| genome sequence of "candidatus walczuchella monophlebidarum" the flavobacterial endosymbiont of llaveia axin axin (hemiptera: coccoidea: monophlebidae). | scale insects (hemiptera: coccoidae) constitute a very diverse group of sap-feeding insects with a large diversity of symbiotic associations with bacteria. here, we present the complete genome sequence, metabolic reconstruction, and comparative genomics of the flavobacterial endosymbiont of the giant scale insect llaveia axin axin. the gene repertoire of its 309,299 bp genome was similar to that of other flavobacterial insect endosymbionts though not syntenic. according to its genetic content, e ... | 2014 | 24610838 |
| an ecological cost associated with protective symbionts of aphids. | beneficial symbioses are widespread and diverse in the functions they provide to the host ranging from nutrition to protection. however, these partnerships with symbionts can be costly for the host. such costs, so called "direct costs", arise from a trade-off between allocating resources to symbiosis and other functions such as reproduction or growth. ecological costs may also exist when symbiosis negatively affects the interactions between the host and other organisms in the environment. althou ... | 2014 | 24683464 |
| aphid facultative symbionts reduce survival of the predatory lady beetle hippodamia convergens. | non-essential facultative endosymbionts can provide their hosts with protection from parasites, pathogens, and predators. for example, two facultative bacterial symbionts of the pea aphid (acyrthosiphon pisum), serratia symbiotica and hamiltonella defensa, protect their hosts from parasitism by two species of parasitoid wasp. previous studies have not explored whether facultative symbionts also play a defensive role against predation in this system. we tested whether feeding on aphids harboring ... | 2014 | 24555501 |
| the pine bark adelgid, pineus strobi, contains two novel bacteriocyte-associated gammaproteobacterial symbionts. | bacterial endosymbionts of the pine bark adelgid, pineus strobi (insecta: hemiptera: adelgidae), were investigated using transmission electron microscopy, 16s and 23s rrna-based phylogeny, and fluorescence in situ hybridization. two morphologically different symbionts affiliated with the gammaproteobacteria were present in distinct bacteriocytes. one of them ("candidatus annandia pinicola") is most closely related to an endosymbiont of adelges tsugae, suggesting that they originate from a lineag ... | 2014 | 24271164 |
| exposure to natural pathogens reveals costly aphid response to fungi but not bacteria. | immune responses are costly, causing trade-offs between defense and other host life history traits. aphids present a special system to explore the costs associated with immune activation since they are missing several humoral and cellular mechanisms thought important for microbial resistance, and it is unknown whether they have alternative, novel immune responses to deal with microbial threat. here we expose pea aphids to an array of heat-killed natural pathogens, which should stimulate immune r ... | 2014 | 24634732 |
| female-biased symbionts and tomato yellow leaf curl virus infections in bemisia tabaci. | the female-biased infection of facultative symbionts has been found in bemisia tabaci; however, whether there are any differences in tomato yellow leaf curl virus (tylcv) and obligate symbiont infection rates between females and males is unknown. determining whether such differences exist would be very important for understanding the spread of the plant virus and of the symbionts. we compared both symbiont infection types, including obligate and facultative symbionts, and the rates of tylcv infe ... | 2014 | 24465416 |
| parallel histories of horizontal gene transfer facilitated extreme reduction of endosymbiont genomes in sap-feeding insects. | bacteria confined to intracellular environments experience extensive genome reduction. in extreme cases, insect endosymbionts have evolved genomes that are so gene-poor that they blur the distinction between bacteria and endosymbiotically derived organelles such as mitochondria and plastids. to understand the host's role in this extreme gene loss, we analyzed gene content and expression in the nuclear genome of the psyllid pachypsylla venusta, a sap-feeding insect that harbors an ancient endosym ... | 2014 | 24398322 |
| phenotypic effect of "candidatus rickettsiella viridis," a facultative symbiont of the pea aphid (acyrthosiphon pisum), and its interaction with a coexisting symbiont. | a gammaproteobacterial facultative symbiont of the genus rickettsiella was recently identified in the pea aphid, acyrthosiphon pisum. infection with this symbiont altered the color of the aphid body from red to green, potentially affecting the host's ecological characteristics, such as attractiveness to different natural enemies. in european populations of a. pisum, the majority of rickettsiella-infected aphids also harbor another facultative symbiont, of the genus hamiltonella. we investigated ... | 2014 | 24212575 |
| the combined effects of bacterial symbionts and aging on life history traits in the pea aphid, acyrthosiphon pisum. | while many endosymbionts have beneficial effects on hosts under specific ecological conditions, there can also be associated costs. in order to maximize their own fitness, hosts must facilitate symbiont persistence while preventing symbiont exploitation of resources, which may require tight regulation of symbiont populations. as a host ages, the ability to invest in such mechanisms may lessen or be traded off with demands of other life history traits, such as survival and reproduction. using the ... | 2014 | 24185857 |
| bacterial small rnas in the genus rickettsia. | rickettsia species are obligate intracellular gram-negative pathogenic bacteria and the etiologic agents of diseases such as rocky mountain spotted fever (rmsf), mediterranean spotted fever, epidemic typhus, and murine typhus. genome sequencing revealed that r. prowazekii has ~25 % non-coding dna, the majority of which is thought to be either "junk dna" or pseudogenes resulting from genomic reduction. these characteristics also define other rickettsia genomes. bacterial small rnas, whose biogene ... | 2015 | 26679185 |
| a metagenomic approach from aphid's hemolymph sheds light on the potential roles of co-existing endosymbionts. | aphids are known to live in symbiosis with specific bacteria, called endosymbionts which can be classified as obligate or accessory. buchnera aphidicola is generally the only obligatory symbiont present in aphids, supplying essential nutrients that are missing in the plants phloem to its host. pentalonia nigronervosa is the main vector of the banana bunchy top virus, one of the most damageable viruses in banana. this aphid is carrying two symbionts: b. aphidicola (bpn) and wolbachia sp. (wpn). t ... | 2015 | 26667400 |
| supergroup c wolbachia, mutualist symbionts of filarial nematodes, have a distinct genome structure. | wolbachia pipientis is possibly the most widespread endosymbiont of arthropods and nematodes. while all wolbachia strains have historically been defined as a single species, 16 monophyletic clusters of diversity (called supergroups) have been described. different supergroups have distinct host ranges and symbiotic relationships, ranging from mutualism to reproductive manipulation. in filarial nematodes, which include parasites responsible for major diseases of humans (such as onchocerca volvulus ... | 2015 | 26631376 |
