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1.
PLoS Negl Trop Dis ; 15(2): e0009179, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33591971

RESUMO

The endosymbiotic bacterium Wolbachia shows viral blocking in its mosquito host, leading to its use in arboviral disease control. Releases with Wolbachia strains wMel and wAlbB infecting Aedes aegypti have taken place in several countries. Mosquito egg survival is a key factor influencing population persistence and this trait is also important when eggs are stored prior to releases. We therefore tested the viability of mosquitoes derived from Wolbachia wMel and wAlbB-infected as well as uninfected eggs after long-term storage under diurnal temperature cycles of 11-19°C and 22-30°C. Eggs stored at 11-19°C had higher hatch proportions than those stored at 22-30°C. Adult Wolbachia density declined when they emerged from eggs stored for longer, which was associated with incomplete cytoplasmic incompatibility (CI) when wMel-infected males were crossed with uninfected females. Females from stored eggs at both temperatures continued to show perfect maternal transmission of Wolbachia, but storage reduced the fecundity of both wMel and wAlbB-infected females relative to uninfected mosquitoes. Furthermore, we found a very strong negative impact of the wAlbB infection on the fertility of females stored at 22-30°C, with almost 80% of females hatching after 11 weeks of storage being infertile. Our findings provide guidance for storing Wolbachia-infected A. aegypti eggs to ensure high fitness adult mosquitoes for release. Importantly, they also highlight the likely impact of egg quiescence on the population dynamics of Wolbachia-infected populations in the field, and the potential for Wolbachia to suppress mosquito populations through cumulative fitness costs across warm and dry periods, with expected effects on dengue transmission.


Assuntos
Aedes/microbiologia , Controle Biológico de Vetores/métodos , Wolbachia/fisiologia , Aedes/fisiologia , Criação de Animais Domésticos/métodos , Animais , Feminino , Fertilidade , Masculino , Óvulo/fisiologia , Temperatura
2.
PLoS Negl Trop Dis ; 15(1): e0008935, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33406151

RESUMO

Brugia malayi is a human filarial nematode responsible for elephantiasis, a debilitating condition that is part of a broader spectrum of diseases called filariasis, including lymphatic filariasis and river blindness. Almost all filarial nematode species infecting humans live in mutualism with Wolbachia endosymbionts, present in somatic hypodermal tissues but also in the female germline which ensures their vertical transmission to the nematode progeny. These α-proteobacteria potentially provision their host with essential metabolites and protect the parasite against the vertebrate immune response. In the absence of Wolbachia wBm, B. malayi females become sterile, and the filarial nematode lifespan is greatly reduced. In order to better comprehend this symbiosis, we investigated the adaptation of wBm to the host nematode soma and germline, and we characterized these cellular environments to highlight their specificities. Dual RNAseq experiments were performed at the tissue-specific and ovarian developmental stage levels, reaching the resolution of the germline mitotic proliferation and meiotic differentiation stages. We found that most wBm genes, including putative effectors, are not differentially regulated between infected tissues. However, two wBm genes involved in stress responses are upregulated in the hypodermal chords compared to the germline, indicating that this somatic tissue represents a harsh environment to which wBm have adapted. A comparison of the B. malayi and C. elegans germline transcriptomes reveals a poor conservation of genes involved in the production of oocytes, with the filarial germline proliferative zone relying on a majority of genes absent from C. elegans. The first orthology map of the B. malayi genome presented here, together with tissue-specific expression enrichment analyses, indicate that the early steps of oogenesis are a developmental process involving genes specific to filarial nematodes, that likely result from evolutionary innovations supporting the filarial parasitic lifestyle.


