Diversification of Wolbachia Endosymbiont in the Culex pipiens Mosquito

Abstract

The α-proteobacteria Wolbachia are among the most common intracellular bacteria and have recently emerged as important drivers of arthropod biology. Wolbachia commonly act as reproductive parasites in arthropods by inducing cytoplasmic incompatibility (CI), a type of conditional sterility between hosts harboring incompatible infections. In this study, we examined the evolutionary histories of Wolbachia infections, known as wPip, in the common house mosquito Culex pipiens, which exhibits the greatest variation in CI crossing patterns observed in any insect. We first investigated a panel of 20 wPip strains for their genetic diversity through a multilocus scheme combining 13 Wolbachia genes. Because Wolbachia depend primarily on maternal transmission for spreading within arthropod populations, we also studied the variability in the coinherited Cx. pipiens mitochondria. In total, we identified 14 wPip haplotypes, which all share a monophyletic origin and clearly cluster into five distinct wPip groups. The diversity of Cx. pipiens mitochondria was extremely reduced, which is likely a consequence of cytoplasmic hitchhiking driven by a unique and recent Wolbachia invasion. Phylogenetic evidence indicates that wPip infections and mitochondrial DNA have codiverged through stable cotransmission within the cytoplasm and shows that a rapid diversification of wPip has occurred. The observed pattern demonstrates that a considerable degree of Wolbachia diversity can evolve within a single host species over short evolutionary periods. In addition, multiple signatures of recombination were found in most wPip genomic regions, leading us to conclude that the mosaic nature of wPip genomes may play a key role in their evolution.

Lateral transfers of insertion sequences between Wolbachia, Cardinium and Rickettsia bacterial endosymbionts

“…In some cases, ISRpe1 transfers might be thus facilitated by the presence of WO bacteriophages that commonly jump between Wolbachia strains (Bordenstein and Wernegreen, 2004;Chafee et al, 2010;Atyame et al, 2011). Occasionally, WO bacteriophages may also undergo distant lateral transfer, as recently reported in Rickettsia (Ishmael et al, 2009), and then introduce ISRpe1 to recipient endosymbionts phylogenetically distant from donor strain.…”

Culex quinquefasciatus mosquitoes do not support replication of Zika virus

“…Mosquitoes were reared and maintained in controlled laboratory conditions. Before experiments, pools of 200 second-instar larvae from the two mosquito lines were homogenized and tested for wPip infection by PCR using the ankyrin domain ank2 gene (primers: F, CTTCTTCTG TGAGTGTACGT and R2, TCCATATCGATCTACTGCG T) according to Atyame et al [53]. Seven-day-old females were fed with the ZIKV strain (NC-2014-5132) isolated from a patient in April 2014 in New Caledonia [16] provided at a titre of 10 7 TCID 50 ml À1 in a blood meal, in capsules of the Hemotek system maintained at 37 C. Fully engorged females were transferred to small boxes and fed with 10 % sucrose until examination.…”

Wolbachia wsp Gene Clones Detect the Distribution of Wolbachia Variants and wsp Hypervariable Regions Among Individuals of a Multistrain Infected Population of Diabrotica barberi (Coleoptera: Chrysomelidae)

“…Multiple infections have been noted in a variety of taxa including butterflies (Hiroki et al 2004), Asiatic rice borer (Chai and Du 2011), tephritid fiies (Jamnongluk et al 2002, Arthofer et al 2009a, Schuler et al 2011, sand fleas (Luchetti et al 2005), bean beetles (Kondo et al 2005, Kondo et al 2011, ants (Reuter and Keller 2003), parasitic wasps (Mouton et al 2003), psocids (Mikac 2007), bumble bees (Li et al 2011), alnus ambrosia beetles (Kawasaki et al 2010), raspberry beetles (Malloch et al 2000, Malloch andFenton 2005), planthoppers (Hughes et al 2011), mosquitoes (Atyame et al 2011), an assortment of heteropteran bugs (Kikuchi and Fukatsu 2003), pirate bugs (Watanabe et al 2012), aphids (Wang et al 2009), bark beetles (Arthofer et al 2009b), and others. Generally the strains participating in multiple infections are not descendants of a common recent ancestor.…”