| conditional reduction of predation risk associated with a facultative symbiont in an insect. | symbionts are widespread among eukaryotes and their impacts on the ecology and evolution of their hosts are meaningful. most insects harbour obligate and facultative symbiotic bacteria that can influence their phenotype. in the pea aphid acyrthosiphon pisum, an astounding symbiotic-mediated phenotype has been recently observed: when infected with the symbiotic bacteria rickettsiella viridis, young red aphid larvae become greener at adulthood and even darker green when co-infected with rickettsie ... | 2015 | 26618776 |
| comparative genomics of candidate phylum tm6 suggests that parasitism is widespread and ancestral in this lineage. | candidate phylum tm6 is a major bacterial lineage recognized through culture-independent rrna surveys to be low abundance members in a wide range of habitats; however, they are poorly characterized due to a lack of pure culture representatives. two recent genomic studies of tm6 bacteria revealed small genomes and limited gene repertoire, consistent with known or inferred dependence on eukaryotic hosts for their metabolic needs. here, we obtained additional near-complete genomes of tm6 population ... | 2015 | 26615204 |
| comparative genomics of candidate phylum tm6 suggests that parasitism is widespread and ancestral in this lineage. | candidate phylum tm6 is a major bacterial lineage recognized through culture-independent rrna surveys to be low abundance members in a wide range of habitats; however, they are poorly characterized due to a lack of pure culture representatives. two recent genomic studies of tm6 bacteria revealed small genomes and limited gene repertoire, consistent with known or inferred dependence on eukaryotic hosts for their metabolic needs. here, we obtained additional near-complete genomes of tm6 population ... | 2015 | 26615204 |
| conservation and role of electrostatics in thymidylate synthase. | conservation of function across families of orthologous enzymes is generally accompanied by conservation of their active site electrostatic potentials. to study the electrostatic conservation in the highly conserved essential enzyme, thymidylate synthase (ts), we conducted a systematic species-based comparison of the electrostatic potential in the vicinity of its active site. whereas the electrostatics of the active site of ts are generally well conserved, the tss from minimal organisms do not c ... | 2015 | 26612036 |
| social niche construction and evolutionary transitions in individuality. | social evolution theory conventionally takes an externalist explanatory stance, treating observed cooperation as explanandum and the positive assortment of cooperative behaviour as explanans. we ask how the circumstances bringing about this positive assortment arose in the first place. rather than merely push the explanatory problem back a step, we move from an externalist to an interactionist explanatory stance, in the spirit of lewontin and the niche construction theorists. we develop a theory ... | 2015 | 26709324 |
| social niche construction and evolutionary transitions in individuality. | social evolution theory conventionally takes an externalist explanatory stance, treating observed cooperation as explanandum and the positive assortment of cooperative behaviour as explanans. we ask how the circumstances bringing about this positive assortment arose in the first place. rather than merely push the explanatory problem back a step, we move from an externalist to an interactionist explanatory stance, in the spirit of lewontin and the niche construction theorists. we develop a theory ... | 2015 | 26709324 |
| slow and fast evolving endosymbiont lineages: positive correlation between the rates of synonymous and non-synonymous substitution. | the availability of complete genome sequences of bacterial endosymbionts with strict vertical transmission to the host progeny opens the possibility to estimate molecular evolutionary rates in different lineages and understand the main biological mechanisms influencing these rates. we have compared the rates of evolution for non-synonymous and synonymous substitutions in nine bacterial endosymbiont lineages, belonging to four clades (baumannia, blochmannia, portiera, and sulcia). the main result ... | 2015 | 26617602 |
| differential temporal changes of primary and secondary bacterial symbionts and whitefly host fitness following antibiotic treatments. | where multiple symbionts coexist in the same host, the selective elimination of a specific symbiont may enable the roles of a given symbiont to be investigated. we treated the mediterranean species of the whitefly bemisia tabaci complex by oral delivery of the antibiotic rifampicin, and then examined the temporal changes of its primary symbiont "candidatus portiera aleyrodidarum" and secondary symbiont "ca. hamiltonella defensa" as well as host fitness for three generations. in adults treated wi ... | 2015 | 26510682 |
| weevil endosymbiont dynamics is associated with a clamping of immunity. | 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 t ... | 2015 | 26482132 |
| whole genome sequence of the soybean aphid endosymbiont buchnera aphidicola and genetic differentiation among biotype-specific strains. | endosymbiosis with microorganisms is common in insects, with more than 10% of species requiring the metabolic capabilities of intracellular bacteria for their nutrient acquisition. aphids harbor an obligate mutualism with the vertically transferred endosymbiont, buchnera aphidicola, which produces key nutrients lacking in the aphid's phloem-based diet that are necessary for normal development and reproduction. it is thought that, in some groups of insects, bacterial symbionts may play key roles ... | 2015 | 26516375 |
| the importance of spatial heterogeneity and self-restraint on mutualism stability - a quantitative review. | understanding the factors that enable mutualisms to evolve and to subsequently remain stable over time, is essential to fully understand patterns of global biodiversity and for evidence based conservation policy. theoretically, spatial heterogeneity of mutualists, through increased likelihood of fidelity between cooperative partners in structured populations, and 'self-restraint' of symbionts, due to selection against high levels of virulence leading to short-term host overexploitation, will res ... | 2015 | 26434680 |
| following the footsteps of chlamydial gene regulation. | regulation of gene expression ensures an organism responds to stimuli and undergoes proper development. although the regulatory networks in bacteria have been investigated in model microorganisms, nearly nothing is known about the evolution and plasticity of these networks in obligate, intracellular bacteria. the phylum chlamydiae contains a vast array of host-associated microbes, including several human pathogens. the chlamydiae are unique among obligate, intracellular bacteria as they undergo ... | 2015 | 26424812 |
