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Paul Baumann - One of the best experts on this subject based on the ideXlab platform.
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biology of bacteriocyte associated Endosymbionts of plant sap sucking insects
Annual Review of Microbiology, 2005Co-Authors: Paul BaumannAbstract:AbstractPsyllids, whiteflies, aphids, and mealybugs are members of the suborder Sternorrhyncha and share a common property, namely the utilization of plant sap as their food source. Each of these insect groups has an obligatory association with a different prokaryotic endosymbiont, and the association is the result of a single infection followed by maternal, vertical transmission of the Endosymbionts. The result of this association is the domestication of the free-living bacterium to serve the purposes of the host, namely the synthesis of essential amino acids. This domestication is probably in all cases accompanied by a major reduction in genome size. The different properties of the genomes and fragments of the genomes of these Endosymbionts suggest that there are different constraints on the permissible evolutionary changes that are probably a function of the gene repertoire of the endosymbiont ancestor and the gene losses that occurred during the reduction of genome size. Pel piacer di porle in lista. ...
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Cospeciation between the primary Endosymbionts of mealybugs and their hosts.
Current microbiology, 2005Co-Authors: Linda Baumann, Paul BaumannAbstract:Mealybugs have an association with prokaryotic Endosymbionts that are located in specialized cells called bacteriocytes. In order to compare the phylogeny of the host with that of the previously published phylogeny of the Endosymbionts, 3.1 to 3.2 kilobase DNA fragments containing mitochondrial cytB (part), nd1,16S ribosomal DNA(rDNA), and 12S rDNA (part) were amplified and sequenced. A phylogenetic analysis of the data and a comparison with the trees obtained from endosymbiont genes and host 18S and 28S rDNA indicated that all the trees were similar. This result is consistent with an infection of a mealybug ancestor with a precursor of the endosymbiont followed by the vertical transmission of the endosymbiont to progeny. Comparison of the guanine + cytosine (G + C) contents of the mealybug mitochondrial genes with the same genes from other members of Sternorrhyncha and Arthropoda indicated that the mealybug genes had unusually low G + C contents in their DNAs (10.2 to 11.1 mol%).
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Endosymbionts of Plant
2005Co-Authors: Sap-sucking Insects, Paul BaumannAbstract:Psyllids, whiteflies, aphids, and mealybugs are members of the suborder Sternorrhyncha and share a common property, namely the utilization of plant sap as their food source. Each of these insect groups has an obligatory association with a different prokaryotic endosymbiont, and the association is the result of a single infection followed by maternal, vertical transmission of the Endosymbionts. The result of this association is the domestication of the free-living bacterium to serve the purposes of the host, namely the synthesis of essential amino acids. This domestication is probably in all cases accompanied by a major reduction in genome size. The different properties of the genomes and fragments of the genomes of these Endosymbionts suggest that there are different constraints on the permissible evolutionary changes that are probably a function of the gene repertoire of the endosymbiont ancestor and the gene losses that occurred during the reduction of genome size.
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Evolutionary relationships of primary prokaryotic Endosymbionts of whiteflies and their hosts.
Applied and environmental microbiology, 2004Co-Authors: Mylo Ly Thao, Paul BaumannAbstract:Whiteflies (Hemiptera: Sternorrhyncha: Aleyrodidae) are plant sap-sucking insects that harbor prokaryotic primary Endosymbionts (P-Endosymbionts) within specialized cells located in their body cavity. Four-kilobase DNA fragments containing 16S-23S ribosomal DNA (rDNA) were amplified from the P-endosymbiont of 24 whiteflies from 22 different species of 2 whitefly subfamilies. In addition, 3-kb DNA fragments containing mitochondrial cytB, nd1, and large-subunit rDNA (LrDNA) were amplified from 17 whitefly species. Comparisons of the P-endosymbiont (16S-23S rDNA) and host (cytB-nd1-LrDNA) phylogenetic trees indicated overall congruence consistent with a single infection of a whitefly ancestor with a bacterium and subsequent cospeciation (cocladogenesis) of the host and the P-endosymbiont. On the basis of both the P-endosymbiont and host trees, the whiteflies could be subdivided into at least five clusters. The major subdivision was between the subfamilies Aleyrodinae and Aleurodicinae. Unlike the P-Endosymbionts of may other insects, the P-Endosymbionts of whiteflies were related to Pseudomonas and possibly to the P-Endosymbionts of psyllids. The lineage consisting of the P-Endosymbionts of whiteflies is given the designation “Candidatus Portiera” gen. nov., with a single species, “Candidatus Portiera aleyrodidarum” sp. nov.
