| partitioning of symbiotic bacteria between generations of an insect: a quantitative study of a buchnera sp. in the pea aphid (acyrthosiphon pisum) reared at different temperatures. | the population of symbiotic buchnera bacteria in parthenogenetic females of the pea aphid acyrthosiphon pisum was determined by quantitative hybridization of a dna probe (groesl) to aphid homogenates. the aphids bore 1 x 10(sup7) to 2 x 10(sup7) bacterial cells per mg (fresh weight). in teneral aphids (i.e., aphids that had moulted to adulthood but that had not initiated reproduction), >75% of the bacteria were in the embryos, and the density of bacteria in the embryos was consistently greater t ... | 1997 | 16535678 |
| a dual-genome microarray for the pea aphid, acyrthosiphon pisum, and its obligate bacterial symbiont, buchnera aphidicola. | the best studied insect-symbiont system is that of aphids and their primary bacterial endosymbiont buchnera aphidicola. buchnera inhabits specialized host cells called bacteriocytes, provides nutrients to the aphid and has co-speciated with its aphid hosts for the past 150 million years. we have used a single microarray to examine gene expression in the pea aphid, acyrthosiphon pisum, and its resident buchnera. very little is known of gene expression in aphids, few studies have examined gene exp ... | 2006 | 16536873 |
| costs and benefits of symbiont infection in aphids: variation among symbionts and across temperatures. | symbiosis is prevalent throughout the tree of life and has had a significant impact on the ecology and evolution of many bacteria and eukaryotes. the benevolence of symbiotic interactions often varies with the environment, and such variation is expected to play an important role in shaping the prevalence and distributions of symbiosis throughout nature. in this study, we examine how the fitness of aphids is influenced by infection with one of three maternally transmitted bacteria, 'candidatus se ... | 2006 | 16537132 |
| attributes of bean yellow mosaic potyvirus transmission from clover to snap beans by four species of aphids (homoptera: aphididae). | after characterization of the natural spread of necrosis-inducing bean yellow mosaic potyvirus (family potyviridae, genus potyvirus, bymv(n)), nonpersistently transmitted from clover, trifolium repens l., to an adjacent field of snap bean, phaseolus vulgaris l., in western oregon, we established a study site enabling us to investigate the virus reservoir, to observe en masse transmission of bymv(n) to bean plants, and to identify aphid species associated with virus spread. colonies of myzus pers ... | 2005 | 16539099 |
| effects of hydrophilic and hydrophobic kaolin-based particle films on pea aphid (homoptera: aphididae) and its entomopathogen pandora neoaphidis (entomophthorales: entomophthoraceae). | hydrophobic and hydrophilic kaolin-based particle films are effective for control of insect pests in certain agricultural crops. how these products interact with potential biological control agents is not well documented. this study was conducted to evaluate the effects of the hydrophobic (m96-018) and hydrophilic (surround wp) kaolin-based particle films (engelhard corporation, iselin, nj) on pea aphid, acyrthosiphon pisum (harris), on peas (pisum spp.), and on the fungal aphid pathogen pandora ... | 2006 | 16573319 |
| symbiont modifies host life-history traits that affect gene flow. | the evolution of herbivore-host plant specialization requires low levels of gene flow between populations on alternate plant species. accordingly, selection for host plant specialization is most effective when genotypes have minimal exposure to, and few mating opportunities with individuals from, alternate habitats. maternally transmitted bacterial symbionts are common in insect herbivores and can influence host fecundity under a variety of conditions. symbiont-mediated effects on host life-hist ... | 2006 | 16600884 |
| phylogeny of the sex-determining gene sex-lethal in insects. | the sex-lethal (sxl) protein belongs to the family of rna-binding proteins and is involved in the regulation of pre-mrna splicing. sxl has undergone an obvious change of function during the evolution of the insect clade. the gene has acquired a pivotal role in the sex-determining pathway of drosophila, although it does not act as a sex determiner in non-drosophilids. we collected sxl sequences of insect species ranging from the pea aphid (acyrtho siphom pisum) to drosophila melanogaster by searc ... | 2006 | 16604108 |
| functional genomics of buchnera and the ecology of aphid hosts. | in many animal groups, mutualistic bacterial symbionts play a central role in host ecology, by provisioning rare nutrients and thus enabling specialization on restricted diets. among such symbionts, genomic studies are most advanced for buchnera, the obligate symbiont of aphids, which feed on phloem sap. the contents of the highly reduced buchnera genomes have verified its role in aphid nutrition. comparisons of buchnera gene sets indicate ongoing, irreversible gene losses that are expected to a ... | 2006 | 16626452 |
| the effect of predators and hymenopterous parasites on population fluctuations of alfalfa aphids. | among alfalfa pests in iran three aphid species, green alfalfa aphid acyrthosiphon pisum harris spotted alfalfa aphid therioaphis trifolii forma maculata buckton and blue alfalfa aphid, acyrthosiphon kondoi shinji are important pests. the green alfalfa aphid can be observed all along the growing season particularly from late may to mid june at karaj climate conditions. during this period, the mean monthly maximum temperature and relative humidity were about 28 degrees c and 60-65% respectively. ... | 2005 | 16628912 |
| infectivity of nanovirus dnas: induction of disease by cloned genome components of faba bean necrotic yellows virus. | circumstantial evidence suggests that the genome of faba bean necrotic yellows virus (fbnyv), a nanovirus, consists of eight distinct, circular, single-stranded dnas, each of about 1 kb and encoding only one protein. here, the use of cloned full-length fbnyv dnas for reproducing fbnyv-like symptoms in vicia faba, the principal natural host of fbnyv, is reported. characteristic symptoms of fbnyv infection were obtained in faba bean plants following biolistic dna delivery or agroinoculation with a ... | 2006 | 16690940 |
| costs and benefits of a superinfection of facultative symbionts in aphids. | symbiotic associations between animals and inherited micro-organisms are widespread in nature. in many cases, hosts may be superinfected with multiple inherited symbionts. acyrthosiphon pisum (the pea aphid) may harbour more than one facultative symbiont (called secondary symbionts) in addition to the obligate primary symbiont, buchnera aphidicola. previously we demonstrated that, in a controlled genetic background, a. pisum infected with either serratia symbiotica or hamiltonella defensa (calle ... | 2006 | 16720402 |
| learning by the parasitoid wasp, aphidius ervi (hymenoptera: braconidae), alters individual fixed preferences for pea aphid color morphs. | learning, defined as changes in behavior that occur due to past experience, has been well documented for nearly 20 species of hymenopterous parasitoids. few studies, however, have explored the influence of learning on population-level patterns of host use by parasitoids in field populations. our study explores learning in the parasitoid aphidius ervi haliday that attacks pea aphids, acyrthosiphon pisum (harris). we used a sequence of laboratory experiments to investigate whether there is a learn ... | 2006 | 16858585 |
