Presence of Extensive <i>Wolbachia</i> Symbiont Insertions Discovered in the Genome of Its Host <i>Glossina morsitans morsitans</i>

Tsetse flies (Glossina spp.) are the cyclical vectors of Trypanosoma spp., which are unicellular parasites responsible for multiple diseases, including nagana in livestock and sleeping sickness in humans in Africa. Glossina species, including Glossina morsitans morsitans (Gmm), for which the Whole Genome Sequence (WGS) is now available, have established symbiotic associations with three endosymbionts: Wigglesworthia glossinidia, Sodalis glossinidius and Wolbachia pipientis (Wolbachia). The presence of Wolbachia in both natural and laboratory populations of Glossina species, including the presence of horizontal gene transfer (HGT) events in a laboratory colony of Gmm, has already been shown. We herein report on the draft genome sequence of the cytoplasmic Wolbachia endosymbiont (cytWol) associated with Gmm. By in silico and molecular and cytogenetic analysis, we discovered and validated the presence of multiple insertions of Wolbachia (chrWol) in the host Gmm genome. We identified at least two large insertions of chrWol, 527,507 and 484,123 bp in size, from Gmm WGS data. Southern hybridizations confirmed the presence of Wolbachia insertions in Gmm genome, and FISH revealed multiple insertions located on the two sex chromosomes (X and Y), as well as on the supernumerary B-chromosomes. We compare the chrWol insertions to the cytWol draft genome in an attempt to clarify the evolutionary history of the HGT events. We discuss our findings in light of the evolution of Wolbachia infections in the tsetse fly and their potential impacts on the control of tsetse populations and trypanosomiasis

Wolbachia pipientis associated with tephritid fruit fly pests: from basic research to applications

Members of the true fruit flies (family Tephritidae) are among the most serious agricultural pests worldwide, whose control and management demands large and costly international efforts. The need for cost-effective and environmentally friendly integrated pest management (IPM) has led to the development and implementation of autocidal control strategies. These approaches include the widely used sterile insect technique and the incompatible insect technique (IIT). IIT relies on maternally transmitted bacteria (namely Wolbachia) to cause a conditional sterility in crosses between released mass-reared Wolbachia-infected males and wild females, which are either uninfected or infected with a different Wolbachia strain (i.e., cytoplasmic incompatibility; CI). Herein, we review the current state of knowledge on Wolbachia-tephritid interactions including infection prevalence in wild populations, phenotypic consequences, and their impact on life history traits. Numerous pest tephritid species are reported to harbor Wolbachia infections, with a subset exhibiting high prevalence. The phenotypic effects of Wolbachia have been assessed in very few tephritid species, due in part to the difficulty of manipulating Wolbachia infection (removal or transinfection). Based on recent methodological advances (high-throughput DNA sequencing) and breakthroughs concerning the mechanistic basis of CI, we suggest research avenues that could accelerate generation of necessary knowledge for the potential use of Wolbachia-based IIT in area-wide integrated pest management (AW-IPM) strategies for the population control of tephritid pests.Instituto de GenéticaFil: Mateos, Mariana. Texas A&M University. Departments of Ecology and Conservation Biology, and Wildlife and Fisheries Sciences; Estados UnidosFil: Martinez Montoya, Humberto. Universidad Autónoma de Tamaulipas. Unidad Académica Multidisciplinaria Reynosa Aztlan. Laboratorio de Genética y Genómica Comparativa; MéxicoFil: Lanzavecchia, Silvia Beatriz. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; ArgentinaFil: Conte, Claudia Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; ArgentinaFil: Guillén, Karina. El Colegio de la Frontera Sur; MéxicoFil: Morán-Aceves, Brenda M. El Colegio de la Frontera Sur; MéxicoFil: Toledo, Jorge. El Colegio de la Frontera Sur; MéxicoFil: Liedo, Pablo. El Colegio de la Frontera Sur; MéxicoFil: Asimakis, Elias D. University of Patras. Department of Environmental Engineering; GreciaFil: Doudoumis, Vangelis. University of Patras. Department of Environmental Engineering; GreciaFil: Kyritsis, Georgios A. University of Thessaly. Department of Agriculture Crop Production and Rural Environment. Laboratory of Entomology and Agricultural Zoology; GreciaFil: Papadopoulos, Nikos T. University of Thessaly. Department of Agriculture Crop Production and Rural Environment. Laboratory of Entomology and Agricultural Zoology; GreciaFil: Augustinos, Antonios A. Hellenic Agricultural Organization. Institute of Industrial and Forage Crops. Department of Plant Protection; GreciaFil: Segura, Diego Fernando. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Agrobiotecnología y Biología Molecular; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética. Laboratorio de Genética de Insectos de Importancia Económica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tsiamis, George. University of Patras. Department of Environmental Engineering; Greci

Detection and Characterization of Wolbachia Infections in Natural Populations of Aphids: Is the Hidden Diversity Fully Unraveled?