| avoidance and potential remedy solutions of chimeras in reconstructing the phylogeny of aphids using the 16s rrna gene of buchnera: a case in lachninae (hemiptera). | it is known that pcr amplification of highly homologous genes from complex dna mixtures can generate a significant proportion of chimeric sequences. the 16s rrna gene is not only widely used in estimating the species diversity of endosymbionts in aphids but also used to explore the co-diversification of aphids and their endosymbionts. thus, chimeric sequences may lead to the discovery of non-existent endosymbiont species and mislead buchnera-based phylogenetic analysis that lead to false conclus ... | 2015 | 26307984 |
| a facultative endosymbiont in aphids can provide diverse ecological benefits. | ecologically important traits of insects are often affected by facultative bacterial endosymbionts. this is best studied in the pea aphid acyrthosiphon pisum, which is frequently infected by one or more of eight facultative symbiont species. many of these symbiont species have been shown to provide one ecological benefit, but we have little understanding of the range of effects that a single strain can have. here, we describe the phenotypes conferred by three strains of the recently discovered b ... | 2015 | 26206380 |
| microbial communities can be described by metabolic structure: a general framework and application to a seasonally variable, depth-stratified microbial community from the coastal west antarctic peninsula. | taxonomic marker gene studies, such as the 16s rrna gene, have been used to successfully explore microbial diversity in a variety of marine, terrestrial, and host environments. for some of these environments long term sampling programs are beginning to build a historical record of microbial community structure. although these 16s rrna gene datasets do not intrinsically provide information on microbial metabolism or ecosystem function, this information can be developed by identifying metabolisms ... | 2015 | 26285202 |
| breaking the computational barriers of pairwise genome comparison. | conventional pairwise sequence comparison software algorithms are being used to process much larger datasets than they were originally designed for. this can result in processing bottlenecks that limit software capabilities or prevent full use of the available hardware resources. overcoming the barriers that limit the efficient computational analysis of large biological sequence datasets by retrofitting existing algorithms or by creating new applications represents a major challenge for the bioi ... | 2015 | 26260162 |
| systems biology definition of the core proteome of metabolism and expression is consistent with high-throughput data. | finding the minimal set of gene functions needed to sustain life is of both fundamental and practical importance. minimal gene lists have been proposed by using comparative genomics-based core proteome definitions. a definition of a core proteome that is supported by empirical data, is understood at the systems-level, and provides a basis for computing essential cell functions is lacking. here, we use a systems biology-based genome-scale model of metabolism and expression to define a functional ... | 2015 | 26261351 |
| inside the pan-genome - methods and software overview. | the number of genomes that have been deposited in databases has increased exponentially after the advent of next-generation sequencing (ngs), which produces high-throughput sequence data; this circumstance has demanded the development of new bioinformatics software and the creation of new areas, such as comparative genomics. in comparative genomics, the genetic content of an organism is compared against other organisms, which helps in the prediction of gene function and coding region sequences, ... | 2015 | 27006628 |
| evidence for specificity in symbiont-conferred protection against parasitoids. | many insects harbour facultative symbiotic bacteria, some of which have been shown to provide resistance against natural enemies. one of the best-known protective symbionts is hamiltonella defensa, which in pea aphid (acyrthosiphon pisum) confers resistance against attack by parasitoid wasps in the genus aphidius (braconidae).we asked (i) whether this symbiont also confers protection against a phylogenetically distant group of parasitoids (aphelinidae) and (ii) whether there are consistent diffe ... | 2015 | 26136451 |
| identification and analysis of the bacterial endosymbiont specialized for production of the chemotherapeutic natural product et-743. | ecteinascidin 743 (et-743, yondelis) is a clinically approved chemotherapeutic natural product isolated from the caribbean mangrove tunicate ecteinascidia turbinata. researchers have long suspected that a microorganism may be the true producer of the anticancer drug, but its genome has remained elusive due to our inability to culture the bacterium in the laboratory using standard techniques. here, we sequenced and assembled the complete genome of the et-743 producer, candidatus endoecteinascidia ... | 2015 | 26013440 |
| draft genomes, phylogenetic reconstruction, and comparative genomics of two novel cohabiting bacterial symbionts isolated from frankliniella occidentalis. | obligate bacterial symbionts are widespread in many invertebrates, where they are often confined to specialized host cells and are transmitted directly from mother to progeny. increasing numbers of these bacteria are being characterized but questions remain about their population structure and evolution. here we take a comparative genomics approach to investigate two prominent bacterial symbionts (bfo1 and bfo2) isolated from geographically separated populations of western flower thrips, frankli ... | 2015 | 26185096 |
| genome wide re-annotation of caldicellulosiruptor saccharolyticus with new insights into genes involved in biomass degradation and hydrogen production. | caldicellulosiruptor saccharolyticus has proven itself to be an excellent candidate for biological hydrogen (h2) production, but still it has major drawbacks like sensitivity to high osmotic pressure and low volumetric h2 productivity, which should be considered before it can be used industrially. a whole genome re-annotation work has been carried out as an attempt to update the incomplete genome information that causes gap in the knowledge especially in the area of metabolic engineering, to imp ... | 2015 | 26196387 |
| transcriptional slippage and rna editing increase the diversity of transcripts in chloroplasts: insight from deep sequencing of vigna radiata genome and transcriptome. | we performed deep sequencing of the nuclear and organellar genomes of three mungbean genotypes: vigna radiata ssp. sublobata tc1966, v. radiata var. radiata nm92 and the recombinant inbred line ril59 derived from a cross between tc1966 and nm92. moreover, we performed deep sequencing of the ril59 transcriptome to investigate transcript variability. the mungbean chloroplast genome has a quadripartite structure including a pair of inverted repeats separated by two single copy regions. a total of 2 ... | 2015 | 26076132 |
| scrambled and not-so-tiny genomes of fungal endosymbionts. | | 2015 | 26056315 |
