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Sample records for host plant type

  1. Potato type I and II proteinase inhibitors: modulating plant physiology and host resistance.

    PubMed

    Turra, David; Lorito, Matteo

    2011-08-01

    Serine protease inhibitors (PIs) are a large and complex group of plant proteins. Members of the potato type I (Pin1) and II (Pin2) proteinase inhibitor families are among the first and most extensively characterized plant PIs. Many insects and phytopathogenic microorganisms use intracellular and extracellular serine proteases playing important roles in pathogenesis. Plants, however, are able to fight these pathogens through the activation of an intricate defence system that leads to the accumulation of various PIs, including Pin1 and Pin2. Several transgenic plants over-expressing members of the Pin1 and Pin2 families have been obtained in the last twenty years and their enhanced defensive capabilities demonstrated against insects, fungi and bacteria. Furthermore, Pin1 and Pin2 genetically engineered plants showed altered regulation of different plant physiological processes (e.g., dehydratation response, programmed cell death, plant growth, trichome density and branching), supporting an endogenous role in various plant species in addition to the well established defensive one. This review summarizes the current knowledge about Pin1 and Pin2 structure, the role of these proteins in plant defence and physiology, and their potential exploitation in biotechnology. PMID:21418020

  2. Functional diversification of the GALA type III effector family contributes to Ralstonia solanacearum adaptation on different plant hosts

    PubMed Central

    Remigi, Philippe; Anisimova, Maria; Guidot, Alice; Genin, Stéphane; Peeters, Nemo

    2011-01-01

    Type III effectors from phytopathogenic bacteria exhibit a high degree of functional redundancy, hampering the evaluation of their precise contribution to pathogenicity. This is illustrated by the GALA type III effectors from Ralstonia solanacearum, which have been shown to be collectively, but not individually, required for disease on Arabidopsis thaliana and tomato. We investigated evolution, redundancy and diversification of this family in order to understand the individual contribution of the GALA effectors to pathogenicity. From sequences available, we reconstructed GALA phylogeny and performed selection studies. We then focused on the GALAs from the reference strain GMI1000 to examine their ability to suppress plant defense responses and contribution to pathogenicity on three different host plants: A. thaliana, tomato (Lycopersicum esculentum) and eggplant (Solanum melongena). The GALA family is well conserved within R. solanacearum species. Patterns of selection detected on some GALA family members, together with experimental results, show that GALAs underwent functional diversification. We conclude that functional divergence of the GALA family likely accounts for its remarkable conservation during R. solanacearum evolution and could contribute to R. solanacearum’s adaptation on several host plants. PMID:21902695

  3. Tuber melanosporum: mating type distribution in a natural plantation and dynamics of strains of different mating types on the roots of nursery-inoculated host plants.

    PubMed

    Rubini, Andrea; Belfiori, Beatrice; Riccioni, Claudia; Arcioni, Sergio; Martin, Francis; Paolocci, Francesco

    2011-02-01

    • In light of the recent finding that Tuber melanosporum, the ectomycorrhizal ascomycete that produces the most highly prized black truffles, is a heterothallic species, we monitored the spatial distribution of strains with opposite mating types (MAT) in a natural truffle ground and followed strain dynamics in artificially inoculated host plants grown under controlled conditions. • In a natural truffle ground, ectomycorrhizas (ECMs), soil samples and fruit bodies were sampled and genotyped to determine mating types. Simple sequence repeat (SSR) markers were also used to fingerprint ECMs and fruit bodies. The ECMs from nursery-inoculated host plants were analysed for mating type at 6 months and 19 months post-inoculation. • In open-field conditions, all ECMs from the same sampling site showed an identical mating type and an identical haploid genotype, based on SSR analysis. Interestingly, the gleba of fruit bodies always demonstrated the same genotype as the surrounding ECMs. Although root tips from nursery-grown plants initially developed ECMs of both mating types, a dominance of ECMs of the same MAT were found after several months. • The present study deepens our understanding of the vegetative and sexual propagation modes of T. melanosporum. These results are highly relevant for truffle cultivation. PMID:20964691

  4. The bacterium Pantoea stewartii uses two different type III secretion systems to colonize its plant host and insect vector.

    PubMed

    Correa, Valdir R; Majerczak, Doris R; Ammar, El-Desouky; Merighi, Massimo; Pratt, Richard C; Hogenhout, Saskia A; Coplin, David L; Redinbaugh, Margaret G

    2012-09-01

    Plant- and animal-pathogenic bacteria utilize phylogenetically distinct type III secretion systems (T3SS) that produce needle-like injectisomes or pili for the delivery of effector proteins into host cells. Pantoea stewartii subsp. stewartii (herein referred to as P. stewartii), the causative agent of Stewart's bacterial wilt and leaf blight of maize, carries phylogenetically distinct T3SSs. In addition to an Hrc-Hrp T3SS, known to be essential for maize pathogenesis, P. stewartii has a second T3SS (Pantoea secretion island 2 [PSI-2]) that is required for persistence in its flea beetle vector, Chaetocnema pulicaria (Melsh). PSI-2 belongs to the Inv-Mxi-Spa T3SS family, typically found in animal pathogens. Mutagenesis of the PSI-2 psaN gene, which encodes an ATPase essential for secretion of T3SS effectors by the injectisome, greatly reduces both the persistence of P. stewartii in flea beetle guts and the beetle's ability to transmit P. stewartii to maize. Ectopic expression of the psaN gene complements these phenotypes. In addition, the PSI-2 psaN gene is not required for P. stewartii pathogenesis of maize and is transcriptionally upregulated in insects compared to maize tissues. Thus, the Hrp and PSI-2 T3SSs play different roles in the life cycle of P. stewartii as it alternates between its insect vector and plant host. PMID:22773631

  5. Host Plant Resistance to Green Peach Aphid, Myzus persicae (Sulzar), by Some Wild Types of Watermelon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The green peach aphid, Myzus persicae (Sulzar), is an important pest of many vegetable crops. It damages crops by feeding and vectoring viruses. Potential sources of plant resistance against M. persicae were examined for watermelon. A multiple choice experiment was conducted with leaves of six wi...

  6. Testing Two Methods that Relate Herbivorous Insects to Host Plants

    PubMed Central

    White, Peter J. T.

    2013-01-01

    Insect herbivores are integral to terrestrial ecosystems. They provide essential food for higher trophic levels and aid in nutrient cycling. In general, research tends to relate individual insect herbivore species to host plant identity, where a species will show preference for one host over another. In contrast, insect herbivore assemblages are often related to host plant richness where an area with a higher richness of hosts will also have a higher richness of herbivores. In this study, the ability of these two approaches (host plant identity/abundance vs. host plant richness) to describe the diversity, richness, and abundance of an herbivorous Lepidoptera assemblage in temperate forest fragments in southern Canada is tested. Analyses indicated that caterpillar diversity, richness, and abundance were better described by quadrat-scale host plant identity and abundance than by host plant richness. Most host plant-herbivore studies to date have only considered investigating host plant preferences at a species level; the type of assemblage level preference shown in this study has been rarely considered. In addition, host plant replacement simulations indicate that increasing the abundance of preferred host plants could increase Lepidoptera richness and abundance by as much as 30% and 40% respectively in disturbed remnant forest fragments. This differs from traditional thinking that suggests higher levels of insect richness can be best obtained by maximizing plant richness. Host plant species that are highly preferred by the forest-dwelling caterpillar assemblage should be given special management and conservation considerations to maximize biodiversity in forest communities. PMID:24205830

  7. WtsE, an AvrE-family type III effector protein of Pantoea stewartii subsp. stewartii, causes cell death in non-host plants.

    PubMed

    Ham, Jong Hyun; Majerczak, Doris; Ewert, Sophie; Sreerekha, Mysore-Venkatarau; Mackey, David; Coplin, David

    2008-09-01

    Pantoea stewartii subsp. stewartii (Pnss) causes Stewart's bacterial wilt of sweet corn and leaf blight of maize. The pathogenicity of Pnss depends on synthesis of extracellular polysaccharide and an Hrp type III secretion system. WtsE, a type III secreted effector protein, is essential for the virulence of Pnss on corn. It belongs to the AvrE family of effectors, which includes DspA/E from Erwinia amylovora and AvrE1 from Pseudomonas syringae. Previously, WtsE was shown to cause disease-associated cell death in its host plant, sweet corn. Here, we examine the biological activity of WtsE in several non-host plants. WtsE induced cell death in Nicotiana benthamiana, tobacco, beet and Arabidopsis thaliana when it was transiently produced in plant cells following agroinfiltration or translocated into plant cells from Pnss, Escherichia coli or Pseudomonas syringae pv. phaseolicola (Pph). WtsE-induced cell death in N. benthamiana, tobacco and beet resembled a hypersensitive response and in N. benthamiana it was delayed by cycloheximide. Interestingly, WtsE strongly promoted the growth of Pnss in N. benthamiana prior to the onset of cell death. Deletion derivatives of WtsE that failed to induce cell death in N. benthamiana and tobacco also did not complement wtsE mutants of Pnss for virulence in sweet corn, indicating a correlation between the two activities. WtsE also induced cell death in A. thaliana, where it suppressed basal defences induced by Pph. Thus, WtsE has growth-promoting, defence-suppressing and cell death-inducing activities in non-host plants. Expression of WtsE also prevented the growth of yeast, possibly due to an innate toxicity to eukaryotic cells. PMID:19018993

  8. Microbiota and Host Nutrition across Plant and Animal Kingdoms.

    PubMed

    Hacquard, Stéphane; Garrido-Oter, Ruben; González, Antonio; Spaepen, Stijn; Ackermann, Gail; Lebeis, Sarah; McHardy, Alice C; Dangl, Jeffrey L; Knight, Rob; Ley, Ruth; Schulze-Lefert, Paul

    2015-05-13

    Plants and animals each have evolved specialized organs dedicated to nutrient acquisition, and these harbor specific bacterial communities that extend the host's metabolic repertoire. Similar forces driving microbial community establishment in the gut and plant roots include diet/soil-type, host genotype, and immune system as well as microbe-microbe interactions. Here we show that there is no overlap of abundant bacterial taxa between the microbiotas of the mammalian gut and plant roots, whereas taxa overlap does exist between fish gut and plant root communities. A comparison of root and gut microbiota composition in multiple host species belonging to the same evolutionary lineage reveals host phylogenetic signals in both eukaryotic kingdoms. The reasons underlying striking differences in microbiota composition in independently evolved, yet functionally related, organs in plants and animals remain unclear but might include differences in start inoculum and niche-specific factors such as oxygen levels, temperature, pH, and organic carbon availability. PMID:25974302

  9. DNA barcoding insect–host plant associations

    PubMed Central

    Jurado-Rivera, José A.; Vogler, Alfried P.; Reid, Chris A.M.; Petitpierre, Eduard; Gómez-Zurita, Jesús

    2008-01-01

    Short-sequence fragments (‘DNA barcodes’) used widely for plant identification and inventorying remain to be applied to complex biological problems. Host–herbivore interactions are fundamental to coevolutionary relationships of a large proportion of species on the Earth, but their study is frequently hampered by limited or unreliable host records. Here we demonstrate that DNA barcodes can greatly improve this situation as they (i) provide a secure identification of host plant species and (ii) establish the authenticity of the trophic association. Host plants of leaf beetles (subfamily Chrysomelinae) from Australia were identified using the chloroplast trnL(UAA) intron as barcode amplified from beetle DNA extracts. Sequence similarity and phylogenetic analyses provided precise identifications of each host species at tribal, generic and specific levels, depending on the available database coverage in various plant lineages. The 76 species of Chrysomelinae included—more than 10 per cent of the known Australian fauna—feed on 13 plant families, with preference for Australian radiations of Myrtaceae (eucalypts) and Fabaceae (acacias). Phylogenetic analysis of beetles shows general conservation of host association but with rare host shifts between distant plant lineages, including a few cases where barcodes supported two phylogenetically distant host plants. The study demonstrates that plant barcoding is already feasible with the current publicly available data. By sequencing plant barcodes directly from DNA extractions made from herbivorous beetles, strong physical evidence for the host association is provided. Thus, molecular identification using short DNA fragments brings together the detection of species and the analysis of their interactions. PMID:19004756

  10. Parasitic plants of the genus Cuscuta and their interaction with susceptible and resistant host plants

    PubMed Central

    Kaiser, Bettina; Vogg, Gerd; Fürst, Ursula B.; Albert, Markus

    2015-01-01

    By comparison with plant–microbe interaction, little is known about the interaction of parasitic plants with their hosts. Plants of the genus Cuscuta belong to the family of Cuscutaceae and comprise about 200 species, all of which live as stem holoparasites on other plants. Cuscuta spp. possess no roots nor fully expanded leaves and the vegetative portion appears to be a stem only. The parasite winds around plants and penetrates the host stems via haustoria, forming direct connections to the vascular bundles of their hosts to withdraw water, carbohydrates, and other solutes. Besides susceptible hosts, a few plants exist that exhibit an active resistance against infestation by Cuscuta spp. For example, cultivated tomato (Solanum lycopersicum) fends off Cuscuta reflexa by means of a hypersensitive-type response occurring in the early penetration phase. This report on the plant–plant dialog between Cuscuta spp. and its host plants focuses on the incompatible interaction of C. reflexa with tomato. PMID:25699071

  11. Host Plant Adaptation in Drosophila mettleri Populations

    PubMed Central

    Castrezana, Sergio; Bono, Jeremy M.

    2012-01-01

    The process of local adaptation creates diversity among allopatric populations, and may eventually lead to speciation. Plant-feeding insect populations that specialize on different host species provide an excellent opportunity to evaluate the causes of ecological specialization and the subsequent consequences for diversity. In this study, we used geographically separated Drosophila mettleri populations that specialize on different host cacti to examine oviposition preference for and larval performance on an array of natural and non-natural hosts (eight total). We found evidence of local adaptation in performance on saguaro cactus (Carnegiea gigantea) for populations that are typically associated with this host, and to chemically divergent prickly pear species (Opuntia spp.) in a genetically isolated population on Santa Catalina Island. Moreover, each population exhibited reduced performance on the alternative host. This finding is consistent with trade-offs associated with adaptation to these chemically divergent hosts, although we also discuss alternative explanations for this pattern. For oviposition preference, Santa Catalina Island flies were more likely to oviposit on some prickly pear species, but all populations readily laid eggs on saguaro. Experiments with non-natural hosts suggest that factors such as ecological opportunity may play a more important role than host plant chemistry in explaining the lack of natural associations with some hosts. PMID:22493678

  12. Host plant adaptation in Drosophila mettleri populations.

    PubMed

    Castrezana, Sergio; Bono, Jeremy M

    2012-01-01

    The process of local adaptation creates diversity among allopatric populations, and may eventually lead to speciation. Plant-feeding insect populations that specialize on different host species provide an excellent opportunity to evaluate the causes of ecological specialization and the subsequent consequences for diversity. In this study, we used geographically separated Drosophila mettleri populations that specialize on different host cacti to examine oviposition preference for and larval performance on an array of natural and non-natural hosts (eight total). We found evidence of local adaptation in performance on saguaro cactus (Carnegiea gigantea) for populations that are typically associated with this host, and to chemically divergent prickly pear species (Opuntia spp.) in a genetically isolated population on Santa Catalina Island. Moreover, each population exhibited reduced performance on the alternative host. This finding is consistent with trade-offs associated with adaptation to these chemically divergent hosts, although we also discuss alternative explanations for this pattern. For oviposition preference, Santa Catalina Island flies were more likely to oviposit on some prickly pear species, but all populations readily laid eggs on saguaro. Experiments with non-natural hosts suggest that factors such as ecological opportunity may play a more important role than host plant chemistry in explaining the lack of natural associations with some hosts. PMID:22493678

  13. Host plants of psyllids in south Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Psyllids typically breed on a narrow range of usually related host plants. However, adult psyllids often feed on a wider array of plants, a strategy which undoubtedly enhances survival and perhaps even reproduction. For example, although the Asian citrus psyllid is the most common species on comme...

  14. How Do Wireworms Find Their Host Plants?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wireworms are important pests of potatoes throughout North America. The means by which wireworms locate the potato host plant are briefly reviewed, and shown to include chemical cues that act to prompt long-distance orientation, and other chemicals that act as feeding stimulants. The possibility o...

  15. THE LOCAL HOSTS OF TYPE Ia SUPERNOVAE

    SciTech Connect

    Neill, James D.; Martin, D. Christopher; Barlow, Tom A.; Foster, Karl; Friedman, Peter G.; Morrissey, Patrick; Wyder, Ted K.; Sullivan, Mark; Howell, D. Andrew; Conley, Alex; Seibert, Mark; Madore, Barry F.; Neff, Susan G.; Schiminovich, David; Bianchi, Luciana; Donas, Jose; Milliard, Bruno; Heckman, Timothy M.; Lee, Young-Wook; Rich, R. Michael

    2009-12-20

    We use multi-wavelength, matched aperture, integrated photometry from the Galaxy Evolution Explorer (GALEX), the Sloan Digital Sky Survey, and the RC3 to estimate the physical properties of 166 nearby galaxies hosting 168 well-observed Type Ia supernovae (SNe Ia). The ultraviolet (UV) imaging of local SN Ia hosts from GALEX allows a direct comparison with higher-redshift hosts measured at optical wavelengths that correspond to the rest-frame UV. Our data corroborate well-known features that have been seen in other SN Ia samples. Specifically, hosts with active star formation produce brighter and slower SNe Ia on average, and hosts with luminosity-weighted ages older than 1 Gyr produce on average more faint, fast, and fewer bright, slow SNe Ia than younger hosts. New results include that in our sample, the faintest and fastest SNe Ia occur only in galaxies exceeding a stellar mass threshold of approx10{sup 10} M{sub sun}, leading us to conclude that their progenitors must arise in populations that are older and/or more metal rich than the general SN Ia population. A low host extinction subsample hints at a residual trend in peak luminosity with host age, after correcting for light-curve shape, giving the appearance that older hosts produce less-extincted SNe Ia on average. This has implications for cosmological fitting of SNe Ia, and suggests that host age could be useful as a parameter in the fitting. Converting host mass to metallicity and computing {sup 56}Ni mass from the supernova light curves, we find that our local sample is consistent with a model that predicts a shallow trend between stellar metallicity and the {sup 56}Ni mass that powers the explosion, but we cannot rule out the absence of a trend. We measure a correlation between {sup 56}Ni mass and host age in the local universe that is shallower and not as significant as that seen at higher redshifts. The details of the age-{sup 56}Ni mass correlations at low and higher redshift imply a luminosity

  16. Interactions between hemiparasitic plants and their hosts

    PubMed Central

    Plavcová, Lenka; Cameron, Duncan D

    2010-01-01

    Hemiparasitic plants display a unique strategy of resource acquisition combining parasitism of other species and own photosynthetic activity. Despite the active photoassimilation and green habit, they acquire substantial amount of carbon from their hosts. The organic carbon transfer has a crucial influence on the nature of the interaction between hemiparasites and their hosts which can oscillate between parasitism and competition for light. In this minireview, we summarize methodical approaches and results of various studies dealing with carbon budget of hemiparasites and the ecological implications of carbon heterotrophy in hemiparasites. PMID:20729638

  17. Electroantennographic bioassay as a screening tool for host plant volatiles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant volatiles play an important role in plant-insect interactions. Herbivorous insects use plant volatiles, known as kairomones, to locate their host plant. When a host plant is an important agronomic or economic commodity feeding damage by these insects can inflict serious economic losses to grow...

  18. Host plant induced variation in gut bacteria of Helicoverpa armigera.

    PubMed

    Priya, Natarajan Gayatri; Ojha, Abhishek; Kajla, Mayur K; Raj, Anand; Rajagopal, Raman

    2012-01-01

    Helicoverpa are important polyphagous agricultural insect pests and they have a worldwide distribution. In this study, we report the bacterial community structure in the midgut of fifth instar larvae of Helicoverpa armigera, a species prevalent in the India, China, South Asia, South East Asia, Southern & Eastern Africa and Australia. Using culturable techniques, we isolated and identified members of Bacillus firmus, Bacillus niabense, Paenibacillus jamilae, Cellulomonas variformis, Acinetobacter schindleri, Micrococcus yunnanesis, Enterobacter sp., and Enterococcus cassiliflavus in insect samples collected from host plants grown in different parts of India. Besides these the presence of Sphingomonas, Ralstonia, Delftia, Paracoccus and Bacteriodetes was determined by culture independent molecular analysis. We found that Enterobacter and Enterococcus were universally present in all our Helicoverpa samples collected from different crops and in different parts of India. The bacterial diversity varied greatly among insects that were from different host plants than those from the same host plant of different locations. This result suggested that the type of host plant greatly influences the midgut bacterial diversity of H. armigera, more than the location of the host plant. On further analyzing the leaf from which the larva was collected, it was found that the H. armigera midgut bacterial community was similar to that of the leaf phyllosphere. This finding indicates that the bacterial flora of the larval midgut is influenced by the leaf surface bacterial community of the crop on which it feeds. Additionally, we found that laboratory made media or the artificial diet is a poor bacterial source for these insects compared to a natural diet of crop plant. PMID:22292034

  19. Plant surface wax affects parasitoid's response to host footprints

    NASA Astrophysics Data System (ADS)

    Rostás, Michael; Ruf, Daniel; Zabka, Vanessa; Hildebrandt, Ulrich

    2008-10-01

    The plant surface is the substrate upon which herbivorous insects and natural enemies meet and thus represents the stage for interactions between the three trophic levels. Plant surfaces are covered by an epicuticular wax layer which is highly variable depending on species, cultivar or plant part. Differences in wax chemistry may modulate ecological interactions. We explored whether caterpillars of Spodoptera frugiperda, when walking over a plant surface, leave a chemical trail (kairomones) that can be detected by the parasitoid Cotesia marginiventris. Chemistry and micromorphology of cuticular waxes of two barley eceriferum wax mutants ( cer-za.126, cer-yp.949) and wild-type cv. Bonus (wt) were assessed. The plants were then used to investigate potential surface effects on the detectability of caterpillar kairomones. Here we provide evidence that C. marginiventris responds to chemical footprints of its host. Parasitoids were able to detect the kairomone on wild-type plants and on both cer mutants but the response to cer-yp.949 (reduced wax, high aldehyde fraction) was less pronounced. Experiments with caterpillar-treated wt and mutant leaves offered simultaneously, confirmed this observation: no difference in wasp response was found when wt was tested against cer-za.126 (reduced wax, wt-like chemical composition) but wt was significantly more attractive than cer-yp.949. This demonstrates for the first time that the wax layer can modulate the detectability of host kairomones.

  20. Relationships of host plant phylogeny, chemistry and host plant specificity of several agents of yellow starthistle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant species used for host specificity testing are usually chosen based on the assumption that the risk of attack by a prospective biological control agent decreases with increasing phylogenetic distance from the target weed. Molecular genetics methods have greatly improved our ability to measure ...

  1. Host-Plant Specialization Mediates the Influence of Plant Abundance on Host Use by Flower Head-Feeding Insects.

    PubMed

    Nobre, Paola A F; Bergamini, Leonardo L; Lewinsohn, Thomas M; Jorge, Leonardo R; Almeida-Neto, Mário

    2016-02-01

    Among-population variation in host use is a common phenomenon in herbivorous insects. The simplest and most trivial explanation for such variation in host use is the among-site variation in plant species composition. Another aspect that can influence spatial variation in host use is the relative abundance of each host-plant species compared to all available hosts. Here, we used endophagous insects that develop in flower heads of Asteraceae species as a study system to investigate how plant abundance influences the pattern of host-plant use by herbivorous insects with distinct levels of host-range specialization. Only herbivores recorded on three or more host species were included in this study. In particular, we tested two related hypotheses: 1) plant abundance has a positive effect on the host-plant preference of herbivorous insects, and 2) the relative importance of plant abundance to host-plant preference is greater for herbivorous species that use a wider range of host-plant species. We analyzed 11 herbivore species in 20 remnants of Cerrado in Southeastern Brazil. For 8 out of 11 herbivore species, plant abundance had a positive influence on host use. In contrast to our expectation, both the most specialized and the most generalist herbivores showed a stronger positive effect of plant species abundance in host use. Thus, we found evidence that although the abundance of plant species is a major factor determining the preferential use of host plants, its relative importance is mediated by the host-range specialization of herbivores. PMID:26637546

  2. Bromeliad-living spiders improve host plant nutrition and growth.

    PubMed

    Romero, Gustavo Q; Mazzafera, Paulo; Vasconcellos-Neto, Joao; Trivelin, Paulo C O

    2006-04-01

    Although bromeliads are believed to obtain nutrients from debris deposited by animals in their rosettes, there is little evidence to support this assumption. Using stable isotope methods, we found that the Neotropical jumping spider Psecas chapoda (Salticidae), which lives strictly associated with the terrestrial bromeliad Bromelia balansae, contributed 18% of the total nitrogen of its host plant in a greenhouse experiment. In a one-year field experiment, plants with spiders produced leaves 15% longer than plants from which the spiders were excluded. This is the first study to show nutrient provisioning in a spider-plant system. Because several animal species live strictly associated with bromeliad rosettes, this type of facultative mutualism involving the Bromeliaceae may be more common than previously thought. PMID:16676522

  3. Evolution of host range in Coleosporium ipomoeae, a plant pathogen with multiple hosts.

    PubMed

    Chappell, Thomas M; Rausher, Mark D

    2016-05-10

    Plants and their pathogens coevolve locally. Previous investigations of one host-one pathogen systems have demonstrated that natural selection favors pathogen genotypes that are virulent on a broad range of host genotypes. In the present study, we examine a system consisting of one pathogen species that infects three host species in the morning glory genus Ipomoea. We show that many pathogen genotypes can infect two or three of the host species when tested on plants from nonlocal communities. By contrast, pathogen genotypes are highly host-specific, infecting only one host species, when tested on host species from the local community. This pattern indicates that within-community evolution narrows the host breadth of pathogen genotypes. Possible evolutionary mechanisms include direct selection for narrow host breadth due to costs of virulence and evolution of ipomoea resistance in the host species. PMID:27114547

  4. The plastic response of Manduca sexta to host and non-host plants.

    PubMed

    Koenig, Christopher; Bretschneider, Anne; Heckel, David G; Grosse-Wilde, Ewald; Hansson, Bill S; Vogel, Heiko

    2015-08-01

    Specialist insect herbivores have evolved efficient ways to adapt to the major defenses of their host plants. Although Manduca sexta, specialized on Solanaceous plants, has become a model organism for insect molecular biology, little is known about its adaptive responses to the chemical defenses of its hosts. To study larval performance and transcriptomic responses to host and non-host plants, we conducted developmental assays and replicated RNAseq experiments with Manduca larvae fed on different Solanaceous plants as well as on a Brassicaceous non-host plant, Brassica napus. Manduca larvae developed fastest on Nicotiana attenuata, but no significant differences in performance were found on larvae fed on other Solanaceae or the non-host B. napus. The RNAseq experiments revealed that Manduca larvae display plastic responses at the gene expression level, and transcriptional signatures specific to the challenges of each host- and non-host plant. Our observations are not consistent with expectations that specialist herbivores would perform poorly on non-host plants. Instead, our findings demonstrate the ability of this specialized insect herbivore to efficiently use a larger repertoire of host plants than it utilizes in the field. PMID:26070471

  5. Electroantennographic bioassay as a screening tool for host plant volatiles.

    PubMed

    Beck, John J; Light, Douglas M; Gee, Wai S

    2012-01-01

    Plant volatiles play an important role in plant-insect interactions. Herbivorous insects use plant volatiles, known as kairomones, to locate their host plant. When a host plant is an important agronomic commodity feeding damage by insect pests can inflict serious economic losses to growers. Accordingly, kairomones can be used as attractants to lure or confuse these insects and, thus, offer an environmentally friendly alternative to pesticides for insect control. Unfortunately, plants can emit a vast number volatiles with varying compositions and ratios of emissions dependent upon the phenology of the commodity or the time of day. This makes identification of biologically active components or blends of volatile components an arduous process. To help identify the bioactive components of host plant volatile emissions we employ the laboratory-based screening bioassay electroantennography (EAG). EAG is an effective tool to evaluate and record electrophysiologically the olfactory responses of an insect via their antennal receptors. The EAG screening process can help reduce the number of volatiles tested to identify promising bioactive components. However, EAG bioassays only provide information about activation of receptors. It does not provide information about the type of insect behavior the compound elicits; which could be as an attractant, repellent or other type of behavioral response. Volatiles eliciting a significant response by EAG, relative to an appropriate positive control, are typically taken on to further testing of behavioral responses of the insect pest. The experimental design presented will detail the methodology employed to screen almond-based host plant volatiles by measurement of the electrophysiological antennal responses of an adult insect pest navel orangeworm (Amyelois transitella) to single components and simple blends of components via EAG bioassay. The method utilizes two excised antennae placed across a "fork" electrode holder. The protocol

  6. Type I Interferons Direct Gammaherpesvirus Host Colonization.

    PubMed

    Tan, Cindy S E; Lawler, Clara; May, Janet S; Belz, Gabrielle T; Stevenson, Philip G

    2016-05-01

    Gamma-herpesviruses colonise lymphocytes. Murid Herpesvirus-4 (MuHV-4) infects B cells via epithelial to myeloid to lymphoid transfer. This indirect route entails exposure to host defences, and type I interferons (IFN-I) limit infection while viral evasion promotes it. To understand how IFN-I and its evasion both control infection outcomes, we used Mx1-cre mice to tag floxed viral genomes in IFN-I responding cells. Epithelial-derived MuHV-4 showed low IFN-I exposure, and neither disrupting viral evasion nor blocking IFN-I signalling markedly affected acute viral replication in the lungs. Maximising IFN-I induction with poly(I:C) increased virus tagging in lung macrophages, but the tagged virus spread poorly. Lymphoid-derived MuHV-4 showed contrastingly high IFN-I exposure. This occurred mainly in B cells. IFN-I induction increased tagging without reducing viral loads; disrupting viral evasion caused marked attenuation; and blocking IFN-I signalling opened up new lytic spread between macrophages. Thus, the impact of IFN-I on viral replication was strongly cell type-dependent: epithelial infection induced little response; IFN-I largely suppressed macrophage infection; and viral evasion allowed passage through B cells despite IFN-I responses. As a result, IFN-I and its evasion promoted a switch in infection from acutely lytic in myeloid cells to chronically latent in B cells. Murine cytomegalovirus also showed a capacity to pass through IFN-I-responding cells, arguing that this is a core feature of herpesvirus host colonization. PMID:27223694

  7. Type I Interferons Direct Gammaherpesvirus Host Colonization

    PubMed Central

    Tan, Cindy S. E.; Lawler, Clara; May, Janet S.; Belz, Gabrielle T.; Stevenson, Philip G.

    2016-01-01

    Gamma-herpesviruses colonise lymphocytes. Murid Herpesvirus-4 (MuHV-4) infects B cells via epithelial to myeloid to lymphoid transfer. This indirect route entails exposure to host defences, and type I interferons (IFN-I) limit infection while viral evasion promotes it. To understand how IFN-I and its evasion both control infection outcomes, we used Mx1-cre mice to tag floxed viral genomes in IFN-I responding cells. Epithelial-derived MuHV-4 showed low IFN-I exposure, and neither disrupting viral evasion nor blocking IFN-I signalling markedly affected acute viral replication in the lungs. Maximising IFN-I induction with poly(I:C) increased virus tagging in lung macrophages, but the tagged virus spread poorly. Lymphoid-derived MuHV-4 showed contrastingly high IFN-I exposure. This occurred mainly in B cells. IFN-I induction increased tagging without reducing viral loads; disrupting viral evasion caused marked attenuation; and blocking IFN-I signalling opened up new lytic spread between macrophages. Thus, the impact of IFN-I on viral replication was strongly cell type-dependent: epithelial infection induced little response; IFN-I largely suppressed macrophage infection; and viral evasion allowed passage through B cells despite IFN-I responses. As a result, IFN-I and its evasion promoted a switch in infection from acutely lytic in myeloid cells to chronically latent in B cells. Murine cytomegalovirus also showed a capacity to pass through IFN-I-responding cells, arguing that this is a core feature of herpesvirus host colonization. PMID:27223694

  8. Aphids alter host-plant nitrogen isotope fractionation

    PubMed Central

    Wilson, Alex C. C.; Sternberg, Leonel da S. L.; Hurley, Katherine B.

    2011-01-01

    Plant sap-feeding insects and blood-feeding parasites are frequently depleted in 15N relative to their diet. Unfortunately, most fluid-feeder/host nitrogen stable-isotope studies simply report stable-isotope signatures, but few attempt to elucidate the mechanism of isotopic trophic depletion. Here we address this deficit by investigating the nitrogen stable-isotope dynamics of a fluid-feeding herbivore-host plant system: the green peach aphid, Myzus persicae, feeding on multiple brassicaceous host plants. M. persicae was consistently more than 6‰ depleted in 15N relative to their hosts, although aphid colonized plants were 1.5‰ to 2.0‰ enriched in 15N relative to uncolonized control plants. Isotopic depletion of aphids relative to hosts was strongly related to host nitrogen content. We tested whether the concomitant aphid 15N depletion and host 15N enrichment was coupled by isotopic mass balance and determined that aphid 15N depletion and host 15N enrichment are uncoupled processes. We hypothesized that colonized plants would have higher nitrate reductase activity than uncolonized plants because previous studies had demonstrated that high nitrate reductase activity under substrate-limiting conditions can result in increased plant δ15N values. Consistent with our hypothesis, nitrate reductase activity in colonized plants was twice that of uncolonized plants. This study offers two important insights that are likely applicable to understanding nitrogen dynamics in fluid-feeder/host systems. First, isotopic separation of aphid and host depends on nitrogen availability. Second, aphid colonization alters host nitrogen metabolism and subsequently host nitrogen stable-isotope signature. Notably, this work establishes a metabolic framework for future hypothesis-driven studies focused on aphid manipulation of host nitrogen metabolism. PMID:21646532

  9. Transgenerational acclimatization in an herbivore-host plant relationship.

    PubMed

    Cahenzli, Fabian; Erhardt, Andreas

    2013-04-01

    Twenty years ago, scientists began to recognize that parental effects are one of the most important influences on progeny phenotype. Consequently, it was postulated that herbivorous insects could produce progeny that are acclimatized to the host plant experienced by the parents to improve progeny fitness, because host plants vary greatly in quality and quantity, and can thus provide important cues about the resources encountered by the next generation. However, despite the possible profound implications for our understanding of host-use evolution of herbivores, host-race formation and sympatric speciation, intense research has been unable to verify transgenerational acclimatization in herbivore-host plant relationships. We reared Coenonympha pamphilus larvae in the parental generation (P) on high- and low-quality host plants, and reared the offspring (F(1)) of both treatments again on high- and low-quality plants. We tested not only for maternal effects, as most previous studies, but also for paternal effects. Our results show that parents experiencing predictive cues on their host plant can indeed adjust progeny's phenotype to anticipated host plant quality. Maternal effects affected female and male offspring, whereas paternal effects affected only male progeny. We here verify, for the first time to our knowledge, the long postulated transgenerational acclimatization in an herbivore-host plant interaction. PMID:23407834

  10. Critical rearing parameters of Tetrastichus planipennisi (Hymenoptera: Eulophidae) as affected by host-plant substrate and host-parasitoid group structure

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Laboratory studies were conducted to evaluate the potential impact of host-plant substrate types, host-parasitoid group size and host to parasitoid ratios on select fitness parameters of the larval parasitoid Tetrastichus planipennisi Yang, newly introduced for biological control of the invasive eme...

  11. A Bacterial Pathogen uses Distinct Type III Secretion Systems to Alternate between Host Kingdom

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gram-negative bacterial pathogens of eukaryotes often secrete proteins directly into host cells via a needle-like protein channel called a ‘type III secretion system’ (T3SS). Bacteria that are adapted to either animal or plant hosts use phylogenetically distinct T3SSs for secreting proteins. Here, ...

  12. Bacterial effectors target the plant cell nucleus to subvert host transcription

    PubMed Central

    Canonne, Joanne; Rivas, Susana

    2012-01-01

    In order to promote virulence, Gram-negative bacteria have evolved the ability to inject so-called type III effector proteins into host cells. The plant cell nucleus appears to be a subcellular compartment repeatedly targeted by bacterial effectors. In agreement with this observation, mounting evidence suggests that manipulation of host transcription is a major strategy developed by bacteria to counteract plant defense responses. It has been suggested that bacterial effectors may adopt at least three alternative, although not mutually exclusive, strategies to subvert host transcription. T3Es may (1) act as transcription factors that directly activate transcription in host cells, (2) affect histone packing and chromatin configuration, and/or (3) directly target host transcription factor activity. Here, we provide an overview on how all these strategies may lead to host transcriptional re-programming and, as a result, to improved bacterial multiplication inside plant cells. PMID:22353865

  13. Directional Selection from Host Plants Is a Major Force Driving Host Specificity in Magnaporthe Species.

    PubMed

    Zhong, Zhenhui; Norvienyeku, Justice; Chen, Meilian; Bao, Jiandong; Lin, Lianyu; Chen, Liqiong; Lin, Yahong; Wu, Xiaoxian; Cai, Zena; Zhang, Qi; Lin, Xiaoye; Hong, Yonghe; Huang, Jun; Xu, Linghong; Zhang, Honghong; Chen, Long; Tang, Wei; Zheng, Huakun; Chen, Xiaofeng; Wang, Yanli; Lian, Bi; Zhang, Liangsheng; Tang, Haibao; Lu, Guodong; Ebbole, Daniel J; Wang, Baohua; Wang, Zonghua

    2016-01-01

    One major threat to global food security that requires immediate attention, is the increasing incidence of host shift and host expansion in growing number of pathogenic fungi and emergence of new pathogens. The threat is more alarming because, yield quality and quantity improvement efforts are encouraging the cultivation of uniform plants with low genetic diversity that are increasingly susceptible to emerging pathogens. However, the influence of host genome differentiation on pathogen genome differentiation and its contribution to emergence and adaptability is still obscure. Here, we compared genome sequence of 6 isolates of Magnaporthe species obtained from three different host plants. We demonstrated the evolutionary relationship between Magnaporthe species and the influence of host differentiation on pathogens. Phylogenetic analysis showed that evolution of pathogen directly corresponds with host divergence, suggesting that host-pathogen interaction has led to co-evolution. Furthermore, we identified an asymmetric selection pressure on Magnaporthe species. Oryza sativa-infecting isolates showed higher directional selection from host and subsequently tends to lower the genetic diversity in its genome. We concluded that, frequent gene loss or gain, new transposon acquisition and sequence divergence are host adaptability mechanisms for Magnaporthe species, and this coevolution processes is greatly driven by directional selection from host plants. PMID:27151494

  14. Directional Selection from Host Plants Is a Major Force Driving Host Specificity in Magnaporthe Species

    PubMed Central

    Zhong, Zhenhui; Norvienyeku, Justice; Chen, Meilian; Bao, Jiandong; Lin, Lianyu; Chen, Liqiong; Lin, Yahong; Wu, Xiaoxian; Cai, Zena; Zhang, Qi; Lin, Xiaoye; Hong, Yonghe; Huang, Jun; Xu, Linghong; Zhang, Honghong; Chen, Long; Tang, Wei; Zheng, Huakun; Chen, Xiaofeng; Wang, Yanli; Lian, Bi; Zhang, Liangsheng; Tang, Haibao; Lu, Guodong; Ebbole, Daniel J.; Wang, Baohua; Wang, Zonghua

    2016-01-01

    One major threat to global food security that requires immediate attention, is the increasing incidence of host shift and host expansion in growing number of pathogenic fungi and emergence of new pathogens. The threat is more alarming because, yield quality and quantity improvement efforts are encouraging the cultivation of uniform plants with low genetic diversity that are increasingly susceptible to emerging pathogens. However, the influence of host genome differentiation on pathogen genome differentiation and its contribution to emergence and adaptability is still obscure. Here, we compared genome sequence of 6 isolates of Magnaporthe species obtained from three different host plants. We demonstrated the evolutionary relationship between Magnaporthe species and the influence of host differentiation on pathogens. Phylogenetic analysis showed that evolution of pathogen directly corresponds with host divergence, suggesting that host-pathogen interaction has led to co-evolution. Furthermore, we identified an asymmetric selection pressure on Magnaporthe species. Oryza sativa-infecting isolates showed higher directional selection from host and subsequently tends to lower the genetic diversity in its genome. We concluded that, frequent gene loss or gain, new transposon acquisition and sequence divergence are host adaptability mechanisms for Magnaporthe species, and this coevolution processes is greatly driven by directional selection from host plants. PMID:27151494

  15. Survey of Reproductive Host Plants of Bemisia tabaci (Hemiptera: Aleyrodidae) in Egypt, Including New Host Records

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Host plants can affect the population dynamics of the sweetpotato whitefly, Bemisia tabaci (Gennadius), and the plants can be potential sources of numerous whitefly-vectored viruses. This important pest attacks a wide range of agricultural plants, and feed on an extensive number of feral species of...

  16. Pepper weevil attraction to volatiles from host and nonhost plants.

    PubMed

    Addesso, Karla M; McAuslane, Heather J

    2009-02-01

    The location of wild and cultivated host plants by pepper weevil (Anthonomus eugenii Cano) may be aided by visual cues, the male-produced aggregation pheromone, herbivore-induced, or constitutive host plant volatiles. The attractiveness of constitutive plant volatiles to pioneer weevils is important in understanding, and perhaps controlling, dispersal of this insect between wild and cultivated hosts. Ten-day-old male and 2- and 10-day-old female weevils were tested in short-range Y-tube assays. Ten-day-old male and female weevils were attracted to the volatiles released by whole plants of three known oviposition hosts, 'Jalapeno' pepper, American black nightshade, and eggplant, as well as tomato, a congener, which supports feeding but not oviposition. Two-day-old females were attracted to all plants tested, including lima bean, an unrelated, nonhost plant. Fruit volatiles from all three hosts and flower volatiles from nightshade and eggplant were also attractive. In choice tests, weevils showed different preferences for the oviposition hosts, depending on age and sex. Upwind response of 10-day-old male and female weevils to host plant volatiles was also tested in long-range wind tunnel assays. Weevils responded to pepper, nightshade, and eggplant volatiles by moving upwind. There was no difference in the observed upwind response of the weevils to the three host plants under no-choice conditions. Reproductively mature pepper weevils can detect, orient to, and discriminate between the volatile plumes of host plants in the absence of visual cues, conspecific feeding damage, or the presence of their aggregation pheromone. PMID:19791617

  17. Genome characteristics of facultatively symbiotic Frankia sp. strains reflect host range and host plant biogeography.

    PubMed

    Normand, Philippe; Lapierre, Pascal; Tisa, Louis S; Gogarten, Johann Peter; Alloisio, Nicole; Bagnarol, Emilie; Bassi, Carla A; Berry, Alison M; Bickhart, Derek M; Choisne, Nathalie; Couloux, Arnaud; Cournoyer, Benoit; Cruveiller, Stephane; Daubin, Vincent; Demange, Nadia; Francino, Maria Pilar; Goltsman, Eugene; Huang, Ying; Kopp, Olga R; Labarre, Laurent; Lapidus, Alla; Lavire, Celine; Marechal, Joelle; Martinez, Michele; Mastronunzio, Juliana E; Mullin, Beth C; Niemann, James; Pujic, Pierre; Rawnsley, Tania; Rouy, Zoe; Schenowitz, Chantal; Sellstedt, Anita; Tavares, Fernando; Tomkins, Jeffrey P; Vallenet, David; Valverde, Claudio; Wall, Luis G; Wang, Ying; Medigue, Claudine; Benson, David R

    2007-01-01

    Soil bacteria that also form mutualistic symbioses in plants encounter two major levels of selection. One occurs during adaptation to and survival in soil, and the other occurs in concert with host plant speciation and adaptation. Actinobacteria from the genus Frankia are facultative symbionts that form N(2)-fixing root nodules on diverse and globally distributed angiosperms in the "actinorhizal" symbioses. Three closely related clades of Frankia sp. strains are recognized; members of each clade infect a subset of plants from among eight angiosperm families. We sequenced the genomes from three strains; their sizes varied from 5.43 Mbp for a narrow host range strain (Frankia sp. strain HFPCcI3) to 7.50 Mbp for a medium host range strain (Frankia alni strain ACN14a) to 9.04 Mbp for a broad host range strain (Frankia sp. strain EAN1pec.) This size divergence is the largest yet reported for such closely related soil bacteria (97.8%-98.9% identity of 16S rRNA genes). The extent of gene deletion, duplication, and acquisition is in concert with the biogeographic history of the symbioses and host plant speciation. Host plant isolation favored genome contraction, whereas host plant diversification favored genome expansion. The results support the idea that major genome expansions as well as reductions can occur in facultative symbiotic soil bacteria as they respond to new environments in the context of their symbioses. PMID:17151343

  18. Regulation of Plant Defense Response to Fungal Pathogens: Two Types of Protein Kinases in the Reversible Phosphorylation of the Host Plasma Membrane H+-ATPase.