| hundreds of flagellar basal bodies cover the cell surface of the endosymbiotic bacterium buchnera aphidicola sp. strain aps. | buchnera aphidicola is the endosymbiotic bacterium of the pea aphid. due to its small genome size, buchnera lacks many essential genes for autogenous life but obtains nutrients from the host. although the buchnera cell is nonmotile, it retains clusters of flagellar genes that lack the late genes necessary for motility, including the flagellin gene. in this study, we show that the flagellar genes are actually transcribed and translated and that the buchnera cell surface is covered with hundreds o ... | 2006 | 16952945 |
| codon usage bias and trna over-expression in buchnera aphidicola after aromatic amino acid nutritional stress on its host acyrthosiphon pisum. | codon usage bias and relative abundances of trna isoacceptors were analysed in the obligate intracellular symbiotic bacterium, buchnera aphidicola from the aphid acyrthosiphon pisum, using a dedicated 35mer oligonucleotide microarray. buchnera is archetypal of organisms living with minimal metabolic requirements and presents a reduced genome with high-evolutionary rate. codonusage in buchnera has been overcome by the high mutational bias towards at bases. however, several lines of evidence for c ... | 2006 | 16963497 |
| cytochrome c oxidase mrna as an internal control for detection of potato virus y and potato leafroll virus from single aphids by a co-amplification rt-pcr assay. | using cytochrome c oxidase subunit 1 (cox1) mrna as the internal control, a triplex reverse transcription-polymerase chain reaction (rt-pcr) for detection of potato virus y (pvy) and potato leafroll virus (plrv) with co-amplification of cox1 from single specimens of various aphid species has been developed. partial length cdna of cox1 from green peach aphid, myzus persicae (sulzer), potato aphid, macrosiphum euphorbiae (thomas), buckthorn aphid, aphis nasturtii (kaltenbach), and pea aphid, acyrt ... | 2006 | 17010449 |
| covariance of phenotypically plastic traits induces an adaptive shift in host selection behaviour. | flexibility in adult body size allows generalist parasitoids to use many host species at a cost of producing a range of adult sizes. consequently, host selection behaviour must also maintain a level of flexibility as adult size is related to capture efficiency. in the present study, we investigated covariance of two plastic traits--size at pupation and host size selection behaviour-using aphidius ervi reared on either acyrthosiphon pisum or aulacorthum solani, generating females of disparate siz ... | 2006 | 17015365 |
| role of host nutrition in symbiont regulation: impact of dietary nitrogen on proliferation of obligate and facultative bacterial endosymbionts of the pea aphid acyrthosiphon pisum. | the impact of host nutrition on symbiont regulation in the pea aphid acyrthosiphon pisum was investigated. the population density of the obligate symbiont buchnera aphidicola positively correlated with dietary nitrogen levels. in contrast, the population density of the facultative symbiont serratia symbiotica increased in aphids reared on low-nitrogen diets, indicating distinct regulatory mechanisms in the same insect host. | 2007 | 17158610 |
| aphidbase: a database for aphid genomic resources. | aphidbase aims to (i) store recently acquired genomic resources on aphids and (ii) compare them to other insect resources as functional annotation tools. for that, the drosophila melanogaster genome has been loaded in the database using the gmod open source software for a comparison with the 17 069 pea aphid unique transcripts (contigs) and the 13 639 gene transcripts of the anopheles gambiae. links to flybase and a.gambiae entrez databases allow a rapid characterization of the putative function ... | 2007 | 17237053 |
| selective elimination of aphid endosymbionts: effects of antibiotic dose and host genotype, and fitness consequences. | multiple endosymbionts commonly coexist in the same host insects. in order to gain an understanding of the biological roles of the individual symbionts in such complex systems, experimental techniques for enabling the selective removal of a specific symbiont from the host are of great importance. by using the pea aphid-buchnera-serratia endosymbiotic system as a model, the efficacy, generality, and fitness consequences of selective elimination techniques at various antibiotic doses and under a v ... | 2007 | 17313660 |
| genetic variation in the effect of a facultative symbiont on host-plant use by pea aphids. | ecological specialisation on different host plants occurs frequently among phytophagous insects and is normally assumed to have a genetic basis. however, insects often carry microbial symbionts, which may play a role in the evolution of specialisation. the bacterium regiella insecticola is a facultative symbiont of pea aphids (acyrthosiphon pisum) where it is found most frequently in aphid clones feeding on trifolium giving rise to the hypothesis that it may improve aphid performance on this pla ... | 2007 | 17415589 |
| aphid thermal tolerance is governed by a point mutation in bacterial symbionts. | symbiosis is a ubiquitous phenomenon generating biological complexity, affecting adaptation, and expanding ecological capabilities. however, symbionts, which can be subject to genetic limitations such as clonality and genomic degradation, also impose constraints on hosts. a model of obligate symbiosis is that between aphids and the bacterium buchnera aphidicola, which supplies essential nutrients. we report a mutation in buchnera of the aphid acyrthosiphon pisum that recurs in laboratory lines a ... | 2007 | 17425405 |
| a gamma-glutamyl transpeptidase of aphidius ervi venom induces apoptosis in the ovaries of host aphids. | parasitism by the endophagous braconid aphidius ervi (hymenoptera, braconidae) has a negative impact on the reproductive activity of its host, acyrthosiphon pisum (homoptera, aphididae). the host castration is induced by the parasitoid venom and is reproduced by the injection of chromatographic fractions highly enriched with two proteins, of 18 (p18) and 36 kda (p36) in size, respectively. here we demonstrate that these bioactive proteins trigger apoptosis of the cells in the germaria and ovario ... | 2007 | 17456440 |
| antibiotics, primary symbionts and wing polyphenism in three aphid species. | the possible role of the primary buchnera symbionts in wing polyphenism is examined in three aphid species. presumptive winged aphids were fed on antibiotic-treated beans to destroy these symbionts. as previously reported, this leads to inhibited growth and low/zero fecundity. when such treatment is applied to the short-day-induced gynoparae (the winged autumn migrant) of the black bean aphid, aphis fabae, it also causes many insects to develop as wingless or winged/wingless intermediate adult f ... | 2007 | 17628287 |
| effect of seasonal abiotic conditions and field margin habitat on the activity of pandora neoaphidis inoculum on soil. | the ability of the aphid pathogenic fungus pandora neoaphidis to remain active in the absence of a resting stage through a combination of continuous infection and as conidia deposited on soil was assessed alongside the potential for planted field margins to act as a refuge for the fungus. p. neoaphidis was able to infect the pea aphid, acyrthosiphon pisum, when maintained under controlled conditions that simulated those that occur seasonally in the uk. although there was a significant inverse re ... | 2008 | 17964597 |