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evidence for multiple acquisition of arsenophonus by whitefly species sternorrhyncha aleyrodidae
Current Microbiology, 2004Co-Authors: Mylo Ly Thao, Paul BaumannAbstract:Whiteflies contain primary prokaryotic Endosymbionts located within specialized host cells. This endosymbiotic association is the result of a single infection of the host followed by vertical transmission of the endosymbiont to the progeny. Whiteflies may also be associated with other bacteria called secondary (S-) Endosymbionts. The nucleotide sequence of the 16S–23S ribosomal DNA from S-Endosymbionts of 13 whitefly species was determined. A phylogenetic analysis of these sequences indicated their grouping into two major clusters, one consisting of two S-Endosymbionts related to previously described T-type Endosymbionts. The second cluster contained the 16S–23S rDNA sequence of the type strain of Arsenophonus nasoniae as well as sequences of S-Endosymbionts from 11 whitefly species. This Arsenophonus cluster contained four S-Endosymbionts with intervening sequences of 70–184 nucleotides in their 23S rDNAs. The phylogenetic tree of the Arsenophonus cluster differed greatly from the phylogenetic tree of the primary Endosymbionts. These results suggest that, unlike the primary endosymbiont, Arsenophonus may infect whiteflies multiple times and may also be horizontally transmitted.
Murad Ghanim - One of the best experts on this subject based on the ideXlab platform.
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global genetic diversity and geographical distribution of bemisia tabaci and its bacterial Endosymbionts
PLOS ONE, 2019Co-Authors: Surapathrudu Kanakala, Murad GhanimAbstract:Bemisia tabaci is one of the most threatening pests in agriculture, causing significant losses to many important crops on a global scale. The dramatic increase and availability of sequence data for B. tabaci species complex and its bacterial Endosymbionts is critical for developing emerging sustainable pest management strategies which are based on pinpointing the global diversity of this important pest and its bacterial Endosymbionts. To unravel the global genetic diversity of B. tabaci species complex focusing on its associated Endosymbionts, along with Israeli whitefly populations collected in this study, we combined available sequences in databases, resulting in a total of 4,253 mitochondrial cytochrome oxidase I (mtCOI) sequences from 82 countries and 1,226 16S/23S rRNA endosymbiont sequences from 32 countries that were analyzed. Using Bayesian phylogenetic analysis, we identified two new B. tabaci groups within the species complex and described the global distribution of Endosymbionts within this complex. Our analyses revealed complex divergence of the different endosymbiont sequences within the species complex, with overall one Hamiltonella, two Porteria (P1 and P2), two Arsenophonus (A1 and A2), two Wolbachia (super-groups O and B), four Cardinium (C1-C4) and three Rickettsia (R1-R3) groups were identified. Our comprehensive analysis provides an updated important resource for this globally important pest and its secondary symbionts, which have been a major subject for research in last three decades.
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diversity and localization of bacterial Endosymbionts from whitefly species collected in brazil
PLOS ONE, 2014Co-Authors: Julio Massaharu Marubayashi, Adi Kliot, Valdir Atsushi Yuki, Jorge Alberto Marques Rezende, Renate Krausesakate, Marcelo Agenor Pavan, Murad GhanimAbstract:Whiteflies (Hemiptera: Aleyrodidae) are sap-sucking insect pests, and some cause serious damage in agricultural crops by direct feeding and by transmitting plant viruses. Whiteflies maintain close associations with bacterial Endosymbionts that can significantly influence their biology. All whitefly species harbor a primary endosymbiont, and a diverse array of secondary Endosymbionts. In this study, we surveyed 34 whitefly populations collected from the states of Sao Paulo, Bahia, Minas Gerais and Parana in Brazil, for species identification and for infection with secondary Endosymbionts. Sequencing the mitochondrial Cytochrome Oxidase I gene revealed the existence of five whitefly species: The sweetpotato whitefly Bemisia tabaci B biotype (recently termed Middle East-Asia Minor 1 or MEAM1), the greenhouse whitefly Trialeurodes vaporariorum, B. tabaci A biotype (recently termed New World 2 or NW2) collected only from Euphorbia, the Acacia whitefly Tetraleurodes acaciae and Bemisia tuberculata both were detected only on cassava. Sequencing rRNA genes showed that Hamiltonella and Rickettsia were highly prevalent in all MEAM1 populations, while Cardinium was close to fixation in only three populations. Surprisingly, some MEAM1 individuals and one NW2 population were infected with Fritschea. Arsenopnohus was the only endosymbiont detected in T. vaporariorum. In T. acaciae and B. tuberculata populations collected from cassava, Wolbachia was fixed in B. tuberculata and was highly prevalent in T. acaciae. Interestingly, while B. tuberculata was additionally infected with Arsenophonus, T. acaciae was infected with Cardinium and Fritschea. Fluorescence in situ hybridization analysis on representative individuals showed that Hamiltonella, Arsenopnohus and Fritschea were localized inside the bacteriome, Cardinium and Wolbachia exhibited dual localization patterns inside and outside the bacteriome, and Rickettsia showed strict localization outside the bacteriome. This study is the first survey of whitely populations collected in Brazil, and provides further insights into the complexity of infection with secondary endosymionts in whiteflies.