    PubMed Central

    Xing, T; Higgins, VJ; Blumwald, E

    1996-01-01

    The role of reversible phosphorylation of the host plasma membrane H+-ATPase in signal transduction during the incompatible interaction between tomato cells and the fungal pathogen Cladosporium fulvum was investigated. Tomato cells (with the Cf-5 resistance gene) or isolated plasma membranes from Cf-5 cells treated with elicitor preparations from race 2.3 or 4 of C. fulvum (containing the avr5 gene product) showed a marked dephosphorylation of plasma membrane H+-ATPase. Similar treatment with elicitor preparations from races 5 and 2.4.5.9.11 (lacking the avr5 gene product) showed no change in dephosphorylation. Elicitor (race 4) treatment of cells, but not of isolated plasma membranes, for 2 hr resulted in rephosphorylation of the ATPase via Ca2+-dependent protein kinases. The initial (first hour) rephosphorylation was enhanced by protein kinase C (PKC) activators and was prevented by PKC inhibitors. Activity of a second kinase appeared after 1 hr and was responsible for the continuing phosphorylation of the H+-ATPase. This latter Ca2+-dependent kinase was inhibited by a calmodulin (CaM) antagonist and by an inhibitor of Ca2+/CaM-dependent protein kinase II. The activation of the Ca2+/CaM-dependent protein kinase depended on the prior activation of the PKC-like kinase. PMID:12239392

  19. Host Plant Specialization in the Sugarcane Aphid Melanaphis sacchari

    PubMed Central

    Nibouche, Samuel; Mississipi, Stelly; Fartek, Benjamin; Delatte, Hélène; Reynaud, Bernard; Costet, Laurent

    2015-01-01

    Most aphids are highly specialized on one or two related plant species and generalist species often include sympatric populations adapted to different host plants. Our aim was to test the hypothesis of the existence of host specialized lineages of the aphid Melanaphis sacchari in Reunion Island. To this end, we investigated the genetic diversity of the aphid and its association with host plants by analyzing the effect of wild sorghum Sorghum bicolor subsp. verticilliflorum or sugarcane as host plants on the genetic structuring of populations and by performing laboratory host transfer experiments to detect trade-offs in host use. Genotyping of 31 samples with 10 microsatellite loci enabled identification of 13 multilocus genotypes (MLG). Three of these, Ms11, Ms16 and Ms15, were the most frequent ones. The genetic structure of the populations was linked to the host plants. Ms11 and Ms16 were significantly more frequently observed on sugarcane, while Ms15 was almost exclusively collected in colonies on wild sorghum. Laboratory transfer experiments demonstrated the existence of fitness trade-offs. An Ms11 isofemale lineage performed better on sugarcane than on sorghum, whereas an Ms15 lineage developed very poorly on sugarcane, and two Ms16 lineages showed no significant difference in performances between both hosts. Both field and laboratory results support the existence of host plant specialization in M. sacchari in Reunion Island, despite low genetic differentiation. This study illustrates the ability of asexual aphid lineages to rapidly undergo adaptive changes including shifting from one host plant to another. PMID:26600253

  20. Host plant preference in Colorado potato beetle (Coleoptera: Chrysomelidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field and laboratory-choice tests were conducted to better understand host plant preference by the Colorado potato beetle, Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae), in Virginia. In laboratory olfactometer studies, L. decemlineata preferred potato over both tomato and eggplant foli...

  1. Host plant genotype influences survival of hybrids between Eurosta solidaginis host races.

    PubMed

    Craig, Timothy P; Itami, Joanne K; Craig, James V

    2007-11-01

    Extrinsic, host-associated environmental factors may influence postmating isolation between herbivorous insect populations and represent a fundamentally ecological cause of speciation. We investigated this issue in experiments on hybrids between the host races of Eurosta solidaginis, a fly that induces galls on the goldenrods Solidago altissima and S. gigantea. To do so, we measured the performance of parental host races and their hybrids on five genotypes of S. gigantea and nine genotypes of S. altissima to test hypotheses about how variation in plant genotype affects performance (i.e., fitness) and potentially influences gene flow between these host races. We found that rates of gall induction and of survival to adult emergence by hybrid larvae were significantly lower than those of both parental host races on both host species, adding support to the hypothesis that there is partial postmating isolation between the host races. Hybrid flies significantly varied in their performance across plant genotypes of both host species. A significant interaction between the effects of plant genotype and mating treatment (parental vs. hybrid crosses) on larval performance indicated that the relative suitability of particular plant genotypes differed between the parental host races and their hybrids. These patterns illustrate a poor correspondence between optimal parental and hybrid environments, consistent with the hypothesis that these host races are partially isolated due to extrinsic (ecological) factors. Based on these findings, we discuss the possibility that plant genotypes in which hybrid performance is high can facilitate hybridization and gene flow between partially reproductively isolated populations of herbivorous insects, thus affecting the dynamics of ecological speciation. PMID:17725623

  2. Genetics, experience, and host-plant preference in Eurosta solidaginis: implications for host shifts and speciation.

    PubMed

    Craig, T P; Horner, J D; Itami, J K

    2001-04-01

    Host-associated mating is crucial in maintaining the partial reproductive isolation between the host races of Eurosta solidaginis (Diptera: Tephritidae), a fly that forms galls on Solidago altissima and S. gigantea. (We refer to flies reared from S. gigantea as gigantea flies and those reared from S. altissima as altissima flies.) We measured the host preference of males and females of both host races, F1 hybrids between the host races, F2, and backcrosses to both host races. Male and female altissima flies and female gigantea flies had high host fidelity, whereas male gigantea flies had low host fidelity. This result suggests that there may be gene flow between the host races due to nonassortative mating that occurs when male gigantea mate with altissima females on S. altissima. This indicates assortative-mating mechanisms in addition to host-associated mating are required to produce the partial reproductive isolation between the host races that has been observed. Nongenetic factors had no influence on host preference. Larval conditioning did not influence host preference: reciprocal F1 hybrids reared in S. altissima and S. gigantea both preferred S. gigantea. Adult experience had no impact on host preference: females preferred their natal host plant regardless of which host they encountered first as an adult. The hypothesis that maternal effects influence preferences was rejected because male and female flies did not show a consistent preference for the host plant of their mother. We also found no evidence that preference was a sex-linked trait because F1 and backcrosses to the host races with different combinations of X chromosomes from the two host races preferred S. gigantea. Our results indicate that host preference is not determined by a large number of genes because preference of hybrids did not correspond to the proportion of the genome derived from each host race. The strength of the ovipuncture preference for S. gigantea by gigantea females, the females

  3. Multifaceted effects of host plants on entomopathogenic nematodes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The success of parasites can be impacted by multi-trophic interactions. Here we investigate aspects of multi-trophic interactions in a system involving an entomopathogenic nematode (EPN), its insect host, and host plant. Novel issues investigated include the impact of tritrophic interactions on nema...

  4. Glucosinolates from Host Plants Influence Growth of the Parasitic Plant Cuscuta gronovii and Its Susceptibility to Aphid Feeding.

    PubMed

    Smith, Jason D; Woldemariam, Melkamu G; Mescher, Mark C; Jander, Georg; De Moraes, Consuelo M

    2016-09-01

    Parasitic plants acquire diverse secondary metabolites from their hosts, including defense compounds that target insect herbivores. However, the ecological implications of this phenomenon, including the potential enhancement of parasite defenses, remain largely unexplored. We studied the translocation of glucosinolates from the brassicaceous host plant Arabidopsis (Arabidopsis thaliana) into parasitic dodder vines (Convolvulaceae; Cuscuta gronovii) and its effects on the parasite itself and on dodder-aphid interactions. Aliphatic and indole glucosinolates reached concentrations in parasite tissues higher than those observed in corresponding host tissues. Dodder growth was enhanced on cyp79B2 cyp79B3 hosts (without indole glucosinolates) but inhibited on atr1D hosts (with elevated indole glucosinolates) relative to wild-type hosts, which responded to parasitism with localized elevation of indole and aliphatic glucosinolates. These findings implicate indole glucosinolates in defense against parasitic plants. Rates of settling and survival on dodder vines by pea aphids (Acyrthosiphon pisum) were reduced significantly when dodder parasitized glucosinolate-producing hosts (wild type and atr1D) compared with glucosinolate-free hosts (cyp79B2 cyp79B3 myb28 myb29). However, settling and survival of green peach aphids (Myzus persicae) were not affected. M. persicae population growth was actually reduced on dodder parasitizing glucosinolate-free hosts compared with wild-type or atr1D hosts, even though stems of the former contain less glucosinolates and more amino acids. Strikingly, this effect was reversed when the aphids fed directly upon Arabidopsis, which indicates an interactive effect of parasite and host genotype on M. persicae that stems from host effects on dodder. Thus, our findings indicate that glucosinolates may have both direct and indirect effects on dodder-feeding herbivores. PMID:27482077

  5. Pollination niche overlap between a parasitic plant and its host.

    PubMed

    Ollerton, Jeff; Stott, Adrian; Allnutt, Emma; Shove, Sam; Taylor, Chloe; Lamborn, Ellen

    2007-03-01

    Niche theory predicts that species which share resources should evolve strategies to minimise competition for those resources, or the less competitive species would be extirpated. Some plant species are constrained to co-occur, for example parasitic plants and their hosts, and may overlap in their pollination niche if they flower at the same time and attract the same pollinators. Using field observations and experiments between 1996 and 2006, we tested a series of hypotheses regarding pollination niche overlap between a specialist parasitic plant Orobanche elatior (Orobanchaceae) and its host Centaurea scabiosa (Asteraceae). These species flower more or less at the same time, with some year-to-year variation. The host is pollinated by a diverse range of insects, which vary in their effectiveness, whilst the parasite is pollinated by a single species of bumblebee, Bombus pascuorum, which is also an effective pollinator of the host plant. The two species therefore have partially overlapping pollination niches. These niches are not finely subdivided by differential pollen placement, or by diurnal segregation of the niches. We therefore found no evidence of character displacement within the pollination niches of these species, possibly because pollinators are not a limiting resource for these plants. Direct observation of pollinator movements, coupled with experimental manipulations of host plant inflorescence density, showed that Bombus pascuorum only rarely moves between inflorescences of the host and the parasite and therefore the presence of one plant is unlikely to be facilitating pollination in the other. This is the first detailed examination of pollination niche overlap in a plant parasite system and we suggest avenues for future research in relation to pollination and other shared interactions between parasitic plants and their hosts. PMID:17146683

  6. Effectors of animal and plant pathogens use a common domain to bind host phosphoinositides

    PubMed Central

    Salomon, Dor; Guo, Yirui; Kinch, Lisa N.; Grishin, Nick V.; Gardner, Kevin H.; Orth, Kim

    2016-01-01

    Bacterial Type III Secretion Systems deliver effectors into host cells to manipulate cellular processes to the advantage of the pathogen. Many host targets of these effectors are found on membranes. Therefore, to identify their targets, effectors often use specialized membrane-localization domains to localize to appropriate host membranes. However, the molecular mechanisms used by many domains are unknown. Here we identify a conserved bacterial phosphoinositide-binding domain (BPD) that is found in functionally diverse Type III effectors of both plant and animal pathogens. We show that members of the BPD family functionally bind phosphoinositides and mediate localization to host membranes. Moreover, NMR studies reveal that the BPD of the newly identified Vibrio parahaemolyticus Type III effector VopR is unfolded in solution, but folds into a specific structure upon binding its ligand phosphatidylinositol-(4,5)-bisphosphate. Thus, our findings suggest a possible mechanism for promoting refolding of Type III effectors after delivery into host cells. PMID:24346350

  7. Divergence in Olfactory Host Plant Preference in D. mojavensis in Response to Cactus Host Use

    PubMed Central

    Stensmyr, Marcus C.; Shann, Jodi; Hansson, Bill S.; Rollmann, Stephanie M.

    2013-01-01

    Divergence in host adaptive traits has been well studied from an ecological and evolutionary perspective, but identification of the proximate mechanisms underlying such divergence is less well understood. Behavioral preferences for host plants are often mediated by olfaction and shifts in preference may be accompanied by changes in the olfactory system. In this study, we examine the evolution of host plant preferences in cactophilic Drosophila mojavensis that feeds and breeds on different cacti throughout its range. We show divergence in electrophysiological responses and olfactory behavior among populations with host plant shifts. Specifically, significant divergence was observed in the Mojave Desert population that specializes on barrel cactus. Differences were observed in electrophysiological responses of the olfactory organs and in behavioral responses to barrel cactus volatiles. Together our results suggest that the peripheral nervous system has changed in response to different ecological environments and that these changes likely contribute to divergence among D. mojavensis populations. PMID:23936137

  8. Divergence in olfactory host plant preference in D. mojavensis in response to cactus host use.

    PubMed

    Date, Priya; Dweck, Hany K M; Stensmyr, Marcus C; Shann, Jodi; Hansson, Bill S; Rollmann, Stephanie M

    2013-01-01

    Divergence in host adaptive traits has been well studied from an ecological and evolutionary perspective, but identification of the proximate mechanisms underlying such divergence is less well understood. Behavioral preferences for host plants are often mediated by olfaction and shifts in preference may be accompanied by changes in the olfactory system. In this study, we examine the evolution of host plant preferences in cactophilic Drosophila mojavensis that feeds and breeds on different cacti throughout its range. We show divergence in electrophysiological responses and olfactory behavior among populations with host plant shifts. Specifically, significant divergence was observed in the Mojave Desert population that specializes on barrel cactus. Differences were observed in electrophysiological responses of the olfactory organs and in behavioral responses to barrel cactus volatiles. Together our results suggest that the peripheral nervous system has changed in response to different ecological environments and that these changes likely contribute to divergence among D. mojavensis populations. PMID:23936137

  9. Adaptation to resistant hosts increases fitness on susceptible hosts in the plant parasitic nematode Globodera pallida.

    PubMed

    Fournet, Sylvain; Eoche-Bosy, Delphine; Renault, Lionel; Hamelin, Frédéric M; Montarry, Josselin

    2016-04-01

    Trade-offs between virulence (defined as the ability to infect a resistant host) and life-history traits are of particular interest in plant pathogens for durable management of plant resistances. Adaptation to plant resistances (i.e., virulence acquisition) is indeed expected to be associated with a fitness cost on susceptible hosts. Here, we investigated whether life-history traits involved in the fitness of the potato cyst nematode Globodera pallida are affected in a virulent lineage compared to an avirulent one. Both lineages were obtained from the same natural population through experimental evolution on resistant and susceptible hosts, respectively. Unexpectedly, we found that virulent lineages were more fit than avirulent lineages on susceptible hosts: they produced bigger cysts, containing more larvae and hatching faster. We thus discuss possible reasons explaining why virulence did not spread into natural G. pallida populations. PMID:27066239

  10. HOST PLANT UTILIZATION, HOST RANGE OSCILLATIONS AND DIVERSIFICATION IN NYMPHALID BUTTERFLIES: A PHYLOGENETIC INVESTIGATION

    PubMed Central

    Nylin, Sören; Slove, Jessica; Janz, Niklas

    2014-01-01

    It has been suggested that phenotypic plasticity is a major factor in the diversification of life, and that variation in host range in phytophagous insects is a good model for investigating this claim. We explore the use of angiosperm plants as hosts for nymphalid butterflies, and in particular the evidence for past oscillations in host range and how they are linked to host shifts and to diversification. At the level of orders of plants, a relatively simple pattern of host use and host shifts emerges, despite the 100 million years of history of the family Nymphalidae. We review the evidence that these host shifts and the accompanying diversifications were associated with transient polyphagous stages, as suggested by the “oscillation hypothesis.” In addition, we investigate all currently polyphagous nymphalid species and demonstrate that the state of polyphagy is rare, has a weak phylogenetic signal, and a very apical distribution in the phylogeny; we argue that these are signs of its transient nature. We contrast our results with data from the bark beetles Dendroctonus, in which a more specialized host use is instead the apical state. We conclude that plasticity in host use is likely to have contributed to diversification in nymphalid butterflies. PMID:24372598

  11. Multifaceted effects of host plants on entomopathogenic nematodes.

    PubMed

    Hazir, Selcuk; Shapiro-Ilan, David I; Hazir, Canan; Leite, Luis G; Cakmak, Ibrahim; Olson, Dawn

    2016-03-01

    The success of parasites can be impacted by multi-trophic interactions. Tritrophic interactions have been observed in parasite-herbivore-host plant systems. Here we investigate aspects of multi-trophic interactions in a system involving an entomopathogenic nematode (EPN), its insect host, and host plant. Novel issues investigated include the impact of tritrophic interactions on nematode foraging behavior, the ability of EPNs to overcome negative tritrophic effects through genetic selection, and interactions with a fourth trophic level (nematode predators). We tested infectivity of the nematode, Steinernema riobrave, to corn earworm larvae (Helicoverpa zea) in three host plants, tobacco, eggplant and tomato. Tobacco reduced nematode virulence and reproduction relative to tomato and eggplant. However, successive selection (5 passages) overcame the deficiency; selected nematodes no longer exhibited reductions in phenotypic traits. Despite the loss in virulence and reproduction nematodes, first passage S. riobrave was more attracted to frass from insects fed tobacco than insects fed on other host plants. Therefore, we hypothesized the reduced virulence and reproduction in S. riobrave infecting tobacco fed insects would be based on a self-medicating tradeoff, such as deterring predation. We tested this hypothesis by assessing predatory success of the mite Sancassania polyphyllae and the springtail Sinella curviseta on nematodes reared on tobacco-fed larvae versus those fed on greater wax moth, Galleria mellonella, tomato fed larvae, or eggplant fed larvae. No advantage was observed in nematodes derived from tobacco fed larvae. In conclusion, our results indicated that insect-host plant diet has an important effect on nematode foraging, infectivity and reproduction. However, negative host plant effects, might be overcome through directed selection. We propose that host plant species should be considered when designing biocontrol programs using EPNs. PMID:26896698

  12. Host Plants of Xylosandrus mutilatus in Mississippi

    SciTech Connect

    Stone, W.D.; Nebeker, T.E.; Gerard, P.D.

    2007-03-15

    Host range of Xylosandrus mutilatus (Blandford) in North America is reported here for the first time. Descriptive data such as number of attacks per host, size of stems at point of attacks, and height of attacks above ground are presented. Hosts observed in Mississippi were Acer rubrum L., Acer saccharum Marsh., Acer palmatum Thunb., Ostrya virginiana (Mill.) K. Koch., Cornus florida L., Fagus grandifolia Ehrh., Liquidamber styraciflua L., Carya spp., Liriodendron tulipifera L., Melia azedarach L., Pinus taeda L., Prunus serotina Ehrh., Prunus americana Marsh., Ulmus alata Michaux, and Vitus rotundifolia Michaux. Liquidamber styraciflua had significantly more successful attacks, significantly higher probability of attacks, and significantly higher number of adult beetles per host tree than did Carya spp., A. rubrum, and L. tulipifera. This information is relevant in determining the impact this exotic beetle may have in nurseries, urban areas, and other forestry systems where this beetle becomes established. (author) [Spanish] El rango de hospederos de Xylosandrus mutilatus (Blandford) en America del Norte esta reportado aqui por la primera vez. Se presentan datos descriptivos como el numero de ataques por hospederos, el tamano de los tallos en el punto de ataque y la altura por encima del nivel de tierra de los ataques. Los hospederos observados en el estado de Mississippi fueron Acer rubrum L., Acer saccharum Marsh., Acer palmatum Thunb., Ostrya virginiana (Mill.) K. Koch., Cornus florida L., Fagus grandifolia Ehrh., Liquidamber styraciflua L., Carya spp., Liriodendron tulipifera L., Melia azedarach L., Pinus taeda L., Prunus serotina Ehrh., Prunus americana Marsh., Ulmus alata Michaux y Vitus rotundifolia Michaux. Liquidamber styraciflua tuvo ataques significativamente mas exitosos, una probabilidad significativamente mas alta de ataques y un numero significativamente mayor de adultos de escarabajos por arbol hospedero que Carya spp., A. rubrum y L. tulipifera

  13. Interactions of Seedborne Bacterial Pathogens with Host and Non-Host Plants in Relation to Seed Infestation and Seedling Transmission

    PubMed Central

    Dutta, Bhabesh; Gitaitis, Ronald; Smith, Samuel; Langston, David

    2014-01-01

    The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea) to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean) and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a null-interacting situation with the same plant species. Flowers of host and non-host plants were inoculated with 1×106 colony forming units (CFUs)/flower for each bacterial species and allowed to develop into fruits or umbels (in case of onion). Seeds harvested from each host/non-host bacterial species combination were assayed for respective bacteria by plating on semi-selective media. Additionally, seedlots for each host/non-host bacterial species combination were also assayed for pathogen transmission by seedling grow-out (SGO) assays under greenhouse conditions. The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating), respectively and they were not significantly different (P = 0.67). The percentage of seedlots infested with null-interacting bacterial species was 16.8% (by plating) and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03). None of the seedlots with incompatible/null-interacting bacteria developed symptoms on seedlings; however, when seedlings were assayed for epiphytic bacterial presence, 19.5 and 9.4% of the lots were positive, respectively. These results indicate that the seeds of non-host plants can become infested with incompatible and null-interacting bacterial species through flower colonization and they can be transmitted via epiphytic colonization of seedlings. In addition, it was also observed that flowers and seeds of non-host plants can be colonized

  14. Interactions of seedborne bacterial pathogens with host and non-host plants in relation to seed infestation and seedling transmission.

    PubMed

    Dutta, Bhabesh; Gitaitis, Ronald; Smith, Samuel; Langston, David

    2014-01-01

    The ability of seed-borne bacterial pathogens (Acidovorax citrulli, Clavibacter michiganensis subsp. michiganensis, Pseudomonas syringae pv. tomato, Xanthomonas euvesicatoria, and Pseudomonas syringae pv. glycinea) to infest seeds of host and non-host plants (watermelon, tomato, pepper, and soybean) and subsequent pathogen transmission to seedlings was investigated. A non-pathogenic, pigmented strain of Serratia marcescens was also included to assess a null-interacting situation with the same plant species. Flowers of host and non-host plants were inoculated with 1 × 10(6) colony forming units (CFUs)/flower for each bacterial species and allowed to develop into fruits or umbels (in case of onion). Seeds harvested from each host/non-host bacterial species combination were assayed for respective bacteria by plating on semi-selective media. Additionally, seedlots for each host/non-host bacterial species combination were also assayed for pathogen transmission by seedling grow-out (SGO) assays under greenhouse conditions. The mean percentage of seedlots infested with compatible and incompatible pathogens was 31.7 and 30.9% (by plating), respectively and they were not significantly different (P = 0.67). The percentage of seedlots infested with null-interacting bacterial species was 16.8% (by plating) and it was significantly lower than the infested lots generated with compatible and incompatible bacterial pathogens (P = 0.03). None of the seedlots with incompatible/null-interacting bacteria developed symptoms on seedlings; however, when seedlings were assayed for epiphytic bacterial presence, 19.5 and 9.4% of the lots were positive, respectively. These results indicate that the seeds of non-host plants can become infested with incompatible and null-interacting bacterial species through flower colonization and they can be transmitted via epiphytic colonization of seedlings. In addition, it was also observed that flowers and seeds of non-host plants can be colonized by

  15. Screening for Host Plant Resistance to Azalea Lace Bug

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Azalea Lace bug (ALB) are a major pest of azaleas in the southeast. Adults and nymphs cause visible damage on the upper leaf surface. Host plant resistance to ALB provides “built-in” plant protection and allows for reduced dependency on pesticide applications for both growers and consumers. We have...

  16. Phylogenetic signal in plant pathogen–host range

    PubMed Central

    Gilbert, Gregory S.; Webb, Campbell O.

    2007-01-01

    What determines which plant species are susceptible to a given plant pathogen is poorly understood. Experimental inoculations with fungal pathogens of plant leaves in a tropical rain forest show that most fungal pathogens are polyphagous but that most plant species in a local community are resistant to any given pathogen. The likelihood that a pathogen can infect two plant species decreases continuously with phylogenetic distance between the plants, even to ancient evolutionary distances. This phylogenetic signal in host range allows us to predict the likely host range of plant pathogens in a local community, providing an important tool for plant ecology, design of agronomic systems, quarantine regulations in international trade, and risk analysis of biological control agents. In particular, the results suggest that the rate of spread and ecological impacts of a disease through a natural plant community will depend strongly on the phylogenetic structure of the community itself and that current regulatory approaches strongly underestimate the local risks of global movement of plant pathogens or their hosts. PMID:17360396

  17. Antagonistic within-host interactions between plant viruses: molecular basis and impact on viral and host fitness.

    PubMed

    Syller, Jerzy; Grupa, Anna

    2016-06-01

    Double infections of related or unrelated viruses frequently occur in single plants, the viral agents being inoculated into the host plant simultaneously (co-infection) or sequentially (super-infection). Plants attacked by viruses activate sophisticated defence pathways which operate at different levels, often at significant fitness costs, resulting in yield reduction in crop plants. The occurrence and severity of the negative effects depend on the type of within-host interaction between the infecting viruses. Unrelated viruses generally interact with each other in a synergistic manner, whereas interactions between related viruses are mostly antagonistic. These can incur substantial fitness costs to one or both of the competitors. A relatively well-known antagonistic interaction is cross-protection, also referred to as super-infection exclusion. This type of interaction occurs when a previous infection with one virus prevents or interferes with subsequent infection by a homologous second virus. The current knowledge on why and how one virus variant excludes or restricts another is scant. Super-infection exclusion between viruses has predominantly been attributed to the induction of RNA silencing, which is a major antiviral defence mechanism in plants. There are, however, presumptions that various mechanisms are involved in this phenomenon. This review outlines the current state of knowledge concerning the molecular mechanisms behind antagonistic interactions between plant viruses. Harmful or beneficial effects of these interactions on viral and host plant fitness are also characterized. Moreover, the review briefly outlines the past and present attempts to utilize antagonistic interactions among viruses to protect crop plants against destructive diseases. PMID:26416204

  18. Increased temperature reduces herbivore host-plant quality.

    PubMed

    Bauerfeind, Stephanie S; Fischer, Klaus

    2013-11-01

    Globally increasing temperatures may strongly affect insect herbivore performance, as their growth and development is directly linked to ambient temperature as well as host-plant quality. In contrast to direct effects of temperature on herbivores, indirect effects mediated via thermal effects on host-plant quality are only poorly understood, despite having the potential to substantially impact performance and thereby to alter responses to the changing climatic conditions. We here use a full-factorial design to explore the direct (larvae were reared at 17 °C or 25 °C) and indirect effects (host plants were reared at 17 °C or 25 °C) of temperature on larval growth and life-history traits in the temperate-zone butterfly Pieris napi. Direct temperature effects reflected the common pattern of prolonged development and increased body mass at lower temperatures. At the higher temperature, efficiency of converting food into body matter was much reduced being accompanied by an increased food intake, suggesting compensatory feeding. Indirect temperature effects were apparent as reduced body mass, longer development time, an increased food intake, and a reduced efficiency of converting food into body matter in larvae feeding on plants grown at the higher temperature, thus indicating poor host-plant quality. The effects of host-plant quality were more pronounced at the higher temperature, at which compensatory feeding was much less efficient. Our results highlight that temperature-mediated changes in host-plant quality are a significant, but largely overlooked source of variation in herbivore performance. Such effects may exaggerate negative effects of global warming, which should be considered when trying to forecast species' responses to climate change. PMID:23775632

  19. Shared weapons of blood- and plant-feeding insects: Surprising commonalities for manipulating hosts.

    PubMed

    Guiguet, Antoine; Dubreuil, Géraldine; Harris, Marion O; Appel, Heidi M; Schultz, Jack C; Pereira, Marcos H; Giron, David

    2016-01-01

    Insects that reprogram host plants during colonization remind us that the insect side of plant-insect story is just as interesting as the plant side. Insect effectors secreted by the salivary glands play an important role in plant reprogramming. Recent discoveries point to large numbers of salivary effectors being produced by a single herbivore species. Since genetic and functional characterization of effectors is an arduous task, narrowing the field of candidates is useful. We present ideas about types and functions of effectors from research on blood-feeding parasites and their mammalian hosts. Because of their importance for human health, blood-feeding parasites have more tools from genomics and other - omics than plant-feeding parasites. Four themes have emerged: (1) mechanical damage resulting from attack by blood-feeding parasites triggers "early danger signals" in mammalian hosts, which are mediated by eATP, calcium, and hydrogen peroxide, (2) mammalian hosts need to modulate their immune responses to the three "early danger signals" and use apyrases, calreticulins, and peroxiredoxins, respectively, to achieve this, (3) blood-feeding parasites, like their mammalian hosts, rely on some of the same "early danger signals" and modulate their immune responses using the same proteins, and (4) blood-feeding parasites deploy apyrases, calreticulins, and peroxiredoxins in their saliva to manipulate the "danger signals" of their mammalian hosts. We review emerging evidence that plant-feeding insects also interfere with "early danger signals" of their hosts by deploying apyrases, calreticulins and peroxiredoxins in saliva. Given emerging links between these molecules, and plant growth and defense, we propose that these effectors interfere with phytohormone signaling, and therefore have a special importance for gall-inducing and leaf-mining insects, which manipulate host-plants to create better food and shelter. PMID:26705897

  20. Host selection behavior and the fecundity of Plutella xylostella (Lepidoptera: Plutellidae) on multiple host plants.

    PubMed

    Huang, Bin; Shi, Zhanghong; Hou, Youming

    2014-01-01

    Insect herbivores often have higher densities on host plants grown in monocultures than those in diverse environments. The underlying mechanisms are thought to be that polyphagous insects have difficulty in selecting food or oviposition sites when multiple host plants exist. However, this hypothesis needs to be extensively investigated. Our field experiments revealed that the population of the diamondback moths, Plutella xylostella (L.) (Lepidoptera: Plutellidae), significantly decreased in a mixed cropping field compared with a monoculture. To determine the reasons for the reduction in population in the mixed cropping field, the takeoff behavior and fecundity of females in no-choice and free-choice laboratory environments were compared by video recordings of host selection by P. xylostella. Adults displayed a significantly higher takeoff frequency in free-choice environments than those in no-choice treatments and preferred landing on Brassica campestris (L.) or Brassica juncea (Coss) plants in contrast with Brassica oleracea (L.). Female adults in the free-choice environment also laid fewer eggs compared with the monoculture. Olfaction experiments demonstrated orientation by P. xylostella to host volatiles when presented with a choice between plant odors and clean air, but females showed no preference when odors from three Brassicaceae species were presented simultaneously. We conclude that mixed cropping alters the host-finding behavior of P. xylostella resulting in reduced oviposition. PMID:25527573

  1. Trans-specific gene silencing between host and parasitic plants.

    PubMed

    Tomilov, Alexey A; Tomilova, Natalia B; Wroblewski, Tadeusz; Michelmore, Richard; Yoder, John I

    2008-11-01

    Species of Orobanchaceae parasitize the roots of nearby host plants to rob them of water and other nutrients. Parasitism can be debilitating to the host plant, and some of the world's most pernicious agricultural pests are parasitic weeds. We demonstrate here that interfering hairpin constructs transformed into host plants can silence expression of the targeted genes in the parasite. Transgenic roots of the hemi-parasitic plant Triphysaria versicolor expressing the GUS reporter gene were allowed to parasitize transgenic lettuce roots expressing a hairpin RNA containing a fragment of the GUS gene (hpGUS). When stained for GUS activity, Triphysaria roots attached to non-transgenic lettuce showed full GUS activity, but those parasitizing transgenic hpGUS lettuce lacked activity in root tissues distal to the haustorium. Transcript quantification indicated a reduction in the steady-state level of GUS mRNA in Triphysaria when they were attached to hpGUS lettuce. These results demonstrate that the GUS silencing signal generated by the host roots was translocated across the haustorium interface and was functional in the parasite. Movement across the haustorium was bi-directional, as demonstrated in double-junction experiments in which non-transgenic Triphysaria concomitantly parasitized two hosts, one transgenic for hpGUS and the other transgenic for a functional GUS gene. Observation of GUS silencing in the second host demonstrated that the silencing trigger could be moved from one host to another using the parasite as a physiological bridge. Silencing of parasite genes by generating siRNAs in the host provides a novel strategy for controlling parasitic weeds. PMID:18643992

  2. Host plant resistance to parasitic weeds; recent progress and bottlenecks.

    PubMed

    Yoder, John I; Scholes, Julie D

    2010-08-01

    Parasitic witchweeds (Striga spp.) and broomrapes (Orobanche and Phelipanche spp.) directly invade the roots of crop plants connecting to the vascular system and abstracting nutrients and water. As a consequence they cause devastating losses in crop yield. Genetic resistance to parasitic weeds is a highly desirable component of any control strategy. Resistance to parasitic plants can occur at different stages of the parasite lifecycle: before attachment to the host, during penetration of the root or after establishment of vascular connections. New studies are beginning to shed light on the molecular mechanisms and signaling pathways involved in plant-plant resistance. The first resistance gene to Striga, encoding a CC-NBS-LRR Resistance protein (R) has been identified and cloned suggesting that host plants resist attack from parasitic plants using similar surveillance mechanisms as those used against fungal and bacterial pathogens. It is becoming clear that the salicylic acid (SA) signaling pathway plays an important role in resistance to parasitic plants and genes encoding pathogenesis-related (PR) proteins are upregulated in a number of the resistant interactions. New strategies for engineering resistance to parasitic plants are also being explored, including the expression of parasite-specific toxins in host roots and RNAi to silence parasite genes crucial for development. PMID:20627804

  3. The Type III Secretion Translocation Pore Senses Host Cell Contact

    PubMed Central

    Armentrout, Erin I.; Rietsch, Arne

    2016-01-01

    Type III secretion systems (T3SS) are nano-syringes used by a wide range of Gram-negative pathogens to promote infection by directly injecting effector proteins into targeted host cells. Translocation of effectors is triggered by host-cell contact and requires assembly of a pore in the host-cell plasma membrane, which consists of two translocator proteins. Our understanding of the translocation pore, how it is assembled in the host cell membrane and its precise role in effector translocation, is extremely limited. Here we use a genetic technique to identify protein-protein contacts between pore-forming translocator proteins, as well as the T3SS needle-tip, that are critical for translocon function. The data help establish the orientation of the translocator proteins in the host cell membrane. Analysis of translocon function in mutants that break these contacts demonstrates that an interaction between the pore-forming translocator PopD and the needle-tip is required for sensing host cell contact. Moreover, tethering PopD at a dimer interface also specifically prevents host-cell sensing, arguing that the translocation pore is actively involved in detecting host cell contact. The work presented here therefore establishes a signal transduction pathway for sensing host cell contact that is initiated by a conformational change in the translocation pore, and is subsequently transmitted to the base of the apparatus via a specific contact between the pore and the T3SS needle-tip. PMID:27022930

  4. Volatile chemical cues guide host location and host selection by parasitic plants.

    PubMed

    Runyon, Justin B; Mescher, Mark C; De Moraes, Consuelo M

    2006-09-29

    The importance of plant volatiles in mediating interactions between plant species is much debated. Here, we demonstrate that the parasitic plant Cuscuta pentagona (dodder) uses volatile cues for host location. Cuscuta pentagona seedlings exhibit directed growth toward nearby tomato plants (Lycopersicon esculentum) and toward extracted tomato-plant volatiles presented in the absence of other cues. Impatiens (Impatiens wallerana) and wheat plants (Triticum aestivum) also elicit directed growth. Moreover, seedlings can distinguish tomato and wheat volatiles and preferentially grow toward the former. Several individual compounds from tomato and wheat elicit directed growth by C. pentagona, whereas one compound from wheat is repellent. These findings provide compelling evidence that volatiles mediate important ecological interactions among plant species. PMID:17008532

  5. Hemipteran and dipteran pests: Effectors and plant host immune regulators.

    PubMed

    Kaloshian, Isgouhi; Walling, Linda L

    2016-04-01

    Hemipteran and dipteran insects have behavioral, cellular and chemical strategies for evading or coping with the host plant defenses making these insects particularly destructive pests worldwide. A critical component of a host plant's defense to herbivory is innate immunity. Here we review the status of our understanding of the receptors that contribute to perception of hemipteran and dipteran pests and highlight the gaps in our knowledge in these early events in immune signaling. We also highlight recent advances in identification of the effectors that activate pattern-triggered immunity and those involved in effector-triggered immunity. PMID:26467026

  6. Growth Characteristics of Rhizophagus clarus Strains and Their Effects on the Growth of Host Plants.

    PubMed

    Lee, Eun-Hwa; Eom, Ahn-Heum

    2015-12-01

    Arbuscular mycorrhizal fungi (AMF) are ubiquitous in the rhizosphere and form symbiotic relationships with most terrestrial plant roots. In this study, four strains of Rhizophagus clarus were cultured and variations in their growth characteristics owing to functional diversity and resultant effects on host plant were investigated. Growth characteristics of the studied R. clarus strains varied significantly, suggesting that AMF retain high genetic variability at the intraspecies level despite asexual lineage. Furthermore, host plant growth response to the R. clarus strains showed that genetic variability in AMF could cause significant differences in the growth of the host plant, which prefers particular genetic types of fungal strains. These results suggest that the intraspecific genetic diversity of AMF could be result of similar selective pressure and may be expressed at a functional level. PMID:26839504

  7. Growth Characteristics of Rhizophagus clarus Strains and Their Effects on the Growth of Host Plants

    PubMed Central

    Lee, Eun-Hwa

    2015-01-01

    Arbuscular mycorrhizal fungi (AMF) are ubiquitous in the rhizosphere and form symbiotic relationships with most terrestrial plant roots. In this study, four strains of Rhizophagus clarus were cultured and variations in their growth characteristics owing to functional diversity and resultant effects on host plant were investigated. Growth characteristics of the studied R. clarus strains varied significantly, suggesting that AMF retain high genetic variability at the intraspecies level despite asexual lineage. Furthermore, host plant growth response to the R. clarus strains showed that genetic variability in AMF could cause significant differences in the growth of the host plant, which prefers particular genetic types of fungal strains. These results suggest that the intraspecific genetic diversity of AMF could be result of similar selective pressure and may be expressed at a functional level. PMID:26839504

  8. The Impact of Hosts on Type Ia Supernovae Cosmology

    NASA Astrophysics Data System (ADS)

    Ashraf Uddin, Syed; Mould, Jeremy; Lidman, Chris

    2015-08-01

    We compile a sample of 595 spectroscopically confirmed Type Ia Supernovae (SNe Ia), with consistently derived host galaxy properties such as stellar mass, specific star-formation rate and projected distances of SNe Ia from host centers, from the CSP, CfA, SDSS, and SNLS surveys. Our results confirm previous findings that SNe Ia are on average significantly brighter in more massive and low-specific star-formation rate hosts after correcting for light-curve parameters. We study, for the first time, the variation of SNe Ia - host correlations with redshift and detect no evolution. We find new evidence that the slope of the stretch-luminosity relation is steeper in SNe Ia that are exploding farther out from host centers and confirm previous finding that the slope of the color-luminosity relation is shallower in massive hosts. We split the sample into pairs of subsets that are based on the properties of the hosts, and fit cosmological models to each subset. We do not find any dependence of the cosmology between the pairs of subsets used. Among different subsets, we find SNe Ia in high-specific star-formation rate have the least intrinsic scatter in luminosity, which supports theoretical prediction. Host stellar mass is the dominant host property for the observed correlations. Adding host mass as the third correction factor in distance measurement, we find no significant change in the measurements of cosmological parameters. Furthermore, we show that the best-fit cosmology is not biased between the SNe Ia samples where redshifts come from hosts and SNe Ia respectively - an important result for future SNe Ia cosmology surveys, such as the Dark Energy Survey.

  9. A bacterial pathogen uses distinct type III secretion systems to alternate between host kingdoms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant and animal-pathogenic bacteria utilize phylogenetically distinct type III secretion systems (T3SS) that produce needle-like injectisomes or pili for the delivery of effector proteins into host cells. Pantoea stewartii subsp. stewartii (Pnss), the causative agent of Stewart’s bacterial wilt and...

  10. Distance and Sex Determine Host Plant Choice by Herbivorous Beetles

    PubMed Central

    Ballhorn, Daniel J.; Kautz, Stefanie; Heil, Martin

    2013-01-01

    Background Plants respond to herbivore damage with the release of volatile organic compounds (VOCs). This indirect defense can cause ecological costs when herbivores themselves use VOCs as cues to localize suitable host plants. Can VOCs reliably indicate food plant quality to herbivores? Methodology We determined the choice behavior of herbivorous beetles (Chrysomelidae: Gynandrobrotica guerreroensis and Cerotoma ruficornis) when facing lima bean plants (Fabaceae: Phaseolus lunatus) with different cyanogenic potential, which is an important constitutive direct defense. Expression of inducible indirect defenses was experimentally manipulated by jasmonic acid treatment at different concentrations. The long-distance responses of male and female beetles to the resulting induced plant volatiles were investigated in olfactometer and free-flight experiments and compared to the short-distance decisions of the same beetles in feeding trials. Conclusion Female beetles of both species were repelled by VOCs released from all induced plants independent of the level of induction. In contrast, male beetles were repelled by strongly induced plants, showed no significant differences in choice behavior towards moderately induced plants, but responded positively to VOCs released from little induced plants. Thus, beetle sex and plant VOCs had a significant effect on host searching behavior. By contrast, feeding behavior of both sexes was strongly determined by the cyanogenic potential of leaves, although females again responded more sensitively than males. Apparently, VOCs mainly provide information to these beetles that are not directly related to food quality. Being induced by herbivory and involved in indirect plant defense, such VOCs might indicate the presence of competitors and predators to herbivores. We conclude that plant quality as a food source and finding a potentially enemy-free space is more important for female than for male insect herbivores, whereas the presence of a

  11. Host Plant Use by Competing Acacia-Ants: Mutualists Monopolize While Parasites Share Hosts

    PubMed Central

    Kautz, Stefanie; Ballhorn, Daniel J.; Kroiss, Johannes; Pauls, Steffen U.; Moreau, Corrie S.; Eilmus, Sascha; Strohm, Erhard; Heil, Martin

    2012-01-01

    Protective ant-plant mutualisms that are exploited by non-defending parasitic ants represent prominent model systems for ecology and evolutionary biology. The mutualist Pseudomyrmex ferrugineus is an obligate plant-ant and fully depends on acacias for nesting space and food. The parasite Pseudomyrmex gracilis facultatively nests on acacias and uses host-derived food rewards but also external food sources. Integrative analyses of genetic microsatellite data, cuticular hydrocarbons and behavioral assays showed that an individual acacia might be inhabited by the workers of several P. gracilis queens, whereas one P. ferrugineus colony monopolizes one or more host trees. Despite these differences in social organization, neither of the species exhibited aggressive behavior among conspecific workers sharing a tree regardless of their relatedness. This lack of aggression corresponds to the high similarity of cuticular hydrocarbon profiles among ants living on the same tree. Host sharing by unrelated colonies, or the presence of several queens in a single colony are discussed as strategies by which parasite colonies could achieve the observed social organization. We argue that in ecological terms, the non-aggressive behavior of non-sibling P. gracilis workers — regardless of the route to achieve this social structure — enables this species to efficiently occupy and exploit a host plant. By contrast, single large and long-lived colonies of the mutualist P. ferrugineus monopolize individual host plants and defend them aggressively against invaders from other trees. Our findings highlight the necessity for using several methods in combination to fully understand how differing life history strategies affect social organization in ants. PMID:22662191

  12. Comparing the Host Galaxies of Type Ia, Type II, and Type Ibc Supernovae

    NASA Astrophysics Data System (ADS)

    Shao, X.; Liang, Y. C.; Dennefeld, M.; Chen, X. Y.; Zhong, G. H.; Hammer, F.; Deng, L. C.; Flores, H.; Zhang, B.; Shi, W. B.; Zhou, L.

    2014-08-01

    We compare the host galaxies of 902 supernovae (SNe), including SNe Ia, SNe II, and SNe Ibc, which are selected by cross-matching the Asiago Supernova Catalog with the Sloan Digital Sky Survey (SDSS) Data Release 7. We selected an additional 213 galaxies by requiring the light fraction of spectral observations to be >15%, which could represent well the global properties of the galaxies. Among these 213 galaxies, 135 appear on the Baldwin-Phillips-Terlevich diagram, which allows us to compare the hosts in terms of whether they are star-forming (SF) galaxies, active galactic nuclei (AGNs; including composites, LINERs, and Seyfert 2s) or absorption-line galaxies (Absorps; i.e., their related emission lines are weak or non-existent). The diagrams related to the parameters D n (4000), Hδ A , stellar masses, star formation rates (SFRs), and specific SFRs for the SNe hosts show that almost all SNe II and most of the SNe Ibc occur in SF galaxies, which have a wide range of stellar masses and low D n (4000). The SNe Ia hosts as SF galaxies following similar trends. A significant fraction of SNe Ia occurs in AGNs and absorption-line galaxies, which are massive and have high D n (4000). The stellar population analysis from spectral synthesis fitting shows that the hosts of SNe II have a younger stellar population than hosts of SNe Ia. These results are compared with those of the 689 comparison galaxies where the SDSS fiber captures less than 15% of the total light. These comparison galaxies appear biased toward higher 12+log(O/H) (~0.1 dex) at a given stellar mass. Therefore, we believe the aperture effect should be kept in mind when the properties of the hosts for different types of SNe are discussed.

  13. Comparing the host galaxies of type Ia, type II, and type Ibc supernovae

    SciTech Connect

    Shao, X.; Liang, Y. C.; Chen, X. Y.; Zhong, G. H.; Deng, L. C.; Zhang, B.; Shi, W. B.; Zhou, L.; Dennefeld, M.; Hammer, F.; Flores, H. E-mail: ycliang@bao.ac.cn

    2014-08-10

    We compare the host galaxies of 902 supernovae (SNe), including SNe Ia, SNe II, and SNe Ibc, which are selected by cross-matching the Asiago Supernova Catalog with the Sloan Digital Sky Survey (SDSS) Data Release 7. We selected an additional 213 galaxies by requiring the light fraction of spectral observations to be >15%, which could represent well the global properties of the galaxies. Among these 213 galaxies, 135 appear on the Baldwin-Phillips-Terlevich diagram, which allows us to compare the hosts in terms of whether they are star-forming (SF) galaxies, active galactic nuclei (AGNs; including composites, LINERs, and Seyfert 2s) or absorption-line galaxies (Absorps; i.e., their related emission lines are weak or non-existent). The diagrams related to the parameters D{sub n}(4000), Hδ{sub A}, stellar masses, star formation rates (SFRs), and specific SFRs for the SNe hosts show that almost all SNe II and most of the SNe Ibc occur in SF galaxies, which have a wide range of stellar masses and low D{sub n}(4000). The SNe Ia hosts as SF galaxies following similar trends. A significant fraction of SNe Ia occurs in AGNs and absorption-line galaxies, which are massive and have high D{sub n}(4000). The stellar population analysis from spectral synthesis fitting shows that the hosts of SNe II have a younger stellar population than hosts of SNe Ia. These results are compared with those of the 689 comparison galaxies where the SDSS fiber captures less than 15% of the total light. These comparison galaxies appear biased toward higher 12+log(O/H) (∼0.1 dex) at a given stellar mass. Therefore, we believe the aperture effect should be kept in mind when the properties of the hosts for different types of SNe are discussed.