| the genome of diuraphis noxia, a global aphid pest of small grains. | the russian wheat aphid, diuraphis noxia kurdjumov, is one of the most important pests of small grains throughout the temperate regions of the world. this phytotoxic aphid causes severe systemic damage symptoms in wheat, barley, and other small grains as a direct result of the salivary proteins it injects into the plant while feeding. | 2015 | 26044338 |
| infection of host plants by cucumber mosaic virus increases the susceptibility of myzus persicae aphids to the parasitoid aphidius colemani. | plant viruses can profoundly alter the phenotypes of their host plants, with potentially far-reaching implications for ecology. yet few studies have explored the indirect, host-mediated, effects of plant viruses on non-vector insects. we examined how infection of cucurbita pepo plants by cucumber mosaic virus (cmv) impacted the susceptibility of aphids (myzus persicae) to attack by the parasitoid wasp aphidius colemani. in semi-natural foraging assays, we observed higher rates of aphid parasitis ... | 2015 | 26043237 |
| signatures of host/symbiont genome coevolution in insect nutritional endosymbioses. | the role of symbiosis in bacterial symbiont genome evolution is well understood, yet the ways that symbiosis shapes host genomes or more particularly, host/symbiont genome coevolution in the holobiont is only now being revealed. here, we identify three coevolutionary signatures that characterize holobiont genomes. the first signature, host/symbiont collaboration, arises when completion of essential pathways requires host/endosymbiont genome complementarity. metabolic collaboration has evolved nu ... | 2015 | 26039986 |
| rethinking evolutionary individuality. | this paper considers whether multispecies biofilms are evolutionary individuals. numerous multispecies biofilms have characteristics associated with individuality, such as internal integrity, division of labor, coordination among parts, and heritable adaptive traits. however, such multispecies biofilms often fail standard reproductive criteria for individuality: they lack reproductive bottlenecks, are comprised of multiple species, do not form unified reproductive lineages, and fail to have a si ... | 2015 | 26039982 |
| whitefly genome expression reveals host-symbiont interaction in amino acid biosynthesis. | whitefly (bemisia tabaci) complex is a serious insect pest of several crop plants worldwide. it comprises several morphologically indistinguishable species, however very little is known about their genetic divergence and biosynthetic pathways. in the present study, we performed transcriptome sequencing of asia 1 species of b. tabaci complex and analyzed the interaction of host-symbiont genes in amino acid biosynthetic pathways. | 2015 | 26000976 |
| bacterial symbionts, buchnera, and starvation on wing dimorphism in english grain aphid, sitobion avenae (f.) (homoptera: aphididae). | wing dimorphism in aphids can be affected by multiple cues, including both biotic (nutrition, crowding, interspecific interactions, the presence of natural enemies, maternal and transgenerational effects, and alarm pheromone) and abiotic factors (temperature, humidity, and photoperiod). the majority of the phloem-feeding aphids carry buchnera, an obligate symbiotic proteobacteria. buchnera has a highly reduced genome size, but encode key enzymes in the tryptophan biosynthetic pathway and is cruc ... | 2015 | 26042046 |
| genome expansion via lineage splitting and genome reduction in the cicada endosymbiont hodgkinia. | comparative genomics from mitochondria, plastids, and mutualistic endosymbiotic bacteria has shown that the stable establishment of a bacterium in a host cell results in genome reduction. although many highly reduced genomes from endosymbiotic bacteria are stable in gene content and genome structure, organelle genomes are sometimes characterized by dramatic structural diversity. previous results from candidatus hodgkinia cicadicola, an endosymbiont of cicadas, revealed that some lineages of this ... | 2015 | 26286984 |
| bacterial symbionts of the leafhopper evacanthus interruptus (linnaeus, 1758) (insecta, hemiptera, cicadellidae: evacanthinae). | plant sap-feeding hemipterans harbor obligate symbiotic microorganisms which are responsible for the synthesis of amino acids missing in their diet. in this study, we characterized the obligate symbionts hosted in the body of the xylem-feeding leafhopper evacanthus interruptus (cicadellidae: evacanthinae: evacanthini) by means of histological, ultrastructural and molecular methods. we observed that e. interruptus is associated with two types of symbiotic microorganisms: bacterium 'candidatus sul ... | 2015 | 25900723 |
| bacterial symbionts of the leafhopper evacanthus interruptus (linnaeus, 1758) (insecta, hemiptera, cicadellidae: evacanthinae). | plant sap-feeding hemipterans harbor obligate symbiotic microorganisms which are responsible for the synthesis of amino acids missing in their diet. in this study, we characterized the obligate symbionts hosted in the body of the xylem-feeding leafhopper evacanthus interruptus (cicadellidae: evacanthinae: evacanthini) by means of histological, ultrastructural and molecular methods. we observed that e. interruptus is associated with two types of symbiotic microorganisms: bacterium 'candidatus sul ... | 2015 | 25900723 |
| endosymbiont evolution: predictions from theory and surprises from genomes. | genome data have created new opportunities to untangle evolutionary processes shaping microbial variation. among bacteria, long-term mutualists of insects represent the smallest and (typically) most at-rich genomes. evolutionary theory provides a context to predict how an endosymbiotic lifestyle may alter fundamental evolutionary processes--mutation, selection, genetic drift, and recombination--and thus contribute to extreme genomic outcomes. these predictions can then be explored by comparing e ... | 2015 | 25866055 |
| yoc, a new strategy for pairwise alignment of collinear genomes. | comparing and aligning genomes is a key step in analyzing closely related genomes. despite the development of many genome aligners in the last 15 years, the problem is not yet fully resolved, even when aligning closely related bacterial genomes of the same species. in addition, no procedures are available to assess the quality of genome alignments or to compare genome aligners. | 2015 | 25885358 |
| genome evolution in an ancient bacteria-ant symbiosis: parallel gene loss among blochmannia spanning the origin of the ant tribe camponotini. | stable associations between bacterial endosymbionts and insect hosts provide opportunities to explore genome evolution in the context of established mutualisms and assess the roles of selection and genetic drift across host lineages and habitats. blochmannia, obligate endosymbionts of ants of the tribe camponotini, have coevolved with their ant hosts for ∼40 my. to investigate early events in blochmannia genome evolution across this ant host tribe, we sequenced blochmannia from two divergent hos ... | 2015 | 25861561 |
| infection dynamic of symbiotic bacteria in the pea aphid acyrthosiphon pisum gut and host immune response at the early steps in the infection process. | in addition to its obligatory symbiont buchnera aphidicola, the pea aphid acyrthosiphon pisum can harbor several facultative bacterial symbionts which can be mutualistic in the context of various ecological interactions. belonging to a genus where many members have been described as pathogen in invertebrates, serratia symbiotica is one of the most common facultative partners found in aphids. the recent discovery of strains able to grow outside their host allowed us to simulate environmental acqu ... | 2015 | 25811863 |