Assuntos
Evolução Biológica , Brugia Malayi/genética , Carisoprodol , Elefantíase/genética , Células Germinativas , Animais , Caenorhabditis elegans , Filariose Linfática/genética , Feminino , Expressão Gênica , Genoma , Humanos , Oogênese , Análise de Sequência de RNA , Simbiose , Wolbachia/fisiologia
3.
Nat Commun ; 11(1): 5235, 2020 10 16.
Artigo em Inglês | MEDLINE | ID: mdl-33067437

RESUMO

Wolbachia is an iconic example of a successful intracellular bacterium. Despite its importance as a manipulator of invertebrate biology, its evolutionary dynamics have been poorly studied from a genomic viewpoint. To expand the number of Wolbachia genomes, we screen over 30,000 publicly available shotgun DNA sequencing samples from 500 hosts. By assembling over 1000 Wolbachia genomes, we provide a substantial increase in host representation. Our phylogenies based on both core-genome and gene content provide a robust reference for future studies, support new strains in model organisms, and reveal recent horizontal transfers amongst distantly related hosts. We find various instances of gene function gains and losses in different super-groups and in cytoplasmic incompatibility inducing strains. Our Wolbachia-host co-phylogenies indicate that horizontal transmission is widespread at the host intraspecific level and that there is no support for a general Wolbachia-mitochondrial synchronous divergence.


Assuntos
Genoma Bacteriano , Wolbachia/genética , Evolução Molecular , Transferência Genética Horizontal , Especificidade de Hospedeiro , Filogenia , Wolbachia/classificação , Wolbachia/fisiologia
4.
PLoS Negl Trop Dis ; 14(9): e0008561, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32881871

RESUMO

Combined incompatible and sterile insect technique (IIT-SIT) has been considered to be an effective and safe approach to control mosquito populations. Immobilization of male adults by chilling is a crucial process required for the packing, transportation and release of the mosquitoes during the implementation of IIT-SIT for mosquito control. In this study, effects of chilling on the Aedes albopictus males with triple Wolbachia infections (HC line), a powerful weapon to fight against the wild type Ae. albopictus population via IIT-SIT, were evaluated under both laboratory and field conditions. Irradiated HC (IHC) males were exposed to 1, 5 and 10°C for 1, 2, 3, 6 and 24 h. The survival rate of the post-chilled IHC males was then monitored. Longevity of post-chilled IHC males was compared to non-chilled males under laboratory and semi-field conditions. Mating competitiveness of IHC/HC males after exposure to 5 or 10°C for 0, 3 and 24 h was then evaluated. Effects of compaction and transportation under chilled conditions on the survival rate of IHC males were also monitored. The optimal chilling conditions for handling IHC males were temperatures between 5 and 10°C for a duration of less than 3 h with no negative impacts on survival rate, longevity and mating competitiveness when compared to non-chilled males. However, the overall quality of post-chilled IHC/HC males decreased when exposed to low temperatures for 24 h. Reduced survival was observed when IHC males were stored at 5°C under a compaction height of 8 cm. Transportation with chilling temperatures fluctuating from 8 to 12°C has no negative impact on the survival of IHC males. This study identified the optimal chilling temperature and duration for the handling and transportation of Ae. albopictus IHC male adults without any detrimental effect on their survival, longevity and mating competitiveness. Further studies are required to develop drone release systems specific for chilled mosquitoes to improve release efficiency, as well as to compare the population suppression efficiency between release of post-chilled and non-chilled males in the field.


Assuntos
Aedes/microbiologia , Aedes/fisiologia , Controle de Mosquitos/métodos , Wolbachia/fisiologia , Animais , Temperatura Baixa , Feminino , Masculino , Reprodução
5.
PLoS Pathog ; 16(8): e1008794, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32813725

RESUMO

Wolbachia are the world's most common, maternally-inherited, arthropod endosymbionts. Their worldwide distribution is due, in part, to a selfish drive system termed cytoplasmic incompatibility (CI) that confers a relative fitness advantage to females that transmit Wolbachia to their offspring. CI results in embryonic death when infected males mate with uninfected females but not infected females. Under the Two-by-One genetic model of CI, males expressing the two phage WO proteins CifA and CifB cause CI, and females expressing CifA rescue CI. While each protein is predicted to harbor three functional domains, there is no knowledge on how sites across these Cif domains, rather than in any one particular domain, contribute to CI and rescue. Here, we use evolution-guided, substitution mutagenesis of conserved amino acids across the Cif proteins, coupled with transgenic expression in uninfected Drosophila melanogaster, to determine the functional impacts of conserved residues evolving mostly under purifying selection. We report that amino acids in CifA's N-terminal unannotated region and annotated catalase-related domain are important for both complete CI and rescue, whereas C-terminal residues in CifA's putative domain of unknown function are solely important for CI. Moreover, conserved CifB amino acids in the predicted nucleases, peptidase, and unannotated regions are essential for CI. Taken together, these findings indicate that (i) all CifA amino acids determined to be crucial in rescue are correspondingly crucial in CI, (ii) an additional set of CifA amino acids are uniquely important in CI, and (iii) CifB amino acids across the protein, rather than in one particular domain, are all crucial for CI. We discuss how these findings advance an expanded view of Cif protein evolution and function, inform the mechanistic and biochemical bases of Cif-induced CI/rescue, and continue to substantiate the Two-by-One genetic model of CI.