  14. Genomics of adaptation to host-plants in herbivorous insects.

    PubMed

    Simon, Jean-Christophe; d'Alençon, Emmanuelle; Guy, Endrick; Jacquin-Joly, Emmanuelle; Jaquiéry, Julie; Nouhaud, Pierre; Peccoud, Jean; Sugio, Akiko; Streiff, Réjane

    2015-11-01

    Herbivorous insects represent the most species-rich lineages of metazoans. The high rate of diversification in herbivorous insects is thought to result from their specialization to distinct host-plants, which creates conditions favorable for the build-up of reproductive isolation and speciation. These conditions rely on constraints against the optimal use of a wide range of plant species, as each must constitute a viable food resource, oviposition site and mating site for an insect. Utilization of plants involves many essential traits of herbivorous insects, as they locate and select their hosts, overcome their defenses and acquire nutrients while avoiding intoxication. Although advances in understanding insect-plant molecular interactions have been limited by the complexity of insect traits involved in host use and the lack of genomic resources and functional tools, recent studies at the molecular level, combined with large-scale genomics studies at population and species levels, are revealing the genetic underpinning of plant specialization and adaptive divergence in non-model insect herbivores. Here, we review the recent advances in the genomics of plant adaptation in hemipterans and lepidopterans, two major insect orders, each of which includes a large number of crop pests. We focus on how genomics and post-genomics have improved our understanding of the mechanisms involved in insect-plant interactions by reviewing recent molecular discoveries in sensing, feeding, digesting and detoxifying strategies. We also present the outcomes of large-scale genomics approaches aimed at identifying loci potentially involved in plant adaptation in these insects. PMID:25846754

  15. Host recognition by the tobacco hornworm is mediated by a host plant compound.

    PubMed

    del Campo, M L; Miles, C I; Schroeder, F C; Mueller, C; Booker, R; Renwick, J A

    2001-05-10

    It is generally believed that animals make decisions about the selection of mates, kin or food on the basis of pre-constructed recognition templates. These templates can be innate or acquired through experience. An example of an acquired template is the feeding preference exhibited by larvae of the moth, Manduca sexta. Naive hatchlings will feed and grow successfully on many different plants or artificial diets, but once they have fed on a natural host they become specialist feeders. Here we show that the induced feeding preference of M. sexta involves the formation of a template to a steroidal glycoside, indioside D, that is present in solanaceous foliage. This compound is both necessary and sufficient to maintain the induced feeding preference. The induction of host plant specificity is at least partly due to a tuning of taste receptors to indioside D. The taste receptors of larvae fed on host plants show an enhanced response to indioside D as compared with other plant compounds tested. PMID:11346793

  16. Host-plant-associated genetic differentiation in Northern French populations of the European corn borer.

    PubMed

    Martel, C; Réjasse, A; Rousset, F; Bethenod, M-T; Bourguet, D

    2003-02-01

    The phytophagous insects that damage crops are often polyphagous, feeding on several types of crop and on weeds. The refuges constituted by noncrop host plants may be useful in managing the evolution in pest species of resistance to the Bacillus thuringiensis toxins produced by transgenic crops. However, the benefits of these refuges may be limited because host-plant diversity may drive genetic divergence and possibly even host-plant-mediated sympatric speciation. The European corn borer, Ostrinia nubilalis Hübner (Lepidoptera: Crambidae), is the main pest of maize in Europe and North America, where it was introduced early in the 20th century. It has a wide host range but feeds principally on mugwort (Artemisia vulgaris L.) and maize (Zea mays L.). O. nubilalis is found on mugwort only in the northern part of France, whereas it is found on maize throughout France. The extent of genetic variation at allozyme markers was investigated in populations collected from the two host plants over the entire geographical distribution of the European corn borer on mugwort in France. Allelic differentiation between pairs of populations and hierarchical analyses of pools of samples from each host plant indicate that the group of populations feeding on maize differed from the group of populations feeding on mugwort. Our results suggest (1) host-plant-related divergent selection at the genomic region surrounding the Mpi locus and (2) limited gene flow between the populations feeding on mugwort and those infesting maize fields. These data indicate that adults emerging from mugwort would not be useful for managing the evolution of resistance to the B. thuringiensis toxins in European corn borer populations. PMID:12634820

  17. Essential host plant cues in the grapevine moth

    NASA Astrophysics Data System (ADS)

    Tasin, Marco; Bäckman, Anna-Carin; Bengtsson, Marie; Ioriatti, Claudio; Witzgall, Peter

    2006-03-01

    Host plant odours attract gravid insect females for oviposition. The identification of these plant volatile compounds is essential for our understanding of plant insect relationships and contributes to plant breeding for improved resistance against insects. Chemical analysis of grape headspace and subsequent behavioural studies in the wind tunnel show that host finding in grapevine moth Lobesia botrana is encoded by a ratio-specific blend of three ubiquitous plant volatiles. The odour signal that attracts mated females to grape consists of the terpenoids ( E)-β-caryophyllene, ( E)-β-farnesene and ( E)-4,8-dimethyl-1,3,7-nonatriene. These compounds represent only a fraction of the volatiles released by grapes, and they are widespread compounds known throughout the plant kingdom. Specificity may be achieved by the blend ratio, which was 100:78:9 in grape headspace. This blend elicited anemotactic behaviour in moths at remarkably small amounts. Females were attracted at release rates of only a few nanograms per minute, at levels nearly as low as those known for the attraction of male moths to the female sex pheromones.

  18. A review of the endemic Hawaiian Drosophilidae and their host plants

    USGS Publications Warehouse

    Magnacca, K.N.; Foote, D.; O'Grady, P. M.

    2008-01-01

    The Hawaiian Drosophilidae is one of the best examples of rapid speciation in nature. Nearly 1,000 species of endemic drosophilids have evolved in situ in Hawaii since a single colonist arrived over 25 million years ago. A number of mechanisms, including ecological adaptation, sexual selection, and geographic isolation, have been proposed to explain the evolution of this hyperdiverse group of species. Here, we examine the known ecological associations of 326 species of endemic Hawaiian Drosophilidae in light of the phylogenetic relationships of these species. Our analysis suggests that the long-accepted belief of strict ecological specialization in this group does not hold for all taxa. While many species have a primary host plant family, females will also oviposit on non-preferred host plant taxa. Host shifting is fairly common in some groups, especially the grimshawi and modified mouthparts species groups of Drosophila, and the Scaptomyza subgenus Elmomyza. Associations with types of substrates (bark, leaves, flowers) are more evolutionarily conserved than associations with host plant families. These data not only give us insight into the role ecology has played in the evolution of this large group, but can help in making decisions about the management of rare and endangered host plants and the insects that rely upon them for survival. Copyright ?? 2008 Magnolia Press.

  19. Gravisensitivity of various host plant -virus systems in simulated microgravity

    NASA Astrophysics Data System (ADS)

    Mishchenko, Lidiya; Taran, Oksana; Gordejchyk, Olga

    In spite of considerable achievements in the study of gravity effects on plant development, some issues of gravitropism, like species-specificity and gravitation response remain unclear. The so-lution of such problems is connected with the aspects of life supply, in piloted space expeditions. The role of microgravity remains practically unstudied in the development of relations in the system host plant-virus, which are important for biotechnologies in crop production. It is ev-ident that the conditions of space flight can act as stressors, and the stress inducted by them favors the reactivation of latest herpes viruses in humans (satish et al., 2009) Viral infections of plants, which also can be in a latest state at certain stages of plant organism development, cause great damage to the growth and development of a host plant. Space flight conditions may cause both reactivation of latent viral infection in plants and its elimination, as it has been found by us for the system WSMW -wheat (Mishchenko et al., 2004). Our further research activities were concentrated on the identification of gravisensitivity in the system virus -potato plant to find out whether there was any species -related specificity of the reaction. In our research we used potato plants of Krymska Rosa, Zhuravushka, Agave, Belarosa, Kupalinka, and Zdubytok varieties. Simulated microgravity was ensured by clinostats KG-8 and Cycle -2. Gravisensitiv-ity has been studied the systems including PVX, PVM and PVY. Virus concentrations have been determined by ELISA using LOEWE reagents (placecountry-regionGermany). Virus iden-tification by morphological features were done by electron microscopy. For the system PVX -potato plant, we found the reduction in virus antigens content with prolonged clinostating. On the 18th day of cultivation, the plants showed a high level of X-virus antigen content on both stationary (control) and clinostated variants. On 36th and 47th day, depending plant variety, clinostated

  20. Variation within and between Frankliniella Thrips Species in Host Plant Utilization

    PubMed Central

    Baez, Ignacio; Reitz, Stuart R.; Funderburk, Joseph E.; Olson, Steve M.

    2011-01-01

    Anthophilous flower thrips in the genus Frankliniella (Thysanoptera: Thripidae) exploit ephemeral plant resources and therefore must be capable of successfully locating appropriate hosts on a repeated basis, yet little is known of interspecific and intraspecific variation in responses to host plant type and nutritional quality. Field trials were conducted over two seasons to determine if the abundance of males and females of three common Frankliniella species, F. occidentalis (Pergande), F. tritici (Fitch) and F. bispinosa (Morgan), their larvae, and a key predator, Orius insidiosus (Say) (Hemiptera: Anthocoridae) were affected by host plant type and plant nutritional quality. Two host plants, pepper, Capsicum annuum L. (Solanales: Solanaceae) and tomato, Solanum lycopersicum L. that vary in suitability for these species were examined, and their nutritional quality was manipulated by applying three levels of nitrogen fertilization (101 kg/ha, 202 kg/ha, 404 kg/ha). F. occidentalis females were more abundant in pepper than in tomato, but males did not show a differential response. Both sexes of F. tritici and F. bispinosa were more abundant in tomato than in pepper. Larval thrips were more abundant in pepper than in tomato. Likewise, O. insidiosus females and nymphs were more abundant in pepper than in tomato. Only F. occidentalis females showed a distinct response to nitrogen fertilization, with abundance increasing with fertilization. These results show that host plant utilization patterns vary among Frankliniella spp. and should not be generalized from results of the intensively studied F. occidentalis. Given the different pest status of these species and their differential abundance in pepper and tomato, it is critical that scouting programs include species identifications for proper management. PMID:21539418

  1. Life histories of hosts and pathogens predict patterns in tropical fungal plant diseases.

    PubMed

    García-Guzmán, Graciela; Heil, Martin

    2014-03-01

    Plant pathogens affect the fitness of their hosts and maintain biodiversity. However, we lack theories to predict the type and intensity of infections in wild plants. Here we demonstrate using fungal pathogens of tropical plants that an examination of the life histories of hosts and pathogens can reveal general patterns in their interactions. Fungal infections were more commonly reported for light-demanding than for shade-tolerant species and for evergreen rather than for deciduous hosts. Both patterns are consistent with classical defence theory, which predicts lower resistance in fast-growing species and suggests that the deciduous habit can reduce enemy populations. In our literature survey, necrotrophs were found mainly to infect shade-tolerant woody species whereas biotrophs dominated in light-demanding herbaceous hosts. Far-red signalling and its inhibitory effects on jasmonic acid signalling are likely to explain this phenomenon. Multiple changes between the necrotrophic and the symptomless endophytic lifestyle at the ecological and evolutionary scale indicate that endophytes should be considered when trying to understand large-scale patterns in the fungal infections of plants. Combining knowledge about the molecular mechanisms of pathogen resistance with classical defence theory enables the formulation of testable predictions concerning general patterns in the infections of wild plants by fungal pathogens. PMID:24171899

  2. Comparing the host galaxies of different type supernovae

    NASA Astrophysics Data System (ADS)

    Liang, Yanchun; Shao, Xu; Dennefeld, Michel; Chen, Xiaoyan; Zhou, Li; Hammer, Francois

    2015-08-01

    We examine and compare the properties of host galaxies of 902 supernovae, including both SNe Ia and Core-collapse supernovae (SNe II and SNe Ibc), selected by cross-matching the Asiago Supernova Catalog with the SDSS DR7 main-galaxy sample. Then, a main working sample consisting 213 galaxies are further selected by requiring the light fraction > 15% covered by the fiber spectral observations. This criterion of light fraction minimizes the aperture effect on the analysis of properties of SN host galaxies. Since 135 among the 213 galaxies appear on the Baldwin-Phillips-Terlevich (BPT) diagram, we then could compare the host properties of different types of SNe on the basis of their BPT diagnosis, i.e. star-forming (SF) galaxies, AGNs, and then the rest 78 “Absorption” galaxies. A comparative sample composed by the remaining 689 galaxies are analyzed simultaneously for comparisons, then the obvious aperture effect on the properties of SN host galaxies are shown. The parameters Dn(4000), HδA, stellar masses, SFRs, specific SFRs and relations of stellar mass with metallicity of SN host galaxies are analyzed in the work.

  3. Recent Evolutionary Radiation and Host Plant Specialization in the Xylella fastidiosa Subspecies Native to the United States

    PubMed Central

    Vickerman, Danel B.; Bromley, Robin E.; Russell, Stephanie A.; Hartman, John R.; Morano, Lisa D.; Stouthamer, Richard

    2013-01-01

    The bacterial pathogen, Xylella fastidiosa, infects many plant species in the Americas, making it a good model for investigating the genetics of host adaptation. We used multilocus sequence typing (MLST) to identify isolates of the native U.S. subsp. multiplex that were largely unaffected by intersubspecific homologous recombination (IHR) and to investigate how their evolutionary history influences plant host specialization. We identified 110 “non-IHR” isolates, 2 minimally recombinant “intermediate” ones (including the subspecific type), and 31 with extensive IHR. The non-IHR and intermediate isolates defined 23 sequence types (STs) which we used to identify 22 plant hosts (73% trees) characteristic of the subspecies. Except for almond, subsp. multiplex showed no host overlap with the introduced subspecies (subspecies fastidiosa and sandyi). MLST sequences revealed that subsp. multiplex underwent recent radiation (<25% of subspecies age) which included only limited intrasubspecific recombination (ρ/θ = 0.02); only one isolated lineage (ST50 from ash) was older. A total of 20 of the STs grouped into three loose phylogenetic clusters distinguished by nonoverlapping hosts (excepting purple leaf plum): “almond,” “peach,” and “oak” types. These host differences were not geographical, since all three types also occurred in California. ST designation was a good indicator of host specialization. ST09, widespread in the southeastern United States, only infected oak species, and all peach isolates were ST10 (from California, Florida, and Georgia). Only ST23 had a broad host range. Hosts of related genotypes were sometimes related, but often host groupings crossed plant family or even order, suggesting that phylogenetically plastic features of hosts affect bacterial pathogenicity. PMID:23354698

  4. Recent evolutionary radiation and host plant specialization in the Xylella fastidiosa subspecies native to the United States.

    PubMed

    Nunney, Leonard; Vickerman, Danel B; Bromley, Robin E; Russell, Stephanie A; Hartman, John R; Morano, Lisa D; Stouthamer, Richard

    2013-04-01

    The bacterial pathogen, Xylella fastidiosa, infects many plant species in the Americas, making it a good model for investigating the genetics of host adaptation. We used multilocus sequence typing (MLST) to identify isolates of the native U.S. subsp. multiplex that were largely unaffected by intersubspecific homologous recombination (IHR) and to investigate how their evolutionary history influences plant host specialization. We identified 110 "non-IHR" isolates, 2 minimally recombinant "intermediate" ones (including the subspecific type), and 31 with extensive IHR. The non-IHR and intermediate isolates defined 23 sequence types (STs) which we used to identify 22 plant hosts (73% trees) characteristic of the subspecies. Except for almond, subsp. multiplex showed no host overlap with the introduced subspecies (subspecies fastidiosa and sandyi). MLST sequences revealed that subsp. multiplex underwent recent radiation (<25% of subspecies age) which included only limited intrasubspecific recombination (ρ/θ = 0.02); only one isolated lineage (ST50 from ash) was older. A total of 20 of the STs grouped into three loose phylogenetic clusters distinguished by nonoverlapping hosts (excepting purple leaf plum): "almond," "peach," and "oak" types. These host differences were not geographical, since all three types also occurred in California. ST designation was a good indicator of host specialization. ST09, widespread in the southeastern United States, only infected oak species, and all peach isolates were ST10 (from California, Florida, and Georgia). Only ST23 had a broad host range. Hosts of related genotypes were sometimes related, but often host groupings crossed plant family or even order, suggesting that phylogenetically plastic features of hosts affect bacterial pathogenicity. PMID:23354698

  5. A locus in Drosophila sechellia affecting tolerance of a host plant toxin.

    PubMed

    Hungate, Eric A; Earley, Eric J; Boussy, Ian A; Turissini, David A; Ting, Chau-Ti; Moran, Jennifer R; Wu, Mao-Lien; Wu, Chung-I; Jones, Corbin D

    2013-11-01

    Many insects feed on only one or a few types of host. These host specialists often evolve a preference for chemical cues emanating from their host and develop mechanisms for circumventing their host's defenses. Adaptations like these are central to evolutionary biology, yet our understanding of their genetics remains incomplete. Drosophila sechellia, an emerging model for the genetics of host specialization, is an island endemic that has adapted to chemical toxins present in the fruit of its host plant, Morinda citrifolia. Its sibling species, D. simulans, and many other Drosophila species do not tolerate these toxins and avoid the fruit. Earlier work found a region with a strong effect on tolerance to the major toxin, octanoic acid, on chromosome arm 3R. Using a novel assay, we narrowed this region to a small span near the centromere containing 18 genes, including three odorant binding proteins. It has been hypothesized that the evolution of host specialization is facilitated by genetic linkage between alleles contributing to host preference and alleles contributing to host usage, such as tolerance to secondary compounds. We tested this hypothesis by measuring the effect of this tolerance locus on host preference behavior. Our data were inconsistent with the linkage hypothesis, as flies bearing this tolerance region showed no increase in preference for media containing M. citrifolia toxins, which D. sechellia prefers. Thus, in contrast to some models for host preference, preference and tolerance are not tightly linked at this locus nor is increased tolerance per se sufficient to change preference. Our data are consistent with the previously proposed model that the evolution of D. sechellia as a M. citrifolia specialist occurred through a stepwise loss of aversion and gain of tolerance to M. citrifolia's toxins. PMID:24037270

  6. The influence of learning on host plant preference in a significant phytopathogen vector, Diaphorina citri

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although specialist herbivorous insects are guided by innate responses to host plant cues, host plant preference may be influenced by experience and is not dictated by instinct alone. The effect of learning on host plant preference was examined in the Asian citrus psyllid, Diaphorina citri, vector ...

  7. Early-type Host Galaxies of Type Ia Supernovae. I. Evidence for Downsizing

    NASA Astrophysics Data System (ADS)

    Kang, Yijung; Kim, Young-Lo; Lim, Dongwook; Chung, Chul; Lee, Young-Wook

    2016-03-01

    Type Ia supernova (SN Ia) cosmology provides the most direct evidence for the presence of dark energy. This result is based on the assumption that the lookback time evolution of SN Ia luminosity, after light curve corrections, would be negligible. Recent studies show, however, that the Hubble residual (HR) of SN Ia is correlated with the mass and morphology of host galaxies, implying the possible dependence of SN Ia luminosity on host galaxy properties. In order to investigate this more directly, we have initiated a spectroscopic survey for early-type host galaxies, for which population age and metallicity can be more reliably determined from the absorption lines. In this first paper of the series, we present here the results from high signal-to-noise ratio (≳100 per pixel) spectra for 27 nearby host galaxies in the southern hemisphere. For the first time in host galaxy studies, we find a significant (∼3.9σ) correlation between host galaxy mass (velocity dispersion) and population age, which is consistent with the “downsizing” trend among non-host early-type galaxies. This result is rather insensitive to the choice of population synthesis models. Since we find no correlation with metallicity, our result suggests that stellar population age is mainly responsible for the relation between host mass and HR. If confirmed, this would imply that the luminosity evolution plays a major role in the systematic uncertainties of SN Ia cosmology.

  8. Diversity of endophytic enterobacteria associated with different host plants.

    PubMed

    Torres, Adalgisa Ribeiro; Araújo, Welington Luiz; Cursino, Luciana; Hungria, Mariangela; Plotegher, Fábio; Mostasso, Fábio Luís; Azevedo, João Lúcio

    2008-08-01

    Fifty-three endophytic enterobacteria isolates from citrus, cocoa, eucalyptus, soybean, and sugar cane were evaluated for susceptibility to the antibiotics ampicillin and kanamycin, and cellulase production. Susceptibility was found on both tested antibiotics. However, in the case of ampicillin susceptibility changed according to the host plant, while all isolates were susceptible to kanamycin. Cellulase production also changed according to host plants. The diversity of these isolates was estimated by employing BOX-PCR genomic fingerprints and 16S rDNA sequencing. In total, twenty-three distinct operational taxonomic units (OTUs) were identified by employing a criterion of 60% fingerprint similarity as a surrogate for an OTU. The 23 OTUs belong to the Pantoea and Enterobacter genera, while their high diversity could be an indication of paraphyletic classification. Isolates representing nine different OTUs belong to Pantoea agglomerans, P. ananatis, P. stewartii, Enterobacter sp., and E. homaechei. The results of this study suggest that plant species may select endophytic bacterial genotypes. It has also become apparent that a review of the Pantoea/Enterobacter genera may be necessary. PMID:18758726

  9. Type I interferons increase host susceptibility to Trypanosoma cruzi infection.

    PubMed

    Chessler, Anne-Danielle C; Caradonna, Kacey L; Da'dara, Akram; Burleigh, Barbara A

    2011-05-01

    Trypanosoma cruzi, the protozoan parasite that causes human Chagas' disease, induces a type I interferon (IFN) (IFN-α/β) response during acute experimental infection in mice and in isolated primary cell types. To examine the potential impact of the type I IFN response in shaping outcomes in experimental T. cruzi infection, groups of wild-type (WT) and type I IFN receptor-deficient (IFNAR(-/-)) 129sv/ev mice were infected with two different T. cruzi strains under lethal and sublethal conditions and several parameters were measured during the acute stage of infection. The results demonstrate that type I IFNs are not required for early host protection against T. cruzi. In contrast, under conditions of lethal T. cruzi challenge, WT mice succumbed to infection whereas IFNAR(-/-) mice were ultimately able to control parasite growth and survive. T. cruzi clearance in and survival of IFNAR(-/-) mice were accompanied by higher levels of IFN-γ production by isolated splenocytes in response to parasite antigen. The suppression of IFN-γ in splenocytes from WT mice was independent of IL-10 levels. While the impact of type I IFNs on the production of IFN-γ and other cytokines/chemokines remains to be fully determined in the context of T. cruzi infection, our data suggest that, under conditions of high parasite burden, type I IFNs negatively impact IFN-γ production, initiating a detrimental cycle that contributes to the ultimate failure to control infection. These findings are consistent with a growing theme in the microbial pathogenesis field in which type I IFNs can be detrimental to the host in a variety of nonviral pathogen infection models. PMID:21402764

  10. Trophic Relationships between the Parasitic Plant Species Phelipanche ramosa (L.) and Different Hosts Depending on Host Phenological Stage and Host Growth Rate.

    PubMed

    Moreau, Delphine; Gibot-Leclerc, Stéphanie; Girardin, Annette; Pointurier, Olivia; Reibel, Carole; Strbik, Florence; Fernández-Aparicio, Mónica; Colbach, Nathalie

    2016-01-01

    Phelipanche ramosa (L.) Pomel (branched broomrape) is a holoparasitic plant that reproduces on crops and also on weeds, which contributes to increase the parasite seed bank in fields. This parasite extracts all its nutrients at the host's expense so that host-parasite trophic relationships are crucial to determine host and parasite growth. This study quantified the intensity with which P. ramosa draws assimilates from its host and analyzed whether it varied with host species, host phenological stage and host growth rate. A greenhouse experiment was conducted on three host species: the crop species Brassica napus (L.) (oilseed rape) and two weed species, Capsella bursa-pastoris (L.) Medik. and Geranium dissectum (L.). Plants were grown with or without P. ramosa and under three light levels to modulate host growth rate. The proportion of host biomass loss due to parasitism by P. ramosa differed between host species (at host fructification, biomass loss ranged from 34 to 84%). B. napus and C. bursa-pastoris displayed a similar response to P. ramosa, probably because they belong to the same botanical family. The sensitivity to P. ramosa in each host species could be related to the precocity of P. ramosa development on them. Host compartments could be ranked as a function of their sensitivity to parasitism, with the reproductive compartment being the most severely affected, followed by stems and roots. The proportion of biomass allocated to leaves was not reduced by parasitism. The proportion of pathosystem biomass allocated to the parasite depended on host species. It generally increased with host stage progression but was constant across light induced-host growth rate, showing that P. ramosa adapts its growth to host biomass production. The rank order of host species in terms of sink strength differed from that in terms of host sensitivity. Finally, for B. napus, the biomass of individual parasite shoots decreased with increasing their number per host plant

  11. A Locus in Drosophila sechellia Affecting Tolerance of a Host Plant Toxin

    PubMed Central

    Hungate, Eric A.; Earley, Eric J.; Boussy, Ian A.; Turissini, David A.; Ting, Chau-Ti; Moran, Jennifer R.; Wu, Mao-Lien; Wu, Chung-I; Jones, Corbin D.

    2013-01-01

    Many insects feed on only one or a few types of host. These host specialists often evolve a preference for chemical cues emanating from their host and develop mechanisms for circumventing their host’s defenses. Adaptations like these are central to evolutionary biology, yet our understanding of their genetics remains incomplete. Drosophila sechellia, an emerging model for the genetics of host specialization, is an island endemic that has adapted to chemical toxins present in the fruit of its host plant, Morinda citrifolia. Its sibling species, D. simulans, and many other Drosophila species do not tolerate these toxins and avoid the fruit. Earlier work found a region with a strong effect on tolerance to the major toxin, octanoic acid, on chromosome arm 3R. Using a novel assay, we narrowed this region to a small span near the centromere containing 18 genes, including three odorant binding proteins. It has been hypothesized that the evolution of host specialization is facilitated by genetic linkage between alleles contributing to host preference and alleles contributing to host usage, such as tolerance to secondary compounds. We tested this hypothesis by measuring the effect of this tolerance locus on host preference behavior. Our data were inconsistent with the linkage hypothesis, as flies bearing this tolerance region showed no increase in preference for media containing M. citrifolia toxins, which D. sechellia prefers. Thus, in contrast to some models for host preference, preference and tolerance are not tightly linked at this locus nor is increased tolerance per se sufficient to change preference. Our data are consistent with the previously proposed model that the evolution of D. sechellia as a M. citrifolia specialist occurred through a stepwise loss of aversion and gain of tolerance to M. citrifolia’s toxins. PMID:24037270

  12. On the environments of Type Ia supernovae within host galaxies

    NASA Astrophysics Data System (ADS)

    Anderson, J. P.; James, P. A.; Förster, F.; González-Gaitán, S.; Habergham, S. M.; Hamuy, M.; Lyman, J. D.

    2015-03-01

    We present constraints on Type Ia supernovae (SNe Ia) progenitors through an analysis of the environments found at the explosion sites of 102 events within star-forming host galaxies. Hα and Galaxy Evolution Explorer near-ultraviolet (UV) images are used to trace on-going and recent star formation (SF), while broad-band B, R, J, K imaging is also analysed. Using pixel statistics we find that SNe Ia show the lowest degree of association with Hα emission of all supernova (SN) types. It is also found that they do not trace near-UV emission. As the latter traces SF on time-scales less than 100 Myr, this rules out any extreme `prompt' delay times as the dominant progenitor channel of SNe Ia. SNe Ia best trace the B-band light distribution of their host galaxies. This implies that the population within star-forming galaxies is dominated by relatively young progenitors. Splitting SNe by their (B - V) colours at maximum light, `redder' events show a higher degree of association with H II regions and are found more centrally within hosts. We discuss possible explanations of this result in terms of line-of-sight extinction and progenitor effects. No evidence for correlations between SN stretch and environment properties is observed.

  13. Effects of host-plant population size and plant sex on a specialist leaf-miner

    NASA Astrophysics Data System (ADS)

    Bañuelos, María-José; Kollmann, Johannes

    2011-03-01

    Animal population density has been related to resource patch size through various hypotheses such as those derived from island biogeography and resource concentration theory. This theoretical framework can be also applied to plant-herbivore interactions, and it can be modified by the sex of the host-plant, and density-dependent relationships. Leaf-miners are specialised herbivores that leave distinct traces on infested leaves in the form of egg scars, mines, signs of predation and emergence holes. This allows the life cycle of the insect to be reconstructed and the success at the different stages to be estimated. The main stages of the leaf-miner Phytomyza ilicis were recorded in eleven populations of the evergreen host Ilex aquifolium in Denmark. Survival rates were calculated and related to population size, sex of the host plant, and egg and mine densities. Host population size was negatively related to leaf-miner prevalence, with larger egg and mine densities in small populations. Percentage of eggs hatching and developing into mines, and percentage of adult flies emerging from mines also differed among host populations, but were not related to population size or host cover. Feeding punctures left by adults were marginally more frequent on male plants, whereas egg scars and mines were more common on females. Overall survival rate from egg stage to adult emergence was higher on female plants. Egg density was negatively correlated with hatching, while mine density was positively correlated with emergence of the larvae. The inverse effects of host population size were not in line with predictions based on island biogeography and resource concentration theory. We discuss how a thorough knowledge of the immigration behaviour of this fly might help to understand the patterns found.

  14. Improving Type Ia Supernova Standard Candle Cosmology Measurements Using Observations of Early-Type Host Galaxies

    NASA Astrophysics Data System (ADS)

    Meyers, Joshua Evan

    Type Ia supernovae (SNe Ia) are the current standard-bearers for dark energy but face several hurdles for their continued success in future large surveys. For example, spectroscopic classification of the myriad SNe soon to be discovered will not be possible, and systematics from uncertainties in dust corrections and the evolution of SN demographics and/or empirical calibrations used to standardize SNe Ia must be studied. Through the identification of low-dust host galaxies and through increased understanding of both the SN - progenitor connections and empirical calibrations, host galaxy information may offer opportunities to improve the cosmological utility of SNe Ia. The first half of this thesis analyzes the sample of SNe Ia discovered by the Hubble Space Telescope (HST) Cluster Supernova Survey augmented with HST-observed SNe Ia in the Great Observatories Origins Deep Survey (GOODS) fields. Correlations between properties of SNe and their host galaxies are examined at high redshift. Using galaxy color and quantitative morphology to determine the red sequence in 25 clusters, a model is developed to distinguish passively evolving early-type galaxies from star-forming galaxies in both clusters and the field. With this approach, 6 early-type cluster member hosts and 11 SN Ia early-type field hosts are identified. For the first time at z > 0.9, the correlation between host galaxy type and the rise and fall time of SN Ia light curves is confirmed. The relatively simple spectral energy distributions of early-type galaxies also enables stellar mass measurements for these hosts. In combination with literature host mass measurements, these measurements are used to show, at z > 0.9, a hint of the correlation between host mass and Hubble residuals reported at lower redshift. By simultaneously fitting cluster galaxy formation histories and dust content to the scatter of the cluster red sequences, it is shown that dust reddening of early-type cluster SN hosts is likely less

  15. Impact of host plant connectivity, crop border and patch size on adult Colorado potato beetle retention.

    PubMed

    Boiteau, Gilles; Vincent, Charles; Leskey, Tracy C; Colpitts, Bruce G; MacKinley, Pamela; Lee, Doo-Hyung

    2014-01-01

    Tagged Colorado potato beetles (CPB), Leptinotarsa decemlineata (Say), were released on potato plants, Solanum tuberosum L., and tracked using a portable harmonic radar system to determine the impact of host plant spatial distribution on the tendency of the pest to remain on the colonized host plant or patch. Results confirmed the long residency time on the host plant and showed that close connection of the plant to neighboring plants hastened dispersal between plants. Tracking walking CPB for over 6 h in small potato plots revealed that all types of mixed borders tested (potato/bare ground, potato/timothy and potato/woodland) acted as a strong barrier and retained beetles within the patch. In another experiment in potato patches surrounded by bare ground borders, tracked walking CPB displayed similar behaviour for up to four days. The distribution of turning angles in the CPB walking paths was not uniform and corresponded to beetles following the edge rows of potato patches in response to the crop border barrier or reversing their direction as they reached the end of a row and therefore a border. Patch size had no or little effect on beetle retention in the patch. The relative distribution of counts of tagged beetles detected among small (16 m2), medium (64 m2) and large size (256 m2) patches of potato four days after initial release remained similar to that of numbers released. Even though mixed crop borders were a strong barrier to walking CPB emigrating from potato patches, the departure rate of beetles over time was high. Results suggest that the effect of mixed borders is largely limited to dispersal by walking and does not apply to beetles leaving host patches by flight. The manipulation of crop borders and patch size seem to have limited potential for the management of CPB emigrating from potato fields. PMID:24816717

  16. Phosphorus source alters host plant response to ectomycorrhizal diversity.

    PubMed

    Baxter, James W; Dighton, John

    2005-11-01

    We examined the influence of phosphorus source and availability on host plant (Pinus rigida) response to ectomycorrhizal diversity under contrasting P conditions. An ectomycorrhizal richness gradient was established with equimolar P supplied as either inorganic phosphate or organic inositol hexaphosphate. We measured growth and N and P uptake of individual P. rigida seedlings inoculated with one, two, or four species of ectomycorrhizal fungi simultaneously and without mycorrhizas in axenic culture. Whereas colonization of P. rigida by individual species of ectomycorrhizal fungi decreased with increasing fungal richness, colonization of all species combined increased. Plant biomass and N content increased across the ectomycorrhizal richness gradient in the organic but not the inorganic P treatment. Plants grown under organic P conditions had higher N concentration than those grown under inorganic P conditions, but there was no effect of richness. Phosphorus content of plants grown in the organic P treatment increased with increasing ectomycorrhizal richness, but there was no response in the inorganic P treatment. Phosphorus concentration was higher in plants grown at the four-species richness level in the organic P treatment, but there was no effect of diversity under inorganic P conditions. Overall, few ectomycorrhizal composition effects were found on plant growth or nutrient status. Phosphatase activities of individual ectomycorrhizal fungi differed under organic P conditions, but there was no difference in total root system phosphatase expression between the inorganic or organic P treatments or across richness levels. Our results provide evidence that plant response to ectomycorrhizal diversity is dependent on the source and availability of P. PMID:15809869

  17. Forty-nine New Host Plant Species for Bemisia tabaci (Hemiptera: Aleyrodidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The sweetpotato whitefly, Bemisia tabaci (Gennadius), is a worldwide pest of numerous agricultural and ornamental crops. In addition to directly feeding on plants, it also acts as a vector of plant viruses of cultivated and uncultivated host plant species. Moreover, host plants can affect the popula...

  18. Trophic Relationships between the Parasitic Plant Species Phelipanche ramosa (L.) and Different Hosts Depending on Host Phenological Stage and Host Growth Rate

    PubMed Central

    Moreau, Delphine; Gibot-Leclerc, Stéphanie; Girardin, Annette; Pointurier, Olivia; Reibel, Carole; Strbik, Florence; Fernández-Aparicio, Mónica; Colbach, Nathalie

    2016-01-01

    Phelipanche ramosa (L.) Pomel (branched broomrape) is a holoparasitic plant that reproduces on crops and also on weeds, which contributes to increase the parasite seed bank in fields. This parasite extracts all its nutrients at the host’s expense so that host–parasite trophic relationships are crucial to determine host and parasite growth. This study quantified the intensity with which P. ramosa draws assimilates from its host and analyzed whether it varied with host species, host phenological stage and host growth rate. A greenhouse experiment was conducted on three host species: the crop species Brassica napus (L.) (oilseed rape) and two weed species, Capsella bursa-pastoris (L.) Medik. and Geranium dissectum (L.). Plants were grown with or without P. ramosa and under three light levels to modulate host growth rate. The proportion of host biomass loss due to parasitism by P. ramosa differed between host species (at host fructification, biomass loss ranged from 34 to 84%). B. napus and C. bursa-pastoris displayed a similar response to P. ramosa, probably because they belong to the same botanical family. The sensitivity to P. ramosa in each host species could be related to the precocity of P. ramosa development on them. Host compartments could be ranked as a function of their sensitivity to parasitism, with the reproductive compartment being the most severely affected, followed by stems and roots. The proportion of biomass allocated to leaves was not reduced by parasitism. The proportion of pathosystem biomass allocated to the parasite depended on host species. It generally increased with host stage progression but was constant across light induced-host growth rate, showing that P. ramosa adapts its growth to host biomass production. The rank order of host species in terms of sink strength differed from that in terms of host sensitivity. Finally, for B. napus, the biomass of individual parasite shoots decreased with increasing their number per host plant

  19. Effects of host plant on life-history traits in the polyphagous spider mite Tetranychus urticae.

    PubMed

    Marinosci, Cassandra; Magalhães, Sara; Macke, Emilie; Navajas, Maria; Carbonell, David; Devaux, Céline; Olivieri, Isabelle

    2015-08-01

    Studying antagonistic coevolution between host plants and herbivores is particularly relevant for polyphagous species that can experience a great diversity of host plants with a large range of defenses. Here, we performed experimental evolution with the polyphagous spider mite Tetranychus urticae to detect how mites can exploit host plants. We thus compared on a same host the performance of replicated populations from an ancestral one reared for hundreds of generations on cucumber plants that were shifted to either tomato or cucumber plants. We controlled for maternal effects by rearing females from all replicated populations on either tomato or cucumber leaves, crossing this factor with the host plant in a factorial design. About 24 generations after the host shift and for all individual mites, we measured the following fitness components on tomato leaf fragments: survival at all stages, acceptance of the host plant by juvenile and adult mites, longevity, and female fecundity. The host plant on which mite populations had evolved did not affect the performance of the mites, but only affected their sex ratio. Females that lived on tomato plants for circa 24 generations produced a higher proportion of daughters than did females that lived on cucumber plants. In contrast, maternal effects influenced juvenile survival, acceptance of the host plant by adult mites and female fecundity. Independently of the host plant species on which their population had evolved, females reared on the tomato maternal environment produced offspring that survived better on tomato as juveniles, but accepted less this host plant as adults and had a lower fecundity than did females reared on the cucumber maternal environment. We also found that temporal blocks affected mite dispersal and both female longevity and fecundity. Taken together, our results show that the host plant species can affect critical parameters of population dynamics, and most importantly that maternal and environmental

  20. Effects of host plant on life-history traits in the polyphagous spider mite Tetranychus urticae

    PubMed Central

    Marinosci, Cassandra; Magalhães, Sara; Macke, Emilie; Navajas, Maria; Carbonell, David; Devaux, Céline; Olivieri, Isabelle

    2015-01-01

    Studying antagonistic coevolution between host plants and herbivores is particularly relevant for polyphagous species that can experience a great diversity of host plants with a large range of defenses. Here, we performed experimental evolution with the polyphagous spider mite Tetranychus urticae to detect how mites can exploit host plants. We thus compared on a same host the performance of replicated populations from an ancestral one reared for hundreds of generations on cucumber plants that were shifted to either tomato or cucumber plants. We controlled for maternal effects by rearing females from all replicated populations on either tomato or cucumber leaves, crossing this factor with the host plant in a factorial design. About 24 generations after the host shift and for all individual mites, we measured the following fitness components on tomato leaf fragments: survival at all stages, acceptance of the host plant by juvenile and adult mites, longevity, and female fecundity. The host plant on which mite populations had evolved did not affect the performance of the mites, but only affected their sex ratio. Females that lived on tomato plants for circa 24 generations produced a higher proportion of daughters than did females that lived on cucumber plants. In contrast, maternal effects influenced juvenile survival, acceptance of the host plant by adult mites and female fecundity. Independently of the host plant species on which their population had evolved, females reared on the tomato maternal environment produced offspring that survived better on tomato as juveniles, but accepted less this host plant as adults and had a lower fecundity than did females reared on the cucumber maternal environment. We also found that temporal blocks affected mite dispersal and both female longevity and fecundity. Taken together, our results show that the host plant species can affect critical parameters of population dynamics, and most importantly that maternal and environmental

  1. Overexpression of host plant urease in transgenic silkworms.

    PubMed

    Jiang, Liang; Huang, Chunlin; Sun, Qiang; Guo, Huizhen; Peng, Zhengwen; Dang, Yinghui; Liu, Weiqiang; Xing, Dongxu; Xu, Guowen; Zhao, Ping; Xia, Qingyou

    2015-06-01

    Bombyx mori and mulberry constitute a model of insect-host plant interactions. Urease hydrolyzes urea to ammonia and is important for the nitrogen metabolism of silkworms because ammonia is assimilated into silk protein. Silkworms do not synthesize urease and acquire it from mulberry leaves. We synthesized the artificial DNA sequence ureas using the codon bias of B. mori to encode the signal peptide and mulberry urease protein. A transgenic vector that overexpresses ure-as under control of the silkworm midgut-specific P2 promoter was constructed. Transgenic silkworms were created via embryo microinjection. RT-PCR results showed that urease was expressed during the larval stage and qPCR revealed the expression only in the midgut of transgenic lines. Urea concentration in the midgut and hemolymph of transgenic silkworms was significantly lower than in a nontransgenic line when silkworms were fed an artificial diet. Analysis of the daily body weight and food conversion efficiency of the fourth and fifth instar larvae and economic characteristics indicated no differences between transgenic silkworms and the nontransgenic line. These results suggested that overexpression of host plant urease promoted nitrogen metabolism in silkworms. PMID:25549597

  2. The Host Galaxies of Local PTF Type Ia Supernovae

    NASA Astrophysics Data System (ADS)

    Sullivan, Mark; Howell, D. Andrew; Nugent, Peter; Hook, Isobel; Maguire, Kate; Blake, Sarah; Pan, Yen-Chen

    2012-02-01

    The discovery of correlations between Type Ia Supernova (SN Ia) peak luminosity and the parameters defining their host galaxy stellar populations has important implications for their use as standardised candles. Using new samples of low-redshift SNe Ia located with the Palomar Transient Factory (PTF), a rolling transient search in the local universe, we propose to continue our campaign to study in detail the host galaxies in which SNe Ia explode. We aim to establish which physical variable (metallicity or age) primarily drives the SN Ia luminosity variations using high signal-to-noise spectroscopy of their environments. These data will also improve the derivation of SN Ia "delay-time" distributions, and place tighter constraints on the nature of their progenitor systems. Evolution in SN Ia properties is now the largest single astrophysical systematic in SN Ia cosmology, with host galaxies playing a critical role in cosmological studies, and detailed study of their environments provides a realistic opportunity to improve their use for studying dark energy. We give a status report on the progress of this program to date, and demonstrate the feasibility of our study using our observations from earlier semesters.

  3. The host galaxies of local PTF Type Ia supernovae

    NASA Astrophysics Data System (ADS)

    Sullivan, Mark; Howell, D. Andrew; Hook, Isobel; Pan, Yen-Chen; Nugent, Peter; Maguire, Kate

    2012-08-01

    The discovery of correlations between Type Ia Supernova (SN Ia) peak luminosity and the parameters defining their host galaxy stellar populations has important implications for their use as standardised candles. Using new samples of low-redshift SNe Ia located with the Palomar Transient Factory (PTF), a rolling transient search in the local universe, we finish our campaign to study in detail the host galaxies in which SNe Ia explode. We aim to establish which physical variable (metallicity or age) primarily drives the SN Ia luminosity variations using high signal-to-noise spectroscopy of their environments. These data will also place tighter constraints on the nature of their progenitor systems. Evolution in SN Ia properties is now the largest single astrophysical systematic in SN Ia cosmology, with host galaxies playing a critical role in cosmological studies, and detailed study of their environments provides a realistic opportunity to improve their use for studying dark energy. We give a status report on the progress of this program to date, and demonstrate the feasibility of our study using our observations from earlier semesters.

  4. Diamondback Moth (Lepidoptera: Plutellidae) Exhibits Oviposition and Larval Feeding Preferences Among Crops, Wild plants, and Ornamentals as Host Plants.

    PubMed

    Newman, K; You, M; Vasseur, L

    2016-04-01

    Diamondback moth, Plutella xylostella (L.) (Lepidoptera: Plutellidae), is an agricultural pest with high reproductive potential, widespread distribution, and high resistance to different types of insecticides. Although diamondback moth is a common research subject, questions remain regarding its spatial and temporal host plant usage patterns and preferences within agroecosystems. We examined the adult oviposition and larval feeding preferences of the diamondback moth to assess the potential of alternate host plants as either reservoirs or trap crops. Adult females and third and fourth instars were offered multiple plant species within the plant family Brassicaceae to examine contact preferences and larval ingestion rates. Adult oviposition and larval feeding preferences were identical, with garden cress (Lepidium sativum) (L.) highly preferred, followed by wintercress (Barbarea vulgaris) (L.) and black mustard (Brassica nigra) (L.). Ingestion rates varied among tested plants, with the lowest rate on black mustard and highest on aubretia (Aubretia deltoidea) (L.). Highly preferred plant species were determined to be unfavorable for larval growth and potentially lethal to neonates, suggesting their possible use as trap crops. Understanding ovipositional and larval feeding preferences of diamondback moth can also aid in the development of more accurate monitoring and control strategies for this pest. PMID:26834144

  5. Host Plants Affect the Foraging Success of Two Parasitoids that Attack Light Brown Apple Moth Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae).