| population dynamics of defensive symbionts in aphids. | vertically transmitted micro-organisms can increase in frequency in host populations by providing net benefits to hosts. while laboratory studies have identified diverse beneficial effects conferred by inherited symbionts of insects, they have not explicitly examined the population dynamics of mutualist symbiont infection within populations. in the pea aphid, acyrthosiphon pisum, the inherited facultative symbiont, hamiltonella defensa, provides protection against parasitism by the wasp, aphidiu ... | 2008 | 18029301 |
| transmission of symbiotic bacteria buchnera to parthenogenetic embryos in the aphid acyrthosiphon pisum (hemiptera: aphidoidea). | all phloem-feeding aphids have an absolute requirement for their primary bacterial symbionts buchnera sp. the bacteria are transmitted vertically to either embryos in the viviparous morph or to eggs in the oviparous morph, with the implication that the symbiont population regularly passes through a genetic 'bottleneck', i.e. only a small proportion of the maternal symbiont population is transmitted to offspring. in this paper, we visualise this process in viviparous aphids using a specific immun ... | 2003 | 18089009 |
| evolutionary genetics of a defensive facultative symbiont of insects: exchange of toxin-encoding bacteriophage. | the facultative endosymbiont of aphids, hamiltonella defensa, kills parasitoid wasp larvae, allowing aphid hosts to survive and reproduce. this protection may depend on toxins that are encoded by the genomes of h. defensa and of its bacteriophage (apse). strains of h. defensa vary in degree of protection conferred upon acyrthosiphon pisum (pea aphid). although h. defensa is known to undergo some horizontal transmission among aphid maternal lineages, divergence, recombination, and population stru ... | 2008 | 18179430 |
| insecticidal activity of a basement membrane-degrading protease against heliothis virescens (fabricius) and acyrthosiphon pisum (harris). | scathl is a cathepsin l-like cysteine protease derived from the flesh fly sarcophaga peregrina that functions in basement membrane (bm) remodeling during insect development. a recombinant baculovirus expressing scathl (acmlf9.scathl) kills larvae of the tobacco budworm, heliothis virescens, significantly faster than the wild-type virus. here, we show that the occurrence of larval melanization prior to death was closely associated with the onset of high cysteine protease activity of scathl in the ... | 2008 | 18395222 |
| [effects of cutting on the population dynamics of main insect pests on alfalfa]. | a systematic investigation was made on the effects of cutting on the population dynamics of main insect pests on alfalfa in dingxi of gansu province. the results showed that the effects of cutting varied significantly with the kinds of insect pests. the seasonal average population densities of therioaphis trifolii, acyrthosiphon pisum and thrips decreased significantly and maintained at a low level under the first cutting in early june, but less variation was observed under the second cutting in ... | 2008 | 18533546 |
| complex interactions between a plant pathogen and insect parasitoid via the shared vector-host: consequences for host plant infection. | plant viruses modify the development of their aphid vectors by inducing physiological changes in the shared host plant. the performance of hymenopterous parasitoids exploiting these aphids can also be modified by the presence of the plant pathogen. we used laboratory and glasshouse microcosms containing beans (vicia faba) as the host plant to examine the interactions between a plant virus (pea enation mosaic virus; pemv) and a hymenopterous parasitoid (aphidius ervi) that share the aphid vector/ ... | 2008 | 18566836 |
| featured organism: reductive evolution in bacteria: buchnera sp., rickettsia prowazekii and mycobacterium leprae. | obligate intracellular bacteria commonly have much reduced genome sizes compared to their nearest free-living relatives. one reason for this is reductive evolution: the loss of genes rendered non-essential due to the intracellular habitat. this can occur because of the presence of orthologous genes in the host, combined with the ability of the bacteria to import the protein or metabolite products of the host genes. in this article we take a look at three such bacteria whose genomes have been ful ... | 2001 | 18628941 |
| the insecticidal activity of recombinant garlic lectins towards aphids. | the heterodimeric and homodimeric garlic lectins asai and asaii were produced as recombinant proteins in the yeast pichia pastoris. the proteins were purified as functional dimeric lectins, but underwent post-translational proteolysis. recombinant asaii was a single homogenous polypeptide which had undergone c-terminal processing similar to that occurring in planta. the recombinant asai was glycosylated and subject to variable and heterogenous proteolysis. both lectins showed insecticidal effect ... | 2008 | 18707000 |
| in silico analyses of peptide paracrines/hormones in aphidoidea. | the aphidoidea is an insect superfamily comprising most of the known aphid species. while small in size, these animals are of considerable economic importance as many members of this taxon are serious agricultural pests, inflicting physical damage upon crop plants and serving as vectors in the transmission of viral plant diseases. in terms of identifying the paracrines/hormones used to modulate behavior, particularly peptides, members of the aphidoidea have largely been ignored, as it is not tra ... | 2008 | 18725225 |
| evaluation of artificial diets for rearing aphis glycines (hemiptera: aphididae). | artificial aphid diets have been previously developed for the pea aphid, acyrthosiphon pisum (harris), and the green peach aphid, myzus persicae (sulzer). the ability to rear aphids on an artificial diet allows for selectively adding or subtracting compounds from an aphid's food source to determine the effect on fecundity and longevity. five diets previously developed for the green peach aphid and the pea aphid were tested for their suitability for rearing soybean aphid, aphis glycines matsumura ... | 2008 | 18767731 |
| plum pox in north america: identification of aphid vectors and a potential role for fruit in virus spread. | abstract thirteen aphid species were tested for their ability to transmit pennsylvania isolates of plum pox virus (ppv) collected in columbia (penn-3), franklin (penn-4), and york (penn-7) counties, pa. four species, aphis fabae, a. spiraecola, brachycaudus persicae, and myzus persicae, consistently transmitted ppv in preliminary transmission tests. two species, metopolophium dirhodum and rhopalosiphum padi, were occasional inefficient vectors. toxoptera citricida, from florida, also was an effe ... | 2004 | 18943108 |
| transmission efficiency of cucumber mosaic virus by aphids associated with virus epidemics in snap bean. | cucumber mosaic virus (cmv) is a major component of the virus complex that has become more pronounced in snap bean in the midwestern and northeastern united states since 2001. multiple-vector-transfer tests were done to estimate the cmv transmission efficiencies (p) of the main aphid species identified in commercial snap bean fields in new york and pennsylvania. the four most efficient vectors (p > 0.05) were aphis gossypii, a. glycines, acyrthosiphon pisum, and therioaphis trifolii, which were ... | 2008 | 18943413 |
| the n-terminal region of the readthrough domain is closely related to aphid vector specificity of soybean dwarf virus. | abstract it has been speculated that the n-terminal half of the readthrough domain (rtd) encoded by open reading frame 5 of soybean dwarf virus (sbdv) is related to the vector specificity. to further investigate this hypothesis, transmissibility via aphids was tested on 17 sbdv isolates and comparisons of the deduced amino acid sequences of the coat protein (cp) and other proteins encoded by the rtd were made between these isolates. isolates were distinguished into four strains: ys, causing yell ... | 2003 | 18943620 |