Assuntos
Proteínas de Bactérias/metabolismo , Evolução Biológica , Citoplasma/metabolismo , Drosophila melanogaster/microbiologia , Infecções por Bactérias Gram-Negativas/metabolismo , Mutação , Wolbachia/fisiologia , Animais , Animais Geneticamente Modificados/microbiologia , Animais Geneticamente Modificados/fisiologia , Proteínas de Bactérias/genética , Citoplasma/microbiologia , Drosophila melanogaster/fisiologia , Feminino , Infecções por Bactérias Gram-Negativas/microbiologia , Infecções por Bactérias Gram-Negativas/patologia , Masculino
6.
J Insect Sci ; 20(3)2020 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-32559297

RESUMO

Wolbachia is a maternally inherited bacterium ubiquitous in insects that has attracted interest as a prospective insect pest-control agent. Here, we detected and characterized Wolbachia in the leafhoppers Matsumuratettix hiroglyphicus (Matsumura) (Cicadellidae: Hemiptera) and Yamatotettix flavovittatus Matsumura (Cicadellidae: Hemiptera), insect vectors of the phytoplasma that cause white leaf disease in sugarcane. The 16S rRNA and wsp gene markers revealed that Wolbachia was not present in the M. hiroglyphicus but naturally occurs in Y. flavovittatus. Additionally, the infection rates in adult leafhoppers ranged from 0 to 100% depending on geographic location. Moreover, Wolbachia was detected in the eggs and first- to fifth-instar nymphs of Y. flavovittatus. A phylogenic tree of Wolbachia indicated that it resided in the monophyletic supergroup B clade and clustered in the Ori subgroup. Furthermore, fluorescence in situ hybridization revealed that Wolbachia localized to the egg apices, randomly distributed in the egg cytoplasm, and was concentrated in the nymph and adult bacteriomes, as well as occasional detection in the thorax and abdomen. To the best of our knowledge, the present study is the first to demonstrate the prevalence of Wolbachia in the leafhopper Y. flavovittatus. The obtained results would provide useful information for the future development of Wolbachia as a biological control agent for the leafhopper vectors.


Assuntos
Hemípteros/microbiologia , Simbiose , Wolbachia/fisiologia , Animais , Feminino , Hemípteros/crescimento & desenvolvimento , Insetos Vetores/crescimento & desenvolvimento , Insetos Vetores/microbiologia , Masculino , Ninfa/crescimento & desenvolvimento , Ninfa/microbiologia , Óvulo/crescimento & desenvolvimento , Óvulo/microbiologia , Doenças das Plantas/microbiologia , Saccharum/microbiologia
8.
PLoS Negl Trop Dis ; 14(4): e0008157, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32302295

RESUMO

The successful establishment of the wMel strain of Wolbachia for the control of arbovirus transmission by Aedes aegypti has been proposed and is being implemented in a number of countries. Here we describe the successful establishment of the wMel strain of Wolbachia in four sites in Yogyakarta, Indonesia. We demonstrate that Wolbachia can be successfully introgressed after transient releases of wMel-infected eggs or adult mosquitoes. We demonstrate that the approach is acceptable to communities and that Wolbachia maintains itself in the mosquito population once deployed. Finally, our data show that spreading rates of Wolbachia in the Indonesian setting are slow which may reflect more limited dispersal of Aedes aegypti than seen in other sites such as Cairns, Australia.