    PubMed

    Feng, Yi; Wratten, Steve; Sandhu, Harpinder; Keller, Michael

    2015-01-01

    The light brown apple moth, Epiphyas postvittana is a key pest of wine grapes in Australia. Two parasitoids, Dolichogenidea tasmanica and Therophilus unimaculatus, attack the larval stage of this pest. D. tasmanica is dominant in vineyards, whereas T. unimaculatus is mainly active in native vegetation. We sought to understand why they differ in their use of habitats. Plants are a major component of habitats of parasitoids, and herbivore-infested plants influence parasitoid foraging efficiency by their architecture and emission of volatile chemicals. We investigated how different plant species infested by E. postvittana could affect the foraging success of the two parasitoid species in both laboratory and field experiments. Four common host-plant species were selected for this study. In paired-choice experiments to determine the innate foraging preferences for plants, both parasitoid species showed differences in innate search preferences among plant species. The plant preference of D. tasmanica was altered by oviposition experience with hosts that were feeding on other plant species. In a behavioral assay, the two parasitoid species allocated their times engaged in various types of behavior differently when foraging on different plant species. For both parasitoids, parasitism on Hardenbergia violacea was the highest of the four plant species. Significantly more larvae dropped from Myoporum insulare when attacked than from the other three host-plant species, which indicates that parasitism is also affected by interactions between plants and host insects. In vineyards, parasitism by D. tasmanica was significantly lower on M. insulare than on the other three host-plant species, but the parasitism rates were similar among the other three plant species. Our results indicate that plants play a role in the habitat preferences of these two parasitoid species by influencing their foraging behavior, and are likely to contribute to their distributions among habitats. PMID

  6. Host Plants Affect the Foraging Success of Two Parasitoids that Attack Light Brown Apple Moth Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae)

    PubMed Central

    Feng, Yi; Wratten, Steve; Sandhu, Harpinder; Keller, Michael

    2015-01-01

    The light brown apple moth, Epiphyas postvittana is a key pest of wine grapes in Australia. Two parasitoids, Dolichogenidea tasmanica and Therophilus unimaculatus, attack the larval stage of this pest. D. tasmanica is dominant in vineyards, whereas T. unimaculatus is mainly active in native vegetation. We sought to understand why they differ in their use of habitats. Plants are a major component of habitats of parasitoids, and herbivore-infested plants influence parasitoid foraging efficiency by their architecture and emission of volatile chemicals. We investigated how different plant species infested by E. postvittana could affect the foraging success of the two parasitoid species in both laboratory and field experiments. Four common host-plant species were selected for this study. In paired-choice experiments to determine the innate foraging preferences for plants, both parasitoid species showed differences in innate search preferences among plant species. The plant preference of D. tasmanica was altered by oviposition experience with hosts that were feeding on other plant species. In a behavioral assay, the two parasitoid species allocated their times engaged in various types of behavior differently when foraging on different plant species. For both parasitoids, parasitism on Hardenbergia violacea was the highest of the four plant species. Significantly more larvae dropped from Myoporum insulare when attacked than from the other three host-plant species, which indicates that parasitism is also affected by interactions between plants and host insects. In vineyards, parasitism by D. tasmanica was significantly lower on M. insulare than on the other three host-plant species, but the parasitism rates were similar among the other three plant species. Our results indicate that plants play a role in the habitat preferences of these two parasitoid species by influencing their foraging behavior, and are likely to contribute to their distributions among habitats. PMID

  7. Host plant susceptibility to the swede midge (Diptera: Cecidomyiidae).

    PubMed

    Hallett, Rebecca H

    2007-08-01

    The relative resistance and susceptibility of various cruciferous plants to swede midge, Contarinia nasturtii (Kieffer) (Diptera: Cecidomyiidae), damage was investigated to provide growers with planting recommendations and to identify potential sources of resistance to the swede midge. Broccoli cultivars experienced more severe damage than cabbage, cauliflower, and Brussels sprouts. The broccoli 'Paragon', 'Eureka', and 'Packman' are highly susceptible to the swede midge, whereas 'Triathlon' and 'Regal' showed reduced susceptibility to damage and slower development of damage symptoms. No differences were found between normal and red cultivars of cabbage and cauliflower in damage severity and progression of damage symptoms. Four new plant species (Brassica juncea Integlifolia group, Erucastrum gallicum (Willd.) O. E. Shulz., Lepidium campestre (L.) R.Br., and Capsella bursa-pastoris (L.) Medic.) are reported as hosts of the swede midge. The weed species Descurainia sophia (L.) Webb, Camelina microcarpa Andrz. ex Dc., and Erysimum cheiranthoides L. exhibited no damage symptoms, and they seem to be nonhost crucifers for the swede midge. PMID:17849887

  8. Host plants of the tarnished plant bug (Heteroptera: Miridae) in Central Texas.

    PubMed

    Esquivel, J F; Mowery, S V

    2007-08-01

    The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), has taken on added importance as a pest of cotton in the Cotton Belt after successful eradication efforts for the boll weevil (Anthonomus grandis grandis Boheman). Because the Southern Blacklands region of Central Texas is in advanced stages of boll weevil eradication, blooming weeds and selected row crops were sampled during a 3-yr study to determine lygus species composition and associated temporal host plants. L. lineolaris was the sole lygus species in the region. Thirteen previously unreported host plants were identified for L. lineolaris, of which 69% supported reproduction. Rapistrum rugosum L. Allioni and Ratibida columnifera (Nuttall) Wooton and Standley were primary weed hosts during the early season (17 March to 31 May). Conyza canadensis L. Cronquist variety canadensis and Ambrosia trifida L. were primary weed hosts during the midseason (1 June to 14 August) and late-season (15 August to 30 November), respectively. Sisymbrium irio L. and Lamium amplexicaule L. sustained L. lineolaris populations during the overwintering period (1 December to 16 March). The proportion of females and numbers of nymphs found in R. rugosum, C. canadensis, A. trifida, and S. irio suggests these weeds supported reproductive adults during the early, mid-, and late season and overwintering period, respectively. Medicago sativa L. was the leading crop host for L. lineolaris; Glycine max L. Merrill did not yield L. lineolaris. Few L. lineolaris were collected in Gossypium hirsutum L. These results provide a more comprehensive assessment of host plants contributing to L. lineolaris populations in central Texas. PMID:17716463

  9. Contemporary evolution of host plant range expansion in an introduced herbivorous beetle Ophraella communa.

    PubMed

    Fukano, Y; Doi, H; Thomas, C E; Takata, M; Koyama, S; Satoh, T

    2016-04-01

    Host range expansion of herbivorous insects is a key event in ecological speciation and insect pest management. However, the mechanistic processes are relatively unknown because it is difficult to observe the ongoing host range expansion in natural population. In this study, we focused on the ongoing host range expansion in introduced populations of the ragweed leaf beetle, Ophraella communa, to estimate the evolutionary process of host plant range expansion of a herbivorous insect. In the native range of North America, O. communa does not utilize Ambrosia trifida, as a host plant, but this plant is extensively utilized in the beetle's introduced range. Larval performance and adult preference experiments demonstrated that native O. communa beetles show better survival on host plant individuals from introduced plant populations than those from native plant populations and they also oviposit on the introduced plant, but not on the native plant. Introduced O. communa beetles showed significantly higher performance on and preference for both introduced and native A. trifida plants, when compared with native O. communa. These results indicate the contemporary evolution of host plant range expansion of introduced O. communa and suggest that the evolutionary change of both the host plant and the herbivorous insect involved in the host range expansion. PMID:26728888

  10. Type Ia supernova Hubble residuals and host-galaxy properties

    SciTech Connect

    Kim, A. G.; Aldering, G.; Aragon, C.; Bailey, S.; Fakhouri, H. K.; Antilogus, P.; Bongard, S.; Canto, A.; Cellier-Holzem, F.; Fleury, M.; Guy, J.; Baltay, C.; Buton, C.; Feindt, U.; Greskovic, P.; Kowalski, M.; Childress, M.; Chotard, N.; Copin, Y.; Gangler, E. [Université de Lyon, F-69622 Lyon; Université de Lyon 1, Villeurbanne; CNRS and others

    2014-03-20

    Kim et al. introduced a new methodology for determining peak-brightness absolute magnitudes of type Ia supernovae from multi-band light curves. We examine the relation between their parameterization of light curves and Hubble residuals, based on photometry synthesized from the Nearby Supernova Factory spectrophotometric time series, with global host-galaxy properties. The K13 Hubble residual step with host mass is 0.013 ± 0.031 mag for a supernova subsample with data coverage corresponding to the K13 training; at <<1σ, the step is not significant and lower than previous measurements. Relaxing the data coverage requirement of the Hubble residual step with the host mass is 0.045 ± 0.026 mag for the larger sample; a calculation using the modes of the distributions, less sensitive to outliers, yields a step of 0.019 mag. The analysis of this article uses K13 inferred luminosities, as distinguished from previous works that use magnitude corrections as a function of SALT2 color and stretch parameters: steps at >2σ significance are found in SALT2 Hubble residuals in samples split by the values of their K13 x(1) and x(2) light-curve parameters. x(1) affects the light-curve width and color around peak (similar to the Δm {sub 15} and stretch parameters), and x(2) affects colors, the near-UV light-curve width, and the light-curve decline 20-30 days after peak brightness. The novel light-curve analysis, increased parameter set, and magnitude corrections of K13 may be capturing features of SN Ia diversity arising from progenitor stellar evolution.

  11. Type Ia Supernova Hubble Residuals and Host-Galaxy Properties

    SciTech Connect

    Nearby Supernova Factory; Kim, A. G.; Aldering, G.; Antilogus, P.; Aragon, C.; Bailey, S.; Baltay, C.; Bongard, S.; Buton, C.; Canto, A.; Cellier-Holzem, F.; Childress, M.; Chotard, N.; Copin, Y.; Fakhouri, H. K.; Feindt, U.; Fleury, M.; Gangler, E.; Greskovic, P.; Guy, J.; Kowalski, M.; Lombardo, S.; Nordin, J.; Nugent, P.; Pain, R.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigault, M.; Runge, K.; Saunders, C.; Scalzo, R.; Smadja, G.; Tao, C.; Thomas, R. C.; Weaver, B. A.

    2014-01-17

    Kim et al. (2013) [K13] introduced a new methodology for determining peak- brightness absolute magnitudes of type Ia supernovae from multi-band light curves. We examine the relation between their parameterization of light curves and Hubble residuals, based on photometry synthesized from the Nearby Supernova Factory spec- trophotometric time series, with global host-galaxy properties. The K13 Hubble residual step with host mass is 0.013 ? 0.031 mag for a supernova subsample with data coverage corresponding to the K13 training; at ? 1?, the step is not significant and lower than previous measurements. Relaxing the data coverage requirement the Hubble residual step with host mass is 0.045 ? 0.026 mag for the larger sample; a calculation using the modes of the distributions, less sensitive to outliers, yields a step of 0.019 mag. The analysis of this article uses K13 inferred luminosities, as distinguished from previous works that use magnitude corrections as a function of SALT2 color and stretch param- eters: Steps at> 2? significance are found in SALT2 Hubble residuals in samples split by the values of their K13 x(1) and x(2) light-curve parameters. x(1) affects the light- curve width and color around peak (similar to the∆m15 and stretch parameters), and x(2) affects colors, the near-UV light-curve width, and the light-curve decline 20 to 30 days after peak brightness. The novel light-curve analysis, increased parameter set, and magnitude corrections of K13 may be capturing features of SN Ia diversity arising from progenitor stellar evolution.

  12. Yersinia type III effectors perturb host innate immune responses

    PubMed Central

    Pha, Khavong; Navarro, Lorena

    2016-01-01

    The innate immune system is the first line of defense against invading pathogens. Innate immune cells recognize molecular patterns from the pathogen and mount a response to resolve the infection. The production of proinflammatory cytokines and reactive oxygen species, phagocytosis, and induced programmed cell death are processes initiated by innate immune cells in order to combat invading pathogens. However, pathogens have evolved various virulence mechanisms to subvert these responses. One strategy utilized by Gram-negative bacterial pathogens is the deployment of a complex machine termed the type III secretion system (T3SS). The T3SS is composed of a syringe-like needle structure and the effector proteins that are injected directly into a target host cell to disrupt a cellular response. The three human pathogenic Yersinia spp. (Y. pestis, Y. enterocolitica, and Y. pseudotuberculosis) are Gram-negative bacteria that share in common a 70 kb virulence plasmid which encodes the T3SS. Translocation of the Yersinia effector proteins (YopE, YopH, YopT, YopM, YpkA/YopO, and YopP/J) into the target host cell results in disruption of the actin cytoskeleton to inhibit phagocytosis, downregulation of proinflammatory cytokine/chemokine production, and induction of cellular apoptosis of the target cell. Over the past 25 years, studies on the Yersinia effector proteins have unveiled tremendous knowledge of how the effectors enhance Yersinia virulence. Recently, the long awaited crystal structure of YpkA has been solved providing further insights into the activation of the YpkA kinase domain. Multisite autophosphorylation by YpkA to activate its kinase domain was also shown and postulated to serve as a mechanism to bypass regulation by host phosphatases. In addition, novel Yersinia effector protein targets, such as caspase-1, and signaling pathways including activation of the inflammasome were identified. In this review, we summarize the recent discoveries made on Yersinia

  13. Type Ia Supernova Hubble Residuals and Host-galaxy Properties

    NASA Astrophysics Data System (ADS)

    Kim, A. G.; Aldering, G.; Antilogus, P.; Aragon, C.; Bailey, S.; Baltay, C.; Bongard, S.; Buton, C.; Canto, A.; Cellier-Holzem, F.; Childress, M.; Chotard, N.; Copin, Y.; Fakhouri, H. K.; Feindt, U.; Fleury, M.; Gangler, E.; Greskovic, P.; Guy, J.; Kowalski, M.; Lombardo, S.; Nordin, J.; Nugent, P.; Pain, R.; Pecontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Rigault, M.; Runge, K.; Saunders, C.; Scalzo, R.; Smadja, G.; Tao, C.; Thomas, R. C.; Weaver, B. A.

    2014-03-01

    Kim et al. introduced a new methodology for determining peak-brightness absolute magnitudes of type Ia supernovae from multi-band light curves. We examine the relation between their parameterization of light curves and Hubble residuals, based on photometry synthesized from the Nearby Supernova Factory spectrophotometric time series, with global host-galaxy properties. The K13 Hubble residual step with host mass is 0.013 ± 0.031 mag for a supernova subsample with data coverage corresponding to the K13 training; at Lt1σ, the step is not significant and lower than previous measurements. Relaxing the data coverage requirement of the Hubble residual step with the host mass is 0.045 ± 0.026 mag for the larger sample; a calculation using the modes of the distributions, less sensitive to outliers, yields a step of 0.019 mag. The analysis of this article uses K13 inferred luminosities, as distinguished from previous works that use magnitude corrections as a function of SALT2 color and stretch parameters: steps at >2σ significance are found in SALT2 Hubble residuals in samples split by the values of their K13 x(1) and x(2) light-curve parameters. x(1) affects the light-curve width and color around peak (similar to the Δm 15 and stretch parameters), and x(2) affects colors, the near-UV light-curve width, and the light-curve decline 20-30 days after peak brightness. The novel light-curve analysis, increased parameter set, and magnitude corrections of K13 may be capturing features of SN Ia diversity arising from progenitor stellar evolution.

  14. Yersinia type III effectors perturb host innate immune responses.

    PubMed

    Pha, Khavong; Navarro, Lorena

    2016-02-26

    The innate immune system is the first line of defense against invading pathogens. Innate immune cells recognize molecular patterns from the pathogen and mount a response to resolve the infection. The production of proinflammatory cytokines and reactive oxygen species, phagocytosis, and induced programmed cell death are processes initiated by innate immune cells in order to combat invading pathogens. However, pathogens have evolved various virulence mechanisms to subvert these responses. One strategy utilized by Gram-negative bacterial pathogens is the deployment of a complex machine termed the type III secretion system (T3SS). The T3SS is composed of a syringe-like needle structure and the effector proteins that are injected directly into a target host cell to disrupt a cellular response. The three human pathogenic Yersinia spp. (Y. pestis, Y. enterocolitica, and Y. pseudotuberculosis) are Gram-negative bacteria that share in common a 70 kb virulence plasmid which encodes the T3SS. Translocation of the Yersinia effector proteins (YopE, YopH, YopT, YopM, YpkA/YopO, and YopP/J) into the target host cell results in disruption of the actin cytoskeleton to inhibit phagocytosis, downregulation of proinflammatory cytokine/chemokine production, and induction of cellular apoptosis of the target cell. Over the past 25 years, studies on the Yersinia effector proteins have unveiled tremendous knowledge of how the effectors enhance Yersinia virulence. Recently, the long awaited crystal structure of YpkA has been solved providing further insights into the activation of the YpkA kinase domain. Multisite autophosphorylation by YpkA to activate its kinase domain was also shown and postulated to serve as a mechanism to bypass regulation by host phosphatases. In addition, novel Yersinia effector protein targets, such as caspase-1, and signaling pathways including activation of the inflammasome were identified. In this review, we summarize the recent discoveries made on Yersinia

  15. Impact of host plant connectivity, crop border and patch size on adult Colorado potato beetle retention

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tagged Colorado potato beetles (CPB), Leptinotarsa decemlineata (Say), were released on potato plants, Solanum tuberosum L., and tracked using a portable harmonic radar system to determine the impact of host plant spatial distribution on the tendency of the pest to remain on the colonized host plant...

  16. [Relationships of Aulacophora beetles feeding behavior with cucurbitacin types in host crops].

    PubMed

    Yang, Xiao; Kong, Chuihua; Liang, Wenju; Zhang, Maoxin; Hu, Fei

    2005-07-01

    Aulacophora fermoralis chinensis and Aulacophora cattigarensis are the two related Aulacophora beetles, but their host selectivity and feeding behavior are significantly different. A. fernzoralis chinensis usually feeds upon Cucumis sativus and Cucurbita moschata, but never upon Luffa acutangula, Momordica charantia and Citrullas lanatus. Its feeding behavior on hosts is to snip a circular trench on their leaves, and then, to feed the leaf tissues isolated by the trench. On the contrary, A. cattigarensis only feeds L. acutangula, and its trenching behavior rarely occurs. This study showed that the host selectivity and feeding behavior of the two beetles were significantly correlated with the types of cucurbitacin biosynthesized by host melon crops. C. sativus and C. moschata might be induced to produce cucurbitacin I by A. fermoralis chinensis feeding, and this compound was responsible for feeding deterrent on A. fermoralis chinensis. Therefore, the feeding behavior of A. fermoralis chinensis was to block the translocation of cucurbitacin I to feeding sites. M. charantia and C. lanatus contained deterrent cucurbitacin D, and thus, both beetles never fed upon them, while L. acutangula contained stimulants cucurbitacin B and E, and made A. cattigarensis directly feed upon it without trenching. The results suggested that the taste responses of insects on specific allelochemicals from plants may play an important role in host selectivity and feeding behavior. PMID:16252877

  17. Structure of a bacterial type III secretion system in contact with a host membrane in situ

    NASA Astrophysics Data System (ADS)

    Nans, Andrea; Kudryashev, Mikhail; Saibil, Helen R.; Hayward, Richard D.

    2015-12-01

    Many bacterial pathogens of animals and plants use a conserved type III secretion system (T3SS) to inject virulence effector proteins directly into eukaryotic cells to subvert host functions. Contact with host membranes is critical for T3SS activation, yet little is known about T3SS architecture in this state or the conformational changes that drive effector translocation. Here we use cryo-electron tomography and sub-tomogram averaging to derive the intact structure of the primordial Chlamydia trachomatis T3SS in the presence and absence of host membrane contact. Comparison of the averaged structures demonstrates a marked compaction of the basal body (4 nm) occurs when the needle tip contacts the host cell membrane. This compaction is coupled to a stabilization of the cytosolic sorting platform-ATPase. Our findings reveal the first structure of a bacterial T3SS from a major human pathogen engaged with a eukaryotic host, and reveal striking `pump-action' conformational changes that underpin effector injection.

  18. Structure of a bacterial type III secretion system in contact with a host membrane in situ

    PubMed Central

    Nans, Andrea; Kudryashev, Mikhail; Saibil, Helen R.; Hayward, Richard D.

    2015-01-01

    Many bacterial pathogens of animals and plants use a conserved type III secretion system (T3SS) to inject virulence effector proteins directly into eukaryotic cells to subvert host functions. Contact with host membranes is critical for T3SS activation, yet little is known about T3SS architecture in this state or the conformational changes that drive effector translocation. Here we use cryo-electron tomography and sub-tomogram averaging to derive the intact structure of the primordial Chlamydia trachomatis T3SS in the presence and absence of host membrane contact. Comparison of the averaged structures demonstrates a marked compaction of the basal body (4 nm) occurs when the needle tip contacts the host cell membrane. This compaction is coupled to a stabilization of the cytosolic sorting platform–ATPase. Our findings reveal the first structure of a bacterial T3SS from a major human pathogen engaged with a eukaryotic host, and reveal striking ‘pump-action' conformational changes that underpin effector injection. PMID:26656452

  19. The Influence of Learning on Host Plant Preference in a Significant Phytopathogen Vector, Diaphorina citri

    PubMed Central

    Stockton, Dara G.; Martini, Xavier; Patt, Joseph M.; Stelinski, Lukasz L.

    2016-01-01

    Although specialist herbivorous insects are guided by innate responses to host plant cues, host plant preference may be influenced by experience and is not dictated by instinct alone. The effect of learning on host plant preference was examined in the Asian citrus psyllid, Diaphorina citri; vector of the causal agent of citrus greening disease or huanglongbing. We investigated: a) whether development on specific host plant species influenced host plant preference in mature D. citri; and b) the extent of associative learning in D. citri in the form of simple and compound conditioning. Learning was measured by cue selection in a 2-choice behavioral assay and compared to naïve controls. Our results showed that learned responses in D. citri are complex and diverse. The developmental host plant species influenced adult host plant preference, with female psyllids preferring the species on which they were reared. However, such preferences were subject to change with the introduction of an alternative host plant within 24–48 hrs, indicating a large degree of experience-dependent response plasticity. Additionally, learning occurred for multiple sensory modalities where novel olfactory and visual environmental cues were associated with the host plant. However, males and females displayed differing discriminatory abilities. In compound conditioning tasks, males exhibited recognition of a compound stimulus alone while females were capable of learning the individual components. These findings suggest D. citri are dynamic animals that demonstrate host plant preference based on developmental and adult experience and can learn to recognize olfactory and visual host plant stimuli in ways that may be sex specific. These experience-based associations are likely used by adults to locate and select suitable host plants for feeding and reproduction and may suggest the need for more tailored lures and traps, which reflect region-specific cultivars or predominate Rutaceae in the area

  20. The Influence of Learning on Host Plant Preference in a Significant Phytopathogen Vector, Diaphorina citri.

    PubMed

    Stockton, Dara G; Martini, Xavier; Patt, Joseph M; Stelinski, Lukasz L

    2016-01-01

    Although specialist herbivorous insects are guided by innate responses to host plant cues, host plant preference may be influenced by experience and is not dictated by instinct alone. The effect of learning on host plant preference was examined in the Asian citrus psyllid, Diaphorina citri; vector of the causal agent of citrus greening disease or huanglongbing. We investigated: a) whether development on specific host plant species influenced host plant preference in mature D. citri; and b) the extent of associative learning in D. citri in the form of simple and compound conditioning. Learning was measured by cue selection in a 2-choice behavioral assay and compared to naïve controls. Our results showed that learned responses in D. citri are complex and diverse. The developmental host plant species influenced adult host plant preference, with female psyllids preferring the species on which they were reared. However, such preferences were subject to change with the introduction of an alternative host plant within 24-48 hrs, indicating a large degree of experience-dependent response plasticity. Additionally, learning occurred for multiple sensory modalities where novel olfactory and visual environmental cues were associated with the host plant. However, males and females displayed differing discriminatory abilities. In compound conditioning tasks, males exhibited recognition of a compound stimulus alone while females were capable of learning the individual components. These findings suggest D. citri are dynamic animals that demonstrate host plant preference based on developmental and adult experience and can learn to recognize olfactory and visual host plant stimuli in ways that may be sex specific. These experience-based associations are likely used by adults to locate and select suitable host plants for feeding and reproduction and may suggest the need for more tailored lures and traps, which reflect region-specific cultivars or predominate Rutaceae in the area

  1. Different uses of plant semiochemicals in host location strategies of the two tachinid parasitoids

    NASA Astrophysics Data System (ADS)

    Ichiki, Ryoko T.; Ho, Giang T. T.; Wajnberg, Eric; Kainoh, Yooichi; Tabata, Jun; Nakamura, Satoshi

    2012-09-01

    Some members of the family Tachinidae (Insecta: Diptera) deposit numerous very small eggs, termed "microtype" eggs, on the food plants of their caterpillar hosts. Parasitization is successful only when the hosts ingest these eggs. To increase the chance of hosts encountering the eggs, microtype tachinid parasitoids have to choose a suitable plant that harbors hosts and lay their eggs near the hosts. In their host location process, semiochemicals emitted by host-infested plants offer the tachinids a reliable cue. We investigated the behavioral responses of two microtype tachinid parasitoids, Pales pavida and Zenillia dolosa, to maize plants infested with their caterpillar host, Mythimna separata, in a wind tunnel. P. pavida females showed a significantly higher rate of landing on caterpillar-infested plants than on mechanically wounded or intact plants, whereas Z. dolosa landed on both the caterpillar-infested and mechanically wounded plants at significantly higher rates than on intact plants. We also examined which part of a caterpillar-infested maize leaf induces oviposition. P. pavida deposited eggs on the margin of the leaf, whereas Z. dolosa preferentially laid eggs around a caterpillar-infested area or a mechanically wounded spot. P. pavida eggs retained their parasitization ability for more than 15 days after they were deposited, whereas the eggs of Z. dolosa could not survive more than 5 days after oviposition. Our results suggest that each tachinid parasitoid employs a different host location strategy to exploit semiochemicals coming from plant-herbivore interaction as cues in order to increase their parasitization success.

  2. Habitat complexity reduces parasitoid foraging efficiency, but does not prevent orientation towards learned host plant odours.

    PubMed

    Kruidhof, H M; Roberts, A L; Magdaraog, P; Muñoz, D; Gols, R; Vet, L E M; Hoffmeister, T S; Harvey, J A

    2015-10-01

    It is well known that many parasitic wasps use herbivore-induced plant odours (HIPVs) to locate their inconspicuous host insects, and are often able to distinguish between slight differences in plant odour composition. However, few studies have examined parasitoid foraging behaviour under (semi-)field conditions. In nature, food plants of parasitoid hosts are often embedded in non-host-plant assemblages that confer both structural and chemical complexity. By releasing both naïve and experienced Cotesia glomerata females in outdoor tents, we studied how natural vegetation surrounding Pieris brassicae-infested Sinapis arvensis and Barbarea vulgaris plants influences their foraging efficiency as well as their ability to specifically orient towards the HIPVs of the host plant species on which they previously had a positive oviposition experience. Natural background vegetation reduced the host-encounter rate of naïve C. glomerata females by 47 %. While associative learning of host plant HIPVs 1 day prior to foraging caused a 28 % increase in the overall foraging efficiency of C. glomerata, it did not reduce the negative influence of natural background vegetation. At the same time, however, females foraging in natural vegetation attacked more host patches on host-plant species on which they previously had a positive oviposition experience. We conclude that, even though the presence of natural vegetation reduces the foraging efficiency of C. glomerata, it does not prevent experienced female wasps from specifically orienting towards the host-plant species from which they had learned the HIPVs. PMID:26001606

  3. Do Native Parasitic Plants Cause More Damage to Exotic Invasive Hosts Than Native Non-Invasive Hosts? An Implication for Biocontrol

    PubMed Central

    Li, Junmin; Jin, Zexin; Song, Wenjing

    2012-01-01

    Field studies have shown that native, parasitic plants grow vigorously on invasive plants and can cause more damage to invasive plants than native plants. However, no empirical test has been conducted and the mechanism is still unknown. We conducted a completely randomized greenhouse experiment using 3 congeneric pairs of exotic, invasive and native, non-invasive herbaceous plant species to quantify the damage caused by parasitic plants to hosts and its correlation with the hosts' growth rate and resource use efficiency. The biomass of the parasitic plants on exotic, invasive hosts was significantly higher than on congeneric native, non-invasive hosts. Parasites caused more damage to exotic, invasive hosts than to congeneric, native, non-invasive hosts. The damage caused by parasites to hosts was significantly positively correlated with the biomass of parasitic plants. The damage of parasites to hosts was significantly positively correlated with the relative growth rate and the resource use efficiency of its host plants. It may be the mechanism by which parasitic plants grow more vigorously on invasive hosts and cause more damage to exotic, invasive hosts than to native, non-invasive hosts. These results suggest a potential biological control effect of native, parasitic plants on invasive species by reducing the dominance of invasive species in the invaded community. PMID:22493703

  4. Dramatic Transcriptional Changes in an Intracellular Parasite Enable Host Switching between Plant and Insect

    PubMed Central

    Oshima, Kenro; Ishii, Yoshiko; Kakizawa, Shigeyuki; Sugawara, Kyoko; Neriya, Yutaro; Himeno, Misako; Minato, Nami; Miura, Chihiro; Shiraishi, Takuya; Yamaji, Yasuyuki; Namba, Shigetou

    2011-01-01

    Phytoplasmas are bacterial plant pathogens that have devastating effects on the yields of crops and plants worldwide. They are intracellular parasites of both plants and insects, and are spread among plants by insects. How phytoplasmas can adapt to two diverse environments is of considerable interest; however, the mechanisms enabling the “host switching” between plant and insect hosts are poorly understood. Here, we report that phytoplasmas dramatically alter their gene expression in response to “host switching” between plant and insect. We performed a detailed characterization of the dramatic change that occurs in the gene expression profile of Candidatus Phytoplasma asteris OY-M strain (approximately 33% of the genes change) upon host switching between plant and insect. The phytoplasma may use transporters, secreted proteins, and metabolic enzymes in a host-specific manner. As phytoplasmas reside within the host cell, the proteins secreted from phytoplasmas are thought to play crucial roles in the interplay between phytoplasmas and host cells. Our microarray analysis revealed that the expression of the gene encoding the secreted protein PAM486 was highly upregulated in the plant host, which is also observed by immunohistochemical analysis, suggesting that this protein functions mainly when the phytoplasma grows in the plant host. Additionally, phytoplasma growth in planta was partially suppressed by an inhibitor of the MscL osmotic channel that is highly expressed in the plant host, suggesting that the osmotic channel might play an important role in survival in the plant host. These results also suggest that the elucidation of “host switching” mechanism may contribute to the development of novel pest controls. PMID:21858041

  5. Specific developmental pathways underlie host specificity in the parasitic plant Orobanche

    PubMed Central

    Hiscock, Simon

    2010-01-01

    Parasitic angiosperms are an ecologically and economically important group of plants. However our understanding of the basis for host specificity in these plants is embryonic. Recently we investigated host specificity in the parasitic angiosperm Orobanche minor, and demonstrated that this host generalist parasite comprises genetically defined races that are physiologically adapted to specific hosts. Populations occurring naturally on red clover (Trifolium pratense) and sea carrot (Daucus carota subsp. gummifer) respectively, showed distinct patterns of host specificity at various developmental stages, and a higher fitness on their natural hosts, suggesting these races are locally adapted. Here we discuss the implications of our findings from a broader perspective. We suggest that differences in signal responsiveness and perception by the parasite, as well as qualitative differences in signal production by the host, may elicit host specificity in this parasitic plant. Together with our earlier demonstration that these O. minor races are genetically distinct based on molecular markers, our recent data provide a snapshot of speciation in action, driven by host specificity. Indeed, host specificity may be an underestimated catalyst for speciation in parasitic plants generally. We propose that identifying host specific races using physiological techniques will complement conventional molecular marker-based approaches to provide a framework for delineating evolutionary relationships among cryptic host-specific parasitic plants. PMID:20081361

  6. Specific developmental pathways underlie host specificity in the parasitic plant Orobanche.

    PubMed

    Thorogood, Chris; Hiscock, Simon

    2010-03-01

    Parasitic angiosperms are an ecologically and economically important group of plants. However our understanding of the basis for host specificity in these plants is embryonic. Recently we investigated host specificity in the parasitic angiosperm Orobanche minor, and demonstrated that this host generalist parasite comprises genetically defined races that are physiologically adapted to specific hosts. Populations occurring naturally on red clover (Trifolium pratense) and sea carrot (Daucus carota subsp. gummifer) respectively, showed distinct patterns of host specificity at various developmental stages, and a higher fitness on their natural hosts, suggesting these races are locally adapted. Here we discuss the implications of our findings from a broader perspective. We suggest that differences in signal responsiveness and perception by the parasite, as well as qualitative differences in signal production by the host, may elicit host specificity in this parasitic plant. Together with our earlier demonstration that these O. minor races are genetically distinct based on molecular markers, our recent data provide a snapshot of speciation in action, driven by host specificity. Indeed, host specificity may be an underestimated catalyst for speciation in parasitic plants generally. We propose that identifying host specific races using physiological techniques will complement conventional molecular marker-based approaches to provide a framework for delineating evolutionary relationships among cryptic host-specific parasitic plants. PMID:20081361

  7. Inbreeding alters resistance to insect herbivory and host plant quality in Mimulus guttatus (Scrophulariaceae).

    PubMed

    Carr, David E; Eubanks, Micky D

    2002-01-01

    Previous studies have demonstrated genetic variation for resistance to insect herbivores and host plant quality. The effect of plant mating system, an important determinant of the distribution of genetic variation, on host plant characteristics has received almost no attention. This study used a controlled greenhouse experiment to examine the effect of self- and cross-pollination in Mimulus guttatus (Scrophulariaceae) on resistance to and host plant quality for the xylem-feeding spittlebug Philaenus spumarius (Homoptera: Cercopidae). Spittlebugs were found to have a negative effect on two important fitness components in M. guttatus, flower production and above ground biomass. One of two M. guttatus populations examined showed a significant interaction between the pollination and herbivore treatments. In this case, the detrimental effects of herbivores on biomass and flower production were much more pronounced in inbred (self) plants. The presence of spittlebug nymphs increased inbreeding depression by as much as three times. Pollination treatments also had significant effects on important components of herbivore fitness, but these effects were in opposite directions in our two host plant populations. Spittlebug nymphs maturing on self plants emerged as significantly larger adults in one of our host plant populations, indicating that inbreeding increased host plant quality. In our second host plant population, spittlebug nymphs took significantly longer to develop to adulthood on self plants, indicating that inbreeding decreased host plant quality. Taken together these results suggest that the degree of inbreeding in host plant populations can have important and perhaps complex effects on the dynamics of plant-herbivore interactions and on mating-system evolution in the host. PMID:11913665

  8. Host plant range of Raoiella indica (Acari: Tenuipalpidae) in areas of invasion of the New World.

    PubMed

    Carrillo, Daniel; Amalin, Divina; Hosein, Farzan; Roda, Amy; Duncan, Rita E; Peña, Jorge E

    2012-08-01

    Raoiella indica has spread rapidly through the Neotropical region where the mite damages economically and ecologically important plants. Three studies were conducted to determine the host plant range of R. indica, using the presence of colonies containing all life stages as an indicator of reproductive suitability. Periodic surveys at the Fairchild Tropical Botanic Garden (Miami Dade County, FL, USA) and the Royal Botanical Gardens (Port of Spain, Trinidad and Tobago) identified 27 new reproductive host plants. The reproductive suitability of two dicotyledonous species and three native Florida palm species was examined. An updated list of reproductive host plants of R. indica is presented. All reported reproductive hosts (91 plant species) of R. indica are monocots from the orders Arecales (Arecaceae), Zingiberales (Heliconiaceae, Musaceae, Strelitziaceae, Zingiberaceae) and Pandanales (Pandanaceae). Most are palms of the family Arecaceae that originated in areas of the Eastern Hemisphere; about one fourth of the reported hosts are native to the New World and could be considered new host associations of R. indica. Six years after the initial detection in the Caribbean, R. indica has expanded its host plant range. Here we report 27 new reproductive host of R. indica that represent 30% of increase on previous host plant records. As this mite continues spreading in the Neotropical region a great diversity of plants is potentially affected. PMID:21915682

  9. Transcriptional Responses in the Hemiparasitic Plant Triphysaria versicolor to Host Plant Signals1[w

    PubMed Central

    Matvienko, Marta; Torres, Manuel J.; Yoder, John I.

    2001-01-01

    Parasitic plants in the Scrophulariaceae use chemicals released by host plant roots to signal developmental processes critical for heterotrophy. Haustoria, parasitic plant structures that attach to and invade host roots, develop on roots of the hemiparasitic plant Triphysaria versicolor within a few hours of exposure to either maize (Zea mays) root exudate or purified haustoria-inducing factors. We prepared a normalized, subtractive cDNA library enriched for transcripts differentially abundant in T. versicolor root tips treated with the allelopathic quinone 2,6-dimethoxybenzoquinone (DMBQ). Northern analyses estimated that about 10% of the cDNAs represent transcripts strongly up-regulated in roots exposed to DMBQ. Northern and reverse northern analyses demonstrated that most DMBQ-responsive messages were similarly up-regulated in T. versicolor roots exposed to maize root exudates. From the cDNA sequences we assembled a unigene set of 137 distinct transcripts and assigned functions by homology comparisons. Many of the proteins encoded by the transcripts are predicted to function in quinone detoxification, whereas others are more likely associated with haustorium development. The identification of genes transcriptionally regulated by haustorium-inducing factors provides a framework for dissecting genetic pathways recruited by parasitic plants during the transition to heterotrophic growth. PMID:11553755

  10. The Use of Arabidopsis to Study Interactions between Parasitic Angiosperms and Their Plant Hosts

    PubMed Central

    Goldwasser, Y.; Westwood, J. H.; Yoder, J. I.

    2002-01-01

    Parasitic plants invade host plants in order to rob them of water, minerals and nutrients. The consequences to the infected hosts can be debilitating and some of the world's most pernicious agricultural weeds are parasitic. Parasitic genera of the Scrophulariaceae and Orobanchaceae directly invade roots of neighboring plants via underground structures called haustoria. The mechanisms by which these parasites identify and associate with host plants present unsurpassed opportunities for studying chemical signaling in plant-plant interactions. Seeds of some parasites require specific host factors for efficient germination, thereby insuring the availability of an appropriate host root prior to germination. A second set of signal molecules is required to induce haustorium development and the beginning of heterotrophy. Later stages in parasitism also require the presence of host factors, although these have not yet been well characterized. Arabidopsis is being used as a model host plant to identify genetic loci associated with stimulating parasite germination, haustorium development, and parasite support. Arabidopsis is also being employed to explore how host plants respond to parasite attack. Current methodologies and recent findings in Arabidopsis – parasitic plant interactions will be discussed. PMID:22303205

  11. 27 CFR 19.672 - Types of plants.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... § 19.672 Types of plants. There are three types of alcohol fuel plants: Small plants, medium plants, and large plants. All alcohol fuel plants are classified according to the amount of spirits that they... apply for the type of permit that fits the applicant's needs based on the type of alcohol fuel plant...

  12. Deceptive chemical signals induced by a plant virus attract insect vectors to inferior hosts

    PubMed Central

    Mauck, Kerry E.; De Moraes, Consuelo M.; Mescher, Mark C.

    2010-01-01

    Previous studies have shown that vector-borne pathogens can alter the phenotypes of their hosts and vectors in ways that influence the frequency and nature of interactions between them, with significant implications for the transmission and spread of disease. For insect-borne pathogens, host odors are particularly likely targets for manipulation, because both plant- and animal-feeding insects use volatile compounds derived from their hosts as key foraging cues. Here, we document the effects of a widespread plant pathogen, Cucumber mosaic virus (CMV), on the quality and attractiveness of one of its host plants (Cucurbita pepo cv. Dixie) for two aphid vectors, Myzus persicae and Aphis gossypii. Our results indicate that CMV greatly reduces host-plant quality—aphids performed poorly on infected plants and rapidly emigrated from them—but increases the attractiveness of infected plants to aphids by inducing elevated emissions of a plant volatile blend otherwise similar to that emitted by healthy plants. Thus, CMV appears to attract vectors deceptively to infected plants from which they then disperse rapidly, a pattern highly conducive to the nonpersistent transmission mechanism employed by CMV and very different from the pattern previously reported for persistently transmitted viruses that require sustained aphid feeding for transmission. In addition to providing a documented example of a pathogen inducing a deceptive signal of host-plant quality to vectors, our results suggest that the transmission mechanism is a major factor shaping pathogen-induced changes in host-plant phenotypes. Furthermore, our findings yield a general hypothesis that, when vector-borne plant or animal pathogens reduce host quality for vectors, pathogen-induced changes in host phenotypes that enhance vector attraction frequently will involve the exaggeration of existing host-location cues. PMID:20133719

  13. Increased plant growth and copper uptake of host and non-host plants by metal-resistant and plant growth-promoting endophytic bacteria.

    PubMed

    Sun, Leni; Wang, Xiaohan; Li, Ya

    2016-05-01

    The effects of inoculation with two metal-resistant and plant growth-promoting endophytic bacteria (Burkholderia sp. GL12 and Bacillus megaterium JL35) were evaluated on the plant growth and Cu uptake in their host Elsholtzia splendens and non-host Brassica napus plants grown in natural Cu-contaminated soil. The two strains showed a high level of ACC deaminase activities. In pot experiments, inoculation with strain GL12 significantly increased root and above-ground tissue dry weights of both plants, consequently increasing the total Cu uptake of E. splendens and Brassica napus by 132% and 48.2% respectively. Inoculation with strain JL35 was found to significantly increase not only the biomass of B. napus, consequently increasing the total Cu uptake of B. napus by 31.3%, but Cu concentration of E. splendens for above-ground tissues by 318% and roots by 69.7%, consequently increasing the total Cu uptake of E. splendens by 223%. The two strains could colonize the rhizosphere soils and root interiors of both plants. Notably, strain JL35 could colonize the shoot tissues and significantly increase the translocation factors and bioaccumulation factors of E. splendens. These results suggested that Burkholderia sp. GL12 and B. megaterium JL35 were valuable bacterial resource which had the potential in improving the efficiency of Cu phytoextraction by E. splendens and B. napus in a natural Cu-contaminated soil. PMID:26587767

  14. The Effect of Different Host Plants on Development and Survival of Nysius natalensis (Hemiptera: Orsillidae).

    PubMed

    Du Plessis, Hannalene; Byrne, Marcus; Van Den Berg, Johnnie

    2015-02-01

    Nysius natalensis Evans (Hemiptera: Orsillidae) is a pest of sunflower in South Africa. Adults invade sunflower fields from their weedy hosts. The host plant suitability for development and survival and the effect of between-generation host switching were studied on different wild host plants and sunflower. Parameters used to assess host plant suitability were nymphal development, head widths, mean mass, and survival. Nymphs and adults were provided with crushed seed of five host plants, as well as a combination of seeds of the five species. Duration of the nymphal stage, development and mortality, and mean development time to adult were recorded. Between-generation host switching was studied by providing first-instar nymphs (F2) with seed of either the same plant species or transferred to different ones. Mean mass and mean head widths of adults (F2) were determined. The food source during the first and second generation, as well as the interaction thereof, has a significant effect on head widths of resultant males and females, as well as on female mass, but first-generation food did not have a significant effect on male mass. Feeding the F2 on sunflower proved to be beneficial to the false chinch bug, as it provided the heaviest males and females as well as females with the biggest head widths. Lack of constant availability of moisture had a detrimental effect on longevity. Host plant switching to sunflower likely happens as a result of senescence of wild host plants prior to winter. PMID:26308814

  15. Host plant record for the fruit flies, Anastrepha fumipennis and A. nascimentoi (Diptera, Tephritidae).

    PubMed

    Uramoto, Keiko; Martins, David S; Lima, Rita C A; Zucchi, Roberto A

    2008-01-01

    The first host plant record for Anastrepha fumipennis Lima (Diptera: Tephritidae) in Geissospermum laeve (Vell.) Baill (Apocynaceae) and for A. nascimentoi Zucchi found in Cathedra bahiensis Sleumer (Olacaceae) was determined in a host plant survey of fruit flies undertaken at the "Reserva Natural da Companhia Vale do Rio Doce". This reserve is located in an Atlantic Rain Forest remnant area, in Linhares county, state of Espírito Santo, Brazil. The phylogenetic relationships of Anastrepha species and their hosts are discussed. The occurrence of these fruit fly species in relation to the distribution range of their host plants is also discussed. PMID:20302458

  16. Host Plant Record for the Fruit Flies, Anastrepha fumipennis and A. nascimentoi (Diptera, Tephritidae)

    PubMed Central

    Uramoto, Keiko; Martins, David S.; Lima, Rita C. A.; Zucchi, Roberto A.

    2008-01-01

    The first host plant record for Anastrepha fumipennis Lima (Diptera: Tephritidae) in Geissospermum laeve (Vell.) Baill (Apocynaceae) and for A. nascimentoi Zucchi found in Cathedra bahiensis Sleumer (Olacaceae) was determined in a host plant survey of fruit flies undertaken at the “Reserva Natural da Companhia Vale do Rio Doce”. This reserve is located in an Atlantic Rain Forest remnant area, in Linhares county, state of Espírito Santo, Brazil. The phylogenetic relationships of Anastrepha species and their hosts are discussed. The occurrence of these fruit fly species in relation to the distribution range of their host plants is also discussed. PMID:20302458

  17. Multitrophic interactions of the silverleaf whitefly,host plants, competing herbivores, and phytopathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our laboratory confirmed that silverleaf whitefly (SLW; Bemisia argentifolii, Bellows & Perring) feeding alters host plant anatomy, physiology and chemistry. The SLW induces a number host plant defenses, including pathogenesis-related (PR) protein accumulation e.g., chitinases, B-1,3-glucanases, pe...

  18. Remote identification of potential boll weevil host plants: Airborne multispectral detection of regrowth cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Regrowth cotton plants can serve as potential hosts for boll weevils during and beyond the production season. Effective methods for timely areawide detection of these host plants are critically needed to expedite eradication in south Texas. We acquired airborne multispectral images of experimental...

  19. Associative learning of host-plant chemical stimuli in immature glassy-winged sharpshooter.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of this study are to determine whether nymphs can associatively learn to recognize olfactory stimuli produced by host plants, and to evaluate the relative importance of olfactory conditioning in host-plant recognition. To provide nymphs for testing, second to fourth instars were plac...