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endosymbiont metacommunities mtdna diversity and the evolution of the bemisia tabaci hemiptera aleyrodidae species complex
Molecular Ecology, 2010Co-Authors: Gwenaelle Gueguen, Murad Ghanim, Fabrice Vavre, Olivier Gnankine, Michel Peterschmitt, Delphine Charif, Elad Chiel, Yuval Gottlieb, Einat ZchorifeinAbstract:Bemisia tabaci, an invasive pest that causes crop damage worldwide, is a highly differentiated species complex, divided into biotypes that have mainly been defined based on mitochondrial DNA sequences. Although Endosymbionts can potentially induce population differentiation, specialization and indirect selection on mtDNA, studies have largely ignored these influential passengers in B. tabaci, despite as many as seven bacterial Endosymbionts have been identified. Here, we investigate the composition of the whole bacterial community in worldwide populations of B. tabaci, together with host genetic differentiation, focusing on the invasive B and Q biotypes. Among 653 individuals studied, more than 95% of them harbour at least one secondary endosymbiont, and multiple infections are very common. In addition, sequence analyses reveal a very high diversity of facultative Endosymbionts in B. tabaci, with some bacterial genus being represented by more than one strain. In the B and Q biotypes, nine different strains of bacteria have been identified. The mtDNA-based phylogeny of B. tabaci also reveals a very high nucleotide diversity that partitions the two ITS clades (B and Q) into six CO1 genetic groups. Each genetic group is in linkage disequilibrium with a specific combination of Endosymbionts. All together, our results demonstrate the rapid dynamics of the bacterial endosymbiont–host associations at a small evolutionary scale, questioning the role of endosymbiotic communities in the evolution of the Bemisia tabaci species complex and strengthening the need to develop a metacommunity theory of inherited Endosymbionts.
Hisayoshi Nozaki - One of the best experts on this subject based on the ideXlab platform.
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two different rickettsial bacteria invading volvox carteri
PLOS ONE, 2015Co-Authors: Kaoru Kawafune, Yuichi Hongoh, Takashi Hamaji, Tomoaki Sakamoto, Tetsuya Kurata, Shunsuke Hirooka, Shinya Miyagishima, Hisayoshi NozakiAbstract:Background Bacteria of the family Rickettsiaceae are principally associated with arthropods. Recently, Endosymbionts of the Rickettsiaceae have been found in non-phagotrophic cells of the volvocalean green algae Carteria cerasiformis, Pleodorina japonica, and Volvox carteri. Such Endosymbionts were present in only C. cerasiformis strain NIES-425 and V. carteri strain UTEX 2180, of various strains of Carteria and V. carteri examined, suggesting that rickettsial Endosymbionts may have been transmitted to only a few algal strains very recently. However, in preliminary work, we detected a sequence similar to that of a rickettsial gene in the nuclear genome of V. carteri strain EVE. Methodology/Principal Findings Here we explored the origin of the rickettsial gene-like sequences in the endosymbiont-lacking V. carteri strain EVE, by performing comparative analyses on 13 strains of V. carteri. By reference to our ongoing genomic sequence of rickettsial Endosymbionts in C. cerasiformis strain NIES-425 cells, we confirmed that an approximately 9-kbp DNA sequence encompassing a region similar to that of four rickettsial genes was present in the nuclear genome of V. carteri strain EVE. Phylogenetic analyses, and comparisons of the synteny of rickettsial gene-like sequences from various strains of V. carteri, indicated that the rickettsial gene-like sequences in the nuclear genome of V. carteri strain EVE were closely related to rickettsial gene sequences of P. japonica, rather than those of V. carteri strain UTEX 2180. Conclusion/Significance At least two different rickettsial organisms may have invaded the V. carteri lineage, one of which may be the direct ancestor of the endosymbiont of V. carteri strain UTEX 2180, whereas the other may be closely related to the endosymbiont of P. japonica. Endosymbiotic gene transfer from the latter rickettsial organism may have occurred in an ancestor of V. carteri. Thus, the rickettsiae may be widely associated with V. carteri, and likely have often been lost during host evolution.