Assuntos
Aedes/microbiologia , Mosquitos Vetores/microbiologia , Wolbachia/fisiologia , Aedes/virologia , Animais , Arbovírus , Austrália , Agentes de Controle Biológico , Transmissão de Doença Infecciosa/prevenção & controle , Feminino , Indonésia , Masculino
9.
PLoS Negl Trop Dis ; 14(4): e0008204, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32243448

RESUMO

Wolbachia are being used to reduce dengue transmission by Aedes aegypti mosquitoes around the world. To date releases have mostly involved Wolbachia strains with limited fitness effects but strains with larger fitness costs could be used to suppress mosquito populations. However, such infections are expected to evolve towards decreased deleterious effects. Here we investigate potential evolutionary changes in the wMelPop infection transferred from Drosophila melanogaster to Aedes aegypti more than ten years (~120 generations) ago. We show that most deleterious effects of this infection have persisted despite strong selection to ameliorate them. The wMelPop-PGYP infection is difficult to maintain in laboratory colonies, likely due to the persistent deleterious effects coupled with occasional maternal transmission leakage. Furthermore, female mosquitoes can be scored incorrectly as infected due to transmission of Wolbachia through mating. Infection loss in colonies was not associated with evolutionary changes in the nuclear background. These findings suggest that Wolbachia transinfections with deleterious effects may have stable phenotypes which could ensure their long-term effectiveness if released in natural populations to reduce population size.


Assuntos
Aedes/microbiologia , Evolução Molecular , Mosquitos Vetores/microbiologia , Controle Biológico de Vetores/métodos , Wolbachia/fisiologia , Animais , Dengue/prevenção & controle , Drosophila melanogaster , Feminino , Interações entre Hospedeiro e Microrganismos , Modelos Lineares , Masculino , Controle de Mosquitos , Dinâmica Populacional , Wolbachia/patogenicidade
10.
PLoS Pathog ; 16(4): e1008433, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32282862

RESUMO

The insect bacterium Wolbachia pipientis is being introgressed into Aedes aegypti populations as an intervention against the transmission of medically important arboviruses. Here we compare Ae. aegypti mosquitoes infected with wMelCS or wAlbB to the widely used wMel Wolbachia strain on an Australian nuclear genetic background for their susceptibility to infection by dengue virus (DENV) genotypes spanning all four serotypes. All Wolbachia-infected mosquitoes were more resistant to intrathoracic DENV challenge than their wildtype counterparts. Blocking of DENV replication was greatest by wMelCS. Conversely, wAlbB-infected mosquitoes were more susceptible to whole body infection than wMel and wMelCS. We extended these findings via mosquito oral feeding experiments, using viremic blood from 36 acute, hospitalised dengue cases in Vietnam, additionally including wMel and wildtype mosquitoes on a Vietnamese nuclear genetic background. As above, wAlbB was less effective at blocking DENV replication in the abdomen compared to wMel and wMelCS. The transmission potential of all Wolbachia-infected mosquito lines (measured by the presence/absence of infectious DENV in mosquito saliva) after 14 days, was significantly reduced compared to their wildtype counterparts, and lowest for wMelCS and wAlbB. These data support the use of wAlbB and wMelCS strains for introgression field trials and the biocontrol of DENV transmission. Furthermore, despite observing significant differences in transmission potential between wildtype mosquitoes from Australia and Vietnam, no difference was observed between wMel-infected mosquitoes from each background suggesting that Wolbachia may override any underlying variation in DENV transmission potential.


Assuntos
Aedes/microbiologia , Aedes/virologia , Vírus da Dengue/fisiologia , Mosquitos Vetores/microbiologia , Mosquitos Vetores/virologia , Wolbachia/fisiologia , Aedes/genética , Aedes/metabolismo , Animais , Feminino , Masculino , Mosquitos Vetores/genética , Mosquitos Vetores/metabolismo , Controle Biológico de Vetores , Replicação Viral
11.
Nat Biotechnol ; 38(4): 482-492, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32265562

RESUMO

The range of the mosquito Aedes aegypti continues to expand, putting more than two billion people at risk of arboviral infection. The sterile insect technique (SIT) has been used to successfully combat agricultural pests at large scale, but not mosquitoes, mainly because of challenges with consistent production and distribution of high-quality male mosquitoes. We describe automated processes to rear and release millions of competitive, sterile male Wolbachia-infected mosquitoes, and use of these males in a large-scale suppression trial in Fresno County, California. In 2018, we released 14.4 million males across three replicate neighborhoods encompassing 293 hectares. At peak mosquito season, the number of female mosquitoes was 95.5% lower (95% CI, 93.6-96.9) in release areas compared to non-release areas, with the most geographically isolated neighborhood reaching a 99% reduction. This work demonstrates the high efficacy of mosquito SIT in an area ninefold larger than in previous similar trials, supporting the potential of this approach in public health and nuisance-mosquito eradication programs.