  20. Variation Within and Between Frankliniella Thrips Species in Host Plant Utilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Anthophilous flower thrips in the genus Frankliniella (Thysanoptera: Thripidae) exploit ephemeral plant resources and therefore must be capable of successfully locating appropriate hosts on a repeated basis, yet little is known of interspecific and intraspecific variation in responses to host plant ...

  1. Volatile fragrances associated with flowers mediate the host plant alternation of a polyphagous mirid bug

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) is an important insect pest of cotton, fruit trees and other crops in China, and exhibits a particularly broad host range. Adult A. lucorum greatly prefers host plants at the flowering stage, and their populations track flowering plants both spatiall...

  2. Endofungal bacterium controls its host by an hrp type III secretion system.

    PubMed

    Lackner, Gerald; Moebius, Nadine; Hertweck, Christian

    2011-02-01

    Burkholderia rhizoxinica and Rhizopus microsporus form a unique symbiosis in which intracellular bacteria produce the virulence factor of the phytopathogenic fungus. Notably, the host strictly requires endobacteria to sporulate. In this study, we show that the endofungal bacteria possess a type III secretion system (T3SS), which has a crucial role in the maintenance of the alliance. Mutants defective in type III secretion show reduced intracellular survival and fail to elicit sporulation of the host. Furthermore, genes coding for T3SS components are upregulated during cocultivation of the bacterial symbiont with their host. This is the first report on a T3SS involved in bacterial-fungal symbiosis. Phylogenetic analysis revealed that the T3SS represents a prototype of a clade of yet uncharacterized T3SSs within the hrp superfamily of T3SSs from plant pathogenic microorganisms. In a control experiment, we demonstrate that under laboratory conditions, rhizoxin production was not required for establishment of the symbiotic interaction. PMID:20720578

  3. Correlations between adult mimicry and larval host plants in ithomiine butterflies.

    PubMed Central

    Willmott, Keith R; Mallet, James

    2004-01-01

    The apparent paradox of multiple coexisting wing pattern mimicry 'rings' in tropical butterflies has been explained as a result of microhabitat partitioning in adults. However, very few studies have tested this hypothesis. In neotropical forests, ithomiine butterflies dominate and display the richest diversity of mimicry rings. We show that co-mimetic species occupy the same larval host-plant species significantly more often than expected in two out of five communities that we surveyed; in one of these, the effect remains significant after phylogenetic correction. This relationship is most probably a result of a third correlated variable, such as microhabitat. Host-plant microhabitat may constrain adult movement, or host-plant choice may depend on butterfly microhabitat preferences and mimicry associations. This link between mimicry and host plant could help explain some host-plant and mimicry shifts, which have been important in the radiation of this speciose tropical group. PMID:15503990

  4. Plant host associations of Penthaleus species and Halotydeus destructor (Acari: Penthaleidae) and implications for integrated pest management.

    PubMed

    Umina, Paul A; Hoffmann, Ary A

    2004-01-01

    Integrated pest management programs seek to minimise reliance on pesticides and provide effective long-term control of pests. Cultural control strategies, such as crop rotations, trap and border crops, and weed management, require a thorough understanding of pest host associations. This paper examines the effects of different plant hosts on the persistence and reproduction of blue oat mites, Penthaleus spp., and the redlegged earth mite, Halotydeus destructor (Tucker), which are major agricultural pests in southern Australia. Field and shade-house experiments were conducted testing several crop and plant types. All species survived and reproduced from one mite season to the next when confined to pasture. Canola and a common weed, 'bristly ox-tongue', were suitable hosts for H. destructor and Penthaleus falcatus (Qin and Halliday), whereas Penthaleus sp. x and Penthaleus major (Dugés) failed to persist on these plants. A mixture of wheat and oats sustained P. sp. x and H. destructor, but not P. falcatus or P. major. Lentils were generally a poor host plant for all mite species. These findings show that earth mite species differ in their ability to persist on different plant types, highlighting the importance of distinguishing mite species before implementing control strategies. Results are discussed with respect to cultural control options for the management of these winter pests. PMID:15285134

  5. Effects of herbicide-treated host plants on the development of Mamestra brassicae L. caterpillars.

    PubMed

    Hahn, Melanie; Geisthardt, Martin; Brühl, Carsten A

    2014-11-01

    Herbicides are widely used pesticides that affect plants by changing their chemistry. In doing so, herbicides might also influence the quality of plants as food for herbivores. To study the effects of herbicides on host plant quality, 3 plant species (Plantago lanceolata L., P. major L., and Ranunculus acris L.) were treated with sublethal rates of either a sulfonylurea (Atlantis WG, Bayer CropScience) or a glyphosate (Roundup LB Plus, Monsanto) herbicide, and the development of caterpillars of the cabbage moth Mamestra brassicae L. that fed on these plants was observed. Of the 6 tested plant-herbicide combinations, 1 combination (R. acris + sulfonylurea herbicide) resulted in significantly lower caterpillar weight, increased time to pupation, and increased overall development time compared with larvae that were fed unsprayed plants. These results might be caused by a lower nutritional value of these host plants or increased concentrations of secondary metabolites that are involved in plant defense. The results of the present and other studies suggest potential risks to herbivores that feed on host plants treated with sublethal rates of herbicides. However, as the effects of herbicides on host plant quality appear to be species-specific and as there are numerous plant-herbicide-herbivore relationships in agricultural landscapes, a general reduction in herbicide contamination of nontarget habitats (e.g., field margins) might mitigate the negative effects of herbicides on host plant quality. PMID:25143001

  6. A mutualistic endophyte alters the niche dimensions of its host plant.

    PubMed

    Kazenel, Melanie R; Debban, Catherine L; Ranelli, Luciana; Hendricks, Will Q; Chung, Y Anny; Pendergast, Thomas H; Charlton, Nikki D; Young, Carolyn A; Rudgers, Jennifer A

    2015-01-01

    Mutualisms can play important roles in influencing species coexistence and determining community composition. However, few studies have tested whether such interactions can affect species distributions by altering the niches of partner species. In subalpine meadows of the Rocky Mountains, USA, we explored whether the presence of a fungal endophyte (genus Epichloë) may shift the niche of its partner plant, marsh bluegrass (Poa leptocoma) relative to a closely related but endophyte-free grass species, nodding bluegrass (Poa reflexa). Using observations and a 3-year field experiment, we tested two questions: (i) Do P. leptocoma and P. reflexa occupy different ecological niches? and (ii) Does endophyte presence affect the relative fitness of P. leptocoma versus P. reflexa in the putative niches of these grass species? The two species were less likely to co-occur than expected by chance. Specifically, P. leptocoma grew closer to water sources and in wetter soils than P. reflexa, and also had higher root colonization by mycorrhizal fungi. Endophyte-symbiotic P. leptocoma seeds germinated with greater frequency in P. leptocoma niches relative to P. reflexa niches, whereas neither endophyte-free (experimentally removed) P. leptocoma seeds nor P. reflexa seeds showed differential germination between the two niche types. Thus, endophyte presence constrained the germination and early survival of host plants to microsites occupied by P. leptocoma. However, endophyte-symbiotic P. leptocoma ultimately showed greater growth than endophyte-free plants across all microsites, indicating a net benefit of the symbiosis at this life history stage. Differential effects of endophyte symbiosis on different host life history stages may thus contribute to niche partitioning between the two congeneric plant species. Our study therefore identifies a symbiotic relationship as a potential mechanism facilitating the coexistence of two species, suggesting that symbiont effects on host niche may

  7. A mutualistic endophyte alters the niche dimensions of its host plant

    PubMed Central

    Kazenel, Melanie R.; Debban, Catherine L.; Ranelli, Luciana; Hendricks, Will Q.; Chung, Y. Anny; Pendergast, Thomas H.; Charlton, Nikki D.; Young, Carolyn A.; Rudgers, Jennifer A.

    2015-01-01

    Mutualisms can play important roles in influencing species coexistence and determining community composition. However, few studies have tested whether such interactions can affect species distributions by altering the niches of partner species. In subalpine meadows of the Rocky Mountains, USA, we explored whether the presence of a fungal endophyte (genus Epichloë) may shift the niche of its partner plant, marsh bluegrass (Poa leptocoma) relative to a closely related but endophyte-free grass species, nodding bluegrass (Poa reflexa). Using observations and a 3-year field experiment, we tested two questions: (i) Do P. leptocoma and P. reflexa occupy different ecological niches? and (ii) Does endophyte presence affect the relative fitness of P. leptocoma versus P. reflexa in the putative niches of these grass species? The two species were less likely to co-occur than expected by chance. Specifically, P. leptocoma grew closer to water sources and in wetter soils than P. reflexa, and also had higher root colonization by mycorrhizal fungi. Endophyte-symbiotic P. leptocoma seeds germinated with greater frequency in P. leptocoma niches relative to P. reflexa niches, whereas neither endophyte-free (experimentally removed) P. leptocoma seeds nor P. reflexa seeds showed differential germination between the two niche types. Thus, endophyte presence constrained the germination and early survival of host plants to microsites occupied by P. leptocoma. However, endophyte-symbiotic P. leptocoma ultimately showed greater growth than endophyte-free plants across all microsites, indicating a net benefit of the symbiosis at this life history stage. Differential effects of endophyte symbiosis on different host life history stages may thus contribute to niche partitioning between the two congeneric plant species. Our study therefore identifies a symbiotic relationship as a potential mechanism facilitating the coexistence of two species, suggesting that symbiont effects on host niche may

  8. Feeding Experience of Bemisia tabaci (Hemiptera: Aleyrodidae) Affects Their Performance on Different Host Plants

    PubMed Central

    Shah, M. Mostafizur Rahman; Liu, Tong-Xian

    2013-01-01

    The sweetpotato whitefly, Bemisia tabaci biotype B is extremely polyphagous with >600 species of host plants. We hypothesized that previous experience of the whitefly on a given host plant affects their host selection and performance on the plants without previous experience. We investigated the host selection for feeding and oviposition of adults and development and survival of immatures of three host-plant-experienced populations of B. tabaci, namely Bemisia-eggplant, Bemisia-tomato and Bemisia-cucumber, on their experienced host plant and each of the three other plant species (eggplant, tomato, cucumber and pepper) without previous experience. We found that the influence of previous experience of the whiteflies varied among the populations. All populations refused pepper for feeding and oviposition, whereas the Bemisia-cucumber and the Bemisia-eggplant strongly preferred cucumber. Bemisia-tomato did not show strong preference to any of the three host palnts. Development time from egg to adult eclosion varied among the populations, being shortest on eggplant, longest on pepper, and intermediate on tomato and cucumber except for the Bemisia-cucumber developed similarly on tomato and pepper. The survivorship from egg to adult eclosion of all populations was highest on eggplant (80-98%), lowest on pepper (0-20%), and intermediate on tomato and cucumber. In conclusion, the effects of previous experience of whiteflies on host selection for feeding and oviposition, development, and survivorship varied depending on host plants, and host plants play a stronger role than previous experience. Preference of feeding and oviposition by adults may not accurately reflect host suitability of immatures. These results provided important information for understanding whitefly population dynamics and dispersal among different crop systems. PMID:24146985

  9. Special Plant Species Determines Diet Breadth of Phytophagous Insects: A Study on Host Plant Expansion of the Host-Specialized Aphis gossypii Glover

    PubMed Central

    Wu, Wei; Liang, Xin Li; Zhao, Hai Yang; Xu, Ting Ting; Liu, Xiang Dong

    2013-01-01

    Host specialization is a ubiquitous character of phytophagous insects. The polyphagous population is usually composed of some subpopulations that can use only a few closely related plants. Cotton-melon aphids, Aphis gossypii Glover exhibited strong host specialization, and the cotton- and cucurbits-specialized biotypes had been clearly identified. However, the experimental work that addressed the roles of plant species in determining diet breadth of phytophagous insects is rare. In the present study, we took the artificial host transfer method to assess the role of two special plants, zucchini Cucurbita zucchini L. and cowpea Vigna unguiculata (Linn.) Walp, in regulating diet breadth of cotton- and cucurbits-specialized A. gossypii collected from cotton and cucumber fields and reared separately on the native host plant for ten years. The results showed that the cotton-specialized aphids did not directly use cucumber whereas the cucurbits-specialized did not use cotton regardless of the coexistence or separation of cotton and cucumber plants. Neither of the cotton- and cucurbits-specialized aphids could use capsicum Capsicum annuum, eggplant Solanum melongenahttp://en.wikipedia.org/wiki/Carolus_Linnaeus, tomato Solanum lycopersicum, maize Zea mayshttp://en.wikipedia.org/wiki/Carl_Linnaeus, and radish Raphanus sativus, however, both of them could use zucchini and cowpea. Moreover, the feeding experience on zucchini led the cotton-specialized aphids to use cucumber well and finally to be transformed into the cucurbits-specialized biotype. The short-term feeding experience on cowpea resulted in the diet breadth expansion of the cucurbits-specialized aphids to use cotton. On the other hand, the diet breadth expansion of the cucurbits- and cotton-specialized aphids was only realized by different species of plant. It concluded that the special host plant did induce the conversion of feeding habits in the cotton- and cucurbits-specialized aphids, and consequently broke the

  10. Special plant species determines diet breadth of phytophagous insects: a study on host plant expansion of the host-specialized Aphis gossypii Glover.

    PubMed

    Wu, Wei; Liang, Xin Li; Zhao, Hai Yang; Xu, Ting Ting; Liu, Xiang Dong

    2013-01-01

    Host specialization is a ubiquitous character of phytophagous insects. The polyphagous population is usually composed of some subpopulations that can use only a few closely related plants. Cotton-melon aphids, Aphis gossypii Glover exhibited strong host specialization, and the cotton- and cucurbits-specialized biotypes had been clearly identified. However, the experimental work that addressed the roles of plant species in determining diet breadth of phytophagous insects is rare. In the present study, we took the artificial host transfer method to assess the role of two special plants, zucchini Cucurbita zucchini L. and cowpea Vigna unguiculata (Linn.) Walp, in regulating diet breadth of cotton- and cucurbits-specialized A. gossypii collected from cotton and cucumber fields and reared separately on the native host plant for ten years. The results showed that the cotton-specialized aphids did not directly use cucumber whereas the cucurbits-specialized did not use cotton regardless of the coexistence or separation of cotton and cucumber plants. Neither of the cotton- and cucurbits-specialized aphids could use capsicum Capsicum annuum, eggplant Solanum melongenahttp://en.wikipedia.org/wiki/Carolus_Linnaeus, tomato Solanum lycopersicum, maize Zea mayshttp://en.wikipedia.org/wiki/Carl_Linnaeus, and radish Raphanus sativus, however, both of them could use zucchini and cowpea. Moreover, the feeding experience on zucchini led the cotton-specialized aphids to use cucumber well and finally to be transformed into the cucurbits-specialized biotype. The short-term feeding experience on cowpea resulted in the diet breadth expansion of the cucurbits-specialized aphids to use cotton. On the other hand, the diet breadth expansion of the cucurbits- and cotton-specialized aphids was only realized by different species of plant. It concluded that the special host plant did induce the conversion of feeding habits in the cotton- and cucurbits-specialized aphids, and consequently broke the

  11. Disruption of Phthorimaea operculella (Lepidoptera: Gelechiidae) oviposition by the application of host plant volatiles

    PubMed Central

    Anfora, Gianfranco; Vitagliano, Silvia; Larsson, Mattias C; Witzgall, Peter; Tasin, Marco; Germinara, Giacinto S; De Cristofaro, Antonio

    2014-01-01

    BACKGROUND Phthorimaea operculella is a key pest of potato. The authors characterised the P. operculella olfactory system, selected the most bioactive host plant volatiles and evaluated their potential application in pest management. The electrophysiological responses of olfactory receptor neurons (ORNs) housed in long sensilla trichodea of P. operculella to plant volatiles and the two main sex pheromone components were evaluated by the single-cell recording (SCR) technique. The four most SCR-active volatiles were tested in a laboratory oviposition bioassay and under storage warehouse conditions. RESULTS The sensitivity of sensilla trichodea to short-chained aldehydes and alcohols and the existence of ORNs tuned to pheromones in females were characterised. Male recordings revealed at least two types of ORN, each of which typically responded to one of the two pheromone components. Hexanal, octanal, nonanal and 1-octen-3-ol significantly disrupted the egg-laying behaviour in a dose-dependent manner. Octanal reduced the P. operculella infestation rate when used under storage conditions. CONCLUSIONS This work provides new information on the perception of plant volatiles and sex pheromones by P. operculella. Laboratory and warehouse experiments show that the use of hexanal, octanal, nonanal and 1-octen-3-ol as host recognition disruptants and/or oviposition deterrents for P. operculella control appears to be a promising strategy. © 2013 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:23794160

  12. Modulating host homeostasis as a strategy in the plant-pathogen arms race.

    PubMed

    Gottig, Natalia; Garavaglia, Betiana S; Daurelio, Lucas D; Valentine, Alex; Gehring, Chris; Orellano, Elena G; Ottado, Jorgelina

    2009-01-01

    In plant-pathogen interactions, pathogens aim to overcome host defense responses while plants employ a battery of responses to limit pathogen growth and thus disease. In this "arms race" between hosts and pathogens, horizontal gene transfer is a potent source of 'pathogenic innovation' for viruses and bacteria. However, bacteria rarely acquire 'eukaryotic-like' genes from their hosts, and where they appear to, evidence for a role of the acquired genes remains outstanding. We have recently reported experimental evidence that the citrus canker causing pathogen Xanthomonas axonopodis pv. citri contains a plant natriuretic peptide-like gene (XacPNP) that encodes a protein that modulates host homeostasis to its advantage. We argue that Xanthomonas PNP has been acquired in an ancient horizontal gene transfer, and given that plant and bacterial PNPs trigger a number of similar physiological responses, we make a case of molecular mimicry. Released XacPNP mimics host PNP and results in a suppressed host response, "improved" host tissue health and consequently better pathogen survival in the lesions. Finally, we propose that Xanthomonas axonopodis pv. citri host interactions can serve as model system to study the role of host homeostasis in plant defense against biotrophic pathogens. PMID:19704897

  13. An overview of NMR-based metabolomics to identify secondary plant compounds involved in host plant resistance.

    PubMed

    Leiss, Kirsten A; Choi, Young H; Verpoorte, Robert; Klinkhamer, Peter G L

    2011-06-01

    Secondary metabolites provide a potential source for the generation of host plant resistance and development of biopesticides. This is especially important in view of the rapid and vast spread of agricultural and horticultural pests worldwide. Multiple pests control tactics in the framework of an integrated pest management (IPM) programme are necessary. One important strategy of IPM is the use of chemical host plant resistance. Up to now the study of chemical host plant resistance has, for technical reasons, been restricted to the identification of single compounds applying specific chemical analyses adapted to the compound in question. In biological processes however, usually more than one compound is involved. Metabolomics allows the simultaneous detection of a wide range of compounds, providing an immediate image of the metabolome of a plant. One of the most universally used metabolomic approaches comprises nuclear magnetic resonance spectroscopy (NMR). It has been NMR which has been applied as a proof of principle to show that metabolomics can constitute a major advancement in the study of host plant resistance. Here we give an overview on the application of NMR to identify candidate compounds for host plant resistance. We focus on host plant resistance to western flower thrips (Frankliniella occidentalis) which has been used as a model for different plant species. PMID:21765818

  14. Life history of Spodoptera exigua (Lepidoptera: Noctuidae) on various host plants.

    PubMed

    Azidah, A A; Sofian-Azirun, M

    2006-12-01

    The incubation period of Spodoptera exigua (Hübner) was not influenced by the host plant, whereas larval development time and pupal period were affected. Larval development time was longest on shallot and lady's finger, followed by cabbage and long bean. Larvae did not develop beyond the first instar when fed on chilli. The pupal period was longer on lady's finger than on cabbage, shallot and long bean. Overall, adult longevity was not influenced by the host plant but there was a difference between female and male longevity among the host plants. Survival of S. exigua was affected by the host plant at the larval stage. The number of larval instars varied between 5 and 8 within and between the studied host plants. Long bean was found to be the most suitable host plant and provide the best food quality for S. exigua compared to the other host plants, as it allowed faster development, fewer larval instars and a higher survival rate. PMID:17201979

  15. Adaptation of a polyphagous herbivore to a novel host plant extensively shapes the transcriptome of herbivore and host.

    PubMed

    Wybouw, Nicky; Zhurov, Vladimir; Martel, Catherine; Bruinsma, Kristie A; Hendrickx, Frederik; Grbić, Vojislava; Van Leeuwen, Thomas

    2015-09-01

    Generalist arthropod herbivores rapidly adapt to a broad range of host plants. However, the extent of transcriptional reprogramming in the herbivore and its hosts associated with adaptation remains poorly understood. Using the spider mite Tetranychus urticae and tomato as models with available genomic resources, we investigated the reciprocal genomewide transcriptional changes in both spider mite and tomato as a consequence of mite's adaptation to tomato. We transferred a genetically diverse mite population from bean to tomato where triplicated populations were allowed to propagate for 30 generations. Evolving populations greatly increased their reproductive performance on tomato relative to their progenitors when reared under identical conditions, indicative of genetic adaptation. Analysis of transcriptional changes associated with mite adaptation to tomato revealed two main components. First, adaptation resulted in a set of mite genes that were constitutively downregulated, independently of the host. These genes were mostly of an unknown function. Second, adapted mites mounted an altered transcriptional response that had greater amplitude of changes when re-exposed to tomato, relative to nonadapted mites. This gene set was enriched in genes encoding detoxifying enzymes and xenobiotic transporters. Besides the direct effects on mite gene expression, adaptation also indirectly affected the tomato transcriptional responses, which were attenuated upon feeding of adapted mites, relative to the induced responses by nonadapted mite feeding. Thus, constitutive downregulation and increased transcriptional plasticity of genes in a herbivore may play a central role in adaptation to host plants, leading to both a higher detoxification potential and reduced production of plant defence compounds. PMID:26211543

  16. Evolution of Plant P-Type ATPases

    PubMed Central

    Pedersen, Christian N. S.; Axelsen, Kristian B.; Harper, Jeffrey F.; Palmgren, Michael G.

    2012-01-01

    Five organisms having completely sequenced genomes and belonging to all major branches of green plants (Viridiplantae) were analyzed with respect to their content of P-type ATPases encoding genes. These were the chlorophytes Ostreococcus tauri and Chlamydomonas reinhardtii, and the streptophytes Physcomitrella patens (a non-vascular moss), Selaginella moellendorffii (a primitive vascular plant), and Arabidopsis thaliana (a model flowering plant). Each organism contained sequences for all five subfamilies of P-type ATPases. Whereas Na+ and H+ pumps seem to mutually exclude each other in flowering plants and animals, they co-exist in chlorophytes, which show representatives for two kinds of Na+ pumps (P2C and P2D ATPases) as well as a primitive H+-ATPase. Both Na+ and H+ pumps also co-exist in the moss P. patens, which has a P2D Na+-ATPase. In contrast to the primitive H+-ATPases in chlorophytes and P. patens, the H+-ATPases from vascular plants all have a large C-terminal regulatory domain as well as a conserved Arg in transmembrane segment 5 that is predicted to function as part of a backflow protection mechanism. Together these features are predicted to enable H+ pumps in vascular plants to create large electrochemical gradients that can be modulated in response to diverse physiological cues. The complete inventory of P-type ATPases in the major branches of Viridiplantae is an important starting point for elucidating the evolution in plants of these important pumps. PMID:22629273

  17. Effect on non-host plants on movements of Colorado potato beetle, Leptinotarsa decemlineata (Say)

    SciTech Connect

    Cort, R.P.

    1982-01-01

    Movements of Colorado potato beetles, Leptinotarsa decemlineata, (Say) (Coleoptera: Chrysomelidae) were studied in experimental plots of potatoes planted in monocultures and in polycultures with beans and/or marigolds. Rates of movement into and out of plots of varying plant composition were measured by mark-recapture of adult beetles. The amount of emigration was not affected by the presence of non-host plants. However, there were significantly more beetles moving into the pure stands of potatoes than into the plots containing non-host plants. This pattern is consistent with the idea that non-host plants act to mask host plants from potential herbivores, but do not affect the insect once it has located a host plant. It is thus unlikely that marigolds or beans repel Colorado potato beetles, since an increase in emigration would be expected if this were true. Beans are more effective than marigolds at deterring immigration, and both non-host plants together have an additive effect greater than one alone.

  18. Cellular and Molecular Interactions of Rhabdoviruses with their Insect and Plant Hosts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The rhabdoviruses form a large family (Rhabdoviridae) whose host ranges include humans, other vertebrates, invertebrates, and plants. There are about 75 plant-infecting rhabdoviruses described, several of which are economically important pathogens that are persistently transmitted to their plant ho...

  19. Disruption of Vector Host Preference with Plant Volatiles May Reduce Spread of Insect-Transmitted Plant Pathogens.

    PubMed

    Martini, Xavier; Willett, Denis S; Kuhns, Emily H; Stelinski, Lukasz L

    2016-05-01

    Plant pathogens can manipulate the odor of their host; the odor of an infected plant is often attractive to the plant pathogen vector. It has been suggested that this odor-mediated manipulation attracts vectors and may contribute to spread of disease; however, this requires further broad demonstration among vector-pathogen systems. In addition, disruption of this indirect chemical communication between the pathogen and the vector has not been attempted. We present a model that demonstrates how a phytophathogen (Candidatus Liberibacter asiaticus) can increase its spread by indirectly manipulating the behavior of its vector (Asian citrus psyllid, Diaphorina citri Kuwayama). The model indicates that when vectors are attracted to pathogen-infected hosts, the proportion of infected vectors increases, as well as, the proportion of infected hosts. Additionally, the peak of infected host populations occurs earlier as compared with controls. These changes in disease dynamics were more important during scenarios with higher vector mortality. Subsequently, we conducted a series of experiments to disrupt the behavior of the Asian citrus psyllid. To do so, we exposed the vector to methyl salicylate, the major compound released following host infection with the pathogen. We observed that during exposure or after pre-exposure to methyl salicylate, the host preference can be altered; indeed, the Asian citrus psyllids were unable to select infected hosts over uninfected counterparts. We suggest mechanisms to explain these interactions and potential applications of disrupting herbivore host preference with plant volatiles for sustainable management of insect vectors. PMID:27193763

  20. Genetic Variability of Stolbur Phytoplasma in Hyalesthes obsoletus (Hemiptera: Cixiidae) and its Main Host Plants in Vineyard Agroecosystems.

    PubMed

    Landi, Lucia; Riolo, Paola; Murolo, Sergio; Romanazzi, Gianfranco; Nardi, Sandro; Isidoro, Nunzio

    2015-08-01

    Bois noir is an economically important grapevine yellows that is induced by 'Candidatus Phytoplasma solani' and principally vectored by the planthopper Hyalesthes obsoletus Signoret (Hemiptera: Cixiidae). This study explores the 'Ca. P. solani' genetic variability associated to the nettle-H. obsoletus and bindweed-H. obsoletus systems in vineyard agroecosystems of the central-eastern Italy. Molecular characterization of 'Ca. P. solani' isolates was carried out using polymerase chain reaction/restriction fragment length polymorphism to investigate the nonribosomal vmp1 gene. Seven phytoplasma vmp-types were detected among the host plants- and insect-associated field-collected samples. The vmp1 gene showed the highest polymorphism in the bindweed-H. obsoletus system, according to restriction fragment length polymorphism analysis, which is in agreement with nucleotide sequence analysis. Five vmp-types were associated with H. obsoletus from bindweed, of which one was solely restricted to planthoppers, with one genotype also in planthoppers from nettle. Type V12 was the most prevalent in both planthoppers and bindweed. H. obsoletus from nettle harbored three vmp-types, of which V3 was predominant. V3 was the only type detected for nettle. Our data demonstrate that planthoppers might have acquired some 'Ca. P. solani' profiles from other plant hosts before landing on nettle or bindweed. Overall, the different vmp1 gene rearrangements observed in these two plant hosts-H. obsoletus systems might represent different adaptations of the pathogen to the two host plants. Molecular information about the complex of vmp-types provides useful data for better understanding of Bois noir epidemiology in vineyard agroecosystem. PMID:26470289

  1. Glycogen catabolism, but not its biosynthesis, affects virulence of Fusarium oxysporum on the plant host.

    PubMed

    Corral-Ramos, Cristina; Roncero, M Isabel G

    2015-04-01

    The role of glycogen metabolism was investigated in the fungal pathogen Fusarium oxysporum. Targeted inactivation was performed of genes responsible for glycogen biosynthesis: gnn1 encoding glycogenin, gls1 encoding glycogen synthase, and gbe1 encoding glycogen branching enzyme. Moreover genes involved in glycogen catabolism were deleted: gph1 encoding glycogen phosphorylase and gdb1 encoding glycogen de-branching enzyme. Glycogen reserves increased steadily during growth of the wild type strain in axenic cultures, to reach up to 1500μg glucose equivalents mg(-1) protein after 14 days. Glycogen accumulation was abolished in mutants lacking biosynthesis genes, whereas it increased by 20-40% or 80%, respectively, in the single and double mutants affected in catabolic genes. Transcript levels of glycogen metabolism genes during tomato plant infection peaked at four days post inoculation, similar to the results observed during axenic culture. Significant differences were observed between gdb mutants and the wild type strain for vegetative hyphal fusion ability. The single mutants defective in glycogen metabolism showed similar levels of virulence in the invertebrate animal model Galleria mellonella. Interestingly, the deletion of gdb1 reduced virulence on the plant host up to 40% compared to the wild type in single and in double mutant backgrounds, whereas the other mutants showed the virulence at the wild-type level. PMID:25865793

  2. Genomes of three facultatively symbiotic Frankia sp. strainsreflect host plant biogeography

    SciTech Connect

    Normand, Philippe; Lapierre, Pascal; Tisa, Louis S.; Gogarten, J.Peter; Alloisio, Nicole; Bagnarol, Emilie; Bassi, Carla A.; Berry,Alison; Bickhart, Derek M.; Choisne, Nathalie; Couloux, Arnaud; Cournoyer, Benoit; Cruveiller, Stephane; Daubin, Vincent; Demange, Nadia; Francino, M. Pilar; Ggoltsman, Eugene; Huang, Ying; Kopp, Olga; Labarre,Laurent; Lapidus, Alla; Lavire, Celine; Marechal, Joelle; Martinez,Michele; Mastronunzio, Juliana E.; Mullin, Beth; Niemann, James; Pujic,Pierre; Rawnsley, Tania; Rouy, Zoe; Schenowitz, Chantal; Sellstedt,Anita; Tavares, Fernando; Tomkins, Jeffrey P.; Vallenet, David; Valverde,Claudio; Wall, Luis; Wang, Ying; Medigue, Claudine; Benson, David R.

    2006-02-01

    Filamentous actinobacteria from the genus Frankia anddiverse woody trees and shrubs together form N2-fixing actinorhizal rootnodule symbioses that are a major source of new soil nitrogen in widelydiverse biomes 1. Three major clades of Frankia sp. strains are defined;each clade is associated with a defined subset of plants from among theeight actinorhizal plant families 2,3. The evolution arytrajectoriesfollowed by the ancestors of both symbionts leading to current patternsof symbiont compatibility are unknown. Here we show that the competingprocesses of genome expansion and contraction have operated in differentgroups of Frankia strains in a manner that can be related to thespeciation of the plant hosts and their geographic distribution. Wesequenced and compared the genomes from three Frankia sp. strains havingdifferent host plant specificities. The sizes of their genomes variedfrom 5.38 Mbp for a narrow host range strain (HFPCcI3) to 7.50Mbp for amedium host range strain (ACN14a) to 9.08 Mbp for a broad host rangestrain (EAN1pec.) This size divergence is the largest yet reported forsuch closely related bacteria. Since the order of divergence of thestrains is known, the extent of gene deletion, duplication andacquisition could be estimated and was found to be inconcert with thebiogeographic history of the symbioses. Host plant isolation favoredgenome contraction, whereas host plant diversification favored genomeexpansion. The results support the idea that major genome reductions aswell as expansions can occur in facultatively symbiotic soil bacteria asthey respond to new environments in the context of theirsymbioses.

  3. 27 CFR 19.672 - Types of plants.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... OF THE TREASURY ALCOHOL DISTILLED SPIRITS PLANTS Distilled Spirits for Fuel Use Obtaining A Permit § 19.672 Types of plants. There are three types of alcohol fuel plants: Small plants, medium plants, and large plants. All alcohol fuel plants are classified according to the amount of spirits that...

  4. Performance of Host-Races of the Fruit Fly, Tephritis conura on a Derived Host Plant, the Cabbage Thistle Cirsium oleraceum: Implications for the Original Host Shift

    PubMed Central

    Diegisser, Thorsten; Johannesen, Jes; Seitz, Alfred

    2008-01-01

    The thistle-infesting fruit fly Tephritis conura Loew (Diptera: Tephritidae) forms host races on the melancholy thistle, Cirsium hetewphyllum (L.) Hill (Asterales: Asteraceae) and the cabbage thistle, Cirsium olemceum (L.). Scop. Previous research indicates that the host shift occurred from C. hetewphyllum to C. oleraceum. In this paper we address whether the host shift involved physiological adaptations by studying oviposition acceptance and survival of the two host races on the derived host C. oleraceum. Performance differed significantly between host races. T. conura originating from C. oleraceum produced adults in 75% of all egg-laying trials in contrast to only 6.6% in T. conura originating from C. hetewphyllum. Population fitness components measured as a function of life-stage was linear decreasing for T. conura on C. oleraceum but stepwise for T. conura on C. heterophyllum. Low performance of T. conura on C. hetewphyllum was determined by low plant acceptance and high mortality during the larval stage, whereas hatching (at least one larva per batch) and pupae survival were not affected. PMID:20302521

  5. Olfactory cues from different plant species in host selection by female pea moths.

    PubMed

    Thöming, Gunda; Norli, Hans Ragnar

    2015-03-01

    In herbivorous insects specialized on few plant species, attraction to host odor may be mediated by volatiles common to all host species, by specific compounds, or combinations of both. The pea moth Cydia nigricana is an important pest of the pea. Volatile signatures of four host plant species were studied to identify compounds involved in pea moth host selection and to improve previously reported attractive volatile blends. P. sativum and alternative Fabaceae host species were compared regarding female attraction, oviposition, and larval performance. Pea moth females were strongly attracted to the sweet pea Lathyrus odoratus, but larval performance on that species was moderate. Chemical analyses of sweet pea odor and electrophysiological responses of moth antennae led to identification of seven sweet-pea-specific compounds and ten compounds common to all tested host species. Blends of these specific and common cues were highly attractive to mated pea moth females in wind tunnel and field experiments. PMID:25675276

  6. Host Plant Determines the Population Size of an Obligate Symbiont (Buchnera aphidicola) in Aphids.

    PubMed

    Zhang, Yuan-Chen; Cao, Wen-Jie; Zhong, Le-Rong; Godfray, H Charles J; Liu, Xiang-Dong

    2016-04-01

    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 populations maintained on cotton for a similar length of time. Aphids collected in the wild from hibiscus and zucchini harbored more Buchnera symbionts than those collected from cucumber and cotton. The effect of aphid genotype on the population size of Buchnera depended on the host plant upon which they fed. When aphids from populations maintained on cucumber or cotton were transferred to novel host plants, host survival and Buchnera population size fluctuated markedly for the first two generations before becoming relatively stable in the third and later generations. Host plant extracts from cucumber, pumpkin, zucchini, and cowpea added to artificial diets led to a significant increase in Buchnera titers in the aphids from the population reared on cotton, while plant extracts from cotton and zucchini led to a decrease in Buchnera titers in the aphids reared on cucumber. Gossypol, a secondary metabolite from cotton, suppressed Buchnera populations in populations from both cotton and cucumber, while cucurbitacin from cucurbit plants led to higher densities. Together, the results suggest that host plants influence Buchnera population processes and that this may provide phenotypic plasticity in host plant use for clonal aphids. PMID:26850304

  7. Green Team Hosts Plant Swap to Encourage Gardening | Poster

    Cancer.gov

    By Carolynne Keenan, Contributing Writer What started out as a way for Howard Young, Ph.D., to thin out his garden last fall turned into the NCI at Frederick Green Team’s Plant Swap. The group held its Fall Plant Swap on October 24, encouraging all members of the Fort Detrick community to pick up a free plant or swap a plant of theirs for another. “Those who love to garden introduce others to the joy of gardening,” said Dolores Winterstein, a member of the Green Team and the coordinator of the Fall Plant Swap.

  8. Resource dependence in a new ecosystem: A host plant and its colonizing community

    NASA Astrophysics Data System (ADS)

    Lakatos, K. Tímea; László, Zoltán; Tóthmérész, Béla

    2016-05-01

    The introduced black locust (Robinia pseudoacacia) has become an invasive plant species in Europe. The introduction of alien plants such as the black locust may modify ecosystem composition and functioning. In response to the presence of a potential host plant, herbivores can adapt and shift to the consumption of the new host plant. In Eastern-Central Europe, the seed predator Bruchophagus robiniae (Hymenoptera: Eurytomidae) is an important consumer of black locust seeds which presumably shifted from its formerly host species to black locust. We tested the influence of host plant abundance on a seed predator - parasitoid community. We found that the seed predator B. robiniae was present in higher numbers in woodlots than in small patches of black locust. The density of the specialist parasitoid Mesopolobus sp. was lower in woodlots than in small patches, while the generalist parasitoid Eupelmus urozonos was evenly distributed between woodlots and small patches of black locust. We found that parasitoid species are influenced by the patch size of host plants, thus characteristics of introduced host plants can also manifest in higher trophic levels.

  9. Volatile fragrances associated with flowers mediate host plant alternation of a polyphagous mirid bug

    PubMed Central

    Pan, Hongsheng; Lu, Yanhui; Xiu, Chunli; Geng, Huihui; Cai, Xiaoming; Sun, Xiaoling; Zhang, Yongjun; Williams III, Livy; Wyckhuys, Kris A. G.; Wu, Kongming

    2015-01-01

    Apolygus lucorum (Hemiptera: Miridae) is an important insect pest of cotton and fruit trees in China. The adults prefer host plants at the flowering stage, and their populations track flowering plants both spatially and temporally. In this study, we examine whether flower preference of its adults is mediated by plant volatiles, and which volatile compositions play an important role in attracting them. In olfactometer tests with 18 key host species, the adults preferred flowering plants over non-flowering plants of each species. Coupled gas chromatography-electroantennography revealed the presence of seven electrophysiologically active compounds from flowering plants. Although the adults responded to all seven synthetic plant volatiles in electroantennography tests, only four (m-xylene, butyl acrylate, butyl propionate and butyl butyrate) elicited positive behavioral responses in Y-tube olfactometer bioassays. The adults were strongly attracted to these four active volatiles in multi-year laboratory and field trials. Our results suggest that these four fragrant volatiles, which are emitted in greater amounts once plants begin to flower, mediate A. lucorum’s preference to flowering host plants. We proved that the use of commonly occurring plant volatiles to recognize a large range of plant species can facilitate host selection and preference of polyphagous insect herbivore. PMID:26423224

  10. Volatile fragrances associated with flowers mediate host plant alternation of a polyphagous mirid bug.

    PubMed

    Pan, Hongsheng; Lu, Yanhui; Xiu, Chunli; Geng, Huihui; Cai, Xiaoming; Sun, Xiaoling; Zhang, Yongjun; Williams Iii, Livy; Wyckhuys, Kris A G; Wu, Kongming

    2015-01-01

    Apolygus lucorum (Hemiptera: Miridae) is an important insect pest of cotton and fruit trees in China. The adults prefer host plants at the flowering stage, and their populations track flowering plants both spatially and temporally. In this study, we examine whether flower preference of its adults is mediated by plant volatiles, and which volatile compositions play an important role in attracting them. In olfactometer tests with 18 key host species, the adults preferred flowering plants over non-flowering plants of each species. Coupled gas chromatography-electroantennography revealed the presence of seven electrophysiologically active compounds from flowering plants. Although the adults responded to all seven synthetic plant volatiles in electroantennography tests, only four (m-xylene, butyl acrylate, butyl propionate and butyl butyrate) elicited positive behavioral responses in Y-tube olfactometer bioassays. The adults were strongly attracted to these four active volatiles in multi-year laboratory and field trials. Our results suggest that these four fragrant volatiles, which are emitted in greater amounts once plants begin to flower, mediate A. lucorum's preference to flowering host plants. We proved that the use of commonly occurring plant volatiles to recognize a large range of plant species can facilitate host selection and preference of polyphagous insect herbivore. PMID:26423224

  11. Host-mediated volatile polymorphism in a parasitic plant influences its attractiveness to pollinators.

    PubMed

    Troncoso, Alejandra J; Cabezas, Nancy J; Faúndez, Eric H; Urzúa, Alejandro; Niemeyer, Hermann M

    2010-02-01

    Host-plants can mediate the interactions between herbivores and their mutualists and also between parasitic plants and their mutualists. The present study reveals how a hemiparasitic plant parasitizing three host species gives rise to three distinct hemiparasite-host neighborhoods which differ in terms of volatile composition and pollinator attractiveness. The study was performed in a population of the mistletoe Tristerix verticillatus infecting three different species of hosts occurring in sympatry within a small area, thus exposing all individuals studied to similar abiotic conditions and pollinator diversity; we assessed the effect of hosts on the hemiparasites' visual and olfactory cues for pollinator attraction. During the study period, the hemiparasite individuals were flowering but the hosts were past their flowering stage. We collected volatile organic compounds from the hemiparasite and its hosts, measured floral display characteristics and monitored bird and insect visitors to inflorescences of T. verticillatus. We showed that: (1) floral patches did not differ in terms of floral display potentially involved in the attraction of pollinators, (2) hosts and hemiparasites on each host were discriminated as distinct chemical populations in terms of their volatile chemical profiles, (3) insect visitation rates differed between hemiparasites parasitizing different hosts, and (4) volatile compounds from the host and the hemiparasite influenced the visitation of hemiparasite flowers by insects. The study showed that a species regarded as "ornithophilic" by its floral morphology was actually mostly visited by insects that interacted with its sexual organs during their visits and carried its pollen, and that host-specific plant-volatile profiles within the T. verticillatus population were associated with differential attractiveness to pollinating insects. PMID:19890665

  12. New host plant and distribution records for Peruvian Tephritinae (Diptera: Tephritidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Distribution and host plant records (all Asteraceae) are reported for 17 species of Tephritinae: Acinia reticulata (stem galls on Tessaria integrifolia); Dracontomyia footei (Baccharis salicifolia); Ensina hyalipennis (Argentina; flowerheads of Sonchus asper); E. longiceps (flowerheads of Hypochaeri...

  13. A Fungal Endosymbiont Affects Host Plant Recruitment Through Seed- and Litter-mediated Mechanisms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    1. Many grass species are associated with maternally transmitted fungal endophytes. Increasing evidence shows that endophytes enhance host plant success under varied conditions, yet studies have rarely considered alternative mechanisms whereby these mutualistic symbionts may affect regeneration from...