| bacterial communities associated with host-adapted populations of pea aphids revealed by deep sequencing of 16s ribosomal dna. | associations between microbes and animals are ubiquitous and hosts may benefit from harbouring microbial communities through improved resource exploitation or resistance to environmental stress. the pea aphid, acyrthosiphon pisum, is the host of heritable bacterial symbionts, including the obligate endosymbiont buchnera aphidicola and several facultative symbionts. while obligate symbionts supply aphids with key nutrients, facultative symbionts influence their hosts in many ways such as protecti ... | 2015 | 25807173 |
| genome reduction and potential metabolic complementation of the dual endosymbionts in the whitefly bemisia tabaci. | the whitefly bemisia tabaci is an important agricultural pest with global distribution. this phloem-sap feeder harbors a primary symbiont, "candidatus portiera aleyrodidarum", which compensates for the deficient nutritional composition of its food sources, and a variety of secondary symbionts. interestingly, all of these secondary symbionts are found in co-localization with the primary symbiont within the same bacteriocytes, which should favor the evolution of strong interactions between symbion ... | 2015 | 25887812 |
| heritable symbiosis: the advantages and perils of an evolutionary rabbit hole. | many eukaryotes have obligate associations with microorganisms that are transmitted directly between generations. a model for heritable symbiosis is the association of aphids, a clade of sap-feeding insects, and buchnera aphidicola, a gammaproteobacterium that colonized an aphid ancestor 150 million years ago and persists in almost all 5,000 aphid species. symbiont acquisition enables evolutionary and ecological expansion; aphids are one of many insect groups that would not exist without heritab ... | 2015 | 25713367 |
| entometabolomics: applications of modern analytical techniques to insect studies. | metabolomic analyses can reveal associations between an organism's metabolome and further aspects of its phenotypic state, an attractive prospect for many life-sciences researchers. the metabolomic approach has been employed in some, but not many, insect study systems, starting in 1990 with the evaluation of the metabolic effects of parasitism on moth larvae. metabolomics has now been applied to a variety of aspects of insect biology, including behaviour, infection, temperature stress responses, ... | 2015 | 27478203 |
| two different rickettsial bacteria invading volvox carteri. | 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 onl ... | 2015 | 25671568 |
| harnessing evolution to elucidate the consequences of symbiosis. | many organisms harbor microbial associates that have profound impacts on host traits. the phenotypic effect of symbionts on their hosts may include changes in development, reproduction, longevity, and defense against natural enemies. determining the consequences of associating with a microbial symbiont requires experimental comparison of hosts with and without symbionts. then, determining the mechanism by which symbionts alter these phenotypes can involve genomic, genetic, and evolutionary appro ... | 2015 | 25668183 |
| mutualism breakdown by amplification of wolbachia genes. | most insect species are associated with vertically transmitted endosymbionts. because of the mode of transmission, the fitness of these symbionts is dependent on the fitness of the hosts. therefore, these endosymbionts need to control their proliferation in order to minimize their cost for the host. the genetic bases and mechanisms of this regulation remain largely undetermined. the maternally inherited bacteria of the genus wolbachia are the most common endosymbionts of insects, providing some ... | 2015 | 25668031 |
| interchangeable allies: exploiting development and selection to swap symbionts. | | 2015 | 25675514 |
| effects of the diet on the microbiota of the red palm weevil (coleoptera: dryophthoridae). | rhynchophorus ferrugineus, also known as the red palm weevil, is regarded as the major pest of palm trees. although studies of the microbiota associated with this species have been performed in recent years, little attention has been dedicated to the influence of the diet in shaping the host bacterial community. here, we investigated the influence of food sources (i.e. palm tissues vs apple based substrate) on the microbial diversity associated with rpw, which was compared with the microbiota as ... | 2015 | 25635833 |
| habitat visualization and genomic analysis of "candidatus pantoea carbekii," the primary symbiont of the brown marmorated stink bug. | phytophagous pentatomid insects can negatively impact agricultural productivity and the brown marmorated stink bug (halyomorpha halys) is an emerging invasive pest responsible for damage to many fruit crops and ornamental plants in north america. many phytophagous stink bugs, including h. halys, harbor gammaproteobacterial symbionts that likely contribute to host development, and characterization of symbiont transmission/acquisition and their contribution to host fitness may offer alternative st ... | 2015 | 25587021 |
| experimental replacement of an obligate insect symbiont. | symbiosis, the close association of unrelated organisms, has been pivotal in biological diversification. in the obligate symbioses found in many insect hosts, organisms that were once independent are permanently and intimately associated, resulting in expanded ecological capabilities. the primary model for this kind of symbiosis is the association between the bacterium buchnera and the pea aphid (acyrthosiphon pisum). a longstanding obstacle to efforts to illuminate genetic changes underlying ob ... | 2015 | 25561531 |
| prefiltering model for homology detection algorithms on gpu. | homology detection has evolved over the time from heavy algorithms based on dynamic programming approaches to lightweight alternatives based on different heuristic models. however, the main problem with these algorithms is that they use complex statistical models, which makes it difficult to achieve a relevant speedup and find exact matches with the original results. thus, their acceleration is essential. the aim of this article was to prefilter a sequence database. to make this work, we have im ... | 2016 | 28008220 |
| modulation of legume defense signaling pathways by native and non-native pea aphid clones. | the pea aphid (acyrthosiphon pisum) is a complex of at least 15 genetically different host races that are native to specific legume plants, but can all develop on the universal host plant vicia faba. despite much research, it is still unclear why pea aphid host races (biotypes) are able to colonize their native hosts while other host races are not. all aphids penetrate the plant and salivate into plant cells when they test plant suitability. thus plants might react differently to the various pea ... | 2016 | 28018405 |