Assuntos
Aedes/microbiologia , Aedes/fisiologia , Controle de Mosquitos/métodos , Mosquitos Vetores/microbiologia , Mosquitos Vetores/fisiologia , Wolbachia/fisiologia , Aedes/crescimento & desenvolvimento , Migração Animal , Animais , California , Feminino , Larva/crescimento & desenvolvimento , Larva/microbiologia , Larva/fisiologia , Masculino , Controle de Mosquitos/estatística & dados numéricos , Mosquitos Vetores/crescimento & desenvolvimento , Dinâmica Populacional , Caracteres Sexuais
12.
PLoS One ; 15(3): e0229727, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32191724

RESUMO

The Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae), holds an impressive record of successful invasions promoted by the growth and development of international fruit trade. Hence, survival of immatures within infested fruit that are subjected to various conditions during transportation seems to be a crucial feature that promotes invasion success. Wolbachia pipientis is a common endosymbiont of insects and other arthropods generating several biological effects on its hosts. Existing information report the influence of Wolbachia on the fitness traits of insect host species, including the Mediterranean fruit fly. However, little is known regarding effects of Wolbachia infection on immature development in different host fruits and temperatures. This study was conducted to determine the development and survival of immature stages of four different Mediterranean fruit fly populations, either infected or uninfected with Wolbachia, in two hosts (apples, bitter oranges) under three constant temperatures (15, 25 and 30°C), constant relative humidity (45-55 ± 5%), and a photoperiod of 14L:10D. Our findings demonstrate both differential response of two fruit fly lines to Wolbachia infection and differential effects of the two Wolbachia strains on the same Mediterranean fruit fly line. Larva-to-pupa and larva-to-adult survival followed similar patterns and varied a lot among the four medfly populations, the two host fruits and the different temperatures. Pupation rates and larval developmental time were higher for larvae implanted in apples compared to bitter oranges. The survival rates of wildish medflies were higher than those of the laboratory adapted ones, particularly in bitter oranges. The Wolbachia infected medflies, expressed lower survival rates and higher developmental times, especially the wCer4 infected line. High temperatures constrained immature development and were lethal for the Wolbachia infected wCer4 medfly line. Lower temperatures inferred longer developmental times to immature stages of all medfly populations tested, in both host fruits. Implications on the ecology and survival of the fly in nature are discussed.


Assuntos
Ceratitis capitata/crescimento & desenvolvimento , Ceratitis capitata/microbiologia , Frutas/parasitologia , Estágios do Ciclo de Vida , Temperatura , Wolbachia/fisiologia , Animais , Larva/crescimento & desenvolvimento , Modelos de Riscos Proporcionais , Pupa/crescimento & desenvolvimento , Análise de Sobrevida
13.
PLoS Negl Trop Dis ; 14(1): e0007958, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31971938

RESUMO

Aedes aegypti mosquitoes infected with the wMel strain of Wolbachia are being released into natural mosquito populations in the tropics as a way of reducing dengue transmission. High temperatures adversely affect wMel, reducing Wolbachia density and cytoplasmic incompatibility in some larval habitats that experience large temperature fluctuations. We monitored the impact of a 43.6°C heatwave on the wMel infection in a natural population in Cairns, Australia, where wMel was first released in 2011 and has persisted at a high frequency. Wolbachia infection frequencies in the month following the heatwave were reduced to 83% in larvae sampled directly from field habitats and 88% in eggs collected from ovitraps, but recovered to be near 100% four months later. Effects of the heatwave on wMel appeared to be stage-specific and delayed, with reduced frequencies and densities in field-collected larvae and adults reared from ovitraps but higher frequencies in field-collected adults. Laboratory experiments showed that the effects of heatwaves on cytoplasmic incompatibility and density are life stage-specific, with first instar larvae being the most vulnerable to temperature effects. Our results indicate that heatwaves in wMel-infected populations will have only temporary effects on Wolbachia frequencies and density once the infection has established in the population. Our results are relevant to ongoing releases of wMel-infected Ae. aegypti in several tropical countries.