  14. The Effect of Host-Plant Phylogenetic Isolation on Species Richness, Composition and Specialization of Insect Herbivores: A Comparison between Native and Exotic Hosts

    PubMed Central

    Grandez-Rios, Julio Miguel; Lima Bergamini, Leonardo; Santos de Araújo, Walter; Villalobos, Fabricio; Almeida-Neto, Mário

    2015-01-01

    Understanding the drivers of plant-insect interactions is still a key issue in terrestrial ecology. Here, we used 30 well-defined plant-herbivore assemblages to assess the effects of host plant phylogenetic isolation and origin (native vs. exotic) on the species richness, composition and specialization of the insect herbivore fauna on co-occurring plant species. We also tested for differences in such effects between assemblages composed exclusively of exophagous and endophagous herbivores. We found a consistent negative effect of the phylogenetic isolation of host plants on the richness, similarity and specialization of their insect herbivore faunas. Notably, except for Jaccard dissimilarity, the effect of phylogenetic isolation on the insect herbivore faunas did not vary between native and exotic plants. Our findings show that the phylogenetic isolation of host plants is a key factor that influences the richness, composition and specialization of their local herbivore faunas, regardless of the host plant origin. PMID:26379159

  15. The impact of microbial symbionts on host plant utilization by herbivorous insects.

    PubMed

    Hansen, Allison K; Moran, Nancy A

    2014-03-01

    Herbivory, defined as feeding on live plant tissues, is characteristic of highly successful and diverse groups of insects and represents an evolutionarily derived mode of feeding. Plants present various nutritional and defensive barriers against herbivory; nevertheless, insects have evolved a diverse array of mechanisms that enable them to feed and develop on live plant tissues. For decades, it has been suggested that insect-associated microbes may facilitate host plant use, and new molecular methodologies offer the possibility to elucidate such roles. Based on genomic data, specialized feeding on phloem and xylem sap is highly dependent on nutrient provisioning by intracellular symbionts, as exemplified by Buchnera in aphids, although it is unclear whether such symbionts play a substantive role in host plant specificity of their hosts. Microorganisms present in the gut or outside the insect body could provide more functions including digestion of plant polymers and detoxification of plant-produced toxins. However, the extent of such contributions to insect herbivory remains unclear. We propose that the potential functions of microbial symbionts in facilitating or restricting the use of host plants are constrained by their location (intracellular, gut or environmental), and by the fidelity of their associations with insect host lineages. Studies in the next decade, using molecular methods from environmental microbiology and genomics, will provide a more comprehensive picture of the role of microbial symbionts in insect herbivory. PMID:23952067

  16. Effects of a native parasitic plant on an exotic invader decrease with increasing host age

    PubMed Central

    Li, Junmin; Yang, Beifen; Yan, Qiaodi; Zhang, Jing; Yan, Min; Li, Maihe

    2015-01-01

    Understanding changes in the interactions between parasitic plants and their hosts in relation to ontogenetic changes in the hosts is crucial for successful use of parasitic plants as biological controls. We investigated growth, photosynthesis and chemical defences in different-aged Bidens pilosa plants in response to infection by Cuscuta australis. We were particularly interested in whether plant responses to parasite infection change with changes in the host plant age. Compared with the non-infected B. pilosa, parasite infection reduced total host biomass and net photosynthetic rates, but these deleterious effects decreased with increasing host age. Parasite infection reduced the concentrations of total phenolics, total flavonoids and saponins in the younger B. pilosa but not in the older B. pilosa. Compared with the relatively older and larger plants, younger and smaller plants suffered from more severe damage and are likely less to recover from the infection, suggesting that C. australis is only a viable biocontrol agent for younger B. pilosa plants. PMID:25838325

  17. Effects of a native parasitic plant on an exotic invader decrease with increasing host age.

    PubMed

    Li, Junmin; Yang, Beifen; Yan, Qiaodi; Zhang, Jing; Yan, Min; Li, Maihe

    2015-01-01

    Understanding changes in the interactions between parasitic plants and their hosts in relation to ontogenetic changes in the hosts is crucial for successful use of parasitic plants as biological controls. We investigated growth, photosynthesis and chemical defences in different-aged Bidens pilosa plants in response to infection by Cuscuta australis. We were particularly interested in whether plant responses to parasite infection change with changes in the host plant age. Compared with the non-infected B. pilosa, parasite infection reduced total host biomass and net photosynthetic rates, but these deleterious effects decreased with increasing host age. Parasite infection reduced the concentrations of total phenolics, total flavonoids and saponins in the younger B. pilosa but not in the older B. pilosa. Compared with the relatively older and larger plants, younger and smaller plants suffered from more severe damage and are likely less to recover from the infection, suggesting that C. australis is only a viable biocontrol agent for younger B. pilosa plants. PMID:25838325

  18. Function of Succinoglycan Polysaccharide in Sinorhizobium meliloti Host Plant Invasion Depends on Succinylation, Not Molecular Weight

    PubMed Central

    Mendis, Hajeewaka C.; Madzima, Thelma F.; Queiroux, Clothilde

    2016-01-01

    ABSTRACT The acidic polysaccharide succinoglycan produced by the rhizobial symbiont Sinorhizobium meliloti 1021 is required for this bacterium to invade the host plant Medicago truncatula and establish a nitrogen-fixing symbiosis. S. meliloti mutants that cannot make succinoglycan cannot initiate invasion structures called infection threads in plant root hairs. S. meliloti exoH mutants that cannot succinylate succinoglycan are also unable to form infection threads, despite the fact that they make large quantities of succinoglycan. Succinoglycan produced by exoH mutants is refractory to cleavage by the glycanases encoded by exoK and exsH, and thus succinoglycan produced by exoH mutants is made only in the high-molecular-weight (HMW) form. One interpretation of the symbiotic defect of exoH mutants is that the low-molecular-weight (LMW) form of succinoglycan is required for infection thread formation. However, our data demonstrate that production of the HMW form of succinoglycan by S. meliloti 1021 is sufficient for invasion of the host M. truncatula and that the LMW form is not required. Here, we show that S. meliloti strains deficient in the exoK- and exsH-encoded glycanases invade M. truncatula and form a productive symbiosis, although they do this with somewhat less efficiency than the wild type. We have also characterized the polysaccharides produced by these double glycanase mutants and determined that they consist of only HMW succinoglycan and no detectable LMW succinoglycan. This demonstrates that LMW succinoglycan is not required for host invasion. These results suggest succinoglycan function is not dependent upon the presence of a small, readily diffusible form. PMID:27329751

  19. Asymmetric impacts of two herbivore ecotypes on similar host plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ecotypes may arise following allopatric separation from source populations. The simultaneous transfer of an exotic plant to a novel environment, along with its stenophagous herbivore, may complicate more traditional patterns of divergence from the plant and insect source populations. We evaluated ...

  20. Identification of Aphis gossypii Glover (Hemiptera: Aphididae) Biotypes from Different Host Plants in North China

    PubMed Central

    Wang, Li; Zhang, Shuai; Luo, Jun-Yu; Wang, Chun-Yi; Lv, Li-Min; Zhu, Xiang-Zhen; Li, Chun-Hua; Cui, Jin-Jie

    2016-01-01

    Background The cotton-melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae), is a polyphagous species with a worldwide distribution and a variety of biotypes. North China is a traditional agricultural area with abundant winter and summer hosts of A. gossypii. While the life cycles of A. gossypii on different plants have been well studied, those of the biotypes of North China are still unclear. Results Host transfer experiments showed that A. gossypii from North China has two host-specialized biotypes: cotton and cucumber. Based on complete mitochondrial sequences, we identified a molecular marker with five single-nucleotide polymorphisms to distinguish the biotypes. Using this marker, a large-scale study of biotypes on primary winter and summer hosts was conducted. All A. gossypii collected from three primary hosts—hibiscus, pomegranate, and Chinese prickly ash—were cotton biotypes, with more cotton-melon aphids found on hibiscus than the other two species. In May, alate cotton and cucumber biotypes coexisted on cotton and cucumber seedlings, but each preferred its natal host. Both biotypes existed on zucchini, although the cucumber biotype was more numerous. Aphids on muskmelon were all cucumber biotypes, whereas most aphids on kidney bean were cotton biotypes. Aphids on seedlings of potato and cowpea belong to other species. In August, aphids on cotton and cucumber were the respective biotypes, with zucchini still hosting both biotypes as before. Thus, the biotypes had different fitnesses on different host plants. Conclusions Two host-specialized biotypes (cotton and cucumber) are present in North China. Hibiscus, pomegranate, and Chinese prickly ash can serve as winter hosts for the cotton biotype but not the cucumber biotype in North China. The fitnesses of the two host-specialized biotypes differ on various summer hosts. When alate aphids migrate to summer hosts, they cannot accurately land on the corresponding plant. PMID:26735973

  1. Influence of Host-Plant Surface Chemicals on the Oviposition of the Cereal Stemborer Busseola Fusca.

    PubMed

    Juma, Gerald; Clément, Gilles; Ahuya, Peter; Hassanali, Ahmed; Derridj, Sylvie; Gaertner, Cyrile; Linard, Romain; Le Ru, Bruno; Frérot, Brigitte; Calatayud, Paul-André

    2016-05-01

    The chemical composition of plant surfaces plays a role in selection of host plants by herbivorous insects. Once the insect reaches the plant, these cues determine host acceptance. Laboratory studies have shown that the stem borer Busseola fusca (Lepidoptera: Noctuidae), an important pest of sorghum and maize in sub-Saharan Africa, is able to differentiate between host and non-host plant species. However, no information is available on the cues used by this insect to seek and accept the host plant. Thus, the role of surface phytochemical stimuli on host selection and oviposition by B. fusca was studied in the laboratory using two host plants, sorghum, Sorghum bicolor, and maize, Zea mays, and one non-host plant, Napier grass, Pennisetum purpureum. The numbers of eggs and egg masses deposited on the three plant species were compared first under no-choice and choice conditions. In both cases, more eggs and egg masses were laid on maize and sorghum than on the non-host. Artificial surrogate stems treated with a water or chloroform surface extract of each plant were then compared with surrogate stems treated with, respectively, water or chloroform as controls, under similar conditions. Surrogate stems treated with plant water extracts did not show an increase in oviposition when compared to controls, indicating that the major compounds in these extracts, i.e., simple sugars and free amino acids, are not significantly responsible for the oviposition preference. By contrast, a chloroform extract of sorghum enhanced oviposition on the surrogate stems compared to the control, while those of maize and Napier grass showed no significant effects. Analysis of the chloroform extract of sorghum showed higher amounts of α-amyrin, ß-amyrin, and n-nonacosane compared to those of maize and Napier grass. A blend of the three chemicals significantly increased oviposition compared to the chloroform-treated control, indicating that these compounds are part of the surface chemical

  2. Non-Host Plant Volatiles Disrupt Sex Pheromone Communication in a Specialist Herbivore.

    PubMed

    Wang, Fumin; Deng, Jianyu; Schal, Coby; Lou, Yonggen; Zhou, Guoxin; Ye, Bingbing; Yin, Xiaohui; Xu, Zhihong; Shen, Lize

    2016-01-01

    The ecological effects of plant volatiles on herbivores are manifold. Little is known, however, about the impacts of non-host plant volatiles on intersexual pheromonal communication in specialist herbivores. We tested the effects of several prominent constitutive terpenoids released by conifers and Eucalyptus trees on electrophysiological and behavioral responses of an oligophagous species, Plutella xylostella, which feeds on Brassicaceae. The non-host plant volatile terpenoids adversely affected the calling behavior (pheromone emission) of adult females, and the orientation responses of adult males to sex pheromone were also significantly inhibited by these terpenoids in a wind tunnel and in the field. We suggest that disruption of both pheromone emission and orientation to sex pheromone may explain, at least in part, an observed reduction in herbivore attack in polyculture compared with monoculture plantings. We also propose that mating disruption of both male and female moths with non-host plant volatiles may be a promising alternative pest management strategy. PMID:27585907

  3. Non-Host Plant Volatiles Disrupt Sex Pheromone Communication in a Specialist Herbivore

    PubMed Central

    Wang, Fumin; Deng, Jianyu; Schal, Coby; Lou, Yonggen; Zhou, Guoxin; Ye, Bingbing; Yin, Xiaohui; Xu, Zhihong; Shen, Lize

    2016-01-01

    The ecological effects of plant volatiles on herbivores are manifold. Little is known, however, about the impacts of non-host plant volatiles on intersexual pheromonal communication in specialist herbivores. We tested the effects of several prominent constitutive terpenoids released by conifers and Eucalyptus trees on electrophysiological and behavioral responses of an oligophagous species, Plutella xylostella, which feeds on Brassicaceae. The non-host plant volatile terpenoids adversely affected the calling behavior (pheromone emission) of adult females, and the orientation responses of adult males to sex pheromone were also significantly inhibited by these terpenoids in a wind tunnel and in the field. We suggest that disruption of both pheromone emission and orientation to sex pheromone may explain, at least in part, an observed reduction in herbivore attack in polyculture compared with monoculture plantings. We also propose that mating disruption of both male and female moths with non-host plant volatiles may be a promising alternative pest management strategy. PMID:27585907

  4. CLAVATA 1-type receptors in plant development.

    PubMed

    Hazak, Ora; Hardtke, Christian S

    2016-08-01

    A fundamental aspect of plant development is the coordination of growth through endogenous signals and its integration with environmental inputs. Similar to animals, plants frequently use cell surface-localized receptors to monitor such stimuli, for instance through plasma membrane-integral receptor-like kinases (RLKs). Compared to other organisms, plants possess a large number of RLKs (more than 600 in Arabidopsis thaliana), which implies that ligand-receptor-mediated molecular mechanisms regulate a wide range of processes during plant development. Here, we focus on A. thaliana RLKs of the CLAVATA 1 (CLV1) type, which orchestrate key steps during plant development, including the regulation of meristem maintenance, anther development, vascular tissue formation, and root system architecture. These receptors are regulated by small signalling peptides that belong to the family of CLE (CLV3 / EMBRYO SURROUNDING REGION) ligands. We discuss different aspects of plant development that are regulated by these receptors in light of their molecular mechanism of action. As so often, the intensive research on this group of plant RLKs has raised many intriguing questions, which remain to be answered. PMID:27340234

  5. 27 CFR 19.672 - Types of plants.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Types of plants. 19.672... OF THE TREASURY LIQUORS DISTILLED SPIRITS PLANTS Distilled Spirits for Fuel Use Obtaining A Permit § 19.672 Types of plants. There are three types of alcohol fuel plants: Small plants, medium...

  6. 27 CFR 19.672 - Types of plants.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Types of plants. 19.672... OF THE TREASURY ALCOHOL DISTILLED SPIRITS PLANTS Distilled Spirits for Fuel Use Obtaining A Permit § 19.672 Types of plants. There are three types of alcohol fuel plants: Small plants, medium...

  7. A Bacterial Parasite Effector Mediates Insect Vector Attraction in Host Plants Independently of Developmental Changes.

    PubMed

    Orlovskis, Zigmunds; Hogenhout, Saskia A

    2016-01-01

    Parasites can take over their hosts and trigger dramatic changes in host appearance and behavior that are typically interpreted as extended phenotypes that promote parasite survival and fitness. For example, Toxoplasma gondii is thought to manipulate the behaviors of infected rodents to aid transmission to cats and parasitic trematodes of the genus Ribeiroia alter limb development in their amphibian hosts to facilitate predation of the latter by birds. Plant parasites and pathogens also reprogram host development and morphology. However, whereas some parasite-induced morphological alterations may have a direct benefit to the fitness of the parasite and may therefore be adaptive, other host alterations may be side effects of parasite infections having no adaptive effects on parasite fitness. Phytoplasma parasites of plants often induce the development of leaf-like flowers (phyllody) in their host plants, and we previously found that the phytoplasma effector SAP54 generates these leaf-like flowers via the degradation of plant MADS-box transcription factors (MTFs), which regulate all major aspects of development in plants. Leafhoppers prefer to reproduce on phytoplasma-infected and SAP54-trangenic plants leading to the hypothesis that leafhopper vectors are attracted to plants with leaf-like flowers. Surprisingly, here we show that leafhopper attraction occurs independently of the presence of leaf-like flowers. First, the leafhoppers were also attracted to SAP54 transgenic plants without leaf-like flowers and to single leaves of these plants. Moreover, leafhoppers were not attracted to leaf-like flowers of MTF-mutant plants without the presence of SAP54. Thus, the primary role of SAP54 is to attract leafhopper vectors, which spread the phytoplasmas, and the generation of leaf-like flowers may be secondary or a side effect of the SAP54-mediated degradation of MTFs. PMID:27446117

  8. A Bacterial Parasite Effector Mediates Insect Vector Attraction in Host Plants Independently of Developmental Changes

    PubMed Central

    Orlovskis, Zigmunds; Hogenhout, Saskia A.

    2016-01-01

    Parasites can take over their hosts and trigger dramatic changes in host appearance and behavior that are typically interpreted as extended phenotypes that promote parasite survival and fitness. For example, Toxoplasma gondii is thought to manipulate the behaviors of infected rodents to aid transmission to cats and parasitic trematodes of the genus Ribeiroia alter limb development in their amphibian hosts to facilitate predation of the latter by birds. Plant parasites and pathogens also reprogram host development and morphology. However, whereas some parasite-induced morphological alterations may have a direct benefit to the fitness of the parasite and may therefore be adaptive, other host alterations may be side effects of parasite infections having no adaptive effects on parasite fitness. Phytoplasma parasites of plants often induce the development of leaf-like flowers (phyllody) in their host plants, and we previously found that the phytoplasma effector SAP54 generates these leaf-like flowers via the degradation of plant MADS-box transcription factors (MTFs), which regulate all major aspects of development in plants. Leafhoppers prefer to reproduce on phytoplasma-infected and SAP54-trangenic plants leading to the hypothesis that leafhopper vectors are attracted to plants with leaf-like flowers. Surprisingly, here we show that leafhopper attraction occurs independently of the presence of leaf-like flowers. First, the leafhoppers were also attracted to SAP54 transgenic plants without leaf-like flowers and to single leaves of these plants. Moreover, leafhoppers were not attracted to leaf-like flowers of MTF-mutant plants without the presence of SAP54. Thus, the primary role of SAP54 is to attract leafhopper vectors, which spread the phytoplasmas, and the generation of leaf-like flowers may be secondary or a side effect of the SAP54-mediated degradation of MTFs. PMID:27446117

  9. Interaction between viral RNA silencing suppressors and host factors in plant immunity.

    PubMed

    Nakahara, Kenji S; Masuta, Chikara

    2014-08-01

    To elucidate events in the molecular arms race between the host and pathogen in evaluating plant immunity, a zigzag model is useful for uncovering aspects common to different host-pathogen interactions. By analogy of the steps in virus-host interactions with the steps in the standard zigzag model outlined in recent papers, we may regard RNA silencing as pattern-triggered immunity (PTI) against viruses, RNA silencing suppressors (RSSs) as effectors to overcome host RNA silencing and resistance gene (R-gene)-mediated defense as effector-triggered immunity (ETI) recognizing RSSs as avirulence proteins. However, because the standard zigzag model does not fully apply to some unique aspects in the interactions between a plant host and virus, we here defined a model especially designed for viruses. Although we simplified the phenomena involved in the virus-host interactions in the model, certain specific interactive steps can be explained by integrating additional host factors into the model. These host factors are thought to play an important role in maintaining the efficacy of the various steps in the main pathway of defense against viruses in this model for virus-plant interactions. For example, we propose candidates that may interact with viral RSSs to induce the resistance response. PMID:24875766

  10. Do fungivores trigger the transfer of protective metabolites from host plants to arbuscular mycorrhizal hyphae?

    PubMed

    Duhamel, Marie; Pel, Roel; Ooms, Astra; Bücking, Heike; Jansa, Jan; Ellers, Jacintha; van Straalen, Nico M; Wouda, Tjalf; Vandenkoornhuyse, Philippe; Kiers, E Toby

    2013-09-01

    A key objective in ecology is to understand how cooperative strategies evolve and are maintained in species networks. Here, we focus on the tri-trophic relationship between arbuscular mycorrhizal (AM) fungi, host plants, and fungivores to ask if host plants are able to protect their mutualistic mycorrhizal partners from being grazed. Specifically, we test whether secondary metabolites are transferred from hosts to fungal partners to increase their defense against fungivores. We grew Plantago lanceolata hosts with and without mycorrhizal inoculum, and in the presence or absence of fungivorous springtails. We then measured fungivore effects on host biomass and mycorrhizal abundance (using quantitative PCR) in roots and soil. We used high-performance liquid chromatography to measure host metabolites in roots, shoots, and hyphae, focusing on catalpol, aucubin, and verbascoside. Our most striking result was that the metabolite catalpol was consistently found in AM fungal hyphae in host plants exposed to fungivores. When fungivores were absent, catalpol was undetectable in hyphae. Our results highlight the potential for plant-mediated protection of the mycorrhizal hyphal network. PMID:24279273

  11. [Characteristics of Natural Selection in Populations of Nodule Bacteria (Rhizobium leguminosarum) Interacting With Different Host Plants].

    PubMed

    Andronov, E E; Igolkina, A A; Kimeklis, A K; Vorobyov, N I; Provorov, N A

    2015-10-01

    Using high throughput sequencing of the nodA gene, we studied the population dynamics of Rhizobium leguminosarum (bv. viciae, bv. trifolii) in rhizospheric and nodular subpopulations associated with the leguminous plants representing different cross-inoculation groups (Vicia sativa, Lathyrus pratensis of the vetch/vetchling/pea group and Trifolium hybridum of the clover group). The "rhizosphere-nodules" transitions result in either an increase or decrease in the frequencies of 10 of the 23 operational taxonomic units (OTUs) (which were identified with 95% similarity) depending on the symbiotic specificity and phylogenetic positions of OTUs. Statistical and bioinformatical analysis of the population structures suggest that the type of natural selection responsible for these changes may be diversifying at the whole-population level and frequency-dependent at the OTU-specific level, ensuring the divergent evolution of rhizobia interacting with different host species. PMID:27169225

  12. Host races in plant-feeding insects and their importance in sympatric speciation.

    PubMed Central

    Drès, Michele; Mallet, James

    2002-01-01

    The existence of a continuous array of sympatric biotypes - from polymorphisms, through ecological or host races with increasing reproductive isolation, to good species - can provide strong evidence for a continuous route to sympatric speciation via natural selection. Host races in plant-feeding insects, in particular, have often been used as evidence for the probability of sympatric speciation. Here, we provide verifiable criteria to distinguish host races from other biotypes: in brief, host races are genetically differentiated, sympatric populations of parasites that use different hosts and between which there is appreciable gene flow. We recognize host races as kinds of species that regularly exchange genes with other species at a rate of more than ca. 1% per generation, rather than as fundamentally distinct taxa. Host races provide a convenient, although admittedly somewhat arbitrary intermediate stage along the speciation continuum. They are a heuristic device to aid in evaluating the probability of speciation by natural selection, particularly in sympatry. Speciation is thereby envisaged as having two phases: (i) the evolution of host races from within polymorphic, panmictic populations; and (ii) further reduction of gene flow between host races until the diverging populations can become generally accepted as species. We apply this criterion to 21 putative host race systems. Of these, only three are unambiguously classified as host races, but a further eight are strong candidates that merely lack accurate information on rates of hybridization or gene flow. Thus, over one-half of the cases that we review are probably or certainly host races, under our definition. Our review of the data favours the idea of sympatric speciation via host shift for three major reasons: (i) the evolution of assortative mating as a pleiotropic by-product of adaptation to a new host seems likely, even in cases where mating occurs away from the host; (ii) stable genetic differences in

  13. Genetic bottlenecks during systemic movement of Cucumber mosaic virus vary in different host plants

    SciTech Connect

    Ali, Akhtar; Roossinck, Marilyn J.

    2010-09-01

    Genetic bottlenecks are stochastic events that narrow variation in a population. We compared bottlenecks during the systemic infection of Cucumber mosaic virus (CMV) in four host plants. We mechanically inoculated an artificial population of twelve CMV mutants to young leaves of tomato, pepper, Nicotiana benthamiana, and squash. The inoculated leaves and primary and secondary systemically infected leaves were sampled at 2, 10, and 15 days post-inoculation. All twelve mutants were detected in all of the inoculated leaves. The number of mutants recovered from the systemically infected leaves of all host species was reduced significantly, indicating bottlenecks in systemic movement. The recovery frequencies of a few of the mutants were significantly different in each host probably due to host-specific selective forces. These results have implications for the differences in virus population variation that is seen in different host plants.

  14. Peptidases and peptidase inhibitors in gut of caterpillars and in the latex of their host plants.

    PubMed

    Ramos, Márcio V; Pereira, Danielle A; Souza, Diego P; Silva, Maria-Lídia S; Alencar, Luciana M R; Sousa, Jeanlex S; Queiroz, Juliany-Fátima N; Freitas, Cleverson D T

    2015-01-01

    Studies investigating the resistance-susceptibility of crop insects to proteins found in latex fluids have been reported. However, latex-bearing plants also host insects. In this study, the gut proteolytic system of Pseudosphinx tetrio, which feeds on Plumeria rubra leaves, was characterized and further challenged against the latex proteolytic system of its own host plant and those of other latex-bearing plants. The gut proteolytic system of Danaus plexippus (monarch) and the latex proteolytic system of its host plant (Calotropis procera) were also studied. The latex proteins underwent extensive hydrolysis when mixed with the corresponding gut homogenates of the hosted insects. The gut homogenates partially digested the latex proteins of foreign plants. The fifth instar of D. plexippus that were fed diets containing foreign latex developed as well as those individuals who were fed diets containing latex proteins from their host plant. In vitro assays detected serine and cysteine peptidase inhibitors in both the gut homogenates and the latex fluids. Curiously, the peptidase inhibitors of caterpillars did not inhibit the latex peptidases of their host plants. However, the peptidase inhibitors of laticifer origin inhibited the proteolysis of gut homogenates. In vivo analyses of the peritrophic membrane proteins of D. plexippus demonstrate resistance against latex peptidases. Only discrete changes were observed when the peritrophic membrane was directly treated with purified latex peptidases in vitro. This study concludes that peptidase inhibitors are involved in the defensive systems of both caterpillars and their host plants. Although latex peptidase inhibitors inhibit gut peptidases (in vitro), the ability of gut peptidases to digest latex proteins (in vivo) regardless of their origin seems to be important in governing the resistance-susceptibility of caterpillars. PMID:25246317

  15. Gibberellins in Penicillium strains: Challenges for endophyte-plant host interactions under salinity stress.

    PubMed

    Leitão, Ana Lúcia; Enguita, Francisco J

    2016-02-01

    The genus Penicillium is one of the most versatile "mycofactories", comprising some species able to produce gibberellins, bioactive compounds that can modulate plant growth and development. Although plants have the ability to synthesize gibberellins, their levels are lower when plants are under salinity stress. It has been recognized that detrimental abiotic conditions, such as saline stress, have negative effects on plants, being the availability of bioactive gibberellins a critical factor for their growth under this conditions. This review summarizes the interplay existing between endophytic Penicillium strains and plant host interactions, with focus on bioactive gibberellins production as a fungal response that allows plants to overcome salinity stress. PMID:26805614

  16. Inbreeding compromises host plant defense gene expression and improves herbivore survival

    PubMed Central

    Portman, Scott L; Kariyat, Rupesh R; Johnston, Michelle A; Stephenson, Andrew G; Marden, James H

    2015-01-01

    Inbreeding commonly occurs in flowering plants and often results in a decline in the plant's defense response. Insects prefer to feed and oviposit on inbred plants more than outbred plants – suggesting that selecting inbred host plants offers them fitness benefits. Until recently, no studies have examined the effects of host plant inbreeding on insect fitness traits such as growth and dispersal ability. In a recent article, we documented that tobacco hornworm (Manduca sexta L.) larvae that fed on inbred horsenettle (Solanum carolinense L.) plants exhibited accelerated larval growth and increased adult flight capacity compared to larvae that fed on outbred plants. Here we report that M. sexta mortality decreased by 38.2% when larvae were reared on inbred horsenettle plants compared to larvae reared on outbreds. Additionally, inbred plants showed a notable reduction in the average relative expression levels of LIPOXYGENEASE-D (LoxD) and 12-OXOPHYTODIENOATE REDUCTASE-3 (OPR3), two genes in the jasmonic acid signaling pathway that are upregulated in response to herbivore damage. Our study presents evidence that furthers our understanding of the biochemical mechanism responsible for differences in insect performance on inbred vs. outbred host plants. PMID:26039489

  17. Patterns of host plant utilization and diversification in the brush-footed butterflies.

    PubMed

    Hamm, Christopher A; Fordyce, James A

    2015-03-01

    Herbivorous insects represent one of the most successful animal radiations known. They occupy a wide range of niches, feed on a great variety of plants, and are species rich; yet the factors that influence their diversification are poorly understood. Host breadth is often cited as a major factor influencing diversification, and, according to the Oscillation Hypothesis, shifts from generalist to specialist feeding states increase the diversification rate for a clade. We explored the relationship between host breadth and diversification within the Nymphalidae (Lepidoptera) and explicitly tested predictions of the Oscillation Hypothesis. We found strong evidence of diversification rate heterogeneity, but no difference in host breadth between clades with a higher diversification rate compared to their sisters. We also found some clades exhibited phylogenetic nonindependence in host breadth and these clades had lower host plant turnover than expected by chance, suggesting host breadth is evolutionarily constrained. Finally, we found that transitions among host breadth categories varied, but the likelihood of reductions in host breadth was greater than that of increases. Our results indicate host breadth is decoupled from diversification rate within the Nymphalidae, and that constraints on diet breadth might play an important role in the evolution of herbivorous insects. PMID:25546268

  18. Transcriptional variation associated with cactus host plant adaptation in Drosophila mettleri populations.

    PubMed

    Hoang, Kim; Matzkin, Luciano M; Bono, Jeremy M

    2015-10-01

    Although the importance of host plant chemistry in plant-insect interactions is widely accepted, the genetic basis of adaptation to host plants is not well understood. Here, we investigate transcriptional changes associated with a host plant shift in Drosophila mettleri. While D. mettleri is distributed mainly throughout the Sonoran Desert where it specializes on columnar cacti (Carnegiea gigantea and Pachycereus pringleii), a population on Santa Catalina Island has shifted to chemically divergent coastal prickly pear cactus (Opuntia littoralis). We compared gene expression of larvae from the Sonoran Desert and Santa Catalina Island when reared on saguaro (C. gigantea), coastal prickly pear and laboratory food. Consistent with expectations based on the complexity and toxicity of cactus relative to laboratory food, within-population comparisons between larvae reared on these food sources revealed transcriptional differences in detoxification and other metabolic pathways. The majority of transcriptional differences between populations on the cactus hosts were independent of the rearing environment and included a disproportionate number of genes involved in processes relevant to host plant adaptation (e.g. detoxification, central metabolism and chemosensory pathways). Comparisons of transcriptional reaction norms between the two populations revealed extensive shared plasticity that likely allowed colonization of coastal prickly pear on Santa Catalina Island. We also found that while plasticity may have facilitated subsequent adaptive divergence in gene expression between populations, the majority of genes that differed in expression on the novel host were not transcriptionally plastic in the presumed ancestral state. PMID:26384860

  19. Host Plant Odors Represent Immiscible Information Entities - Blend Composition and Concentration Matter in Hawkmoths

    PubMed Central

    Haverkamp, Alexander; Hansson, Bill S.; Knaden, Markus

    2013-01-01

    Host plant choice is of vital importance for egg laying herbivorous insects that do not exhibit brood care. Several aspects, including palatability, nutritional quality and predation risk, have been found to modulate host preference. Olfactory cues are thought to enable host location. However, experimental data on odor features that allow choosing among alternative hosts while still in flight are not available. It has previously been shown that M. sexta females prefer Datura wrightii compared to Nicotiana attenuata. The bouquet of the latter is more intense and contains compounds typically emitted by plants after feeding-damage to attract the herbivore’s enemies. In this wind tunnel study, we offered female gravid hawkmoths (Manduca sexta) odors from these two ecologically relevant, attractive, non-flowering host species. M. sexta females preferred surrogate leaves scented with vegetative odors form both host species to unscented control leaves. Given a choice between species, females preferred the odor bouquet emitted by D. wrightii to that of N. attenuata. Harmonizing, i.e. adjusting, volatile intensity to similar levels did not abolish but significantly weakened this preference. Superimposing, i.e. mixing, the highly attractive headspaces of both species, however, abolished discrimination between scented and non-scented surrogate leaves. Beyond ascertaining the role of blend composition in host plant choice, our results raise the following hypotheses. (i) The odor of a host species is perceived as a discrete odor ‘Gestalt’, and its core properties are lost upon mixing two attractive scents (ii). Stimulus intensity is a secondary feature affecting olfactory-based host choice (iii). Constitutively smelling like a plant that is attracting herbivore enemies may be part of a plant’s strategy to avoid herbivory where alternative hosts are available to the herbivore. PMID:24116211

  20. Narrow-Host-Range Bacteriophages That Infect Rhizobium etli Associate with Distinct Genomic Types

    PubMed Central

    Santamaría, Rosa Isela; Bustos, Patricia; Sepúlveda-Robles, Omar; Lozano, Luis; Rodríguez, César; Fernández, José Luis; Juárez, Soledad; Kameyama, Luis; Guarneros, Gabriel; Dávila, Guillermo

    2014-01-01

    In this work, we isolated and characterized 14 bacteriophages that infect Rhizobium etli. They were obtained from rhizosphere soil of bean plants from agricultural lands in Mexico using an enrichment method. The host range of these phages was narrow but variable within a collection of 48 R. etli strains. We obtained the complete genome sequence of nine phages. Four phages were resistant to several restriction enzymes and in vivo cloning, probably due to nucleotide modifications. The genome size of the sequenced phages varied from 43 kb to 115 kb, with a median size of ∼45 to 50 kb. A large proportion of open reading frames of these phage genomes (65 to 70%) consisted of hypothetical and orphan genes. The remainder encoded proteins needed for phage morphogenesis and DNA synthesis and processing, among other functions, and a minor percentage represented genes of bacterial origin. We classified these phages into four genomic types on the basis of their genomic similarity, gene content, and host range. Since there are no reports of similar sequences, we propose that these bacteriophages correspond to novel species. PMID:24185856

  1. Host Range and Selectivity of the Hemiparasitic Plant Thesium chinense (Santalaceae)

    PubMed Central

    Suetsugu, Kenji; Kawakita, Atsushi; Kato, Makoto

    2008-01-01

    Background and Aims Thesium chinense is a hemiparasitic plant that is common in grassland habitats of eastern Asia. Although the physiology of Thesium has been well studied in attempts to control its weedy habit, there have been few ecological investigations of its parasitic life history. Thesium chinense is thought to parasitize species of Poaceae, but evidence remains circumstantial. Methods A vegetation survey was conducted to test whether any plant species occurs significantly more often in plots with T. chinense than expected. In addition, haustorial connections were examined directly by excavating the roots and post-attachment host selectivity was evaluated by comparing the observed numbers of haustoria on different hosts against those expected according to the relative below-ground biomass. Haustorium sizes were also compared among host species. Key Results Only two of the 38 species recorded, Lespedeza juncea and Eragrostis curvula, occurred more often in plots with Thesium than expected. In contrast to this, T. chinense parasitized 22 plant species in 11 families, corresponding to 57·9 % of plant species found at the study site. Haustoria were non-randomly distributed among host species, suggesting that there is some post-attachment host selectivity. Thesium chinense generally preferred the Poaceae, although haustoria formed on the Fabaceae were larger than those on other hosts. Conclusions This is the first quantitative investigation of the host range and selectivity of hemiparasitic plants of the Santalales. The preference for Fabaceae as hosts may be linked to the greater nutrient availability in these nitrogen-fixing plants. PMID:18492736

  2. New and simple methods for studying Hemipteran stylets, bacteriomes and salivary sheaths in host plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many hemipteran insects are important agricultural pests because they cause direct feeding damage to their host plants and/or because they transmit plant disease agents including viruses and bacteria. Microscopic and behavioral studies on five hemipteran species from four families (Psyllidae, Aphidi...

  3. Virulent Hessian fly larvae manipulate the free amino acid content of host wheat plants.

    PubMed

    Saltzmann, Kurt D; Giovanini, Marcelo P; Zheng, Cheng; Williams, Christie E

    2008-11-01

    Gall-forming insects induce host plants to form specialized structures (galls) that provide immature life stages of the insect access to host plant nutrients and protection from natural enemies. Feeding by larvae of the Hessian fly (Mayetiola destructor Say) causes susceptible host wheat plants to produce a gall-like nutritive tissue that supports larval growth and development. To determine if changes in host plant free amino acid levels are associated with virulent Biotype L Hessian fly larval feeding, we quantified free amino acid levels in crown tissues of susceptible Newton wheat plants 1, 4, and 7 days after Hessian fly egg hatch. Hessian fly-infested susceptible plants were more responsive than resistant plants or uninfested controls, showing higher concentrations of alanine, glutamic acid, glycine, phenylalanine, proline, and serine 4 days after egg hatch. This 4-day post-hatch time point corresponds to the maturation of nutritive tissue cells in susceptible plants and the onset of rapid larval growth. By 7 days after egg hatch, when virulent second instars are actively feeding on the contents of nutritive tissue cells, the aromatic amino acids phenylalanine and tyrosine were more abundant compared to uninfested controls, but the levels of other free amino acids were no longer elevated. Changes in free amino acid abundance described in this report were associated with increased levels of mRNA encoded by wheat genes involved in amino acid synthesis and transport. PMID:18841417

  4. Update on Host Plant Resistance Studies of Banded Sunflower Moth and Sunflower Moth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Breeding pest-resistance crop cultivars to insects and diseases is one of the primary goals of integrated pest management programs worldwide. Host plant resistance is a tactic that uses the plant's own defenses to reduce injury from pest attack. Among the sunflower (Helianthus annuus L.) insect pest...

  5. Virulent Hessian Fly Larvae Manipulate the Free Amino Acid Content Of Host Wheat Plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Virulent Hessian fly larvae induce their host wheat plants to provide a favorable environment for larval development by altering plant gene expression and promoting the formation of nutritive tissue at larval feeding sites. To determine whether Hessian fly larvae manipulate the nutrient content of t...

  6. HOST GALAXY PROPERTIES AND HUBBLE RESIDUALS OF TYPE Ia SUPERNOVAE FROM THE NEARBY SUPERNOVA FACTORY

    SciTech Connect

    Childress, M.; Aldering, G.; Aragon, C.; Bailey, S.; Fakhouri, H. K.; Hsiao, E. Y.; Kim, A. G.; Loken, S.; Antilogus, P.; Bongard, S.; Canto, A.; Cellier-Holzem, F.; Guy, J.; Baltay, C.; Buton, C.; Kerschhaggl, M.; Kowalski, M.; Chotard, N.; Copin, Y.; Gangler, E. [Universite de Lyon, F-69622, Lyon; Universite de Lyon 1, Villeurbanne; CNRS and others

    2013-06-20

    We examine the relationship between Type Ia supernova (SN Ia) Hubble residuals and the properties of their host galaxies using a sample of 115 SNe Ia from the Nearby Supernova Factory. We use host galaxy stellar masses and specific star formation rates fitted from photometry for all hosts, as well as gas-phase metallicities for a subset of 69 star-forming (non-active galactic nucleus) hosts, to show that the SN Ia Hubble residuals correlate with each of these host properties. With these data we find new evidence for a correlation between SN Ia intrinsic color and host metallicity. When we combine our data with those of other published SN Ia surveys, we find the difference between mean SN Ia brightnesses in low- and high-mass hosts is 0.077 {+-} 0.014 mag. When viewed in narrow (0.2 dex) bins of host stellar mass, the data reveal apparent plateaus of Hubble residuals at high and low host masses with a rapid transition over a short mass range (9.8 {<=} log (M{sub *}/M{sub Sun }) {<=} 10.4). Although metallicity has been a favored interpretation for the origin of the Hubble residual trend with host mass, we illustrate how dust in star-forming galaxies and mean SN Ia progenitor age both evolve along the galaxy mass sequence, thereby presenting equally viable explanations for some or all of the observed SN Ia host bias.

  7. Odour Maps in the Brain of Butterflies with Divergent Host-Plant Preferences

    PubMed Central

    Schäpers, Alexander; Mozuraitis, Raimondas; Hansson, Bill S.; Janz, Niklas

    2011-01-01

    Butterflies are believed to use mainly visual cues when searching for food and oviposition sites despite that their olfactory system is morphologically similar to their nocturnal relatives, the moths. The olfactory ability in butterflies has, however, not been thoroughly investigated. Therefore, we performed the first study of odour representation in the primary olfactory centre, the antennal lobes, of butterflies. Host plant range is highly variable within the butterfly family Nymphalidae, with extreme specialists and wide generalists found even among closely related species. Here we measured odour evoked Ca2+ activity in the antennal lobes of two nymphalid species with diverging host plant preferences, the specialist Aglais urticae and the generalist Polygonia c-album. The butterflies responded with stimulus-specific combinations of activated glomeruli to single plant-related compounds and to extracts of host and non-host plants. In general, responses were similar between the species. However, the specialist A. urticae responded more specifically to its preferred host plant, stinging nettle, than P. c-album. In addition, we found a species-specific difference both in correlation between responses to two common green leaf volatiles and the sensitivity to these compounds. Our results indicate that these butterflies have the ability to detect and to discriminate between different plant-related odorants. PMID:21901154

  8. Integration of Visual and Olfactory Cues in Host Plant Identification by the Asian Longhorned Beetle, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae).

    PubMed

    Yv, Fei L; Hai, Xiaoxia; Wang, Zhigang; Yan, Aihua; Liu, Bingxiang; Bi, Yongguo

    2015-01-01

    Some insects use host and mate cues, including odor, color, and shape, to locate and recognize their preferred hosts and mates. Previous research has shown that the Asian longicorn beetle, Anoplophora glabripennis (Motschulsky), uses olfactory cues to locate host plants and differentiate them from non-host plants. However, whether A. glabripennis adults use visual cues or a combination of visual and olfactory cues remains unclear. In this study, we tested the host location and recognition behavior in A. glabripennis, which infests a number of hardwood species and causes considerable economic losses in North America, Europe and Asia. We determined the relative importance of visual and olfactory cues from Acer negundo in host plant location and recognition, as well as in the discrimination of non-host plants (Sabina chinensis and Pinus bungeana), by female and male A. glabripennis. Visual and olfactory cues from the host plants (A. negundo), alone and combined, attracted significantly more females and males than equivalent cues from non-host plants (S. chinensis and P. bungeana). Furthermore, the combination of visual and olfactory cues of host plants attracted more adults than either cue alone, and visual cues alone attracted significantly more adults than olfactory cues alone. This finding suggests that adult A. glabripennis has an innate preference for the visual and/or olfactory cues of its host plants (A. negundo) over those of the non-host plant and visual cues are initially more important than olfactory cues for orientation; furthermore, this finding also suggests that adults integrate visual and olfactory cues to find their host plants. Our results indicate that different modalities of host plant cues should be considered together to understand fully the communication between host plants and Asian longhorned beetles. PMID:26556100

  9. Integration of Visual and Olfactory Cues in Host Plant Identification by the Asian Longhorned Beetle, Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae)

    PubMed Central

    L.Yv, Fei; Hai, Xiaoxia; Wang, Zhigang; Yan, Aihua; Liu, Bingxiang; Bi, Yongguo

    2015-01-01

    Some insects use host and mate cues, including odor, color, and shape, to locate and recognize their preferred hosts and mates. Previous research has shown that the Asian longicorn beetle, Anoplophora glabripennis (Motschulsky), uses olfactory cues to locate host plants and differentiate them from non-host plants. However, whether A. glabripennis adults use visual cues or a combination of visual and olfactory cues remains unclear. In this study, we tested the host location and recognition behavior in A. glabripennis, which infests a number of hardwood species and causes considerable economic losses in North America, Europe and Asia. We determined the relative importance of visual and olfactory cues from Acer negundo in host plant location and recognition, as well as in the discrimination of non-host plants (Sabina chinensis and Pinus bungeana), by female and male A. glabripennis. Visual and olfactory cues from the host plants (A. negundo), alone and combined, attracted significantly more females and males than equivalent cues from non-host plants (S. chinensis and P. bungeana). Furthermore, the combination of visual and olfactory cues of host plants attracted more adults than either cue alone, and visual cues alone attracted significantly more adults than olfactory cues alone. This finding suggests that adult A. glabripennis has an innate preference for the visual and/or olfactory cues of its host plants (A. negundo) over those of the non-host plant and visual cues are initially more important than olfactory cues for orientation; furthermore, this finding also suggests that adults integrate visual and olfactory cues to find their host plants. Our results indicate that different modalities of host plant cues should be considered together to understand fully the communication between host plants and Asian longhorned beetles. PMID:26556100

  10. Host plant volatiles induce oriented flight behaviour in male European grapevine moths, Lobesia botrana.

    PubMed

    von Arx, Martin; Schmidt-Büsser, Daniela; Guerin, Patrick M

    2011-10-01

    The European grapevine moth Lobesia botrana relies on a female produced sex pheromone for long-distance mate finding. Grapevine moth males compete heavily during limited time windows for females. The aim of this study was to investigate the perception of host plant volatiles by grapevine moth males and whether such compounds elicit upwind oriented flights. We compared five host plant headspace extracts by means of gas chromatography linked electroantennogram (EAG) recording. We identified 12 common host plant volatiles (aliphatic esters, aldehydes, and alcohols, aromatic compounds and terpenes) that elicit EAG responses from grapevine moth males and that occur in at least three of the host plant volatile headspace extracts tested. Subsequently the behavioural response of grapevine moth males to four these compounds presented singly and in mixtures (1-hexanol, 1-octen-3-ol, (Z)-3-hexenyl acetate and (E)-β-caryophyllene) was recorded in a wind tunnel. Grapevine moth males engaged in upwind flights to all of four compounds when released singly at 10,000 pg/min and to all, except 1-octen-3-ol, when released at 100 pg/min. A blend of the four host plant volatiles released at 10,000 pg/min and mixed at a ratio based on the analysis of Vitis vinifera cv. Solaris volatile emissions attracted significantly more males than any single compound. Grapevine moth males perceive and respond to host plant volatiles at biologically relevant levels indicating that host plant volatiles figure as olfactory cues and that L. botrana males can discern places where the likelihood of encountering females is higher. PMID:21729701

  11. Unmasking host and microbial strategies in the Agrobacterium-plant defense tango.

    PubMed

    Hwang, Elizabeth E; Wang, Melinda B; Bravo, Janis E; Banta, Lois M

    2015-01-01

    Coevolutionary forces drive adaptation of both plant-associated microbes and their hosts. Eloquently captured in the Red Queen Hypothesis, the complexity of each plant-pathogen relationship reflects escalating adversarial strategies, but also external biotic and abiotic pressures on both partners. Innate immune responses are triggered by highly conserved pathogen-associated molecular patterns, or PAMPs, that are harbingers of microbial presence. Upon cell surface receptor-mediated recognition of these pathogen-derived molecules, host plants mount a variety of physiological responses to limit pathogen survival and/or invasion. Successful pathogens often rely on secretion systems to translocate host-modulating effectors that subvert plant defenses, thereby increasing virulence. Host plants, in turn, have evolved to recognize these effectors, activating what has typically been characterized as a pathogen-specific form of immunity. Recent data support the notion that PAMP-triggered and effector-triggered defenses are complementary facets of a convergent, albeit differentially regulated, set of immune responses. This review highlights the key players in the plant's recognition and signal transduction pathways, with a focus on the aspects that may limit Agrobacterium tumefaciens infection and the ways it might overcome those defenses. Recent advances in the field include a growing appreciation for the contributions of cytoskeletal dynamics and membrane trafficking to the regulation of these exquisitely tuned defenses. Pathogen counter-defenses frequently manipulate the interwoven hormonal pathways that mediate host responses. Emerging systems-level analyses include host physiological factors such as circadian cycling. The existing literature indicates that varying or even conflicting results from different labs may well be attributable to environmental factors including time of day of infection, temperature, and/or developmental stage of the host plant. PMID:25873923

  12. Host-specific races in the holoparasitic angiosperm Orobanche minor: implications for speciation in parasitic plants

    PubMed Central

    Thorogood, C. J.; Rumsey, F. J.; Hiscock, S. J.