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a rickettsial endosymbiont inhabiting the cytoplasm of volvox carteri volvocales chlorophyceae
Phycologia, 2014Co-Authors: Kaoru Kawafune, Yuichi Hongoh, Hisayoshi NozakiAbstract:A bacterial endosymbiont was previously observed in the green alga Volvox carteri strain UTEX 2180 using transmission electron microscopy, although its phylogenetic status was unknown. Here, we identified the bacterial endosymbiont based on analyses of the 16S ribosomal RNA (rRNA) gene. The endosymbiont of V. carteri belongs to the “hydra group” characterized by non-arthropod hosts, within the eubacterial family Rickettsiaceae (Rickettsiales; Alphaproteobacteria). In the hydra group, the endosymbiont formed a clade with the Endosymbionts of the volvocaleans Carteria cerasiformis and Pleodorina japonica and the ciliate Diophrys appendiculata but was separated from the Endosymbionts of marine green macroalgae (Bryopsis spp.). Fluorescence in situ hybridization using a probe specific for the 16S rRNA of the V. carteri endosymbiont confirmed our molecular identification and the distribution of the endosymbiont within the host cytoplasm. Rickettsial Endosymbionts were not detected in eight other strains of V. ...
Yuichi Hongoh - One of the best experts on this subject based on the ideXlab platform.
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acetogenesis from h2 plus co2 and nitrogen fixation by an endosymbiotic spirochete of a termite gut cellulolytic protist
Proceedings of the National Academy of Sciences of the United States of America, 2015Co-Authors: Moriya Ohkuma, Satoko Noda, Satoshi Hattori, Toshiya Iida, Masahiro Yuki, David Starns, Junichi Inoue, Alistair C Darby, Yuichi HongohAbstract:Abstract Symbiotic associations of cellulolytic eukaryotic protists and diverse bacteria are common in the gut microbial communities of termites. Besides cellulose degradation by the gut protists, reductive acetogenesis from H2 plus CO2 and nitrogen fixation by gut bacteria play crucial roles in the host termites’ nutrition by contributing to the energy demand of termites and supplying nitrogen poor in their diet, respectively. Fractionation of these activities and the identification of key genes from the gut community of the wood-feeding termite Hodotermopsis sjoestedti revealed that substantial activities in the gut—nearly 60% of reductive acetogenesis and almost exclusively for nitrogen fixation—were uniquely attributed to the endosymbiotic bacteria of the cellulolytic protist in the genus Eucomonympha. The rod-shaped Endosymbionts were surprisingly identified as a spirochete species in the genus Treponema, which usually exhibits a characteristic spiral morphology. The Endosymbionts likely use H2 produced by the protist for these dual functions. Although H2 is known to inhibit nitrogen fixation in some bacteria, it seemed to rather stimulate this important mutualistic process. In addition, the single-cell genome analyses revealed the endosymbiont's potentials of the utilization of sugars for its energy requirement, and of the biosynthesis of valuable nutrients such as amino acids from the fixed nitrogen. These metabolic interactions are suitable for the dual functions of the endosymbiont and reconcile its substantial contributions in the gut.