| functional evaluation of proteins in watery and gel saliva of aphids. | gel and watery saliva are regarded as key players in aphid-piant interactions. the salivary composition seems to be influenced by the variable environment encountered by the stylet tip. milieu sensing has been postulated to provide information needed for proper stylet navigation and for the required switches between gel and watery saliva secretion during stylet progress. both the chemical and physical factors involved in sensing of the stylet's environment are discussed. to investigate the saliv ... | 2016 | 28018380 |
| association between gut microbiota and diapause preparation in the cabbage beetle: a new perspective for studying insect diapause. | gut microbiota mediate the nutritional metabolism and play important roles in human obesity. diapausing insects accumulate large fat reserves and develop obese phenotypes in order to survive unfavorable conditions. however, the possibility of an association between gut microbiota and insect diapause has not been investigated. we used the illumina miseq platform to compare gut bacterial community composition in nondiapause- (i.e. reproductive) and diapause-destined female cabbage beetles, colaphe ... | 2016 | 27934967 |
| initiator trna genes template the 3' cca end at high frequencies in bacteria. | while the cca sequence at the mature 3' end of trnas is conserved and critical for translational function, a genetic template for this sequence is not always contained in trna genes. in eukaryotes and archaea, the cca ends of trnas are synthesized post-transcriptionally by cca-adding enzymes. in bacteria, trna genes template cca sporadically. | 2016 | 27927177 |
| annotation of the asian citrus psyllid genome reveals a reduced innate immune system. | citrus production worldwide is currently facing significant losses due to citrus greening disease, also known as huanglongbing. the citrus greening bacteria, candidatus liberibacter asiaticus (clas), is a persistent propagative pathogen transmitted by the asian citrus psyllid, diaphorina citri kuwayama (hemiptera: liviidae). hemipterans characterized to date lack a number of insect immune genes, including those associated with the imd pathway targeting gram-negative bacteria. the d. citri draft ... | 2016 | 27965582 |
| protein domain architectures provide a fast, efficient and scalable alternative to sequence-based methods for comparative functional genomics. | a functional comparative genome analysis is essential to understand the mechanisms underlying bacterial evolution and adaptation. detection of functional orthologs using standard global sequence similarity methods faces several problems; the need for defining arbitrary acceptance thresholds for similarity and alignment length, lateral gene acquisition and the high computational cost for finding bi-directional best matches at a large scale. we investigated the use of protein domain architectures ... | 2016 | 27703668 |
| heat stress affects facultative symbiont-mediated protection from a parasitoid wasp. | many insects carry facultative bacterial symbionts, which provide benefits including resistance to natural enemies and abiotic stresses. little is known about how these beneficial phenotypes are affected when biotic or abiotic threats occur simultaneously. the pea aphid (acyrthosiphon pisum) can host several well-characterized symbiont species. the symbiont known as x-type can protect against both parasitoid wasps and heat stress. here, we used three pea aphid genotypes that were naturally infec ... | 2016 | 27875577 |
| amino acid transporters implicated in endocytosis of buchnera during symbiont transmission in the pea aphid. | many insects host their obligate, maternally transmitted symbiotic bacteria in specialized cells called bacteriocytes. one of the best-studied insect nutritional endosymbioses is that of the aphid and its endosymbiont, buchnera aphidicola. aphids and buchnera are metabolically and developmentally integrated, but the molecular mechanisms underlying buchnera transmission and coordination with aphid development remain largely unknown. previous work using electron microscopy to study aphid asexual e ... | 2016 | 27895889 |
| comparative analysis of rnai-based methods to down-regulate expression of two genes expressed at different levels in myzus persicae. | with the increasing availability of aphid genomic data, it is necessary to develop robust functional validation methods to evaluate the role of specific aphid genes. this work represents the first study in which five different techniques, all based on rna interference and on oral acquisition of double-stranded rna (dsrna), were developed to silence two genes, aly and eph, potentially involved in polerovirus transmission by aphids. efficient silencing of only eph transcripts, which are less abund ... | 2016 | 27869783 |
| aphis glycines virus 2, a novel insect virus with a unique genome structure. | the invasive soybean aphid, aphis glycines, is a major pest in soybeans, resulting in substantial economic loss. we analyzed the a. glycines transcriptome to identify sequences derived from viruses of a. glycines. we identified sequences derived from a novel virus named aphis glycines virus 2 (apglv2). the assembled virus genome sequence was confirmed by reverse transcription polymerase chain reaction (rt-pcr) and sanger sequencing, conserved domains were characterized, and distribution, and tra ... | 2016 | 27869772 |
| when obligate partners melt down. | insect hosts derive benefits from their obligate symbionts, including nutrient supplementation and the ability to colonize otherwise inhospitable niches. but long-term symbionts sometimes also limit the ecological range of their hosts; in particular, they are often more temperature sensitive than the hosts themselves. even small increases in average temperature, comparable to those occurring under current conditions of climate change, can kill symbionts and, with them, their hosts. in some cases ... | 2016 | 27935842 |
| metabolic complementation in bacterial communities: necessary conditions and optimality. | bacterial communities may display metabolic complementation, in which different members of the association partially contribute to the same biosynthetic pathway. in this way, the end product of the pathway is synthesized by the community as a whole. however, the emergence and the benefits of such complementation are poorly understood. herein, we present a simple model to analyze the metabolic interactions among bacteria, including the host in the case of endosymbiotic bacteria. the model conside ... | 2016 | 27774085 |
| disruption of phenylalanine hydroxylase reduces adult lifespan and fecundity, and impairs embryonic development in parthenogenetic pea aphids. | phenylalanine hydroxylase (pah) is a key tyrosine-biosynthetic enzyme involved in neurological and melanin-associated physiological processes. despite extensive investigations in holometabolous insects, a pah contribution to insect embryonic development has never been demonstrated. here, we have characterized, for the first time, the pah gene in a hemimetabolous insect, the aphid acyrthosiphon pisum. phylogenetic and sequence analyses confirmed that appah is closely related to metazoan pah, exhi ... | 2016 | 27694983 |