    2009-01-01

    Background and Aims Orobanche minor is a root-holoparasitic angiosperm that attacks a wide range of host species, including a number of commonly cultivated crops. The extent to which genetic divergence among natural populations of O. minor is influenced by host specificity has not been determined previously. Here, the host specificity of natural populations of O. minor is quantified for the first time, and evidence that this species may comprise distinct physiological races is provided. Methods A tripartite approach was used to examine the physiological basis for the divergence of populations occurring on different hosts: (1) host–parasite interactions were cultivated in rhizotron bioassays in order to quantify the early stages of the infection and establishment processes; (2) using reciprocal-infection experiments, parasite races were cultivated on their natural and alien hosts, and their fitness determined in terms of biomass; and (3) the anatomy of the host–parasite interface was investigated using histochemical techniques, with a view to comparing the infection process on different hosts. Key Results Races occurring naturally on red clover (Trifolium pratense) and sea carrot (Daucus carota ssp. gummifer) showed distinct patterns of host specificity: parasites cultivated in cross-infection studies showed a higher fitness on their natural hosts, suggesting that races show local adaptation to specific hosts. In addition, histological evidence suggests that clover and carrot roots vary in their responses to infection. Different root anatomy and responses to infection may underpin a physiological basis for host specificity. Conclusions It is speculated that host specificity may isolate races of Orobanche on different hosts, accelerating divergence and ultimately speciation in this genus. The rapid life cycle and broad host range of O. minor make this species an ideal model with which to study the interactions of parasitic plants with their host associates. PMID

  13. Shrinkage of Genome Size in a Plant RNA Virus upon Transfer of an Essential Viral Gene into the Host Genome

    PubMed Central

    Tromas, Nicolas; Zwart, Mark P.; Forment, Javier; Elena, Santiago F.

    2014-01-01

    Nonretroviral integrated RNA viruses (NIRVs) are genes of nonretroviral RNA viruses found in the genomes of many eukaryotic organisms. NIRVs are thought to sometimes confer virus resistance, meaning that they could impact spread of the virus in the host population. However, a NIRV that is expressed may also impact the evolution of virus populations within host organisms. Here, we experimentally addressed the evolution of a virus in a host expressing a NIRV using Tobacco etch virus (TEV), a plant RNA virus, and transgenic tobacco plants expressing its replicase, NIb. We found that a virus missing the NIb gene, TEV-ΔNIb, which is incapable of autonomous replication in wild-type plants, had a higher fitness than the full-length TEV in the transgenic plants. Moreover, when the full-length TEV was evolved by serial passages in transgenic plants, we observed genomic deletions within NIb—and in some cases the adjacent cistrons—starting from the first passage. When we passaged TEV and TEV-ΔNIb in transgenic plants, we found mutations in proteolytic sites, but these only occurred in TEV-ΔNIb lineages, suggesting the adaptation of polyprotein processing to altered NIb expression. These results raise the possibility that NIRV expression can indeed induce the deletion of the corresponding genes in the viral genome, resulting in the formation of viruses that are replication defective in hosts that do not express the same NIRV. Moreover, virus genome evolution was contingent upon the deletion of the viral replicase, suggesting NIRV expression could also alter patterns of virus evolution. PMID:24558257

  14. Noncoding RNAs of Plant Viruses and Viroids: Sponges of Host Translation and RNA Interference Machinery.

    PubMed

    Miller, W Allen; Shen, Ruizhong; Staplin, William; Kanodia, Pulkit

    2016-03-01

    Noncoding sequences in plant viral genomes are well-known to control viral replication and gene expression in cis. However, plant viral and viroid noncoding (nc)RNA sequences can also regulate gene expression acting in trans, often acting like 'sponges' that bind and sequester host cellular machinery to favor viral infection. Noncoding sequences of small subgenomic (sg)RNAs of Barley yellow dwarf virus (BYDV) and Red clover necrotic mosaic virus (RCNMV) contain a cap-independent translation element that binds translation initiation factor eIF4G. We provide new evidence that a sgRNA of BYDV can globally attenuate host translation, probably by sponging eIF4G. Subgenomic ncRNA of RCNMV is generated via 5' to 3' degradation by a host exonuclease. The similar noncoding subgenomic flavivirus (sf)RNA, inhibits the innate immune response, enhancing viral pathogenesis. Cauliflower mosaic virus transcribes massive amounts of a 600-nt ncRNA, which is processed into small RNAs that overwhelm the host's RNA interference (RNAi) system. Viroids use the host RNAi machinery to generate viroid-derived ncRNAs that inhibit expression of host defense genes by mimicking a microRNA. More examples of plant viral and viroid ncRNAs are likely to be discovered, revealing fascinating new weaponry in the host-virus arms race. PMID:26900786

  15. Species Differentiation of Chinese Mollitrichosiphum (Aphididae: Greenideinae) Driven by Geographical Isolation and Host Plant Acquirement

    PubMed Central

    Zhang, Ruiling; Huang, Xiaolei; Jiang, Liyun; Lei, Fumin; Qiao, Gexia

    2012-01-01

    The impact of both the uplift of the Qinghai-Tibetan Plateau (QTP) and the separation of the Taiwan and Hainan Islands on the evolution of the fauna and flora in adjacent regions has been a topic of considerable interest. Mollitrichosiphum is a polyphagous insect group with a wide range of host plants (14 families) and distributions restricted to Southeast Asia. Based on the mitochondrial Cytochrome C Oxidase Subunit I (COI) and Cytochrome b (Cytb) genes, the nuclear elongation factor-1α (EF-1α) gene, and the detailed distribution and host plant data, we investigated the species differentiation modes of the Chinese Mollitrichosiphum species. Phylogenetic analyses supported the monophyly of Mollitrichosiphum. The divergence time of Mollitrichosiphum tenuicorpus (c. 11.0 mya (million years ago)), Mollitrichosiphum nandii and Mollitrichosiphum montanum (c. 10.6 mya) was within the time frame of the uplift of the QTP. Additionally, basal species mainly fed on Fagaceae, while species that fed on multiple plants diverged considerably later. Ancestral state reconstruction suggests that Fagaceae may be the first acquired host, and the acquisition of new hosts and the expansion of host range may have promoted species differentiation within this genus. Overall, it can be concluded that geographical isolation and the expansion of the host plant range may be the main factors driving species differentiation of Mollitrichosiphum. PMID:22949873

  16. Analysis of three Xanthomonas axonopodis pv. citri effector proteins in pathogenicity and their interactions with host plant proteins.

    PubMed

    Dunger, Germán; Garofalo, Cecilia G; Gottig, Natalia; Garavaglia, Betiana S; Rosa, María C Pereda; Farah, Chuck S; Orellano, Elena G; Ottado, Jorgelina

    2012-10-01

    Xanthomonas axonopodis pv. citri, the bacterium responsible for citrus canker, uses effector proteins secreted by a type III protein secretion system to colonize its hosts. Among the putative effector proteins identified for this bacterium, we focused on the analysis of the roles of AvrXacE1, AvrXacE2 and Xac3090 in pathogenicity and their interactions with host plant proteins. Bacterial deletion mutants in avrXacE1, avrXacE2 and xac3090 were constructed and evaluated in pathogenicity assays. The avrXacE1 and avrXacE2 mutants presented lesions with larger necrotic areas relative to the wild-type strain when infiltrated in citrus leaves. Yeast two-hybrid studies were used to identify several plant proteins likely to interact with AvrXacE1, AvrXacE2 and Xac3090. We also assessed the localization of these effector proteins fused to green fluorescent protein in the plant cell, and observed that they co-localized to the subcellular spaces in which the plant proteins with which they interacted were predicted to be confined. Our results suggest that, although AvrXacE1 localizes to the plant cell nucleus, where it interacts with transcription factors and DNA-binding proteins, AvrXacE2 appears to be involved in lesion-stimulating disease 1-mediated cell death, and Xac3090 is directed to the chloroplast where its function remains to be clarified. PMID:22435635

  17. The Role of Female Search Behaviour in Determining Host Plant Range in Plant Feeding Insects: A Test of the Information Processing Hypothesis

    NASA Astrophysics Data System (ADS)

    Janz, Niklas; Nylin, Soren

    1997-05-01

    Recent theoretical studies have suggested that host range in herbivorous insects may be more restricted by constraints on information processing on the ovipositing females than by trade-offs in larval feeding efficiency. We have investigated if females from polyphagous species have to pay for their ability to localize and evaluate plants from different species with a lower ability to discriminate between conspecific host plants with differences in quality. Females of the monophagous butterflies Polygonia satyrus, Vanessa indica and Inachis io and the polyphagous P. c-album and Cynthia cardui (all in Lepidoptera, Nymphalidae) were given a simultaneous choice of stinging nettles (Urtica dioica) of different quality. In addition, the same choice trial was given to females from two populations of P. c-album with different degrees of specificity. As predicted from the information processing hypothesis, all specialists discriminated significantly against the bad quality nettle, whereas the generalists laid an equal amount of eggs on both types of nettle. There were no corresponding differences between specialist and generalist larvae in their ability to utilize poor quality leaves. Our study therefore suggests that female host-searching behaviour plays an important role in determining host plant range.

  18. Remote sensing of plant functional types.

    PubMed

    Ustin, Susan L; Gamon, John A

    2010-06-01

    Conceptually, plant functional types represent a classification scheme between species and broad vegetation types. Historically, these were based on physiological, structural and/or phenological properties, whereas recently, they have reflected plant responses to resources or environmental conditions. Often, an underlying assumption, based on an economic analogy, is that the functional role of vegetation can be identified by linked sets of morphological and physiological traits constrained by resources, based on the hypothesis of functional convergence. Using these concepts, ecologists have defined a variety of functional traits that are often context dependent, and the diversity of proposed traits demonstrates the lack of agreement on universal categories. Historically, remotely sensed data have been interpreted in ways that parallel these observations, often focused on the categorization of vegetation into discrete types, often dependent on the sampling scale. At the same time, current thinking in both ecology and remote sensing has moved towards viewing vegetation as a continuum rather than as discrete classes. The capabilities of new remote sensing instruments have led us to propose a new concept of optically distinguishable functional types ('optical types') as a unique way to address the scale dependence of this problem. This would ensure more direct relationships between ecological information and remote sensing observations. PMID:20569415

  19. Butterfly Larval Host Plant use in a Tropical Urban Context: Life History Associations, Herbivory, and Landscape Factors

    PubMed Central

    Tiple, Ashish D.; Khurad, Arun M.; Dennis, Roger L. H.

    2011-01-01

    This study examines butterfly larval host plants, herbivory and related life history attributes within Nagpur City, India. The larval host plants of 120 butterfly species are identified and their host specificity, life form, biotope, abundance and perennation recorded; of the 126 larval host plants, most are trees (49), with fewer herbs (43), shrubs (22), climbers (7) and stem parasites (2). They include 89 wild, 23 cultivated, 11 wild/cultivated and 3 exotic plant species; 78 are perennials, 43 annuals and 5 biannuals. Plants belonging to Poaceae and Fabaceae are most widely used by butterfly larvae. In addition to distinctions in host plant family affiliation, a number of significant differences between butterfly families have been identified in host use patterns: for life forms, biotopes, landforms, perennation, host specificity, egg batch size and ant associations. These differences arising from the development of a butterfly resource database have important implications for conserving butterfly species within the city area. Differences in overall butterfly population sizes within the city relate mainly to the number of host plants used, but other influences, including egg batch size and host specificity are identified. Much of the variation in population size is unaccounted for and points to the need to investigate larval host plant life history and strategies as population size is not simply dependent on host plant abundance. PMID:21864159

  20. Butterfly larval host plant use in a tropical urban context: life history associations, herbivory, and landscape factors.

    PubMed

    Tiple, Ashish D; Khurad, Arun M; Dennis, Roger L H

    2011-01-01

    This study examines butterfly larval host plants, herbivory and related life history attributes within Nagpur City, India. The larval host plants of 120 butterfly species are identified and their host specificity, life form, biotope, abundance and perennation recorded; of the 126 larval host plants, most are trees (49), with fewer herbs (43), shrubs (22), climbers (7) and stem parasites (2). They include 89 wild, 23 cultivated, 11 wild/cultivated and 3 exotic plant species; 78 are perennials, 43 annuals and 5 biannuals. Plants belonging to Poaceae and Fabaceae are most widely used by butterfly larvae. In addition to distinctions in host plant family affiliation, a number of significant differences between butterfly families have been identified in host use patterns: for life forms, biotopes, landforms, perennation, host specificity, egg batch size and ant associations. These differences arising from the development of a butterfly resource database have important implications for conserving butterfly species within the city area. Differences in overall butterfly population sizes within the city relate mainly to the number of host plants used, but other influences, including egg batch size and host specificity are identified. Much of the variation in population size is unaccounted for and points to the need to investigate larval host plant life history and strategies as population size is not simply dependent on host plant abundance. PMID:21864159

  1. Phytopathogenicity of Serratia marcescens strains in different plant host species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Strains of Seriatia marcescens (Sm), cause of cucurbit yellow vine disease (CYVD), colonize many niches (water, soil, humans, animals, insects, plants). To assess whether phytopathogenicity is strain-specific, tobacco leaves were needle-inoculated with various Sm strains. A HR-like response was ob...

  2. Influence of the pathogen Candidatus Liberibacter solanacearum on tomato host plant volatiles and psyllid vector settlement.

    PubMed

    Mas, Flore; Vereijssen, Jessica; Suckling, David M

    2014-12-01

    Candidatus Liberibacter solanacearum (CLso) is an unculturable bacterium vectored by the tomato potato psyllid (TPP) Bactericera cockerelli and has been associated with Zebra chip disease in potato and with other economically relevant symptoms observed in solanaceous crops. By altering their host and vector's biological system, pathogens are able to induce changes that benefit them by increasing their transmission rate. Understanding these changes can enable better targeting of mechanisms to control pathogen outbreaks. Here, we explored how the CLso infectious status affects the volatile organic compounds (VOCs) of the tomato plant, and whether the CLso infectious status of TPP influences host plant settlement. These chemical and behavioral changes can ultimately affect the rate of encounter between the host and the vector. Results from headspace volatile collection of tomato plants showed that CLso infected tomato plants emitted a qualitatively and quantitatively different blend of VOCs compared to sham-infected plants. By a factorial experiment, we showed that CLso negative (CLso-) TPP preferred to settle 70 % more often on infected tomato plants, while CLso positive (CLso+) TPP were found 68 % more often on sham-infected tomato plants. These results provide new evidence in favor of both host and vector manipulation by CLso. PMID:25378121

  3. Host plant defense signaling in response to a coevolved herbivore combats introduced herbivore attack

    PubMed Central

    Woodard, Anastasia M; Ervin, Gary N; Marsico, Travis D

    2012-01-01

    Defense-free space resulting from coevolutionarily naïve host plants recently has been implicated as a factor facilitating invasion success of some insect species. Host plants, however, may not be entirely defenseless against novel herbivore threats. Volatile chemical-mediated defense signaling, which allows plants to mount specific, rapid, and intense responses, may play a role in systems experiencing novel threats. Here we investigate defense responses of host plants to a native and exotic herbivore and show that (1) host plants defend more effectively against the coevolved herbivore, (2) plants can be induced to defend against a newly-associated herbivore when in proximity to plants actively defending against the coevolved species, and (3) these defenses affect larval performance. These findings highlight the importance of coevolved herbivore-specific defenses and suggest that naïveté or defense limitations can be overcome via defense signaling. Determining how these findings apply across various host–herbivore systems is critical to understand mechanisms of successful herbivore invasion. PMID:22837849

  4. Repression of host RNA polymerase II transcription by herpes simplex virus type 1.

    PubMed Central

    Spencer, C A; Dahmus, M E; Rice, S A

    1997-01-01

    Lytic infection of mammalian cells with herpes simplex virus type 1 (HSV-1) results in rapid repression of host gene expression and selective activation of the viral genome. This transformation in gene expression is thought to involve repression of host transcription and diversion of the host RNA polymerase (RNAP II) transcription machinery to the viral genome. However, the extent of virus-induced host transcription repression and the mechanisms responsible for these major shifts in transcription specificities have not been examined. To determine how HSV-1 accomplishes repression of host RNAP II transcription, we assayed transcription patterns on several cellular genes in cells infected with mutant and wild-type HSV-1. Our results suggest that HSV-1 represses RNAP II transcription on most cellular genes. However, each cellular gene we examined responds differently to the transcription repressive effects of virus infection, both quantitatively and with respect to the involvement of viral gene products. Virus-induced shutoff of host RNAP II transcription requires expression of multiple immediate-early genes. In contrast, expression of delayed-early and late genes and viral DNA replication appear to contribute little to repression of host cell RNAP II transcription. Modification of RNAP II to the intermediately phosphorylated (II(I)) form appears unlinked to virus-induced repression of host cell transcription. However, full repression of host transcription is correlated with depletion of the hyperphosphorylated (IIO) form of RNAP II. PMID:9032335

  5. Congruence and Diversity of Butterfly-Host Plant Associations at Higher Taxonomic Levels

    PubMed Central

    Ferrer-Paris, José R.; Sánchez-Mercado, Ada; Viloria, Ángel L.; Donaldson, John

    2013-01-01

    We aggregated data on butterfly-host plant associations from existing sources in order to address the following questions: (1) is there a general correlation between host diversity and butterfly species richness?, (2) has the evolution of host plant use followed consistent patterns across butterfly lineages?, (3) what is the common ancestral host plant for all butterfly lineages? The compilation included 44,148 records from 5,152 butterfly species (28.6% of worldwide species of Papilionoidea) and 1,193 genera (66.3%). The overwhelming majority of butterflies use angiosperms as host plants. Fabales is used by most species (1,007 spp.) from all seven butterfly families and most subfamilies, Poales is the second most frequently used order, but is mostly restricted to two species-rich subfamilies: Hesperiinae (56.5% of all Hesperiidae), and Satyrinae (42.6% of all Nymphalidae). We found a significant and strong correlation between host plant diversity and butterfly species richness. A global test for congruence (Parafit test) was sensitive to uncertainty in the butterfly cladogram, and suggests a mixed system with congruent associations between Papilionidae and magnoliids, Hesperiidae and monocots, and the remaining subfamilies with the eudicots (fabids and malvids), but also numerous random associations. The congruent associations are also recovered as the most probable ancestral states in each node using maximum likelihood methods. The shift from basal groups to eudicots appears to be more likely than the other way around, with the only exception being a Satyrine-clade within the Nymphalidae that feed on monocots. Our analysis contributes to the visualization of the complex pattern of interactions at superfamily level and provides a context to discuss the timing of changes in host plant utilization that might have promoted diversification in some butterfly lineages. PMID:23717448

  6. Ecological specialization of the aphid Aphis gossypii Glover on cultivated host plants.

    PubMed

    Carletto, J; Lombaert, E; Chavigny, P; Brévault, T; Lapchin, L; Vanlerberghe-Masutti, F

    2009-05-01

    Many plant-feeding insect species considered to be polyphagous are in fact composed of genetically differentiated sympatric populations that use different hosts and between which gene flow still exists. We studied the population genetic structure of the cotton-melon aphid Aphis gossypii that is considered as one of the most polyphagous aphid species. We used eight microsatellites to analyse the genetic diversity of numerous samples of A. gossypii collected over several years at a large geographical scale on annual crops from different plant families. The number of multilocus genotypes detected was extremely low and the genotypes were found to be associated with host plants. Five host races were unambiguously identified (Cucurbitaceae, cotton, eggplant, potato and chili- or sweet pepper). These host races were dominated by asexual clones. Plant transfer experiments using several specialized clones further confirmed the existence of host-associated trade-offs. Finally, both genetic and experimental data suggested that plants of the genus Hibiscus may be used as refuge for the specialized clones. Resource abundance is discussed as a key factor involved in the process of ecological specialization in A. gossypii. PMID:19635073

  7. Bioactivity of Fungal Endophytes as a Function of Endophyte Taxonomy and the Taxonomy and Distribution of Their Host Plants

    PubMed Central

    Higginbotham, Sarah J.; Arnold, A. Elizabeth; Ibañez, Alicia; Spadafora, Carmenza; Coley, Phyllis D.; Kursar, Thomas A.

    2013-01-01

    Fungal endophytes – fungi that grow within plant tissues without causing immediate signs of disease – are abundant and diverse producers of bioactive secondary metabolites. Endophytes associated with leaves of tropical plants are an especially exciting and relatively untapped source of novel compounds. However, one major challenge in drug discovery lies in developing strategies to efficiently recover highly bioactive strains. As part of a 15-year drug discovery project, foliar endophytes were isolated from 3198 plant samples (51 orders, 105 families and at least 232 genera of angiosperms and ferns) collected in nine geographically distinct regions of Panama. Extracts from culture supernatants of >2700 isolates were tested for bioactivity (in vitro percent inhibition of growth, % IG) against a human breast cancer cell line (MCF-7) and the causative agents of malaria, leishmaniasis, and Chagas' disease. Overall, 32.7% of endophyte isolates were highly active in at least one bioassay, including representatives of diverse fungal lineages, host lineages, and collection sites. Up to 17% of isolates tested per assay were highly active. Most bioactive strains were active in only one assay. Fungal lineages differed in the incidence and degree of bioactivity, as did fungi from particular plant taxa, and greater bioactivity was observed in endophytes isolated from plants in cloud forests vs. lowland forests. Our results suggest that using host taxonomy and forest type to tailor plant collections, and selecting endophytes from specific orders or families for cultivation, will markedly increase the efficiency and efficacy of discovering bioactive metabolites for particular pharmaceutical targets. PMID:24066037

  8. Microbial Hub Taxa Link Host and Abiotic Factors to Plant Microbiome Variation.

    PubMed

    Agler, Matthew T; Ruhe, Jonas; Kroll, Samuel; Morhenn, Constanze; Kim, Sang-Tae; Weigel, Detlef; Kemen, Eric M

    2016-01-01

    Plant-associated microorganisms have been shown to critically affect host physiology and performance, suggesting that evolution and ecology of plants and animals can only be understood in a holobiont (host and its associated organisms) context. Host-associated microbial community structures are affected by abiotic and host factors, and increased attention is given to the role of the microbiome in interactions such as pathogen inhibition. However, little is known about how these factors act on the microbial community, and especially what role microbe-microbe interaction dynamics play. We have begun to address this knowledge gap for phyllosphere microbiomes of plants by simultaneously studying three major groups of Arabidopsis thaliana symbionts (bacteria, fungi and oomycetes) using a systems biology approach. We evaluated multiple potential factors of microbial community control: we sampled various wild A. thaliana populations at different times, performed field plantings with different host genotypes, and implemented successive host colonization experiments under lab conditions where abiotic factors, host genotype, and pathogen colonization was manipulated. Our results indicate that both abiotic factors and host genotype interact to affect plant colonization by all three groups of microbes. Considering microbe-microbe interactions, however, uncovered a network of interkingdom interactions with significant contributions to community structure. As in other scale-free networks, a small number of taxa, which we call microbial "hubs," are strongly interconnected and have a severe effect on communities. By documenting these microbe-microbe interactions, we uncover an important mechanism explaining how abiotic factors and host genotypic signatures control microbial communities. In short, they act directly on "hub" microbes, which, via microbe-microbe interactions, transmit the effects to the microbial community. We analyzed two "hub" microbes (the obligate biotrophic

  9. Determinants of parasitoid communities of willow-galling sawflies: habitat overrides physiology, host plant and space.

    PubMed

    Nyman, Tommi; Leppänen, Sanna A; Várkonyi, Gergely; Shaw, Mark R; Koivisto, Reijo; Barstad, Trond Elling; Vikberg, Veli; Roininen, Heikki

    2015-10-01

    Studies on the determinants of plant-herbivore and herbivore-parasitoid associations provide important insights into the origin and maintenance of global and local species richness. If parasitoids are specialists on herbivore niches rather than on herbivore taxa, then alternating escape of herbivores into novel niches and delayed resource tracking by parasitoids could fuel diversification at both trophic levels. We used DNA barcoding to identify parasitoids that attack larvae of seven Pontania sawfly species that induce leaf galls on eight willow species growing in subarctic and arctic-alpine habitats in three geographic locations in northern Fennoscandia, and then applied distance- and model-based multivariate analyses and phylogenetic regression methods to evaluate the hierarchical importance of location, phylogeny and different galler niche dimensions on parasitoid host use. We found statistically significant variation in parasitoid communities across geographic locations and willow host species, but the differences were mainly quantitative due to extensive sharing of enemies among gallers within habitat types. By contrast, the divide between habitats defined two qualitatively different network compartments, because many common parasitoids exhibited strong habitat preference. Galler and parasitoid phylogenies did not explain associations, because distantly related arctic-alpine gallers were attacked by a species-poor enemy community dominated by two parasitoid species that most likely have independently tracked the gallers' evolutionary shifts into the novel habitat. Our results indicate that barcode- and phylogeny-based analyses of food webs that span forested vs. tundra or grassland environments could improve our understanding of vertical diversification effects in complex plant-herbivore-parasitoid networks. PMID:26340615

  10. Fungal small RNAs suppress plant immunity by hijacking host RNA interference pathways.

    PubMed

    Weiberg, Arne; Wang, Ming; Lin, Feng-Mao; Zhao, Hongwei; Zhang, Zhihong; Kaloshian, Isgouhi; Huang, Hsien-Da; Jin, Hailing

    2013-10-01

    Botrytis cinerea, the causative agent of gray mold disease, is an aggressive fungal pathogen that infects more than 200 plant species. Here, we show that some B. cinerea small RNAs (Bc-sRNAs) can silence Arabidopsis and tomato genes involved in immunity. These Bc-sRNAs hijack the host RNA interference (RNAi) machinery by binding to Arabidopsis Argonaute 1 (AGO1) and selectively silencing host immunity genes. The Arabidopsis ago1 mutant exhibits reduced susceptibility to B. cinerea, and the B. cinerea dcl1 dcl2 double mutant that can no longer produce these Bc-sRNAs displays reduced pathogenicity on Arabidopsis and tomato. Thus, this fungal pathogen transfers "virulent" sRNA effectors into host plant cells to suppress host immunity and achieve infection, which demonstrates a naturally occurring cross-kingdom RNAi as an advanced virulence mechanism. PMID:24092744

  11. Exploring the host parasitism of the migratory plant-parasitic nematode Ditylenchus destuctor by expressed sequence tags analysis.

    PubMed

    Peng, Huan; Gao, Bing-li; Kong, Ling-an; Yu, Qing; Huang, Wen-kun; He, Xu-feng; Long, Hai-bo; Peng, De-liang

    2013-01-01

    The potato rot nematode, Ditylenchus destructor, is a very destructive nematode pest on many agriculturally important crops worldwide, but the molecular characterization of its parasitism of plant has been limited. The effectors involved in nematode parasitism of plant for several sedentary endo-parasitic nematodes such as Heterodera glycines, Globodera rostochiensis and Meloidogyne incognita have been identified and extensively studied over the past two decades. Ditylenchus destructor, as a migratory plant parasitic nematode, has different feeding behavior, life cycle and host response. Comparing the transcriptome and parasitome among different types of plant-parasitic nematodes is the way to understand more fully the parasitic mechanism of plant nematodes. We undertook the approach of sequencing expressed sequence tags (ESTs) derived from a mixed stage cDNA library of D. destructor. This is the first study of D. destructor ESTs. A total of 9800 ESTs were grouped into 5008 clusters including 3606 singletons and 1402 multi-member contigs, representing a catalog of D. destructor genes. Implementing a bioinformatics' workflow, we found 1391 clusters have no match in the available gene database; 31 clusters only have similarities to genes identified from D. africanus, the most closely related species to D. destructor; 1991 clusters were annotated using Gene Ontology (GO); 1550 clusters were assigned enzyme commission (EC) numbers; and 1211 clusters were mapped to 181 KEGG biochemical pathways. 22 ESTs had similarities to reported nematode effectors. Interestedly, most of the effectors identified in this study are involved in host cell wall degradation or modification, such as 1,4-beta-glucanse, 1,3-beta-glucanse, pectate lyase, chitinases and expansin, or host defense suppression such as calreticulin, annexin and venom allergen-like protein. This result implies that the migratory plant-parasitic nematode D. destructor secrets similar effectors to those of sedentary

  12. Exploring the Host Parasitism of the Migratory Plant-Parasitic Nematode Ditylenchus destuctor by Expressed Sequence Tags Analysis

    PubMed Central

    Peng, Huan; Gao, Bing-li; Kong, Ling-an; Yu, Qing; Huang, Wen-kun; He, Xu-feng; Long, Hai-bo; Peng, De-liang

    2013-01-01

    The potato rot nematode, Ditylenchus destructor, is a very destructive nematode pest on many agriculturally important crops worldwide, but the molecular characterization of its parasitism of plant has been limited. The effectors involved in nematode parasitism of plant for several sedentary endo-parasitic nematodes such as Heterodera glycines, Globodera rostochiensis and Meloidogyne incognita have been identified and extensively studied over the past two decades. Ditylenchus destructor, as a migratory plant parasitic nematode, has different feeding behavior, life cycle and host response. Comparing the transcriptome and parasitome among different types of plant-parasitic nematodes is the way to understand more fully the parasitic mechanism of plant nematodes. We undertook the approach of sequencing expressed sequence tags (ESTs) derived from a mixed stage cDNA library of D. destructor. This is the first study of D. destructor ESTs. A total of 9800 ESTs were grouped into 5008 clusters including 3606 singletons and 1402 multi-member contigs, representing a catalog of D. destructor genes. Implementing a bioinformatics' workflow, we found 1391 clusters have no match in the available gene database; 31 clusters only have similarities to genes identified from D. africanus, the most closely related species to D. destructor; 1991 clusters were annotated using Gene Ontology (GO); 1550 clusters were assigned enzyme commission (EC) numbers; and 1211 clusters were mapped to 181 KEGG biochemical pathways. 22 ESTs had similarities to reported nematode effectors. Interestedly, most of the effectors identified in this study are involved in host cell wall degradation or modification, such as 1,4-beta-glucanse, 1,3-beta-glucanse, pectate lyase, chitinases and expansin, or host defense suppression such as calreticulin, annexin and venom allergen-like protein. This result implies that the migratory plant-parasitic nematode D. destructor secrets similar effectors to those of sedentary

  13. Host Plants Identification for Adult Agrotis ipsilon, a Long-Distance Migratory Insect

    PubMed Central

    Liu, Yongqiang; Fu, Xiaowei; Mao, Limi; Xing, Zhenlong; Wu, Kongming

    2016-01-01

    In this study, we determined the host relationship of Agrotis ipsilon moths by identifying pollen species adhering them during their long-distance migration. Pollen carried by A. ipsilon moths was collected from 2012 to 2014 on a small island in the center of the Bohai Strait, which is a seasonal migration pathway of this pest species. Genomic DNA of single pollen grains was amplified by using whole genome amplification technology, and a portion of the chloroplast rbcL sequence was then amplified from this material. Pollen species were identified by a combination of DNA barcoding and pollen morphology. We found 28 species of pollen from 18 families on the tested moths, mainly from Angiosperm, Dicotyledoneae. From this, we were able to determine that these moths visit woody plants more than herbaceous plants that they carry more pollen in the early and late stages of the migration season, and that the amounts of pollen transportation were related to moth sex, moth body part, and plant species. In general, 31% of female and 26% of male moths were found to be carrying pollen. Amounts of pollen on the proboscis was higher for female than male moths, while the reverse was true for pollen loads on the antennae. This work provides a new approach to study the interactions between noctuid moth and their host plants. Identification of plant hosts for adult moths furthers understanding of the coevolution processes between moths and their host plants. PMID:27271592

  14. Host Plants Identification for Adult Agrotis ipsilon, a Long-Distance Migratory Insect.

    PubMed

    Liu, Yongqiang; Fu, Xiaowei; Mao, Limi; Xing, Zhenlong; Wu, Kongming

    2016-01-01

    In this study, we determined the host relationship of Agrotis ipsilon moths by identifying pollen species adhering them during their long-distance migration. Pollen carried by A. ipsilon moths was collected from 2012 to 2014 on a small island in the center of the Bohai Strait, which is a seasonal migration pathway of this pest species. Genomic DNA of single pollen grains was amplified by using whole genome amplification technology, and a portion of the chloroplast rbcL sequence was then amplified from this material. Pollen species were identified by a combination of DNA barcoding and pollen morphology. We found 28 species of pollen from 18 families on the tested moths, mainly from Angiosperm, Dicotyledoneae. From this, we were able to determine that these moths visit woody plants more than herbaceous plants that they carry more pollen in the early and late stages of the migration season, and that the amounts of pollen transportation were related to moth sex, moth body part, and plant species. In general, 31% of female and 26% of male moths were found to be carrying pollen. Amounts of pollen on the proboscis was higher for female than male moths, while the reverse was true for pollen loads on the antennae. This work provides a new approach to study the interactions between noctuid moth and their host plants. Identification of plant hosts for adult moths furthers understanding of the coevolution processes between moths and their host plants. PMID:27271592

  15. The Impact of Environmental Conditions on Efficiency of Host Plant DNA Barcoding for Polyphagous Beetles.

    PubMed

    Kajtoch, Łukasz; Mazur, Miłosz A

    2015-04-01

    Recently, several papers were published dealing with host plant identification for selected species of insects, including beetles. These studies took advantage of the DNA barcoding approach and generally showed that it is possible to identify diet composition from plant DNA present in insect guts. However, none of these studies considered how the impact of environmental conditions affected the likelihood of insect feeding and, therefore, the presence of host plant DNA that could be amplified and sequenced. In the present study, individuals of the polyphagous weevil Centricnemus leucogrammus (Germar, 1824) (Curculionidae: Entiminae) were used to test the hypothesis that harsh environmental conditions limited its feeding activity. The diet of 50 specimens collected during favourable conditions in the middle of the species reproductive period was compared against the diet of 50 specimens collected during harsh environmental conditions. Results clearly showed that almost no weevils fed during rainy and cold conditions and only a minority of individuals (20%) fed during the drought condition (on drought-resistant plants). It is important to consider such factors in any studies dealing with host plant identification and feeding behaviour. Results of ecological studies could lead to erroneous conclusions, e.g., underestimation of number and composition of host plants in the diet of studies species. PMID:26313186

  16. The bacterial pathogen Xylella fastidiosa affects the leaf ionome of plant hosts during infection.

    PubMed

    De La Fuente, Leonardo; Parker, Jennifer K; Oliver, Jonathan E; Granger, Shea; Brannen, Phillip M; van Santen, Edzard; Cobine, Paul A

    2013-01-01

    Xylella fastidiosa is a plant pathogenic bacterium that lives inside the host xylem vessels, where it forms biofilm believed to be responsible for disrupting the passage of water and nutrients. Here, Nicotiana tabacum was infected with X. fastidiosa, and the spatial and temporal changes in the whole-leaf ionome (i.e. the mineral and trace element composition) were measured as the host plant transitioned from healthy to diseased physiological status. The elemental composition of leaves was used as an indicator of the physiological changes in the host at a specific time and relative position during plant development. Bacterial infection was found to cause significant increases in concentrations of calcium prior to the appearance of symptoms and decreases in concentrations of phosphorous after symptoms appeared. Field-collected leaves from multiple varieties of grape, blueberry, and pecan plants grown in different locations over a four-year period in the Southeastern US showed the same alterations in Ca and P. This descriptive ionomics approach characterizes the existence of a mineral element-based response to X. fastidiosa using a model system suitable for further manipulation to uncover additional details of the role of mineral elements during plant-pathogen interactions. This is the first report on the dynamics of changes in the ionome of the host plant throughout the process of infection by a pathogen. PMID:23667547

  17. Survival relative to new and ancestral host plants, phytoplasma infection, and genetic constitution in host races of a polyphagous insect disease vector

    PubMed Central

    Maixner, Michael; Albert, Andreas; Johannesen, Jes

    2014-01-01

    Dissemination of vectorborne diseases depends strongly on the vector's host range and the pathogen's reservoir range. Because vectors interact with pathogens, the direction and strength of a vector's host shift is vital for understanding epidemiology and is embedded in the framework of ecological specialization. This study investigates survival in host-race evolution of a polyphagous insect disease vector, Hyalesthes obsoletus, whether survival is related to the direction of the host shift (from field bindweed to stinging nettle), the interaction with plant-specific strains of obligate vectored pathogens/symbionts (stolbur phytoplasma), and whether survival is related to genetic differentiation between the host races. We used a twice repeated, identical nested experimental design to study survival of the vector on alternative hosts and relative to infection status. Survival was tested with Kaplan–Meier analyses, while genetic differentiation between vector populations was quantified with microsatellite allele frequencies. We found significant direct effects of host plant (reduced survival on wrong hosts) and sex (males survive longer than females) in both host races and relative effects of host (nettle animals more affected than bindweed animals) and sex (males more affected than females). Survival of bindweed animals was significantly higher on symptomatic than nonsymptomatic field bindweed, but in the second experiment only. Infection potentially had a positive effect on survival in nettle animals but due to low infection rates the results remain suggestive. Genetic differentiation was not related to survival. Greater negative plant-transfer effect but no negative effect of stolbur in the derived host race suggests preadaptation to the new pathogen/symbiont strain before strong diversifying selection during the specialization process. Physiological maladaptation or failure to accept the ancestral plant will have similar consequences, namely positive assortative

  18. Survival relative to new and ancestral host plants, phytoplasma infection, and genetic constitution in host races of a polyphagous insect disease vector.

    PubMed

    Maixner, Michael; Albert, Andreas; Johannesen, Jes

    2014-08-01

    Dissemination of vectorborne diseases depends strongly on the vector's host range and the pathogen's reservoir range. Because vectors interact with pathogens, the direction and strength of a vector's host shift is vital for understanding epidemiology and is embedded in the framework of ecological specialization. This study investigates survival in host-race evolution of a polyphagous insect disease vector, Hyalesthes obsoletus, whether survival is related to the direction of the host shift (from field bindweed to stinging nettle), the interaction with plant-specific strains of obligate vectored pathogens/symbionts (stolbur phytoplasma), and whether survival is related to genetic differentiation between the host races. We used a twice repeated, identical nested experimental design to study survival of the vector on alternative hosts and relative to infection status. Survival was tested with Kaplan-Meier analyses, while genetic differentiation between vector populations was quantified with microsatellite allele frequencies. We found significant direct effects of host plant (reduced survival on wrong hosts) and sex (males survive longer than females) in both host races and relative effects of host (nettle animals more affected than bindweed animals) and sex (males more affected than females). Survival of bindweed animals was significantly higher on symptomatic than nonsymptomatic field bindweed, but in the second experiment only. Infection potentially had a positive effect on survival in nettle animals but due to low infection rates the results remain suggestive. Genetic differentiation was not related to survival. Greater negative plant-transfer effect but no negative effect of stolbur in the derived host race suggests preadaptation to the new pathogen/symbiont strain before strong diversifying selection during the specialization process. Physiological maladaptation or failure to accept the ancestral plant will have similar consequences, namely positive assortative

  19. Unmasking host and microbial strategies in the Agrobacterium-plant defense tango

    PubMed Central

    Hwang, Elizabeth E.; Wang, Melinda B.; Bravo, Janis E.; Banta, Lois M.

    2015-01-01

    Coevolutionary forces drive adaptation of both plant-associated microbes and their hosts. Eloquently captured in the Red Queen Hypothesis, the complexity of each plant–pathogen relationship reflects escalating adversarial strategies, but also external biotic and abiotic pressures on both partners. Innate immune responses are triggered by highly conserved pathogen-associated molecular patterns, or PAMPs, that are harbingers of microbial presence. Upon cell surface receptor-mediated recognition of these pathogen-derived molecules, host plants mount a variety of physiological responses to limit pathogen survival and/or invasion. Successful pathogens often rely on secretion systems to translocate host-modulating effectors that subvert plant defenses, thereby increasing virulence. Host plants, in turn, have evolved to recognize these effectors, activating what has typically been characterized as a pathogen-specific form of immunity. Recent data support the notion that PAMP-triggered and effector-triggered defenses are complementary facets of a convergent, albeit differentially regulated, set of immune responses. This review highlights the key players in the plant’s recognition and signal transduction pathways, with a focus on the aspects that may limit Agrobacterium tumefaciens infection and the ways it might overcome those defenses. Recent advances in the field include a growing appreciation for the contributions of cytoskeletal dynamics and membrane trafficking to the regulation of these exquisitely tuned defenses. Pathogen counter-defenses frequently manipulate the interwoven hormonal pathways that mediate host responses. Emerging systems-level analyses include host physiological factors such as circadian cycling. The existing literature indicates that varying or even conflicting results from different labs may well be attributable to environmental factors including time of day of infection, temperature, and/or developmental stage of the host plant. PMID:25873923

  20. Herbivore-induced plant volatiles mediate host selection by a root herbivore.

    PubMed

    Robert, Christelle A M; Erb, Matthias; Duployer, Marianne; Zwahlen, Claudia; Doyen, Gwladys R; Turlings, Ted C J

    2012-06-01

    In response to herbivore attack, plants mobilize chemical defenses and release distinct bouquets of volatiles. Aboveground herbivores are known to use changes in leaf volatile patterns to make foraging decisions, but it remains unclear whether belowground herbivores also use volatiles to select suitable host plants. We therefore investigated how above- and belowground infestation affects the performance of the root feeder Diabrotica virgifera virgifera, and whether the larvae of this specialized beetle are able to use volatile cues to assess from a distance whether a potential host plant is already under herbivore attack. Diabrotica virgifera larvae showed stronger growth on roots previously attacked by conspecific larvae, but performed more poorly on roots of plants whose leaves had been attacked by larvae of the moth Spodoptera littoralis. Fittingly, D. virgifera larvae were attracted to plants that were infested with conspecifics, whereas they avoided plants that were attacked by S. littoralis. We identified (E)-β-caryophyllene, which is induced by D. virgifera, and ethylene, which is suppressed by S. littoralis, as two signals used by D. virgifera larvae to locate plants that are most suitable for their development. Our study demonstrates that soil-dwelling insects can use herbivore-induced changes in root volatile emissions to identify suitable host plants. PMID:22486361

  1. Manipulation of Plant Host Susceptibility: An Emerging Role for Viral Movement Proteins?

    PubMed Central

    Amari, Khalid; Vazquez, Franck; Heinlein, Manfred

    2012-01-01

    Viruses encode viral suppressors of RNA silencing (VSRs) to counteract RNA silencing, a major antiviral defense response in plants. Recent studies indicate a role of virus-derived siRNAs in manipulating the expression of specific host genes and that certain plant viral movement proteins (MPs) can act as viral enhancers of RNA silencing (VERs) by stimulating the spread of silencing between cells. This suggests that viruses have evolved complex responses capable to efficiently hijack the host RNA silencing machinery to their own advantage. We draw here a dynamic model of the interaction of plant viruses with the silencing machinery during invasion of the host. The model proposes that cells at the spreading front of infection, where infection starts from zero and the VSR levels are supposedly low, represent potential sites for viral manipulation of host gene expression by using virus- and host-derived small RNAs. Viral MPs may facilitate the spread of silencing to produce a wave of small RNA-mediated gene expression changes ahead of the infection to increase host susceptibility. When experimentally ascertained, this hypothetical model will call for re-defining viral movement and the function of viral MPs. PMID:22639637

  2. Complex inheritance of larval adaptation in Plutella xylostella to a novel host plant

    PubMed Central

    Henniges-Janssen, K; Reineke, A; Heckel, D G; Groot, A T

    2011-01-01

    Studying the genetics of host shifts and range expansions in phytophagous insects contributes to our understanding of the evolution of host plant adaptation. We investigated the recent host range expansion to pea, in the pea-adapted strain (P-strain) of the crucifer-specialist diamondback moth, Plutella xylostella (Lepidoptera: Plutellidae). Larval survivorship on the novel host plant pea and a typical crucifer host (kale) was measured in reciprocal F1, F2 and backcrosses between the P-strain and a strain reared only on crucifers (C-strain). Reciprocal F1 hybrids differed: offspring from P-strain mothers survived better on pea, indicating a maternal effect. However, no evidence for sex-linkage was found. Backcrosses to the P-strain produced higher survivorship on pea than C-strain backcrosses, suggesting recessive inheritance. In a linkage analysis with amplified fragment length polymorphism markers using P-strain backcrosses, two, four and five linkage groups contributing to survival on pea were identified in three different families respectively, indicating oligogenic inheritance. Thus, the newly evolved ability to survive on pea has a complex genetic basis, and the P-strain is still genetically heterogeneous and not yet fixed for all the alleles enabling it to survive on pea. Survivorship on kale was variable, but not related to survivorship on pea. This pattern may characterize the genetic inheritance of early host plant adaptation in oligophagous insect species. PMID:21673741

  3. Microbial Hub Taxa Link Host and Abiotic Factors to Plant Microbiome Variation

    PubMed Central

    Agler, Matthew T.; Ruhe, Jonas; Kroll, Samuel; Morhenn, Constanze; Kim, Sang-Tae; Weigel, Detlef; Kemen, Eric M.

    2016-01-01

    Plant-associated microorganisms have been shown to critically affect host physiology and performance, suggesting that evolution and ecology of plants and animals can only be understood in a holobiont (host and its associated organisms) context. Host-associated microbial community structures are affected by abiotic and host factors, and increased attention is given to the role of the microbiome in interactions such as pathogen inhibition. However, little is known about how these factors act on the microbial community, and especially what role microbe–microbe interaction dynamics play. We have begun to address this knowledge gap for phyllosphere microbiomes of plants by simultaneously studying three major groups of Arabidopsis thaliana symbionts (bacteria, fungi and oomycetes) using a systems biology approach. We evaluated multiple potential factors of microbial community control: we sampled various wild A. thaliana populations at different times, performed field plantings with different host genotypes, and implemented successive host colonization experiments under lab conditions where abiotic factors, host genotype, and pathogen colonization was manipulated. Our results indicate that both abiotic factors and host genotype interact to affect plant colonization by all three groups of microbes. Considering microbe–microbe interactions, however, uncovered a network of interkingdom interactions with significant contributions to community structure. As in other scale-free networks, a small number of taxa, which we call microbial “hubs,” are strongly interconnected and have a severe effect on communities. By documenting these microbe–microbe interactions, we uncover an important mechanism explaining how abiotic factors and host genotypic signatures control microbial communities. In short, they act directly on “hub” microbes, which, via microbe–microbe interactions, transmit the effects to the microbial community. We analyzed two “hub” microbes (the

  4. Impact of Vector Dispersal and Host-Plant Fidelity on the Dissemination of an Emerging Plant Pathogen

    PubMed Central

    Johannesen, Jes; Foissac, Xavier; Kehrli, Patrik; Maixner, Michael

    2012-01-01

    Dissemination of vector-transmitted pathogens depend on the survival and dispersal of the vector and the vector's ability to transmit the pathogen, while the host range of vector and pathogen determine the breath of transmission possibilities. In this study, we address how the interaction between dispersal and plant fidelities of a pathogen (stolbur phytoplasma tuf-a) and its vector (Hyalesthes obsoletus: Cixiidae) affect the emergence of the pathogen. Using genetic markers, we analysed the geographic origin and range expansion of both organisms in Western Europe and, specifically, whether the pathogen's dissemination in the northern range is caused by resident vectors widening their host-plant use from field bindweed to stinging nettle, and subsequent host specialisation. We found evidence for common origins of pathogen and vector south of the European Alps. Genetic patterns in vector populations show signals of secondary range expansion in Western Europe leading to dissemination of tuf-a pathogens, which might be newly acquired and of hybrid origin. Hence, the emergence of stolbur tuf-a in the northern range was explained by secondary immigration of vectors carrying stinging nettle-specialised tuf-a, not by widening the host-plant spectrum of resident vectors with pathogen transmission from field bindweed to stinging nettle nor by primary co-migration from the resident vector's historical area of origin. The introduction of tuf-a to stinging nettle in the northern range was therefore independent of vector's host-plant specialisation but the rapid pathogen dissemination depended on the vector's host shift, whereas the general dissemination elsewhere was linked to plant specialisation of the pathogen but not of the vector. PMID:23284774

  5. 7 CFR 301.92-2 - Restricted, regulated, and associated articles; lists of proven hosts and associated plant taxa.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... of proven hosts and associated plant taxa. 301.92-2 Section 301.92-2 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...; lists of proven hosts and associated plant taxa. (a) Restricted articles. The following are...