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two different rickettsial bacteria invading volvox carteri
PLOS ONE, 2015Co-Authors: Kaoru Kawafune, Yuichi Hongoh, Takashi Hamaji, Tomoaki Sakamoto, Tetsuya Kurata, Shunsuke Hirooka, Shinya Miyagishima, Hisayoshi NozakiAbstract:Background Bacteria of the family Rickettsiaceae are principally associated with arthropods. Recently, Endosymbionts of the Rickettsiaceae have been found in non-phagotrophic cells of the volvocalean green algae Carteria cerasiformis, Pleodorina japonica, and Volvox carteri. Such Endosymbionts were present in only C. cerasiformis strain NIES-425 and V. carteri strain UTEX 2180, of various strains of Carteria and V. carteri examined, suggesting that rickettsial Endosymbionts may have been transmitted to only a few algal strains very recently. However, in preliminary work, we detected a sequence similar to that of a rickettsial gene in the nuclear genome of V. carteri strain EVE. Methodology/Principal Findings Here we explored the origin of the rickettsial gene-like sequences in the endosymbiont-lacking V. carteri strain EVE, by performing comparative analyses on 13 strains of V. carteri. By reference to our ongoing genomic sequence of rickettsial Endosymbionts in C. cerasiformis strain NIES-425 cells, we confirmed that an approximately 9-kbp DNA sequence encompassing a region similar to that of four rickettsial genes was present in the nuclear genome of V. carteri strain EVE. Phylogenetic analyses, and comparisons of the synteny of rickettsial gene-like sequences from various strains of V. carteri, indicated that the rickettsial gene-like sequences in the nuclear genome of V. carteri strain EVE were closely related to rickettsial gene sequences of P. japonica, rather than those of V. carteri strain UTEX 2180. Conclusion/Significance At least two different rickettsial organisms may have invaded the V. carteri lineage, one of which may be the direct ancestor of the endosymbiont of V. carteri strain UTEX 2180, whereas the other may be closely related to the endosymbiont of P. japonica. Endosymbiotic gene transfer from the latter rickettsial organism may have occurred in an ancestor of V. carteri. Thus, the rickettsiae may be widely associated with V. carteri, and likely have often been lost during host evolution.
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a rickettsial endosymbiont inhabiting the cytoplasm of volvox carteri volvocales chlorophyceae
Phycologia, 2014Co-Authors: Kaoru Kawafune, Yuichi Hongoh, Hisayoshi NozakiAbstract:A bacterial endosymbiont was previously observed in the green alga Volvox carteri strain UTEX 2180 using transmission electron microscopy, although its phylogenetic status was unknown. Here, we identified the bacterial endosymbiont based on analyses of the 16S ribosomal RNA (rRNA) gene. The endosymbiont of V. carteri belongs to the “hydra group” characterized by non-arthropod hosts, within the eubacterial family Rickettsiaceae (Rickettsiales; Alphaproteobacteria). In the hydra group, the endosymbiont formed a clade with the Endosymbionts of the volvocaleans Carteria cerasiformis and Pleodorina japonica and the ciliate Diophrys appendiculata but was separated from the Endosymbionts of marine green macroalgae (Bryopsis spp.). Fluorescence in situ hybridization using a probe specific for the 16S rRNA of the V. carteri endosymbiont confirmed our molecular identification and the distribution of the endosymbiont within the host cytoplasm. Rickettsial Endosymbionts were not detected in eight other strains of V. ...
Abdelaziz Heddi - One of the best experts on this subject based on the ideXlab platform.
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Spatial and morphological reorganization of endosymbiosis during metamorphosis accommodates adult metabolic requirements in a weevil.
Proceedings of the National Academy of Sciences of the United States of America, 2020Co-Authors: Justin Maire, Nicolas Parisot, Mariana Galvao Ferrarini, Agnès Vallier, Benjamin Gillet, Sandrine Hughes, Séverine Balmand, Carole Vincent-monégat, Anna Zaidman-rémy, Abdelaziz HeddiAbstract:Bacterial intracellular symbiosis (endosymbiosis) is widespread in nature and impacts many biological processes. In holometabolous symbiotic insects, metamorphosis entails a complete and abrupt internal reorganization that creates a constraint for endosymbiont transmission from larvae to adults. To assess how endosymbiosis copes-and potentially evolves-throughout this major host-tissue reorganization, we used the association between the cereal weevil Sitophilus oryzae and the bacterium Sodalis pierantonius as a model system. S. pierantonius are contained inside specialized host cells, the bacteriocytes, that group into an organ, the bacteriome. Cereal weevils require metabolic inputs from their endosymbiont, particularly during adult cuticle synthesis, when endosymbiont load increases dramatically. By combining dual RNA-sequencing analyses and cell imaging, we show that the larval bacteriome dissociates at the onset of metamorphosis and releases bacteriocytes that undergo endosymbiosis-dependent transcriptomic changes affecting cell motility, cell adhesion, and cytoskeleton organization. Remarkably, bacteriocytes turn into spindle cells and migrate along the midgut epithelium, thereby conveying Endosymbionts to midgut sites where future mesenteric caeca will develop. Concomitantly, endosymbiont genes encoding a type III secretion system and a flagellum apparatus are transiently up-regulated while Endosymbionts infect putative stem cells and enter their nuclei. Infected cells then turn into new differentiated bacteriocytes and form multiple new bacteriomes in adults. These findings show that endosymbiosis reorganization in a holometabolous insect relies on a synchronized host-symbiont molecular and cellular "choreography" and illustrates an adaptive feature that promotes bacteriome multiplication to match increased metabolic requirements in emerging adults.