| identification, characterization, and relatedness of luteovirus isolates from forage legumes. | abstract virus isolates from forage legumes collected from eight different states were identified as luteoviruses closely related to soybean dwarf luteovirus dwarfing (sbdv-d) and yellowing (sbdv-y) described in japan. all isolates produced reddened leaf margins in subterranean clover and were transmitted in a persistent manner by acrythosiphon pisum, but not by aulacorthum solani. specific monoclonal antibodies raised against sbdv-y were differentially reactive with endemic isolates. immunoblot ... | 1999 | 18944749 |
| carbohydrate-binding activity of the type-2 ribosome-inactivating protein sna-i from elderberry (sambucus nigra) is a determining factor for its insecticidal activity. | in recent years, different classes of proteins have been reported to promote toxic effects when ingested. type-2 ribosome-inactivating proteins (rips) are a group of chimeric proteins built up of an a-chain with rna n-glycosidase activity and a b-chain with lectin activity. these proteins are thought to play a role in plant protection. sambucus nigra agglutinin i (sna-i) is a type-2 rip, isolated from the bark of elderberry (s. nigra l.). this study demonstrated the insecticidal potency of sna-i ... | 2008 | 18951590 |
| baculovirus-expressed virus-like particles of pea enation mosaic virus vary in size and encapsidate baculovirus mrnas. | pea enation mosaic virus (pemv: family luteoviridae) is transmitted in a persistent, circulative manner by aphids. we inserted cdnas encoding the structural proteins of pemv, the coat protein (cp) and coat protein-read through domain (cprt) into the genome of the baculovirus autographa californica multiple nucleopolyhedrovirus with and without a histidine tag or an upstream kozak consensus sequence. the sf21 cell line provided the highest level of cp expression of the cell lines tested and resul ... | 2009 | 19013202 |
| symbiotic bacteria enable insect to use a nutritionally inadequate diet. | animals generally require a dietary supply of various nutrients (vitamins, essential amino acids, etc.) because their biosynthetic capabilities are limited. the capacity of aphids to use plant phloem sap, with low essential amino acid content, has been attributed to their symbiotic bacteria, buchnera aphidicola, which can synthesize these nutrients; but this has not been demonstrated empirically. we demonstrate here that phloem sap obtained from the severed stylets of pea aphids acyrthosiphon pi ... | 2009 | 19129128 |
| the dynamics and time scale of ongoing genomic erosion in symbiotic bacteria. | among cellular organisms, symbiotic bacteria provide the extreme examples of genome degradation and reduction. however, only isolated snapshots of eroding symbiont genomes have previously been available. we documented the dynamics of symbiont genome evolution by sequencing seven strains of buchnera aphidicola from pea aphid hosts. we estimated a spontaneous mutation rate of at least 4 x 10(-9) substitutions per site per replication, which is more than 10 times as high as the rates previously est ... | 2009 | 19150844 |
| do plant viruses facilitate their aphid vectors by inducing symptoms that alter behavior and performance? | aphids can respond both positively and negatively to virus-induced modifications of the shared host plant. it can be speculated that viruses dependent on aphids for their transmission might evolve to induce changes in the host plant that attract aphids and improve their performance, subsequently enhancing the success of the pathogen itself. we studied how pea aphids [acyrthosiphon pisum (harris)] responded to infection of tic beans (vicia faba l.) by three viruses with varying degrees of depende ... | 2008 | 19161702 |
| pea aphid as both host and vector for the phytopathogenic bacterium pseudomonas syringae. | aphids are widespread agricultural pests that are capable of disseminating plant viral diseases; however, despite coming into frequent contact with epiphytic bacteria, aphids are considered to have no role in bacterial transmission. here, we demonstrate the ability of pea aphids to vector the phytopathogen pseudomonas syringae pv. syringae b728a (psyb728a). while feeding on plants colonized by epiphytic bacteria, aphids acquire the bacteria, which colonize the digestive tract, multiply, and are ... | 2009 | 19201955 |
| allelic and genotypic diversity in long-term asexual populations of the pea aphid, acyrthosiphon pisum in comparison with sexual populations. | many aphid species exhibit geographical variation in the mode of reproduction that ranges from cyclical parthenogenesis with a sexual phase to obligate parthenogenesis (asexual reproduction). theoretical studies predict that organisms reproducing asexually should maintain higher allelic diversity per locus but lower genotypic diversity than organisms reproducing sexually. to corroborate this hypothesis, we evaluated genotypic and allelic diversities in the sexual and asexual populations of the p ... | 2009 | 19207245 |
| the insect caspases. | developmental and tissue homeostasis is a delicate balance between cell proliferation and cell death. the activation of caspases, a conserved family of cysteine proteases, is a main event in the initiation and execution of programmed cell death. while caspases have been characterized from many organisms, comparatively little is known about insect caspases. in drosophila melanogaster, seven caspases have been characterized; three initiators and four effectors. in mosquitoes, several putative casp ... | 2009 | 19212814 |
| genotypic variation and the role of defensive endosymbionts in an all-parthenogenetic host-parasitoid interaction. | models of host-parasite coevolution predict pronounced genetic dynamics if resistance and infectivity are genotype-specific or associated with costs, and if selection is fueled by sufficient genetic variation. we addressed these assumptions in the black bean aphid, aphis fabae, and its parasitoid lysiphlebus fabarum. parasitoid genotypes differed in infectivity and host clones exhibited huge variation for susceptibility. this variation occurred at two levels. clones harboring hamiltonella defens ... | 2009 | 19228189 |
| a fragile metabolic network adapted for cooperation in the symbiotic bacterium buchnera aphidicola. | in silico analyses provide valuable insight into the biology of obligately intracellular pathogens and symbionts with small genomes. there is a particular opportunity to apply systems-level tools developed for the model bacterium escherichia coli to study the evolution and function of symbiotic bacteria which are metabolically specialised to overproduce specific nutrients for their host and, remarkably, have a gene complement that is a subset of the e. coli genome. | 2009 | 19232131 |
| the readthrough domain of pea enation mosaic virus coat protein is not essential for virus stability in the hemolymph of the pea aphid. | a fraction of the coat protein (cp) subunits in virions of members of the family luteoviridae contain a c-terminal extension called the readthrough domain (rtd). the rtd is necessary for persistent aphid transmission, but its role is unknown. it has been reported to be required for virion stability in the hemolymph. here, we tested whether this was the case for pea enation mosaic virus (pemv) virions in the pea aphid (acyrthosiphon pisum) using rna1delta, a natural deletion mutant lacking the mi ... | 2009 | 19240978 |