Aphids are a serious threat to agriculture, despite being a rather small group of insects. The about 4,000 species worldwide engage in highly interesting and complex relationships with their microbial fauna. One of the key symbionts in arthropods is Wolbachia, an α-Proteobacterium implicated in many important biological processes and believed to be a potential tool for biological control. Aphids were thought not to harbour Wolbachia; however, current data suggest that its presence in aphids has been missed, probably due to the low titre of the infection and/or to the high divergence of the Wolbachia strains of aphids. The goal of the present study is to map the Wolbachia infection status of natural aphids populations, along with the characterization of the detected Wolbachia strains. Out of 425 samples from Spain, Portugal, Greece, Israel and Iran, 37 were found to be infected. Our results, based mainly on 16S rRNA gene sequencing, indicate the presence of two new Wolbachia supergroups prevailing in aphids, along with some strains belonging either to supergroup B or to supergroup A

<i>Wolbachia</i> Infections and Mitochondrial Diversity of Two Chestnut Feeding <i>Cydia</i> Species

<div><p><i>Cydia splendana</i> and <i>C. fagiglandana</i> are two closely related chestnut feeding lepidopteran moth species. In this study, we surveyed the bacterial endosymbiont <i>Wolbachia</i> in these two species. Infection rates were 31% in <i>C. splendana</i> and 77% in <i>C. fagiglandana</i>. MLST analysis showed that these two species are infected with two quite diverse <i>Wolbachia</i> strains. <i>C. splendana</i> with Sequence Type (ST) 409 from the A-supergroup and <i>C. fagiglandana</i> with ST 150 from the B-supergroup. One individual of <i>C. splendana</i> was infected with ST 150, indicating horizontal transfer between these sister species. The mitochondrial DNA of the two <i>Cydia</i> species showed a significantly different mtDNA diversity, which was inversely proportional to their infection rates.</p></div

<i>Wolbachia</i> infection status in Greek <i>C. splendana</i> and <i>C. fagiglandana</i> populations. (n.d.: not detected).

<p><i>Wolbachia</i> infection status in Greek <i>C. splendana</i> and <i>C. fagiglandana</i> populations. (n.d.: not detected).</p

MLST and wsp allele profiles of <i>Wolbachia</i> strains in Greek <i>Cydia</i> populations.

<p>Identical nucleotide sequences at a given locus for different strain were assigned the same arbitrary allele number. Each strain was then identified by the combination of the five MLST allelic numbers, representing its allelic profile. Each unique allelic profile was assigned an ST (Sequence Type), which ultimately characterizes a strain <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0112795#pone.0112795-Seger1" target="_blank">[53]</a>. Wsp profiles are shown in the last left column, respectively. (HVR: Hyper Variable Region).</p><p>MLST and wsp allele profiles of <i>Wolbachia</i> strains in Greek <i>Cydia</i> populations.</p

Distribution map of the sampled Greek populations (taken from NASA Earth Observatory–public domain).

<p>Underlined acronyms indicate those populations that participated in the MLST analysis.</p

Neighbor-Joining Tree of <i>Cydia splendana</i> (Splenda 1–49) and <i>C. fagiglandana</i> (Fagi 1–17) haplotypes.

<p>Calculations were based on 792 bp of mtDNA COI. Bootstrap support values above 80% are presented above nodes, and the horizontal bar represents 0.005 Tamura-Nei distance. Shaded haplotypes indicate those that contained at least one <i>Wolbachia</i> infected individual. Arrows identify the haplotypes that were MLST genotyped.</p

Maximum Likelihood inference phylogeny based on the concatenated MLST data (2,079 bp or 2073 bp).

<p>The two <i>Wolbachia</i> strains present in <i>Cydia</i> are indicated in bold letters; the other strains represent supergroups A, B, D, F and H. Strains are characterized by the names of their host species, the ID code and the ST number from the MLST database (excluding the strain of <i>Pammene fasciana</i>, unpublished data). <i>Wolbachia</i> supergroups are shown to the right of the host species names. ML bootstrap values based on 1000 replicates are given (only values>50% are indicated). *This <i>Wolbachia</i> stain was detected in all C. <i>fagiglandana</i> and in the <i>C. splendana</i> (8E. 1BK) specimens.</p