi ¹

Affiliations:
1) São Paulo State University (UNESP), Institute of Biosciences, Humanities and Exact Sciences, São José do Rio Preto, São Paulo, Brazil; 2) Laboratoire Evolution, Génomes, Comportement, Ecologie (EGCE), CNRS, IRD, Université Paris-Saclay, Gif-sur-Yvette, France

Keywords:
g. phylogenetics; l. Wolbachia

Wolbachia is an endosymbiotic genus of Alphaproteobacteria that infects a wide range of arthropods and nematodes. This endosymbiont is typically transmitted vertically, but in some cases, horizontal transmission has been reported. The horizontal transmission can occur in different ways in nature, such as parasitism, cannibalism and predation of infected individuals, hybrid introgression and shared ecological niches. Some species of Drosophila saltans group are infected by this endosymbiont, such as Drosophila sturtevanti (wStv), D. prosaltans (wPro) and D. septentriosaltans (wSpt). Here, we analyze the horizontal acquisition of Wolbachia in the host species D. sturtevanti and D. lehrmanae. We inferred a phylogenetic tree, in MrBayes, with 129 Wolbachia genomes (7 sequenced by us and 122 from database) and compared it with the phylogeny of the hosts. The single copy orthologs genes (17) were identified in OrthoFinder and used in the analysis. In general, the phylogeny generated showed that most strains were grouped into their defined supergroups according to the literature. However, six strains (namely, wAlb, wAgra, wNik, wAdent, wStv and wStv-like), belonging to supergroup A, grouped together and distant from the other members of this supergroup. The formation of this last clade is interesting because the phylogeny of these strains demonstrates disagreement with the phylogeny of their hosts. Thus, this result suggests wStv (host D. sturtevanti) and wStv-like (host D. lehrmanae) were acquired by horizontal transmission, since wPro and wSpt strains also infective of saltans group species were positioned phylogenetically distant. This result suggests that this infection may have occurred in a common ancestor of D. sturtevanti and D. lehrmanae. The closest strain phylogenetically to wStv and wStv-like is wAdent, which infects a fungus-growing ant (Apterostigma dentigerum) belonging to the order Hymenoptera and family Formicidae. This host is widely distributed in Central and South America, co-occurring with D. sturtevanti, which provides some explanation for horizontal transmission. However, this question remains open, due to the lack of knowledge of the interaction of these host species. As new genomes are sequenced and added in this analysis, the route of this horizontal transmission may be clarified.