| symbionts modify interactions between insects and natural enemies in the field. | eukaryotes commonly host communities of heritable symbiotic bacteria, many of which are not essential for their hosts' survival and reproduction. there is laboratory evidence that these facultative symbionts can provide useful adaptations, such as increased resistance to natural enemies. however, we do not know how symbionts affect host fitness when the latter are subject to attack by a natural suite of parasites and pathogens. here, we test whether two protective symbionts, regiella insecticola ... | 2016 | 27561159 |
| vat, an amazing gene conferring resistance to aphids and viruses they carry: from molecular structure to field effects. | we review half a century of research on cucumis melo resistance to aphis gossypii from molecular to field levels. the vat gene is unique in conferring resistance to both a. gossypii and the viruses it transmits. this double phenotype is aphid clone-dependent and has been observed in 25 melon accessions, mostly from asia. it is controlled by a cluster of genes including cc-nlr, which has been characterized in detail. copy-number polymorphisms (for the whole gene and for a domain that stands out i ... | 2016 | 27725823 |
| bacteriome-localized intracellular symbionts in pollen-feeding beetles of the genus dasytes (coleoptera, dasytidae). | several insect taxa are associated with intracellular symbionts that provision limiting nutrients to their hosts. such tightly integrated symbioses are especially common in insects feeding on nutritionally challenging diets like phloem sap or vertebrate blood, but also occur in seed-eating and omnivorous taxa. here, we characterize an intracellular symbiosis in pollen-feeding beetles of the genus dasytes (coleoptera, dasytidae). high-throughput tag-encoded 16s amplicon pyrosequencing of adult d. ... | 2016 | 27713733 |
| genome sequence of candidatus arsenophonus lipopteni, the exclusive symbiont of a blood sucking fly lipoptena cervi (diptera: hippoboscidae). | candidatus arsenophonus lipopteni (enterobacteriaceae, gammaproteobacteria) is an obligate intracellular symbiont of the blood feeding deer ked, lipoptena cervi (diptera: hippoboscidae). the bacteria reside in specialized cells derived from host gut epithelia (bacteriocytes) forming a compact symbiotic organ (bacteriome). compared to the closely related complex symbiotic system in the sheep ked, involving four bacterial species, lipoptena cervi appears to maintain its symbiosis exclusively with ... | 2016 | 27660670 |
| biology, pest status, microbiome and control of kudzu bug (hemiptera: heteroptera: plataspidae): a new invasive pest in the u.s. | soybean is an important food crop, and insect integrated pest management (ipm) is critical to the sustainability of this production system. in recent years, the introduction into the united states of the kudzu bug currently identified as megacopta cribraria (f.), poses a threat to soybean production. the kudzu bug was first discovered in the state of georgia, u.s. in 2009 and since then has spread to most of the southeastern states. because it was not found in the north american subcontinent bef ... | 2016 | 27649166 |
| draft genome sequence of the bactrocera oleae symbiont "candidatus erwinia dacicola". | "candidatus erwinia dacicola" is a gammaproteobacterium that forms a symbiotic association with the agricultural pest bactrocera oleae here, we present a 2.1-mb draft hybrid genome assembly for "ca. erwinia dacicola" generated from single-cell and metagenomic data. | 2016 | 27634990 |
| essential functions linked with structural disorder in organisms of minimal genome. | intrinsically disordered regions (idrs) of proteins fulfill important regulatory roles in most organisms. however, the proteins of certain endosymbiont and intracellular pathogenic bacteria with extremely reduced genomes contain disproportionately small amounts of idrs, consisting almost entirely of folded domains. as their genomes co-evolving with their hosts have been reduced in unrelated lineages, the proteomes of these bacteria represent independently evolved minimal protein sets. we systema ... | 2016 | 27608806 |
| snapshots of a shrinking partner: genome reduction in serratia symbiotica. | genome reduction is pervasive among maternally-inherited endosymbiotic organisms, from bacteriocyte- to gut-associated ones. this genome erosion is a step-wise process in which once free-living organisms evolve to become obligate associates, thereby losing non-essential or redundant genes/functions. serratia symbiotica (gammaproteobacteria), a secondary endosymbiont present in many aphids (hemiptera: aphididae), displays various characteristics that make it a good model organism for studying gen ... | 2016 | 27599759 |
| insect symbionts in food webs. | recent research has shown that the bacterial endosymbionts of insects are abundant and diverse, and that they have numerous different effects on their hosts' biology. here we explore how insect endosymbionts might affect the structure and dynamics of insect communities. using the obligate and facultative symbionts of aphids as an example, we find that there are multiple ways that symbiont presence might affect food web structure. many symbionts are now known to help their hosts escape or resist ... | 2016 | 27481779 |
| symbiosis studies in microbial ecology. | | 2016 | 27682576 |
| convergent evolution of trna gene targeting preferences in compact genomes. | in gene-dense genomes, mobile elements are confronted with highly selective pressure to amplify without causing excessive damage to the host. the targeting of trna genes as potentially safe integration sites has been developed by retrotransposons in various organisms such as the social amoeba dictyostelium discoideum and the yeast saccharomyces cerevisiae. in d. discoideum, trna gene-targeting retrotransposons have expanded to approximately 3 % of the genome. recently obtained genome sequences o ... | 2016 | 27583033 |
| small rna regulators of plant-hemipteran interactions: micromanagers with versatile roles. | non-coding small rnas (srnas) in plants have important roles in regulating biological processes, including development, reproduction, and stress responses. recent research indicates significant roles for srna-mediated gene silencing during plant-hemipteran interactions that involve all three of these biological processes. plant responses to hemipteran feeding are determined by changes in the host transcriptome that appear to be fine-tuned by srnas. the role of srna in plant defense responses is ... | 2016 | 27625654 |
| novel insights into insect-microbe interactions-role of epigenomics and small rnas. | it has become increasingly clear that microbes form close associations with the vast majority of animal species, especially insects. in fact, an array of diverse microbes is known to form shared metabolic pathways with their insect hosts. a growing area of research in insect-microbe interactions, notably for hemipteran insects and their mutualistic symbionts, is to elucidate the regulation of this inter-domain metabolism. this review examines two new emerging mechanisms of gene regulation and th ... | 2016 | 27540386 |