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Weevil endosymbiont dynamics is associated with a clamping of immunity
BMC genomics, 2015Co-Authors: Florent Masson, Nicolas Parisot, Agnès Vallier, Séverine Balmand, Carole Vincent-monégat, Anna Zaidman-rémy, Aurélien Vigneron, Yves Mone, Marie-christine Carpentier, Abdelaziz HeddiAbstract:Insects subsisting on nutritionally unbalanced diets have evolved long-term mutualistic relationships with intracellular symbiotic bacteria (Endosymbionts). The endosymbiont population load undergoes changes along with insect development. In the cereal weevil Sitophilus oryzae, the midgut Endosymbionts Sodalis pierantonius drastically multiply following adult metamorphosis and rapidly decline until total elimination when the insect achieves its cuticle synthesis. Whilst symbiont load was shown to timely meet insect metabolic needs, little is known about the host molecular and immune processes underlying this dynamics. We performed RNA sequencing analysis on weevil midguts at three representative phases of the endosymbiont dynamics (i.e. increase, climax and decrease). To screen genes which transcriptional changes are specifically related to symbiont dynamics and not to the intrinsic development of the midgut, we further have monitored by RT-qPCR sixteen gene transcript levels in symbiotic and artificially non-symbiotic (aposymbiotic) weevils. We also localized the Endosymbionts during the elimination process by fluorescence microscopy. Functional analysis of the host differentially expressed genes by RNA sequencing showed that the main transcriptional changes occur during endosymbiont growth phase and affect cell proliferation, apoptosis, autophagy, phagocytosis, and metabolism of fatty acids and nucleic acids. We also showed that symbiont dynamics alters the expression of several genes involved in insect development. Our results strengthened the implication of apoptosis and autophagy processes in symbiont elimination and recycling. Remarkably, apart from the coleoptericin A that is known to target Endosymbionts and controls their division and location, no gene coding antimicrobial peptide was upregulated during the symbiont growth and elimination phases. We show that endosymbiont dynamics parallels numerous transcriptional changes in weevil developing adults and affects several biological processes, including metabolism and development. It also triggers cell apoptosis, autophagy and gut epithelial cell swelling and delamination. Strikingly, immunity is repressed during the whole process, presumably avoiding tissue inflammation and allowing insects to optimize nutrient recovery from recycled endosymbiont.
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Insects recycle Endosymbionts when the benefit is over.
Current biology : CB, 2014Co-Authors: Aurélien Vigneron, Agnès Vallier, Séverine Balmand, Carole Vincent-monégat, Anna Zaidman-rémy, Florent Masson, Marjolaine Rey, Emre Aksoy, Etienne Aubailly-giraud, Abdelaziz HeddiAbstract:Symbiotic associations are widespread in nature and represent a driving force in evolution. They are known to impact fitness, and thereby shape the host phenotype. Insects subsisting on nutritionally poor substrates have evolved mutualistic relationships with intracellular symbiotic bacteria (Endosymbionts) that supply them with metabolic components lacking in their diet. In many species, Endosymbionts are hosted within specialized host cells, called the bacteriocytes, and transmitted vertically across host generations. How hosts balance the costs and benefits of having Endosymbionts, and whether and how they adjust symbiont load to their physiological needs, remains largely unexplored. By investigating the cereal weevil Sitophilus association with the Sodalis pierantonius endosymbiont, we discover that endosymbiont populations intensively multiply in young adults, before being rapidly eliminated within few days. We show that young adults strongly depend on Endosymbionts and that endosymbiont proliferation after metamorphosis matches a drastic host physiological need for the tyrosine (Tyr) and phenylalanine (Phe) amino acids to rapidly build their protective exoskeleton. Tyr and Phe are precursors of the dihydroxyphenylalanine (DOPA) molecule that is an essential component for the cuticle synthesis. Once the cuticle is achieved, DOPA reaches high amounts in insects, which triggers endosymbiont elimination. This elimination relies on apoptosis and autophagy activation, allowing digestion and recycling of the endosymbiont material. Thus, the weevil-endosymbiont association reveals an adaptive interplay between metabolic and cellular functions that minimizes the cost of symbiosis and speeds up the exoskeleton formation during a critical phase when emerging adults are especially vulnerable.