| species response to environmental change: impacts of food web interactions and evolution. | how environmental change affects species abundances depends on both the food web within which species interact and their potential to evolve. using field experiments, we investigated both ecological and evolutionary responses of pea aphids (acyrthosiphon pisum), a common agricultural pest, to increased frequency of episodic heat shocks. one predator species ameliorated the decrease in aphid population growth with increasing heat shocks, whereas a second predator did not, with this contrast cause ... | 2009 | 19265021 |
| aphids acquired symbiotic genes via lateral gene transfer. | aphids possess bacteriocytes, which are cells specifically differentiated to harbour the obligate mutualist buchnera aphidicola (gamma-proteobacteria). buchnera has lost many of the genes that appear to be essential for bacterial life. from the bacteriocyte of the pea aphid acyrthosiphon pisum, we previously identified two clusters of expressed sequence tags that display similarity only to bacterial genes. southern blot analysis demonstrated that they are encoded in the aphid genome. in this stu ... | 2009 | 19284544 |
| effects of bacillus thuringiensis delta-endotoxins on the pea aphid (acyrthosiphon pisum). | four bacillus thuringiensis delta-endotoxins, cry3a, cry4aa, cry11aa, and cyt1aa, were found to exhibit low to moderate toxicity on the pea aphid, acyrthosiphon pisum, in terms both of mortality and growth rate. cry1ab was essentially nontoxic except at high rates. to demonstrate these effects, we had to use exhaustive buffer-based controls. | 2009 | 19447954 |
| acid-base-driven matrix-assisted mass spectrometry for targeted metabolomics. | the ability to charge huge biomolecules without breaking them apart has made matrix-assisted laser desorption/ionization (maldi) mass spectrometry an indispensable tool for biomolecular analysis. conventional, empirically selected matrices produce abundant matrix ion clusters in the low-mass region (<500 da), hampering the application of maldi-ms to metabolomics. an ionization mode of maild, a rational protocol for matrix selection based on brønsted-lowry acid-base theory and its application to ... | 2009 | 19520825 |
| impact of environmental stress on aphid clonal resistance to parasitoids: role of hamiltonella defensa bacterial symbiosis in association with a new facultative symbiont of the pea aphid. | resistance to endoparasitoids in aphids involves complex interactions between insect and microbial players. it is now generally accepted that the facultative bacterial symbiont hamiltonella defensa of the pea aphid acyrthosiphon pisum is implicated in its resistance to the parasitoid aphidius ervi. it has also been shown that heat negatively affects pea aphid resistance, suggesting the thermosensitivity of its defensive symbiosis. here we examined the effects of heat and uv-b on the resistance o ... | 2009 | 19545573 |
| effects of manduca sexta allatostatin and an analog on the pea aphid acyrthosiphon pisum (hemiptera: aphididae) and degradation by enzymes from the aphid gut. | the c-type allatostatin, manduca sexta allatostatin (manse-as) and the analog delta r(3)delta r(5)manse-as, where r residues were replaced by their d-isomers, were tested for oral toxicity against the pea aphid acyrthosiphon pisum (harris) by incorporation into an artificial diet. both peptides had significant dose-dependent feeding suppression effects, resulting in mortality, reduced growth and fecundity compared with control insects. the delta r(3)delta r(5)manse-as analog had an estimated lc( ... | 2010 | 19560498 |
| morph-dependent expression and subcellular localization of host serine carboxypeptidase in bacteriocytes of the pea aphid associated with degradation of the endosymbiotic bacterium buchnera. | pea aphids form a mutualistic association with the endosymbiotic bacterium buchnera, which is harbored in specialized host cells called bacteriocytes. the adult aphids display dimorphism in which there are winged and wingless morphs. we previously reported that the buchnera density in bacteriocytes of the winged morph (alate) decreases around final ecdysis, whereas that in the wingless morph (aptera) does not decrease; the decrease in density in alatae is accompanied by activation of the host ly ... | 2009 | 19583501 |
| evolution of the gene lineage encoding the carbon dioxide receptor in insects. | a heterodimer of the insect chemoreceptors gr21a and gr63a has been shown to be the carbon dioxide receptor in drosophila melanogaster (meigen) (diptera: drosophilidae). comparison of the genes encoding these two proteins across the 12 available drosophilid fly genomes allows refined definition of their n-termini. these genes are highly conserved, along with a paralog of gr21a, in the anopheles gambiae, aedes aegypti, and culex pipiens mosquitoes, as well as in the silk moth bombyx mori and the ... | 2009 | 19613462 |
| reconstitution of authentic nanovirus from multiple cloned dnas. | we describe a new plant single-stranded dna (ssdna) virus, a nanovirus isolate originating from the faba bean in ethiopia. we applied rolling circle amplification (rca) to extensively copy the individual circular dnas of the nanovirus genome. by sequence analyses of more than 208 individually cloned genome components, we obtained a representative sample of eight polymorphic swarms of circular dnas, each about 1 kb in size. from these heterogeneous dna populations after rca, we inferred consensus ... | 2009 | 19656882 |
| intraguild interactions between the entomopathogenic fungus pandora neoaphidis and an aphid predator and parasitoid at the population scale. | the interactions that occur between the entomopathogenic fungus pandora neoaphidis and a predator (coccinella septempunctata) and a parasitoid (aphidius ervi) were assessed in microcosm and polytunnel experiments. transmission of p. neoaphidis to the pea aphid, acyrthosiphon pisum, was enhanced in the presence of both c. septempunctata and a. ervi in microcosm experiments done under fixed abiotic conditions. in contrast, the reproductive success of a. ervi was reduced in the presence of p. neoap ... | 2009 | 19682460 |
| bacteriophages encode factors required for protection in a symbiotic mutualism. | bacteriophages are known to carry key virulence factors for pathogenic bacteria, but their roles in symbiotic bacteria are less well understood. the heritable symbiont hamiltonella defensa protects the aphid acyrthosiphon pisum from attack by the parasitoid aphidius ervi by killing developing wasp larvae. in a controlled genetic background, we show that a toxin-encoding bacteriophage is required to produce the protective phenotype. phage loss occurs repeatedly in laboratory-held h. defensa-infec ... | 2009 | 19696350 |
| facultative symbionts in aphids and the horizontal transfer of ecologically important traits. | aphids engage in symbiotic associations with a diverse assemblage of heritable bacteria. in addition to their obligate nutrient-provisioning symbiont, buchnera aphidicola, aphids may also carry one or more facultative symbionts. unlike obligate symbionts, facultative symbionts are not generally required for survival or reproduction and can invade novel hosts, based on both phylogenetic analyses and transfection experiments. facultative symbionts are mutualistic in the context of various ecologic ... | 2010 | 19728837 |