| heat sensitivity of wmel wolbachia during aedes aegypti development. | the wmel strain of wolbachia bacteria is known to prevent dengue and zika virus transmission in the mosquito vector aedes aegypti. accordingly, the release of wmel-infected a. aegypti in endemic regions has been recommended by the world health organization as a potential strategy for controlling dengue and zika outbreaks. however, the utility of this approach could be limited if high temperatures in the aquatic habitats where a. aegypti develop are detrimental to wolbachia. we exposed wmel-infec ... | 2016 | 27459519 |
| ribosomal frameshifting and transcriptional slippage: from genetic steganography and cryptography to adventitious use. | genetic decoding is not 'frozen' as was earlier thought, but dynamic. one facet of this is frameshifting that often results in synthesis of a c-terminal region encoded by a new frame. ribosomal frameshifting is utilized for the synthesis of additional products, for regulatory purposes and for translational 'correction' of problem or 'savior' indels. utilization for synthesis of additional products occurs prominently in the decoding of mobile chromosomal element and viral genomes. one class of re ... | 2016 | 27436286 |
| bacterial cell biology outside the streetlight. | as much as vertical transmission of microbial symbionts requires their deep integration into the host reproductive and developmental biology, symbiotic lifestyle might profoundly affect bacterial growth and proliferation. this review describes the reproductive oddities displayed by bacteria associated - more or less intimately - with multicellular eukaryotes. | 2016 | 27306428 |
| correction for traverse and ochman, conserved rates and patterns of transcription errors across bacterial growth states and lifestyles. | | 2016 | 27402746 |
| cellular and molecular remodelling of a host cell for vertical transmission of bacterial symbionts. | various insects require intracellular bacteria that are restricted to specialized cells (bacteriocytes) and are transmitted vertically via the female ovary, but the transmission mechanisms are obscure. we hypothesized that, in the whitefly bemisia tabaci, where intact bacteriocytes (and not isolated bacteria) are transferred to oocytes, the transmission mechanism would be evident as cellular and molecular differences between the nymph (pre-adult) and adult bacteriocytes. we demonstrate dramatic ... | 2016 | 27358364 |
| defying muller's ratchet: ancient heritable endobacteria escape extinction through retention of recombination and genome plasticity. | heritable endobacteria, which are transmitted from one host generation to the next, are subjected to evolutionary forces that are different from those experienced by free-living bacteria. in particular, they suffer consequences of muller's ratchet, a mechanism that leads to extinction of small asexual populations due to fixation of slightly deleterious mutations combined with the random loss of the most-fit genotypes, which cannot be recreated without recombination. mycoplasma-related endobacter ... | 2016 | 27329757 |
| genome evolution in the obligate but environmentally active luminous symbionts of flashlight fish. | the luminous bacterial symbionts of anomalopid flashlight fish are thought to be obligately dependent on their hosts for growth and share several aspects of genome evolution with unrelated obligate symbionts, including genome reduction. however, in contrast to most obligate bacteria, anomalopid symbionts have an active environmental phase that may be important for symbiont transmission. here we investigated patterns of evolution between anomalopid symbionts compared with patterns in free-living ... | 2016 | 27389687 |
| seasonal changes in the endosymbiotic consortia of aphids from the genus cinara. | buchnera aphidicola is the primary endosymbiont of aphids with which it maintains an obligate mutualistic symbiotic relationship. insects also maintain facultative symbiotic relationships with secondary symbionts, and serratia symbiotica is the most common in aphids. the presence of both symbionts in aphids of the subfamily lachninae has been widely studied by our group. we examined two closely related aphids, cinara tujafilina and c. cedri in the present study. even though both b. aphidicola st ... | 2016 | 27297891 |
| reinventing the wheel and making it round again: evolutionary convergence in buchnera-serratia symbiotic consortia between the distantly related lachninae aphids tuberolachnus salignus and cinara cedri. | virtually all aphids (aphididae) harbor buchnera aphidicola as an obligate endosymbiont to compensate nutritional deficiencies arising from their phloem diet. many species within the lachninae subfamily seem to be consistently associated also with serratia symbiotica we have previously shown that both cinara (cinara) cedri and cinara (cupressobium) tujafilina (lachninae: eulachnini tribe) have indeed established co-obligate associations with both buchnera and s. symbiotica however, while buchner ... | 2016 | 27190007 |
| nitrogen hurdle of host alternation for a polyphagous aphid and the associated changes of endosymbionts. | low proportion of essential amino acids (eaas) is one of the barriers for animals to use phloem as a diet. endosymbionts with eaas synthesis functions are considered crucial for ameliorating the lack of eaas in insects' diets. in this study, we transferred the insects from a cabbage-reared myzus persicae population onto 3 new plant species including eggplant, tobacco and spinach. the performance on these plants was evaluated and the dynamics of endosymbionts in relation to this host alternation ... | 2016 | 27094934 |
| bacterial communities of the cotton aphid aphis gossypii associated with bt cotton in northern china. | aphids are infected with a wide variety of endosymbionts that can confer ecologically relevant traits. however, the bacterial communities of most aphid species are still poorly characterized. this study investigated the bacterial diversity of the cotton aphid aphis gossypii associated with bt cotton in northern china by targeting the v4 region of the 16s rdna using the illumina miseq platform. our sequencing data revealed that bacterial communities of a. gossypii were generally dominated by the ... | 2016 | 27079679 |
| host plant determines the population size of an obligate symbiont (buchnera aphidicola) in aphids. | buchnera aphidicolais an obligate endosymbiont that provides aphids with several essential nutrients. though much is known about aphid-buchnera interactions, the effect of the host plant on buchnera population size remains unclear. here we used quantitative pcr (qpcr) techniques to explore the effects of the host plant on buchnera densities in the cotton-melon aphid, aphis gossypii buchneratiters were significantly higher in populations that had been reared on cucumber for over 10 years than in ... | 2016 | 26850304 |
| holes in the hologenome: why host-microbe symbioses are not holobionts. | the advent of relatively inexpensive tools for characterizing microbial communities has led to an explosion of research exploring the diversity, ecology, and evolution of microbe-host systems. some now question whether existing conceptual frameworks are adequate to explain microbe-host systems. one popular paradigm is the "holobiont-hologenome," which argues that a host and its microbiome evolve as a single cooperative unit of selection (i.e., a superorganism). we argue that the hologenome is ba ... | 2016 | 27034285 |