Assuntos
Aedes/microbiologia , Temperatura Alta , Wolbachia/fisiologia , Animais , Austrália , Feminino , Interações Hospedeiro-Patógeno , Wolbachia/classificação
14.
Appl Environ Microbiol ; 86(6)2020 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-31900308

RESUMO

The horn fly, Haematobia irritans irritans, is a hematophagous parasite of livestock distributed throughout Europe, Africa, Asia, and the Americas. Welfare losses on livestock due to horn fly infestation are estimated to cost between $1 billion and $2.5 billion (U.S. dollars) annually in North America and Brazil. The endosymbiotic bacterium Wolbachia pipientis is a maternally inherited manipulator of reproductive biology in arthropods and naturally infects laboratory colonies of horn flies from Kerrville, TX, and Alberta, Canada, but it has also been identified in wild-caught samples from Canada, the United States, Mexico, and Hungary. Reassembly of PacBio long-read and Illumina genomic DNA libraries from the Kerrville H. i. irritans genome project allowed for a complete and circularized 1.3-Mb Wolbachia genome (wIrr). Annotation of wIrr yielded 1,249 coding genes, 34 tRNAs, 3 rRNAs, and 5 prophage regions. Comparative genomics and whole-genome Bayesian evolutionary analysis of wIrr compared to published Wolbachia genomes suggested that wIrr is most closely related to and diverged from Wolbachia supergroup A strains known to infect Drosophila spp. Whole-genome synteny analyses between wIrr and closely related genomes indicated that wIrr has undergone significant genome rearrangements while maintaining high nucleotide identity. Comparative analysis of the cytoplasmic incompatibility (CI) genes of wIrr suggested two phylogenetically distinct CI loci and acquisition of another cifB homolog from phylogenetically distant supergroup A Wolbachia strains, suggesting horizontal acquisition of these loci. The wIrr genome provides a resource for future examination of the impact Wolbachia may have in both biocontrol and potential insecticide resistance of horn flies.IMPORTANCE Horn flies, Haematobia irritans irritans, are obligate hematophagous parasites of cattle having significant effects on production and animal welfare. Control of horn flies mainly relies on the use of insecticides, but issues with resistance have increased interest in development of alternative means of control. Wolbachia pipientis is an endosymbiont bacterium known to have a range of effects on host reproduction, such as induction of cytoplasmic incompatibility, feminization, male killing, and also impacts vector transmission. These characteristics of Wolbachia have been exploited in biological control approaches for a range of insect pests. Here we report the assembly and annotation of the circular genome of the Wolbachia strain of the Kerrville, TX, horn fly (wIrr). Annotation of wIrr suggests its unique features, including the horizontal acquisition of additional transcriptionally active cytoplasmic incompatibility loci. This study provides the foundation for future studies of Wolbachia-induced biological effects for control of horn flies.


Assuntos
Genes Bacterianos , Muscidae/microbiologia , Simbiose , Wolbachia/fisiologia , Animais , Transferência Genética Horizontal , Simbiose/genética , Wolbachia/genética
15.
Sci Rep ; 10(1): 63, 2020 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-31919396

RESUMO

Mosquitoes that carry Wolbachia endosymbionts may help control the spread of arboviral diseases, such as dengue, Zika and chikungunya. Wolbachia frequencies systematically increase only when the frequency-dependent advantage due to cytoplasmic incompatibility exceeds frequency-independent costs, which may be intrinsic to the Wolbachia and/or can be associated with the genetic background into which Wolbachia are introduced. Costs depend on field conditions such as the environmental pesticide load. Introduced mosquitoes need adequate protection against insecticides to ensure survival after release. We model how insecticide resistance of transinfected mosquitoes determines the success of local Wolbachia introductions and link our theoretical results to field data. Two Ae. aegypti laboratory strains carrying Wolbachia were released in an isolated district of Rio de Janeiro, Brazil: wMelBr (susceptible to pyrethroids) and wMelRio (resistant to pyrethroids). Our models elucidate why releases of the susceptible strain failed to result in Wolbachia establishment, while releases of the resistant strain led to Wolbachia transforming the native Ae. aegypti population. The results highlight the importance of matching insecticide resistance levels in release stocks to those in the target natural populations during Wolbachia deployment.