| impact of host developmental age on the transcriptome of the symbiotic bacterium buchnera aphidicola in the pea aphid (acyrthosiphon pisum). | of the 617 genes from buchnera aphidicola, the obligate bacterial symbiont of the pea aphid, 23% were differentially expressed in embryos compared to adults. genes involved in flagellar apparatus and riboflavin synthesis exhibited particularly robust upregulation in embryos, suggesting functional differences between the symbiosis in the adult and embryo insect. | 2009 | 19783752 |
| aphidius ervi teratocytes release an extracellular enolase. | we report the cloning of a gene and the characterization of the encoded protein, which is released by the teratocytes of the parasitoid aphidius ervi in the haemocoel of the host aphid acyrthosiphon pisum. the studied protein was identified by lc-ms/ms, and the gathered information used for isolating the full length cdna. the corresponding gene was made of 3 exons and 2 introns, and was highly expressed in the adult wasps and in parasitized hosts. the translation product, which was named ae-eno, ... | 2009 | 19786101 |
| a single genetic locus in the phytopathogen pantoea stewartii enables gut colonization and pathogenicity in an insect host. | aphids are typically exposed to a variety of epiphytic and phytopathogenic bacteria, many of which have entomopathogenic potential. here we describe the interaction between pantoea stewartii ssp. stewartii dc283 (dc283), an enteric phytopathogen and causal agent of stewart's wilt, and the pea aphid, acyrthosiphon pisum. when ingested by aphids, dc283 establishes and aggregates in the crop and gut, preventing honeydew flow and excretion, resulting in aphid death in 72 h. a mutagenesis screen iden ... | 2010 | 19788413 |
| post-pleistocene radiation of the pea aphid complex revealed by rapidly evolving endosymbionts. | adaptation to different resources has the potential to cause rapid species diversification, but few studies have been able to quantify the time scale of recent adaptive radiations. the pea aphid, acyrthosiphon pisum, a model of speciation for host-specialized parasites, consists of several biotypes (races or species) living on distinct legume hosts. to document this radiation, we used rapidly evolving sequences from buchnera, the maternally transmitted bacterial endosymbiont of aphids. analyses ... | 2009 | 19805299 |
| ingested double-stranded rnas can act as species-specific insecticides. | a serious shortcoming of many insecticides is that they can kill non-target species. to address this issue, we harnessed the sequence specificity of rna interference (rnai) to design orally-delivered double-stranded (ds) rnas that selectively killed target species. fruit flies (drosophila melanogaster), flour beetles (tribolium castaneum), pea aphids (acyrthosiphon pisum), and tobacco hornworms (manduca sexta) were selectively killed when fed species-specific dsrna targeting vatpase transcripts. ... | 2009 | 19815067 |
| modeling temporal trends in aphid vector dispersal and cucumber mosaic virus epidemics in snap bean. | cucumber mosaic virus (cmv) has become a major limiting factor in snap bean production in the great lakes region of north america, and epidemics have occurred more frequently since the soybean aphid, aphis glycines matsumura, was introduced. major aphid vectors of cmv epidemics were identified by statistically relating their temporal dispersal trends to the incidence of cmv. alates were monitored weekly using water pan traps in 74 snap bean fields in new york and pennsylvania from 2002 to 2006. ... | 2009 | 19825288 |
| integrated metabonomic-proteomic analysis of an insect-bacterial symbiotic system. | the health of animals, including humans, is dependent on their resident microbiota, but the complexity of the microbial communities makes these associations difficult to study in most animals. exceptionally, the microbiology of the pea aphid acyrthosiphon pisum is dominated by a single bacterium buchnera aphidicola (b. aphidicola). a (1)h nmr-based metabonomic strategy was applied to investigate metabolic profiles of aphids fed on a low essential amino acid diet and treated by antibiotic to elim ... | 2010 | 19860485 |
| the rap1 gene confers effective, race-specific resistance to the pea aphid in medicago truncatula independent of the hypersensitive reaction. | plant resistance to pathogens is commonly associated with a hypersensitive response (hr), but the degree to which the hr is responsible for incompatibility is subject to debate. resistance to aphids is likely to share features with resistance to pathogens but is less well understood. here, we report effective resistance to the pea aphid acyrthosiphon pisum in medicago truncatula. aphids lost weight and died rapidly (within two days) on the resistant genotype jemalong, which developed necrotic le ... | 2009 | 19888829 |
| effects of facultative symbionts and heat stress on the metabolome of pea aphids. | we examined metabolite pools of pea aphids with different facultative symbiont infections, and characterized their effects on aphid metabolism in baseline and heat stress conditions. the bacterial symbiont serratia symbiotica protects aphid hosts from the detrimental results of heat stress and shields the obligate symbiont buchnera from effects of heat. we investigated whether broad effects on metabolism might correlate with this protection. both facultative symbiont infection and heat treatment ... | 2010 | 19907504 |
| systemic analysis of the symbiotic function of buchnera aphidicola, the primary endosymbiont of the pea aphid acyrthosiphon pisum. | buchnera aphidicola is the primary obligate intracellular symbiont of most aphid species. b. aphidicola and aphids have been evolving in parallel since their association started, about 150 myr ago. both partners have lost their autonomy, and aphid diversification has been confined to smaller ecological niches by this co-evolution. b. aphidicola has undergone major genomic and biochemical changes as a result of adapting to intracellular life. several genomes of b. aphidicola from different aphid ... | 2009 | 19909925 |
| transcriptomic analysis of intestinal genes following acquisition of pea enation mosaic virus by the pea aphid acyrthosiphon pisum. | viruses in the family luteoviridae are strictly transmitted by aphids in a non-propagative, circulative and persistent mode. virions ingested by aphids successively cross the gut and the accessory salivary gland epithelia before being released, together with saliva, into the plant vasculature. virion transport through aphid cells occurs by a transcytosis mechanism. this study conducted a transcriptomic analysis of intestinal genes of the pea aphid acyrthosiphon pisum following uptake of pea enat ... | 2010 | 19923264 |
| discovery of a novel insect neuropeptide signaling system closely related to the insect adipokinetic hormone and corazonin hormonal systems. | neuropeptides and their g protein-coupled receptors (gpcrs) play a central role in the physiology of insects. one large family of insect neuropeptides are the adipokinetic hormones (akhs), which mobilize lipids and carbohydrates from the insect fat body. other peptides are the corazonins that are structurally related to the akhs but represent a different neuropeptide signaling system. we have previously cloned an orphan gpcr from the malaria mosquito anopheles gambiae that was structurally inter ... | 2010 | 20068045 |
| symbiosis as a source of selectable epigenetic variation: taking the heat for the big guy. | evolutionary developmental biology is based on the principle that evolution arises from hereditable changes in development. most of this new work has centred on changes in the regulatory components of the genome. however, recent studies (many of them documented in this volume) have shown that development also includes interactions between the organism and its environment. one area of interest concerns the importance of symbionts for the production of the normal range of phenotypes. many, if not ... | 2010 | 20083641 |