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Endosymbiont diversity among sibling weevil species competing for the same resource
BMC Evolutionary Biology, 2013Co-Authors: Adrien Merville, Agnès Vallier, Abdelaziz Heddi, Samuel Venner, Hélène Henri, Frédéric Menu, Fabrice Vavre, Marie-claude Bel-vennerAbstract:BACKGROUND: Whereas the impact of Endosymbionts on the ecology of their hosts is well known in some insect species, the question of whether host communities are influenced by Endosymbionts remains largely unanswered. Notably, the coexistence of host species competing with each other, which is expected to be stabilized by their ecological differences, could be facilitated by differences in their Endosymbionts. Yet, the composition of endosymbiotic communities housed by natural communities of competing host species is still almost unknown. In this study, we started filling this gap by describing and comparing the bacterial endosymbiotic communities of four sibling weevil species (Curculio spp.) that compete with each other to lay eggs into oak acorns (Quercus spp.) and exhibit marked ecological differences. RESULTS: All four species housed the primary endosymbiont Candidatus Curculioniphilus buchneri, yet each of these had a clearly distinct community of secondary Endosymbionts, including Rickettsia, Spiroplasma, and two Wolbachia strains. Notably, three weevil species harbored their own predominant facultative endosymbiont and possessed the remaining symbionts at a residual infection level. CONCLUSIONS: The four competing species clearly harbor distinct endosymbiotic communities. We discuss how such endosymbiotic communities could spread and keep distinct in the four insect species, and how these symbionts might affect the organization and species richness of host communities.
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Long-Term Evolutionary Stability of Bacterial Endosymbiosis in Curculionoidea: Additional Evidence of Symbiont Replacement in the Dryophthoridae Family
Molecular Biology and Evolution, 2008Co-Authors: Cyrille Conord, Agnès Vallier, Séverine Balmand, Laurence Despres, Christian Miquel, Stéphanie Zundel, Guy Lemperiere, Abdelaziz HeddiAbstract:Bacterial intracellular symbiosis (endosymbiosis) is well documented in the insect world where it is believed to play a crucial role in adaptation and evolution. However, although Coleopteran insects are of huge ecological and economical interest, endosymbiont molecular analysis is limited to the Dryophthoridae family. Here, we have analyzed the intracellular symbiotic bacteria in 2 Hylobius species belonging to the Molytinae subfamily (Curculionoidea superfamily) that exhibit different features from the Dryophthoridae insects in terms of their ecology and geographical spanning. Fluorescence in situ hybridization has shown that both Hylobius species harbor rod-shaped pleiomorphic symbiotic bacteria in the oocyte and in the bacteria-bearing organ (the bacteriome), with a shape and location similar to those of the Dryophthoridae bacteriome. Phylogenetic analysis of the 16S ribosomal DNA gene sequences, using the heterogeneous model of DNA evolution, has placed the Hylobius spp. Endosymbionts (H-group) at the basal position of the ancestral R-clade of Dryophthoridae Endosymbionts named Candidatus Nardonella but relatively distant from the S-clade of Sitophilus spp. Endosymbionts. Endosymbionts from the H-group and the R-clade evolved more quickly compared with free-living enteric bacteria and Endosymbionts from the S- and D-clades of Dryophthoridae. They are AT biased (58.3% A + T), and they exhibit AT-rich insertions at the same position as previously described in the Candidatus Nardonella 16S rDNA sequence. Moreover, the host phylogenetic tree based on the mitochondrial COI gene was shown to be highly congruent with the H-group and the R-clade, the divergence of which was estimated to be around 125 MYA. These new molecular data show that endosymbiosis is old in Curculionids, going back at least to the common ancestor of Molytinae and Dryophthoridae, and is evolutionary stable, except in 2 Dryophthoridae clades, providing additional and independent supplementary evidence for endosymbiont replacement in these taxa.