Assuntos
Aedes/microbiologia , Resistência a Inseticidas , Wolbachia/fisiologia , Animais , Resistência a Inseticidas/efeitos dos fármacos , Inseticidas/toxicidade , Modelos Biológicos , Dinâmica Populacional , Piretrinas/toxicidade , Simbiose , Wolbachia/efeitos dos fármacos , Wolbachia/isolamento & purificação
16.
Curr Opin Insect Sci ; 37: 8-15, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31726321

RESUMO

Wolbachia pipientis, one of the most dominant insect-symbiotic bacteria, highjacks the female germline of insects for its own propagation across host generations. Such strict dependence on female gametes in trans-generational propagation has driven Wolbachia to devise ingenious strategies to enhance female fertility. In Drosophila melanogaster females with female-sterile mutant alleles of the master sex-determining gene Sex-lethal (Sxl), Wolbachia colonizing female germline stem cells (GSCs) support the maintenance of GSCs, thereby rescuing the defective ovarian development. In the germ cell cytoplasm, Wolbachia are often found in proximity to ribonucleoprotein-complex processing bodies (P bodies), where the Wolbachia-derived protein TomO interacts with RNAs encoding Nanos and Orb proteins, which support the GSC maintenance and oocyte polarization, respectively. Thus, manipulation of host RNA is the key to successful vertical transmission of Wolbachia.


Assuntos
Drosophila melanogaster/microbiologia , Células-Tronco de Oogônios/microbiologia , Wolbachia/fisiologia , Animais , Proteínas de Bactérias/metabolismo , Proteínas de Drosophila/metabolismo , Drosophila melanogaster/genética , Feminino , Células-Tronco de Oogônios/metabolismo , RNA/metabolismo , Simbiose
17.
Microb Ecol ; 79(4): 1011-1020, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31820073

RESUMO

Wolbachia are inherited intracellular bacteria that cause male-specific death in some arthropods, called male-killing. To date, three Wolbachia strains have been identified in the oriental tea tortrix Homona magnanima (Tortricidae, Lepidoptera); however, none of these caused male-killing in the Japanese population. Here, we describe a male-killing Wolbachia strain in Taiwanese H. magnanima. From field-collected H. magnanima, two female-biased host lines were established, and antibiotic treatments revealed Wolbachia (wHm-t) as the causative agent of male-killing. The wsp and MLST genes in wHm-t are identical to corresponding genes in the nonmale-killing strain wHm-c from the Japanese population, implying a close relationship of the two strains. Crossing the Japanese and Taiwanese H. magnanima revealed that Wolbachia genotype rather than the host genetic background was responsible for the presence of the male-killing phenotype. Quantitative PCR analyses revealed that the density of wHm-t was higher than that of other Wolbachia strains in H. magnanima, including wHm-c. The densities of wHm-t were also heterogeneous between host lines. Notably, wHm-t in the low-density and high-density lines carried identical wsp and MLST genes but had distinct lethal patterns. Furthermore, over 90% of field-collected lines of H. magnanima in Taiwan were infected with wHm-t, although not all host lines harboring wHm-t showed male-killing. The host lines that showed male-killing harbored a high density of Wolbachia compared to the host lines that did not show male-killing. Thus, the differences in the phenotypes appear to be dependent on biological and genetic characteristics of closely related Wolbachia strains.