| [co-metabolic activity of aphid acyrthosiphon pisum and symbiotic bacterium buchnera aphidicola str. aps]. | | 2009 | 20088388 |
| insecticidal activity of recombinant avidin produced in yeast. | an expression construct encoding chicken (gallus gallus) avidin was assembled from amplified fragments of genomic dna. recombinant, functional avidin was produced in pichia pastoris, with yields of up to 80 mg/l of culture supernatant. the recombinant avidin had similar insecticidal activity to egg white avidin when assayed against larvae of a lepidopteran crop pest, cabbage moth (mamestra brassicae), causing >90% reduction in growth and 100% mortality when fed in optimised diets at levels of 1. ... | 2010 | 20132821 |
| two novel proteins expressed by the venom glands of apis mellifera and nasonia vitripennis share an ancient c1q-like domain. | an in-depth proteomic study of previously unidentified two-dimensional polyacrylamide gel electrophoresis spots of honey bee (apis mellifera, hymenoptera) venom revealed a new protein with a c1q conserved domain (c1q-vp). blastp searching revealed a strong identity with only two proteins from other insect species: the jewel wasp, nasonia vitripennis (hymenoptera), and the green pea aphid, acyrthosiphon pisum (hemiptera). in higher organisms, c1q is the first subcomponent of the classical complem ... | 2010 | 20167013 |
| genome sequence of the pea aphid acyrthosiphon pisum. | aphids are important agricultural pests and also biological models for studies of insect-plant interactions, symbiosis, virus vectoring, and the developmental causes of extreme phenotypic plasticity. here we present the 464 mb draft genome assembly of the pea aphid acyrthosiphon pisum. this first published whole genome sequence of a basal hemimetabolous insect provides an outgroup to the multiple published genomes of holometabolous insects. pea aphids are host-plant specialists, they can reprodu ... | 2010 | 20186266 |
| bacterial genes in the aphid genome: absence of functional gene transfer from buchnera to its host. | genome reduction is typical of obligate symbionts. in cellular organelles, this reduction partly reflects transfer of ancestral bacterial genes to the host genome, but little is known about gene transfer in other obligate symbioses. aphids harbor anciently acquired obligate mutualists, buchnera aphidicola (gammaproteobacteria), which have highly reduced genomes (420-650 kb), raising the possibility of gene transfer from ancestral buchnera to the aphid genome. in addition, aphids often harbor oth ... | 2010 | 20195500 |
| a peptide that binds the pea aphid gut impedes entry of pea enation mosaic virus into the aphid hemocoel. | development of ways to block virus transmission by aphids could lead to novel and broad-spectrum means of controlling plant viruses. viruses in the luteoviridae enhanced are obligately transmitted by aphids in a persistent manner that requires virion accumulation in the aphid hemocoel. to enter the hemocoel, the virion must bind and traverse the aphid gut epithelium. by screening a phage display library, we identified a 12-residue gut binding peptide (gbp3.1) that binds to the midgut and hindgut ... | 2010 | 20223498 |
| the pea aphid genome sequence brings theories of insect defense into question. | the genome sequence of the pea aphid is the first for a basal hemimetabolous insect and provides insights into developmental plasticity, symbiosis and insect immunity. | 2010 | 20236492 |
| binding properties of the n-acetylglucosamine and high-mannose n-glycan pp2-a1 phloem lectin in arabidopsis. | phloem protein2 (pp2) is a component of the phloem protein bodies found in sieve elements. we describe here the lectin properties of the arabidopsis (arabidopsis thaliana) pp2-a1. using a recombinant protein produced in escherichia coli, we demonstrated binding to n-acetylglucosamine oligomers. glycan array screening showed that pp2-a1 also bound to high-mannose n-glycans and 9-acyl-n-acetylneuraminic sialic acid. fluorescence spectroscopy-based titration experiments revealed that pp2-a1 had two ... | 2010 | 20442276 |
| e-rnai: a web application for the multi-species design of rnai reagents--2010 update. | the design of rna interference (rnai) reagents is an essential step for performing loss-of-function studies in many experimental systems. the availability of sequenced and annotated genomes greatly facilitates rnai experiments in an increasing number of organisms that were previously not genetically tractable. the e-rnai web-service, accessible at http://www.e-rnai.org/, provides a computational resource for the optimized design and evaluation of rnai reagents. the 2010 update of e-rnai now cove ... | 2010 | 20444868 |
| comparative analysis of the acyrthosiphon pisum genome and expressed sequence tag-based gene sets from other aphid species. | to study gene repertoires and their evolution within aphids, we compared the complete genome sequence of acyrthosiphon pisum (reference gene set) and expressed sequence tag (est) data from three other species: myzus persicae, aphis gossypii and toxoptera citricida. we assembled ests, predicted coding sequences, and identified potential pairs of orthologues (reciprocical best hits) with a. pisum. pairwise comparisons show that a fraction of the genes evolve fast (high ratio of non-synonymous to s ... | 2010 | 20482638 |
| sugar transporters of the major facilitator superfamily in aphids; from gene prediction to functional characterization. | analysis of the pea aphid (acyrthosiphon pisum) genome using signatures specific to the major facilitator superfamily (pfam clan cl0015) and the sugar_tr family (pfam family pf00083) has identified 54 genes encoding potential sugar transporters, of which 38 have corresponding ests. twenty-nine genes contain the interpro ipr003663 hexose transporter signature. the protein encoded by ap_st3, the most abundantly expressed sugar transporter gene, was functionally characterized by expression as a rec ... | 2010 | 20482643 |
| identification and characterization of circadian clock genes in the pea aphid acyrthosiphon pisum. | the molecular basis of circadian clocks is highly evolutionarily conserved and has been best characterized in drosophila and mouse. analysis of the acyrthosiphon pisum genome revealed the presence of orthologs of the following genes constituting the core of the circadian clock in drosophila: period (per), timeless (tim), clock, cycle, vrille, and pdp1. however, the presence in a. pisum of orthologs of a mammal-type in addition to a drosophila-type cryptochrome places the putative aphid clockwork ... | 2010 | 20482645 |
| chitinase-like proteins encoded in the genome of the pea aphid, acyrthosiphon pisum. | in insects, chitinases play an essential role in the degradation of old exoskeleton and turnover of the gut lining. in silico screening of the entire genome of the pea aphid (hemimetabola), acyrthosiphon pisum, detected nine genes encoding putative chitinase-like proteins, including six enzymatically active chitinases, one imaginal disc growth factor, and one endo-beta-n-acetylglucosaminidase. screening of the genomes of aedes aegypti, anopheles gambiae, apis mellifera, bombyx mori, culex quinqu ... | 2010 | 20482649 |
| genomic evidence for complementary purine metabolism in the pea aphid, acyrthosiphon pisum, and its symbiotic bacterium buchnera aphidicola. | the purine salvage pathway recycles purines to nucleotides, promoting efficient utilization of purine nucleotides. exceptionally among animals with completely sequenced genomes, the pea aphid lacks key purine recycling genes that code for purine nucleoside phosphorylase and adenosine deaminase, indicating that the aphid can neither metabolize nucleosides to the corresponding purines, nor adenosine to inosine. purine metabolism genes in the symbiotic bacterium buchnera complement aphid genes, and ... | 2010 | 20482654 |
