WhyWolbachia-induced cytoplasmic incompatibility is so common

Abstract

Cytoplasmic incompatibility (CI) is the most common reproductive manipulation produced by Wolbachia , obligately intracellular alphaproteobacteria that infect approximately half of all insect species. Once infection frequencies within host populations approach 10%, intense CI can drive Wolbachia to near fixation within 10 generations. However, natural selection among Wolbachia variants within individual host populations does not favor enhanced CI. Indeed, variants that do not cause CI but increase host fitness or are more reliably maternally transmitted are expected to spread if infected females remain protected from CI. Nevertheless, approximately half of analyzed Wolbachia infections cause detectable CI. Why? The frequency and persistence of CI are more plausibly explained by preferential spread to new host species (clade selection) rather than by natural selection among variants within host populations. CI-causing Wolbachia lineages preferentially spread into new host species because 1) CI increases equilibrium Wolbachia frequencies within host populations, and 2) CI-causing variants can remain at high frequencies within populations even when conditions change so that initially beneficial Wolbachia infections become harmful. An epidemiological model describing Wolbachia acquisition and loss by host species and the loss of CI-induction within Wolbachia lineages yields simple expressions for the incidence of Wolbachia infections and the fraction of those infections causing CI. Supporting a determinative role for differential interspecific spread in maintaining CI, many Wolbachia infections were recently acquired by their host species, many show evidence for contemporary spatial spread or retreat, and rapid evolution of CI-inducing loci, especially degradation, is common.

Editorial: Emerging mosquito-borne diseases and novel biocontrol strategies

“…Biological control agents are important alternatives or complements to chemical insecticides. Combined with genetic approaches (e.g., transgenesis and paratransgenesis) and other biological rear and release theories, novel approaches, including entomopathogenic fungi (Metarhizium anisopliae and Beauveria bassiana) , symbiotic bacteria (Wolbachia) (Turelli et al, 2022), lethal bacteria (Bacillus thuringiensis)…”

“…Thus, there is a growing need for more sustainable, environmentally friendly, and low-cost vector control strategies that can be implemented on a large scale to harness insecticide-resistant mosquitoes and reduce mosquito-borne disease burden.Biological control agents are important alternatives or complements to chemical insecticides. Combined with genetic approaches (e.g., transgenesis and paratransgenesis) and other biological rear and release theories, novel approaches, including entomopathogenic fungi (Metarhizium anisopliae and Beauveria bassiana) , symbiotic bacteria (Wolbachia) (Turelli et al, 2022), lethal bacteria (Bacillus thuringiensis)Frontiers in Cellular and Infection Microbiology frontiersin.org 01…”

Modelling Emergence ofWolbachiaToxin-Antidote Protein Functions with an Evolutionary Algorithm

“…CI is common because it increases equilibrium frequencies and infection persistence, thereby increasing the chances of Wolbachia being transferred to new species hosts. 16 Yet in the insect, selection does not act to preserve or increase CI rates. 17 Importantly, evolutionary dynamics and selective pressures operating at the lowest molecular level and at the moment CI emerged in evolutionary history have never been described.…”

Cytoplasmic incompatibility and female fecundity associated with Wolbachia infection in a cricket species

“…CI is the most widespread endosymbiotic manipulation among arthropods, and has been detected in Coleoptera, Diptera, Hymenoptera, Hemiptera, Lepidoptera, Orthoptera, Isopoda, Trombidiformes and Mesostigmata (Kageyama et al, 2012;Ma et al, 2014;Werren et al, 2008). Turellia et al (2022) argued that CI is common because higher intraspecific frequencies make CI-causing Wolbachia lineages more likely to spread to new hosts than non-CI lineages, and once established in new hosts, CI-causing Wolbachia is likely to persist much longer.…”

“…CI is the most widespread endosymbiotic manipulation among arthropods, and has been detected in Coleoptera, Diptera, Hymenoptera, Hemiptera, Lepidoptera, Orthoptera, Isopoda, Trombidiformes and Mesostigmata (Kageyama et al, 2012; Ma et al, 2014; Werren et al, 2008). Turellia et al (2022) argued that CI is common because higher intraspecific frequencies make CI‐causing Wolbachia lineages more likely to spread to new hosts than non‐CI lineages, and once established in new hosts, CI‐causing Wolbachia is likely to persist much longer. CI generally refers to factors localized in the cytoplasm of sperm and eggs that render them incompatible with each other, resulting in unviable embryos when uninfected females mate with infected males (Shropshire & Bordenstein, 2019; Werren et al, 2008).…”