Assuntos
Mariposas/microbiologia , Wolbachia/fisiologia , Animais , Proteínas de Insetos/análise , Larva/genética , Larva/crescimento & desenvolvimento , Larva/microbiologia , Mariposas/genética , Mariposas/crescimento & desenvolvimento , Fenótipo , Fatores Sexuais , Razão de Masculinidade , Simbiose , Taiwan , Wolbachia/genética
18.
Insect Mol Biol ; 29(2): 193-204, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31596027

RESUMO

The endosymbiont Wolbachia is known for manipulating host reproduction in selfish ways. However, the molecular mechanisms have not yet been investigated in embryos. Here, we found that Wolbachia had no effect on the number of deposited eggs in Tetranychus urticae Koch (Acari: Tetranychidae) but caused two types of reproductive manipulation: killing uninfected female embryos via cytoplasmic incompatibility (CI) and increasing the hatching ratio of infected female embryos. RNA sequencing analyses showed that 145 genes were differentially expressed between Wolbachia-infected (WI) and Wolbachia-uninfected (WU) embryos. Wolbachia infection down-regulated messenger RNA (mRNA) expression of glutathione S-transferase that could buffer oxidative stress. In addition, 1613 and 294 genes were identified as CI-specific up-/down-regulated genes. Compared to WU and WI embryos, embryos of CI cross strongly expressed genes involved in transcription, translation, tissue morphogenesis, DNA damage and mRNA surveillance. In contrast, most of the genes associated with energy production and metabolism were down-regulated in the CI embryos compared to the WU and WI embryos, which provides some clues as to the cause of death of CI embryos. These results identify several genes that could be candidates for explaining Wolbachia-induced CI. Our data form a basis to help elucidate the molecular consequences of CI in embryos.


Assuntos
Tetranychidae/fisiologia , Transcriptoma , Wolbachia/fisiologia , Animais , Citoplasma , Embrião não Mamífero/microbiologia , Embrião não Mamífero/fisiologia , Feminino , Masculino , Reprodução , Tetranychidae/embriologia , Tetranychidae/crescimento & desenvolvimento , Tetranychidae/microbiologia
19.
J Bacteriol ; 202(4)2020 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-31659008

RESUMO

The most common intracellular symbiont on the planet-Wolbachia pipientis-is infamous largely for the reproductive manipulations induced in its host. However, more recent evidence suggests that this bacterium may also serve as a nutritional mutualist in certain host backgrounds and for certain metabolites. We performed a large-scale analysis of conserved gene content across all sequenced Wolbachia genomes to infer potential nutrients made by these symbionts. We review and critically evaluate the prior research supporting a beneficial role for Wolbachia and suggest future experiments to test hypotheses of metabolic provisioning.


Assuntos
Simbiose/fisiologia , Wolbachia/fisiologia , Trifosfato de Adenosina/metabolismo , Transporte Biológico , Genoma Bacteriano , Heme/metabolismo , Fenômenos Fisiológicos da Nutrição , Wolbachia/genética
20.
Insect Mol Biol ; 29(1): 19-37, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31265751

RESUMO

Wolbachia and Spiroplasma are both maternally inherited endosymbionts in arthropods, and they can co-infect the same species. However, how they interact with each other in the same host is not clear. Here we investigate a co-infected Tetranychus truncatus spider mite strain that shares the same genetic background with singly infected and uninfected strains to detect the impacts of the two symbionts on their host. We found that Wolbachia-infected and Spiroplasma-infected mites can suffer significant fitness costs involving decreased fecundity, although with no effect on lifespan or development. Wolbachia induced incomplete cytoplasmic incompatibility in T. truncatus both in singly infected and doubly infected strains, resulting in female killing. In both females and males of the co-infected spider mite strain, Wolbachia density was higher than Spiroplasma density. Transcriptome analysis of female adults showed that the most differentially expressed genes were found between the co-infected strain and both the singly infected Spiroplasma strain and uninfected strain. The Wolbachia strain had the fewest differentially expressed genes compared with the co-infected strain, consistent with the higher density of Wolbachia in the co-infected strain. Wolbachia, therefore, appears to have a competitive advantage in host mites over Spiroplasma and is likely maintained in populations by cytoplasmic incompatibility despite having deleterious fitness effects.


Assuntos
Spiroplasma/fisiologia , Tetranychidae/microbiologia , Wolbachia/fisiologia , Animais , Coinfecção/microbiologia , Feminino , Fertilidade , Perfilação da Expressão Gênica , Masculino , Simbiose , Tetranychidae/genética , Tetranychidae/metabolismo
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