| genomic insight into the amino acid relations of the pea aphid, acyrthosiphon pisum, with its symbiotic bacterium buchnera aphidicola. | the pea aphid genome includes 66 genes contributing to amino acid biosynthesis and 93 genes to amino acid degradation. in several respects, the pea aphid gene inventory complements that of its symbiotic bacterium, buchnera aphidicola (buchnera aps). unlike other insects with completely sequenced genomes, the pea aphid lacks the capacity to synthesize arginine, which is produced by buchnera aps. however, consistent with other insects, it has genes coding for individual reactions in essential amin ... | 2010 | 20482655 |
| mechanisms for stable coexistence in an insect community. | in this paper, we formulate a three-species ecological community model consisting of two aphid species (acyrthosiphon pisum and megoura viciae) and a specialist parasitoid (aphidius ervi) that attacks only one of the aphids (a pisum). the model incorporates both density-mediated and trait-mediated host-parasitoid interactions. our analysis shows that the model possesses much richer and more realistic dynamics than earlier models. our theoretical results reveal a new mechanism for stable coexiste ... | 2010 | 20578788 |
| dynamics of a recurrent buchnera mutation that affects thermal tolerance of pea aphid hosts. | mutations in maternally transmitted symbionts can affect host fitness. in this study we investigate a mutation in an obligate bacterial symbiont (buchnera), which has dramatic effects on the heat tolerance of pea aphid hosts (acyrthosiphon pisum). the heat-sensitive allele arises through a single base deletion in a homopolymer within the promoter of ibpa, which encodes a universal small heat-shock protein. in laboratory cultures reared under cool conditions (20°), the rate of fixation (1.4 × 10( ... | 2010 | 20610410 |
| combining next-generation sequencing strategies for rapid molecular resource development from an invasive aphid species, aphis glycines. | aphids are one of the most important insect taxa in terms of ecology, evolutionary biology, genetics and genomics, and interactions with endosymbionts. additionally, many aphids are serious pest species of agricultural and horticultural plants. recent genetic and genomic research has expanded molecular resources for many aphid species, including the whole genome sequencing of the pea aphid, acrythosiphon pisum. however, the invasive soybean aphid, aphis glycines, lacks in any significant molecul ... | 2010 | 20614011 |
| cyt toxin expression reveals an inverse regulation of insect and plant virulence factors of dickeya dadantii. | the plant pathogenic bacteria dickeya dadantii is also a pathogen of the pea aphid acyrthosiphon pisum. the genome of the bacteria contains four cyt genes, encoding homologues of bacillus thuringiensis cyt toxins, which are involved in its pathogenicity to insects. we show here that these genes are transcribed as an operon, and we determined the conditions necessary for their expression. their expression is induced at high temperature and at an osmolarity equivalent to that found in the plant ph ... | 2010 | 20649641 |
| sources of variation in dietary requirements in an obligate nutritional symbiosis. | the nutritional symbiosis between aphids and their obligate symbiont, buchnera aphidicola, is often characterized as a highly functional partnership in which the symbiont provides the host with essential nutrients. despite this, some aphid lineages exhibit dietary requirements for nutrients typically synthesized by buchnera, suggesting that some aspect of the symbiosis is disrupted. to examine this phenomenon in the pea aphid, acyrthosiphon pisum, populations were assayed using defined artificia ... | 2011 | 20667882 |
| mammalian herbivore breath alerts aphids to flee host plant. | mammalian herbivores profoundly influence plant-dwelling insects [1]. most studies have focused on the indirect effect of herbivory on insect populations via damage to the host plant [2,3]. many insects, however, are in danger of being inadvertently ingested during herbivore feeding. here, we report that pea aphids (acyrthosiphon pisum) are able to sense the elevated heat and humidity of the breath of an approaching herbivore and thus salvage most of the colony by simultaneously dropping off the ... | 2010 | 20692607 |
| aphid reproductive investment in response to mortality risks. | aphids are striking in their prodigious reproductive capacity and reliance on microbial endosymbionts, which provision their hosts with necessary amino acids and provide protection against parasites and heat stress. perhaps as a result of this bacterial dependence, aphids have limited immune function that may leave them vulnerable to bacterial pathogens. an alternative, non-immunological response that may be available to infected aphids is to increase reproduction, thereby ameliorating fitness l ... | 2010 | 20716370 |
| how the insect immune system interacts with an obligate symbiotic bacterium. | the animal immune system provides defence against microbial infection, and the evolution of certain animal-microbial symbioses is predicted to involve adaptive changes in the host immune system to accommodate the microbial partner. for example, the reduced humoral immune system in the pea aphid acyrthosiphon pisum, including an apparently non-functional immune deficiency (imd) signalling pathway and absence of peptidoglycan recognition proteins (pgrps), has been suggested to be an adaptation for ... | 2011 | 20719775 |
| effects of bacterial secondary symbionts on host plant use in pea aphids. | aphids possess several facultative bacterial symbionts that have important effects on their hosts' biology. these have been most closely studied in the pea aphid (acyrthosiphon pisum), a species that feeds on multiple host plants. whether secondary symbionts influence host plant utilization is unclear. we report the fitness consequences of introducing different strains of the symbiont hamiltonella defensa into three aphid clones collected on lathyrus pratensis that naturally lack symbionts, and ... | 2011 | 20843842 |
| interspecific symbiont transfection confers a novel ecological trait to the recipient insect. | in japan, pea aphids acyrthosiphon pisum mainly feed on vetch and clover, and many aphid clones produce more progeny on vetch than on clover. in this context, particular genotypes of the facultative symbiont regiella insecticola enhance reproduction of infected pea aphids specifically on clover, thereby broadening the suitable food plant range of the insect. a species that is sympatric to a. pisum, vetch aphids megoura crassicauda, are commonly found on vetch but not on clover. laboratory rearin ... | 2010 | 20880856 |
| conditional facilitation of an aphid vector, acyrthosiphon pisum, by the plant pathogen, pea enation mosaic virus. | plant pathogens can induce symptoms that affect the performance of insect herbivores utilizing the same host plant. previous studies examining the effects of infection of tic bean, vicia faba l. (fabales: fabaceae), by pea enation mosaic virus (pemv), an important disease of legume crops, indicated there were no changes in the growth and reproductive rate of its primary vector the pea aphid, acyrthosiphon pisum (harris) (hemiptera: aphididae). here, we report the results of laboratory experiment ... | 2010 | 21067425 |