  6. 7 CFR 301.92-2 - Restricted, regulated, and associated articles; lists of proven hosts and associated plant taxa.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... of proven hosts and associated plant taxa. 301.92-2 Section 301.92-2 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...; lists of proven hosts and associated plant taxa. (a) Restricted articles. The following are...

  7. 7 CFR 301.92-2 - Restricted, regulated, and associated articles; lists of proven hosts and associated plant taxa.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... of proven hosts and associated plant taxa. 301.92-2 Section 301.92-2 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...; lists of proven hosts and associated plant taxa. (a) Restricted articles. The following are...

  8. 7 CFR 301.92-2 - Restricted, regulated, and associated articles; lists of proven hosts and associated plant taxa.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... of proven hosts and associated plant taxa. 301.92-2 Section 301.92-2 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...; lists of proven hosts and associated plant taxa. (a) Restricted articles. The following are...

  9. 7 CFR 301.92-2 - Restricted, regulated, and associated articles; lists of proven hosts and associated plant taxa.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... of proven hosts and associated plant taxa. 301.92-2 Section 301.92-2 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE...; lists of proven hosts and associated plant taxa. (a) Restricted articles. The following are...

  10. Effects of Host Plant Factors on the Bacterial Communities Associated with Two Whitefly Sibling Species

    PubMed Central

    Su, Ming-Ming; Guo, Lei; Tao, Yun-Li; Zhang, You-Jun; Wan, Fang-Hao; Chu, Dong

    2016-01-01

    Background Although discrepancy in the specific traits and ecological characteristics of Bemisia tabaci between species are partially attributed to the B. tabaci-associated bacteria, the factors that affect the diversity of B. tabaci-associated bacteria are not well-understood. We used the metagenomic approach to characterize the B. tabaci-associated bacterial community because the approach is an effective tool to identify the bacteria. Methodology and Results To investigate the effects of the host plant and a virus, tomato yellow leaf curl virus (TYLCV), on the bacterial communities of B. tabaci sibling species B and Q, we analyzed the bacterial communities associated with whitefly B and Q collected from healthy cotton, healthy tomato, and TYLCV-infected tomato. The analysis used miseq-based sequencing of a variable region of the bacterial 16S rDNA gene. For the bacteria associated with B. tabaci, we found that the influence of the host plant species was greater than that of the whitefly cryptic species. With further analysis of host plants infected with the TYLCV, the virus had no significant effects on the B. tabaci-associated bacterial community. Conclusions The effects of different plant hosts and TYLCV-infection on the diversity of B. tabaci-associated bacterial communities were successfully analyzed in this study. To explain why B. tabaci sibling species with different host ranges differ in performance, the analysis of the bacterial community may be essential to the explanation. PMID:27008327

  11. [Effects of host plants on development and fecundity of Brontispa longissima (Gestro)].

    PubMed

    Li, Ya; Cheng, Li-Sheng; Peng, Zheng-Qiang; Ju, Rui-Ting; Wan, Fang-Hao

    2007-09-01

    With Cocos nucifera, Hyophorbe lagenicaulis, Washingtonia filifera, Roystonea regia and Areca catechu as test host plants, this paper studied the effects of their un-spread leaves on the development and fecundity of experimental population of Brontispa longissima. The results showed that the development duration of one generation B. longissima fed on different hosts varied significantly, with the longest (72.8 days) on W. filifera and the shortest (39.8 days) on H. lagenicaulis. The average pupa weight of B. longissima was bigger on H. lagenicaulis than on the other four host plants, and the female B. longissima had the highest fecundity (157.6 ova) on W. filifera while the lowest one (65.2 ova) on A. catechu. The longevity of B. longissima adults fed on H. lagenicaulis was 207.52 days, being significantly longer than that on the other host plants. The trend index of experimental population of B. longissima fed on the five host plants was 53.57, 54.98, 48.56, 20.46 and 11.54, respectively. PMID:18062312

  12. Geography and major host evolutionary transitions shape the resource use of plant parasites.

    PubMed

    Calatayud, Joaquín; Hórreo, José Luis; Madrigal-González, Jaime; Migeon, Alain; Rodríguez, Miguel Á; Magalhães, Sara; Hortal, Joaquín

    2016-08-30

    The evolution of resource use in herbivores has been conceptualized as an analog of the theory of island biogeography, assuming that plant species are islands separated by phylogenetic distances. Despite its usefulness, this analogy has paradoxically led to neglecting real biogeographical processes in the study of macroevolutionary patterns of herbivore-plant interactions. Here we show that host use is mostly determined by the geographical cooccurrence of hosts and parasites in spider mites (Tetranychidae), a globally distributed group of plant parasites. Strikingly, geography accounts for most of the phylogenetic signal in host use by these parasites. Beyond geography, only evolutionary transitions among major plant lineages (i.e., gymnosperms, commelinids, and eudicots) shape resource use patterns in these herbivores. Still, even these barriers have been repeatedly overcome in evolutionary time, resulting in phylogenetically diverse parasite communities feeding on similar hosts. Therefore, our results imply that patterns of apparent evolutionary conservatism may largely be a byproduct of the geographic cooccurrence of hosts and parasites. PMID:27535932

  13. Type III secretion: a bacterial device for close combat with cells of their eukaryotic host.

    PubMed

    Cornelis, G R

    2000-05-29

    Salmonella, Shigella, Yersinia, Pseudomonas aeruginosa, enteropathogenic Escherichia coli and several plant-pathogenic Gram-negative bacteria use a new type of systems called 'type III secretion' to attack their host. These systems are activated by contact with a eukaryotic cell membrane and they allow bacteria to inject bacterial proteins across the two bacterial membranes and the eukaryotic cell membrane to reach a given compartment and destroy or subvert the target cell. These systems consist of a secretion apparatus made up of about 25 individual proteins and a set of proteins released by this apparatus. Some of these released proteins are 'effectors' that are delivered by extracellular bacteria into the cytosol of the target cell while the others are 'translocators' that help the 'effectors' to cross the membrane of the eukaryotic cell. Most of the 'effectors' act on the cytoskeleton or on intracellular signalling cascades. One of the proteins injected by the enteropathogenic E. coli serves as a membrane receptor for the docking of the bacterium itself at the surface of the cell. PMID:10874740

  14. Preference of a Polyphagous Mirid Bug, Apolygus lucorum (Meyer-Dür) for Flowering Host Plants

    PubMed Central

    Pan, Hongsheng; Lu, Yanhui; Wyckhuys, Kris A. G.; Wu, Kongming

    2013-01-01

    Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) is one of the most important herbivores in a broad range of cultivated plants, including cotton, cereals, vegetables, and fruit crops in China. In this manuscript, we report on a 6-year long study in which (adult) A. lucorum abundance was recorded on 174 plant species from 39 families from early July to mid-September. Through the study period per year, the proportion of flowering plants exploited by adult A. lucorum was significantly greater than that of non-flowering plants. For a given plant species, A. lucorum adults reached peak abundance at the flowering stage, when the plant had the greatest attraction to the adults. More specifically, mean adult abundance on 26 species of major host plants and their relative standard attraction were 10.3–28.9 times and 9.3–19.5 times higher at flowering stage than during non-flowering periods, respectively. Among all the tested species, A. lucorum adults switched food plants according to the succession of flowering plant species. In early July, A. lucorum adults preferred some plant species in bloom, such as Vigna radiata, Gossypium hirsutum, Helianthus annuus and Chrysanthemum coronarium; since late July, adults dispersed into other flowering hosts (e.g. Ricinus communis, Impatiens balsamina, Humulus scandens, Ocimum basilicum, Agastache rugosus and Coriandrum sativum); in early September, they largely migrated to flowering Artemisia spp. (e.g. A. argyi, A. lavandulaefolia, A. annua and A. scoparia). Our findings underscore the important role of flowering plays in the population dynamics and inter-plant migration of this mirid bug. Also, our work helps understand evolutionary aspects of host plant use in polyphagous insects such as A. lucorum, and provides baseline information for the development of sustainable management strategies of this key agricultural pest. PMID:23874835

  15. Arbuscular mycorrhizal fungal phylogenetic groups differ in affecting host plants along heavy metal levels.

    PubMed

    He, Lei; Yang, Haishui; Yu, Zhenxing; Tang, Jianjun; Xu, Ligen; Chen, Xin

    2014-10-01

    Arbuscular mycorrhizal fungi (AMF) are important components of soil microbial communities, and play important role in plant growth. However, the effects of AMF phylogenetic groups (Glomeraceae and non-Glomeraceae) on host plant under various heavy metal levels are not clear. Here we conducted a meta-analysis to compare symbiotic relationship between AMF phylogenetic groups (Glomeraceae and non-Glomeraceae) and host plant functional groups (herbs vs. trees, and non-legumes vs. legumes) at three heavy metal levels. In the meta-analysis, we calculate the effect size (ln(RR)) by taking the natural logarithm of the response ratio of inoculated to non-inoculated shoot biomass from each study. We found that the effect size of Glomeraceae increased, but the effect size of non-Glomeraceae decreased under high level of heavy metal compared to low level. According to the effect size, both Glomeraceae and non-Glomeraceae promoted host plant growth, but had different effects under various heavy metal levels. Glomeraceae provided more benefit to host plants than non-Glomeraceae did under heavy metal condition, while non-Glomeraceae provided more benefit to host plants than Glomeraceae did under no heavy metal. AMF phylogenetic groups also differed in promoting plant functional groups under various heavy metal levels. Interacting with Glomeraceae, herbs and legumes grew better than trees and non-legumes did under high heavy metal level, while trees and legumes grew better than herbs and non-legumes did under medium heavy metal level. Interacting with non-Glomeraceae, herbs and legumes grew better than trees and non-legumes did under no heavy metal. We suggested that the combination of legume with Glomeraceae could be a useful way in the remediation of heavy metal polluted environment. PMID:25288547

  16. Nitric oxide production by necrotrophic pathogen Macrophomina phaseolina and the host plant in charcoal rot disease of jute: complexity of the interplay between necrotroph-host plant interactions.

    PubMed

    Sarkar, Tuhin Subhra; Biswas, Pranjal; Ghosh, Subrata Kumar; Ghosh, Sanjay

    2014-01-01

    M. phaseolina, a global devastating necrotrophic fungal pathogen causes charcoal rot disease in more than 500 host plants. With the aim of understanding the plant-necrotrophic pathogen interaction associated with charcoal rot disease of jute, biochemical approach was attempted to study cellular nitric oxide production under diseased condition. This is the first report on M. phaseolina infection in Corchorus capsularis (jute) plants which resulted in elevated nitric oxide, reactive nitrogen species and S nitrosothiols production in infected tissues. Time dependent nitric oxide production was also assessed with 4-Amino-5-Methylamino-2',7'-Difluorofluorescein Diacetate using single leaf experiment both in presence of M. phaseolina and xylanases obtained from fungal secretome. Cellular redox status and redox active enzymes were also assessed during plant fungal interaction. Interestingly, M. phaseolina was found to produce nitric oxide which was detected in vitro inside the mycelium and in the surrounding medium. Addition of mammalian nitric oxide synthase inhibitor could block the nitric oxide production in M. phaseolina. Bioinformatics analysis revealed nitric oxide synthase like sequence with conserved amino acid sequences in M. phaseolina genome sequence. In conclusion, the production of nitric oxide and reactive nitrogen species may have important physiological significance in necrotrophic host pathogen interaction. PMID:25208092

  17. Nitric Oxide Production by Necrotrophic Pathogen Macrophomina phaseolina and the Host Plant in Charcoal Rot Disease of Jute: Complexity of the Interplay between Necrotroph–Host Plant Interactions

    PubMed Central

    Sarkar, Tuhin Subhra; Biswas, Pranjal; Ghosh, Subrata Kumar; Ghosh, Sanjay

    2014-01-01

    M. phaseolina, a global devastating necrotrophic fungal pathogen causes charcoal rot disease in more than 500 host plants. With the aim of understanding the plant-necrotrophic pathogen interaction associated with charcoal rot disease of jute, biochemical approach was attempted to study cellular nitric oxide production under diseased condition. This is the first report on M. phaseolina infection in Corchorus capsularis (jute) plants which resulted in elevated nitric oxide, reactive nitrogen species and S nitrosothiols production in infected tissues. Time dependent nitric oxide production was also assessed with 4-Amino-5-Methylamino-2′,7′-Difluorofluorescein Diacetate using single leaf experiment both in presence of M. phaseolina and xylanases obtained from fungal secretome. Cellular redox status and redox active enzymes were also assessed during plant fungal interaction. Interestingly, M. phaseolina was found to produce nitric oxide which was detected in vitro inside the mycelium and in the surrounding medium. Addition of mammalian nitric oxide synthase inhibitor could block the nitric oxide production in M. phaseolina. Bioinformatics analysis revealed nitric oxide synthase like sequence with conserved amino acid sequences in M. phaseolina genome sequence. In conclusion, the production of nitric oxide and reactive nitrogen species may have important physiological significance in necrotrophic host pathogen interaction. PMID:25208092

  18. Brachypodium distachyon is a suitable host plant for study of Barley yellow dwarf virus.

    PubMed

    Tao, Ye; Nadege, Soumou Wansim; Huang, Caiping; Zhang, Penghui; Song, Shuang; Sun, Liying; Wu, Yunfeng

    2016-04-01

    Barley yellow dwarf viruses (BYDVs) belong to the family Luteoviridae and cause disease in cereals. Because of the large and complex genome of cereal plants, it is difficult to study host-virus interactions. In order to establish a model host system for the studies on BYDVs, we examined the susceptibility of a monocot model plant, Brachypodium distachyon, to BYDV-GAV infection. Fourteen days after BYDV-GAV inoculation by aphid transmission, B. distachyon plants (inbred line Bd21-3) showed conspicuous disease symptoms such as leaf reddening, dwarfness and root stunting. Virus accumulation was detected in both shoots and roots using reverse transcription PCR and triple antibody sandwich ELISA. Compared with infected wheat plants, B. distachyon plants developed more severe disease symptoms and accumulated a higher level of BYDV-GAV. Under transmission electron microscope, we observed that virus particles accumulated in companion cells and BYDV-GAV infection was associated with the deformation of chloroplasts in the infected leaves of B. distachyon plants. Our results suggest that B. distachyon is a suitable and promising experimental model plant for the host-BYDV-GAV pathosystem and possibly for other BYDVs. PMID:26814813

  19. The xylem as battleground for plant hosts and vascular wilt pathogens

    PubMed Central

    Yadeta, Koste A.; J. Thomma, Bart P. H.

    2013-01-01

    Vascular wilts are among the most destructive plant diseases that occur in annual crops as well as in woody perennials. These diseases are generally caused by soil-borne bacteria, fungi, and oomycetes that infect through the roots and enter the water-conducting xylem vessels where they proliferate and obstruct the transportation of water and minerals. As a consequence, leaves wilt and die, which may lead to impairment of the whole plant and eventually to death of the plant. Cultural, chemical, and biological measures to control this group of plant pathogens are generally ineffective, and the most effective control strategy is the use of genetic resistance. Owing to the fact that vascular wilt pathogens live deep in the interior of their host plants, studies into the biology of vascular pathogens are complicated. However, to design novel strategies to combat vascular wilt diseases, understanding the (molecular) biology of vascular pathogens and the molecular mechanisms underlying plant defense against these pathogens is crucial. In this review, we discuss the current knowledge on interactions of vascular wilt pathogens with their host plants, with emphasis on host defense responses against this group of pathogens. PMID:23630534

  20. Plant-Herbivore Interaction: Dissection of the Cellular Pattern of Tetranychus urticae Feeding on the Host Plant

    PubMed Central

    Bensoussan, Nicolas; Santamaria, M. Estrella; Zhurov, Vladimir; Diaz, Isabel; Grbić, Miodrag; Grbić, Vojislava

    2016-01-01

    The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is one of the most polyphagous herbivores feeding on cell contents of over 1100 plant species including more than 150 crops. It is being established as a model for chelicerate herbivores with tools that enable tracking of reciprocal responses in plant-spider mite interactions. However, despite their important pest status and a growing understanding of the molecular basis of interactions with plant hosts, knowledge of the way mites interface with the plant while feeding and the plant damage directly inflicted by mites is lacking. Here, utilizing histology and microscopy methods, we uncovered several key features of T. urticae feeding. By following the stylet path within the plant tissue, we determined that the stylet penetrates the leaf either in between epidermal pavement cells or through a stomatal opening, without damaging the epidermal cellular layer. Our recordings of mite feeding established that duration of the feeding event ranges from several minutes to more than half an hour, during which time mites consume a single mesophyll cell in a pattern that is common to both bean and Arabidopsis plant hosts. In addition, this study determined that leaf chlorotic spots, a common symptom of mite herbivory, do not form as an immediate consequence of mite feeding. Our results establish a cellular context for the plant-spider mite interaction that will support our understanding of the molecular mechanisms and cell signaling associated with spider mite feeding. PMID:27512397

  1. Plant-Herbivore Interaction: Dissection of the Cellular Pattern of Tetranychus urticae Feeding on the Host Plant.

    PubMed

    Bensoussan, Nicolas; Santamaria, M Estrella; Zhurov, Vladimir; Diaz, Isabel; Grbić, Miodrag; Grbić, Vojislava

    2016-01-01

    The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae), is one of the most polyphagous herbivores feeding on cell contents of over 1100 plant species including more than 150 crops. It is being established as a model for chelicerate herbivores with tools that enable tracking of reciprocal responses in plant-spider mite interactions. However, despite their important pest status and a growing understanding of the molecular basis of interactions with plant hosts, knowledge of the way mites interface with the plant while feeding and the plant damage directly inflicted by mites is lacking. Here, utilizing histology and microscopy methods, we uncovered several key features of T. urticae feeding. By following the stylet path within the plant tissue, we determined that the stylet penetrates the leaf either in between epidermal pavement cells or through a stomatal opening, without damaging the epidermal cellular layer. Our recordings of mite feeding established that duration of the feeding event ranges from several minutes to more than half an hour, during which time mites consume a single mesophyll cell in a pattern that is common to both bean and Arabidopsis plant hosts. In addition, this study determined that leaf chlorotic spots, a common symptom of mite herbivory, do not form as an immediate consequence of mite feeding. Our results establish a cellular context for the plant-spider mite interaction that will support our understanding of the molecular mechanisms and cell signaling associated with spider mite feeding. PMID:27512397

  2. Long Frontal Projections Help Battus philenor (Lepidoptera: Papilionidae) Larvae Find Host Plants

    PubMed Central

    Kandori, Ikuo; Tsuchihara, Kazuko; Suzuki, Taichi A.; Yokoi, Tomoyuki; Papaj, Daniel R.

    2015-01-01

    Animals sometimes develop conspicuous projections on or near their heads as, e.g., weaponry, burrowing or digging tools, and probes to search for resources. The frontal projections that insects generally use to locate and assess resources are segmented appendages, including antennae, maxillary palps, and labial palps. There is no evidence to date that arthropods, including insects, use projections other than true segmental appendages to locate food. In this regard, it is noteworthy that some butterfly larvae possess a pair of long antenna-like projections on or near their heads. To date, the function of these projections has not been established. Larvae of pipevine swallowtail butterflies Battus philenor (Papilionidae) have a pair of long frontal fleshy projections that, like insect antennae generally, can be actively moved. In this study, we evaluated the possible function of this pair of long moveable frontal projections. In laboratory assays, both frontal projections and lateral ocelli were shown to increase the frequency with which search larvae found plants. The frontal projections increased finding of host and non-host plants equally, suggesting that frontal projections do not detect host-specific chemical cues. Detailed SEM study showed that putative mechanosensillae are distributed all around the frontal as well as other projections. Taken together, our findings suggest that the frontal projections and associated mechanosensillae act as vertical object detectors to obtain tactile information that, together with visual information from lateral ocelli and presumably chemical information from antennae and mouthparts, help larvae to find host plants. Field observations indicate that host plants are small and scattered in southern Arizona locations. Larvae must therefore find multiple host plants to complete development and face significant challenges in doing so. The frontal projections may thus be an adaptation for finding a scarce resource before starving to

  3. Trichobaris weevils distinguish amongst toxic host plants by sensing volatiles that do not affect larval performance.

    PubMed

    Lee, Gisuk; Joo, Youngsung; Diezel, Celia; Lee, Eun Ju; Baldwin, Ian T; Kim, Sang-Gyu

    2016-07-01

    Herbivorous insects use plant metabolites to inform their host plant selection for oviposition. These host-selection behaviours are often consistent with the preference-performance hypothesis; females oviposit on hosts that maximize the performance of their offspring. However, the metabolites used for these oviposition choices and those responsible for differences in offspring performance remain unknown for ecologically relevant interactions. Here, we examined the host-selection behaviours of two sympatric weevils, the Datura (Trichobaris compacta) and tobacco (T. mucorea) weevils in field and glasshouse experiments with transgenic host plants specifically altered in different components of their secondary metabolism. Adult females of both species strongly preferred to feed on D. wrightii rather than on N. attenuata leaves, but T. mucorea preferred to oviposit on N. attenuata, while T. compacta oviposited only on D. wrightii. These oviposition behaviours increased offspring performance: T. compacta larvae only survived in D. wrightii stems and T. mucorea larvae survived better in N. attenuata than in D. wrightii stems. Choice assays with nicotine-free, JA-impaired, and sesquiterpene-over-produced isogenic N. attenuata plants revealed that although half of the T. compacta larvae survived in nicotine-free N. attenuata lines, nicotine did not influence the oviposition behaviours of both the nicotine-adapted and nicotine-sensitive species. JA-induced sesquiterpene volatiles are key compounds influencing T. mucorea females' oviposition choices, but these sesquiterpenes had no effect on larval performance. We conclude that adult females are able to choose the best host plant for their offspring and use chemicals different from those that influence larval performance to inform their oviposition decisions. PMID:27146082

  4. Long Frontal Projections Help Battus philenor (Lepidoptera: Papilionidae) Larvae Find Host Plants.

    PubMed

    Kandori, Ikuo; Tsuchihara, Kazuko; Suzuki, Taichi A; Yokoi, Tomoyuki; Papaj, Daniel R

    2015-01-01

    Animals sometimes develop conspicuous projections on or near their heads as, e.g., weaponry, burrowing or digging tools, and probes to search for resources. The frontal projections that insects generally use to locate and assess resources are segmented appendages, including antennae, maxillary palps, and labial palps. There is no evidence to date that arthropods, including insects, use projections other than true segmental appendages to locate food. In this regard, it is noteworthy that some butterfly larvae possess a pair of long antenna-like projections on or near their heads. To date, the function of these projections has not been established. Larvae of pipevine swallowtail butterflies Battus philenor (Papilionidae) have a pair of long frontal fleshy projections that, like insect antennae generally, can be actively moved. In this study, we evaluated the possible function of this pair of long moveable frontal projections. In laboratory assays, both frontal projections and lateral ocelli were shown to increase the frequency with which search larvae found plants. The frontal projections increased finding of host and non-host plants equally, suggesting that frontal projections do not detect host-specific chemical cues. Detailed SEM study showed that putative mechanosensillae are distributed all around the frontal as well as other projections. Taken together, our findings suggest that the frontal projections and associated mechanosensillae act as vertical object detectors to obtain tactile information that, together with visual information from lateral ocelli and presumably chemical information from antennae and mouthparts, help larvae to find host plants. Field observations indicate that host plants are small and scattered in southern Arizona locations. Larvae must therefore find multiple host plants to complete development and face significant challenges in doing so. The frontal projections may thus be an adaptation for finding a scarce resource before starving to

  5. Feeding on Host Plants with Different Concentrations and Structures of Pyrrolizidine Alkaloids Impacts the Chemical-Defense Effectiveness of a Specialist Herbivore

    PubMed Central

    Cunha, Beatriz P.; Solferini, Vera N.

    2015-01-01

    Sequestration of chemical defenses from host plants is a strategy widely used by herbivorous insects to avoid predation. Larvae of the arctiine moth Utetheisa ornatrix feeding on unripe seeds and leaves of many species of Crotalaria (Leguminosae) sequester N-oxides of pyrrolizidine alkaloids (PAs) from these host plants, and transfer them to adults through the pupal stage. PAs confer protection against predation on all life stages of U. ornatrix. As U. ornatrix also uses other Crotalaria species as host plants, we evaluated whether the PA chemical defense against predation is independent of host plant use. We fed larvae from hatching to pupation with either leaves or seeds of one of eight Crotalaria species (C. incana, C. juncea, C. micans, C. ochroleuca, C. pallida, C. paulina, C. spectabilis, and C. vitellina), and tested if adults were preyed upon or released by the orb-weaving spider Nephila clavipes. We found that the protection against the spider was more effective in adults whose larvae fed on seeds, which had a higher PA concentration than leaves. The exceptions were adults from larvae fed on C. paulina, C. spectabilis and C. vitellina leaves, which showed high PA concentrations. With respect to the PA profile, we describe for the first time insect-PAs in U. ornatrix. These PAs, biosynthesized from the necine base retronecine of plant origin, or monocrotaline- and senecionine-type PAs sequestered from host plants, were equally active in moth chemical defense, in a dose-dependent manner. These results are also partially explained by host plant phylogeny, since PAs of the host plants do have a phylogenetic signal (clades with high and low PA concentrations in leaves) which is reflected in the adult defense. PMID:26517873

  6. Penicillium expansum volatiles reduce pine weevil attraction to host plants.

    PubMed

    Azeem, Muhammad; Rajarao, Gunaratna Kuttuva; Nordenhem, Henrik; Nordlander, Göran; Borg-Karlson, Anna Karin

    2013-01-01

    The pine weevil Hylobius abietis (L.) is a severe pest of conifer seedlings in reforested areas of Europe and Asia. To identify minimally toxic and ecologically sustainable compounds for protecting newly planted seedlings, we evaluated the volatile metabolites produced by microbes isolated from H. abietis feces and frass. Female weevils deposit feces and chew bark at oviposition sites, presumably thus protecting eggs from feeding conspecifics. We hypothesize that microbes present in feces/frass are responsible for producing compounds that deter weevils. Here, we describe the isolation of a fungus from feces and frass of H. abietis and the biological activity of its volatile metabolites. The fungus was identified by morphological and molecular methods as Penicillium expansum Link ex. Thom. It was cultured on sterilized H. abietis frass medium in glass flasks, and volatiles were collected by SPME and analyzed by GC-MS. The major volatiles of the fungus were styrene and 3-methylanisole. The nutrient conditions for maximum production of styrene and 3-methylanisole were examined. Large quantities of styrene were produced when the fungus was cultured on grated pine bark with yeast extract. In a multi-choice arena test, styrene significantly reduced male and female pine weevils' attraction to cut pieces of Scots pine twigs, whereas 3-methylanisole only reduced male weevil attraction to pine twigs. These studies suggest that metabolites produced by microbes may be useful as compounds for controlling insects, and could serve as sustainable alternatives to synthetic insecticides. PMID:23297108

  7. The Effect of Host Galaxies on Type Ia Supernovae in the SDSS-II Supernova Survey

    SciTech Connect

    Lampeitl, Hubert; Smith, Mathew; Nichol, Robert C.; Bassett, Bruce; Cinabro, David; Dilday, Benjamin; Foley, Ryan J.; Frieman, Joshua A.; Garnavich, Peter M.; Goobar, Ariel; Im, Myungshin; /Seoul Natl. U. /Rutgers U., Piscataway

    2010-05-01

    We present an analysis of the host galaxy dependencies of Type Ia Supernovae (SNe Ia) from the full three year sample of the SDSS-II Supernova Survey. We re-discover, to high significance, the strong correlation between host galaxy type and the width of the observed SN light curve, i.e., fainter, quickly declining SNe Ia favor passive host galaxies, while brighter, slowly declining Ia's favor star-forming galaxies. We also find evidence (at between 2 to 3{sigma}) that SNe Ia are {approx_equal} 0.1 magnitudes brighter in passive host galaxies, than in star-forming hosts, after the SN Ia light curves have been standardized using the light curve shape and color variations: This difference in brightness is present in both the SALT2 and MCLS2k2 light curve fitting methodologies. We see evidence for differences in the SN Ia color relationship between passive and star-forming host galaxies, e.g., for the MLCS2k2 technique, we see that SNe Ia in passive hosts favor a dust law of R{sub V} {approx_equal} 1, while SNe Ia in star-forming hosts require R{sub V} {approx} 2. The significance of these trends depends on the range of SN colors considered. We demonstrate that these effects can be parameterized using the stellar mass of the host galaxy (with a confidence of > 4{sigma}) and including this extra parameter provides a better statistical fit to our data. Our results suggest that future cosmological analyses of SN Ia samples should include host galaxy information.

  8. Virus Infection of Plants Alters Pollinator Preference: A Payback for Susceptible Hosts?

    PubMed Central

    Davey, Matthew P.; Bruce, Toby J. A.; Caulfield, John C.; Furzer, Oliver J.; Reed, Alison; Robinson, Sophie I.; Miller, Elizabeth; Davis, Christopher N.; Pickett, John A.; Whitney, Heather M.; Glover, Beverley J.; Carr, John P.

    2016-01-01

    Plant volatiles play important roles in attraction of certain pollinators and in host location by herbivorous insects. Virus infection induces changes in plant volatile emission profiles, and this can make plants more attractive to insect herbivores, such as aphids, that act as viral vectors. However, it is unknown if virus-induced alterations in volatile production affect plant-pollinator interactions. We found that volatiles emitted by cucumber mosaic virus (CMV)-infected tomato (Solanum lycopersicum) and Arabidopsis thaliana plants altered the foraging behaviour of bumblebees (Bombus terrestris). Virus-induced quantitative and qualitative changes in blends of volatile organic compounds emitted by tomato plants were identified by gas chromatography-coupled mass spectrometry. Experiments with a CMV mutant unable to express the 2b RNA silencing suppressor protein and with Arabidopsis silencing mutants implicate microRNAs in regulating emission of pollinator-perceivable volatiles. In tomato, CMV infection made plants emit volatiles attractive to bumblebees. Bumblebees pollinate tomato by ‘buzzing’ (sonicating) the flowers, which releases pollen and enhances self-fertilization and seed production as well as pollen export. Without buzz-pollination, CMV infection decreased seed yield, but when flowers of mock-inoculated and CMV-infected plants were buzz-pollinated, the increased seed yield for CMV-infected plants was similar to that for mock-inoculated plants. Increased pollinator preference can potentially increase plant reproductive success in two ways: i) as female parents, by increasing the probability that ovules are fertilized; ii) as male parents, by increasing pollen export. Mathematical modeling suggested that over a wide range of conditions in the wild, these increases to the number of offspring of infected susceptible plants resulting from increased pollinator preference could outweigh underlying strong selection pressures favoring pathogen resistance

  9. Virus Infection of Plants Alters Pollinator Preference: A Payback for Susceptible Hosts?

    PubMed

    Groen, Simon C; Jiang, Sanjie; Murphy, Alex M; Cunniffe, Nik J; Westwood, Jack H; Davey, Matthew P; Bruce, Toby J A; Caulfield, John C; Furzer, Oliver J; Reed, Alison; Robinson, Sophie I; Miller, Elizabeth; Davis, Christopher N; Pickett, John A; Whitney, Heather M; Glover, Beverley J; Carr, John P

    2016-08-01

    Plant volatiles play important roles in attraction of certain pollinators and in host location by herbivorous insects. Virus infection induces changes in plant volatile emission profiles, and this can make plants more attractive to insect herbivores, such as aphids, that act as viral vectors. However, it is unknown if virus-induced alterations in volatile production affect plant-pollinator interactions. We found that volatiles emitted by cucumber mosaic virus (CMV)-infected tomato (Solanum lycopersicum) and Arabidopsis thaliana plants altered the foraging behaviour of bumblebees (Bombus terrestris). Virus-induced quantitative and qualitative changes in blends of volatile organic compounds emitted by tomato plants were identified by gas chromatography-coupled mass spectrometry. Experiments with a CMV mutant unable to express the 2b RNA silencing suppressor protein and with Arabidopsis silencing mutants implicate microRNAs in regulating emission of pollinator-perceivable volatiles. In tomato, CMV infection made plants emit volatiles attractive to bumblebees. Bumblebees pollinate tomato by 'buzzing' (sonicating) the flowers, which releases pollen and enhances self-fertilization and seed production as well as pollen export. Without buzz-pollination, CMV infection decreased seed yield, but when flowers of mock-inoculated and CMV-infected plants were buzz-pollinated, the increased seed yield for CMV-infected plants was similar to that for mock-inoculated plants. Increased pollinator preference can potentially increase plant reproductive success in two ways: i) as female parents, by increasing the probability that ovules are fertilized; ii) as male parents, by increasing pollen export. Mathematical modeling suggested that over a wide range of conditions in the wild, these increases to the number of offspring of infected susceptible plants resulting from increased pollinator preference could outweigh underlying strong selection pressures favoring pathogen resistance

  10. Contrasting Effects of Land Use Intensity and Exotic Host Plants on the Specialization of Interactions in Plant-Herbivore Networks

    PubMed Central

    de Araújo, Walter Santos; Vieira, Marcos Costa; Lewinsohn, Thomas M.; Almeida-Neto, Mário

    2015-01-01

    Human land use tends to decrease the diversity of native plant species and facilitate the invasion and establishment of exotic ones. Such changes in land use and plant community composition usually have negative impacts on the assemblages of native herbivorous insects. Highly specialized herbivores are expected to be especially sensitive to land use intensification and the presence of exotic plant species because they are neither capable of consuming alternative plant species of the native flora nor exotic plant species. Therefore, higher levels of land use intensity might reduce the proportion of highly specialized herbivores, which ultimately would lead to changes in the specialization of interactions in plant-herbivore networks. This study investigates the community-wide effects of land use intensity on the degree of specialization of 72 plant-herbivore networks, including effects mediated by the increase in the proportion of exotic plant species. Contrary to our expectation, the net effect of land use intensity on network specialization was positive. However, this positive effect of land use intensity was partially canceled by an opposite effect of the proportion of exotic plant species on network specialization. When we analyzed networks composed exclusively of endophagous herbivores separately from those composed exclusively of exophagous herbivores, we found that only endophages showed a consistent change in network specialization at higher land use levels. Altogether, these results indicate that land use intensity is an important ecological driver of network specialization, by way of reducing the local host range of herbivore guilds with highly specialized feeding habits. However, because the effect of land use intensity is offset by an opposite effect owing to the proportion of exotic host species, the net effect of land use in a given herbivore assemblage will likely depend on the extent of the replacement of native host species with exotic ones. PMID

  11. Contrasting effects of land use intensity and exotic host plants on the specialization of interactions in plant-herbivore networks.

    PubMed

    de Araújo, Walter Santos; Vieira, Marcos Costa; Lewinsohn, Thomas M; Almeida-Neto, Mário

    2015-01-01

    Human land use tends to decrease the diversity of native plant species and facilitate the invasion and establishment of exotic ones. Such changes in land use and plant community composition usually have negative impacts on the assemblages of native herbivorous insects. Highly specialized herbivores are expected to be especially sensitive to land use intensification and the presence of exotic plant species because they are neither capable of consuming alternative plant species of the native flora nor exotic plant species. Therefore, higher levels of land use intensity might reduce the proportion of highly specialized herbivores, which ultimately would lead to changes in the specialization of interactions in plant-herbivore networks. This study investigates the community-wide effects of land use intensity on the degree of specialization of 72 plant-herbivore networks, including effects mediated by the increase in the proportion of exotic plant species. Contrary to our expectation, the net effect of land use intensity on network specialization was positive. However, this positive effect of land use intensity was partially canceled by an opposite effect of the proportion of exotic plant species on network specialization. When we analyzed networks composed exclusively of endophagous herbivores separately from those composed exclusively of exophagous herbivores, we found that only endophages showed a consistent change in network specialization at higher land use levels. Altogether, these results indicate that land use intensity is an important ecological driver of network specialization, by way of reducing the local host range of herbivore guilds with highly specialized feeding habits. However, because the effect of land use intensity is offset by an opposite effect owing to the proportion of exotic host species, the net effect of land use in a given herbivore assemblage will likely depend on the extent of the replacement of native host species with exotic ones. PMID

  12. The developmental race between maturing host plants and their butterfly herbivore - the influence of phenological matching and temperature.

    PubMed

    Posledovich, Diana; Toftegaard, Tenna; Wiklund, Christer; Ehrlén, Johan; Gotthard, Karl

    2015-11-01

    Interactions between herbivorous insects and their host plants that are limited in time are widespread. Therefore, many insect-plant interactions result in a developmental race, where herbivores need to complete their development before plants become unsuitable, while plants strive to minimize damage from herbivores by outgrowing them. When spring phenologies of interacting species change asymmetrically in response to climate warming, there will be a change in the developmental state of host plants at the time of insect herbivore emergence. In combination with altered temperatures during the subsequent developmental period, this is likely to affect interaction strength as well as fitness of interacting species. Here, we experimentally explore whether the combined effect of phenological matching and thermal conditions influence the outcome of an insect-host interaction. We manipulated both developmental stages of the host plants at the start of the interaction and temperature during the subsequent developmental period in a model system of a herbivorous butterfly, Anthocharis cardamines, and five of its Brassicaceae host plant species. Larval performance characteristics were favoured by earlier stages of host plants at oviposition as well as by higher developmental temperatures on most of the host species. The probability of a larva needing a second host plant covered the full range from no influence of either phenological matching or temperature to strong effects of both factors, and complex interactions between them. The probability of a plant outgrowing a larva was dependent only on the species identity. This study demonstrates that climatic variation can influence the outcome of consumer-resource interactions in multiple ways and that its effects differ among host plant species. Therefore, climate warming is likely to change the temporal match between larval and plant development in some plant species, but not in the others. This is likely to have important

  13. Quantification of the host response proteome after herpes simplex virus type 1 infection.

    PubMed

    Berard, Alicia R; Coombs, Kevin M; Severini, Alberto

    2015-05-01

    Viruses employ numerous host cell metabolic functions to propagate and manage to evade the host immune system. For herpes simplex virus type 1 (HSV1), a virus that has evolved to efficiently infect humans without seriously harming the host in most cases, the virus-host interaction is specifically interesting. This interaction can be best characterized by studying the proteomic changes that occur in the host during infection. Previous studies have been successful at identifying numerous host proteins that play important roles in HSV infection; however, there is still much that we do not know. This study identifies host metabolic functions and proteins that play roles in HSV infection, using global quantitative stable isotope labeling by amino acids in cell culture (SILAC) proteomic profiling of the host cell combined with LC-MS/MS. We showed differential proteins during early, mid and late infection, using both cytosolic and nuclear fractions. We identified hundreds of differentially regulated proteins involved in fundamental cellular functions, including gene expression, DNA replication, inflammatory response, cell movement, cell death, and RNA post-transcriptional modification. Novel differentially regulated proteins in HSV infections include some previously identified in other virus systems, as well as fusion protein, involved in malignant liposarcoma (FUS) and hypoxia up-regulated 1 protein precursor (HYOU1), which have not been identified previously in any virus infection. PMID:25815715

  14. Fibroblasts—a key host cell type in tumor initiation, progression, and metastasis

    PubMed Central

    Strell, Carina; Rundqvist, Helene

    2012-01-01

    Tumor initiation, growth, invasion, and metastasis occur as a consequence of a complex interplay between the host environment and cancer cells. Fibroblasts are now recognized as a key host cell type involved in host–cancer signaling. This review discusses some recent studies that highlight the roles of fibroblasts in tumor initiation, early progression, invasion, and metastasis. Some clinical studies describing the prognostic significance of fibroblast-derived markers and signatures are also discussed. PMID:22509805

  15. Effect of host plant chemistry on genetic differentiation and reduction of gene flow among Anastrepha fraterculus (Diptera: Tephritidae) populations exploiting sympatric, synchronic hosts.

    PubMed

    Oroño, Luis; Paulin, Laura; Alberti, Andrea C; Hilal, Mirna; Ovruski, Sergio; Vilardi, Juan C; Rull, Juan; Aluja, Martin

    2013-08-01

    Herbivore host specialization includes changes in behavior, driven by locally induced adaptations to specific plants. These adaptations often result in sexual isolation that can be gauged through detection of reduced gene flow between host associated populations. Hypothetically, reduced gene flow can be mediated both by differential response to specific plant kairomones and by the influence of larval diet on some adult traits such as pheromone composition. These hypotheses could serve as a model to explain rapid radiation of phytophagous tephritid fruit flies, a group that includes several complexes of cryptic species. The South American Fruit Fly Anastrepha fraterculus (Wiedemann) is a complex of at least seven cryptic species among which pheromone mediated sexual isolation resulted in rapid differentiation. Cryptic species also exhibit differences in host affiliation. In search of a model explaining rapid radiation in this group, we studied host plant chemical composition and genetic structure of three host associated sympatric populations of A. fraterculus. Chemical composition among host plant fruit varied widely both for nutrient and potentially toxic secondary metabolite content. Adaptation to plant chemistry appears to have produced population differentiation. We found host mediated differentiation to be stronger between populations exploiting sympatric synchronic hosts differing in chemical composition, than between populations that exploit hosts that fruit in succession. Gene flow among such host associated populations was extremely low. We propose as a working hypothesis for future research, that for those differences to persist over time, isolating mechanisms such as male produced sex pheromones and female preferences resulting from adaptation to different larval diets should evolve. PMID:23905743

  16. Chemical ecology of the luna moth : Effects of host plant on detoxification enzyme activity.

    PubMed

    Lindroth, R L

    1989-07-01

    The effects of food plant on larval performance and midgut detoxification enzymes were investigated in larvae of the luna moth,Actias luna. Neonate larvae were fed leaves of black cherry, cottonwood, quaking aspen, white willow, red oak, white oak, tulip tree, paper birch, black walnut, butternut, or shagbark hickory. First instar survival, larval duration, and pupal weights were monitored as indices of food quality. Midgut enzyme preparations from fifth instars were assayed for β-glucosidase, quinone reductase, polysubstrate monooxygenase, esterase, and glutathione transferase activities. Larval survival on seven of the 11 plant species, including several recorded host plants, was extremely poor. Larvae performed well, and quite similarly, on birch, walnut, butternut, and hickory. Activities of all enzyme systems except β-glucosidase were significantly influenced by larval host plant. Of the systems assayed, quinone reductase and glutathione transferase activities were especially high. Comparisons of these values with published values for other Lepidoptera support the hypothesis that these enzyme systems are involved in conferring tolerance to juglone and related quinones occurring in members of the plant family Juglandaceae. Results suggest that host plant utilization by luna is more specialized at the individual or population level than at the species level and that biochemical detoxification systems may play a role in such specialization. PMID:24272292

  17. Host-directed therapy of tuberculosis based on interleukin-1 and type I interferon crosstalk

    PubMed Central

    Mayer-Barber, Katrin D.; Andrade, Bruno B.; Oland, Sandra D.; Amaral, Eduardo P.; Barber, Daniel L.; Gonzales, Jacqueline; Derrick, Steven C.; Shi, Ruiru; Kumar, Nathella Pavan; Wei, Wang; Yuan, Xing; Zhang, Guolong; Cai, Ying; Babu, Subash; Catalfamo, Marta; Salazar, Andres M.; Via, Laura E.; Barry, Clifton E.; Sher, Alan

    2016-01-01

    Tuberculosis remains second only to HIV/AIDS as the leading cause of mortality worldwide due to a single infectious agent1. Despite chemotherapy, the global tuberculosis epidemic has intensified because of HIV co-infection, the lack of an effective vaccine and the emergence of multi-drug-resistant bacteria2–5. Alternative host-directed strategies could be exploited to improve treatment efficacy and outcome, contain drug-resistant strains and reduce disease severity and mortality6. The innate inflammatory response elicited by Mycobacterium tuberculosis (Mtb) represents a logical host target7. Here we demonstrate that interleukin-1 (IL-1) confers host resistance through the induction of eicosanoids that limit excessive type I interferon (IFN) production and foster bacterial containment. We further show that, in infected mice and patients, reduced IL-1 responses and/or excessive type I IFN induction are linked to an eicosanoid imbalance associated with disease exacerbation. Host-directed immunotherapy with clinically approved drugs that augment prostaglandin E2 levels in these settings prevented acute mortality of Mtb-infected mice. Thus, IL-1 and type I IFNs represent two major counter-regulatory classes of inflammatory cytokines that control the outcome of Mtb infection and are functionally linked via eicosanoids. Our findings establish proof of concept for host-directed treatment strategies that manipulate the host eicosanoid network and represent feasible alternatives to conventional chemotherapy. PMID:24990750

  18. Host-directed therapy of tuberculosis based on interleukin-1 and type I interferon crosstalk.

    PubMed

    Mayer-Barber, Katrin D; Andrade, Bruno B; Oland, Sandra D; Amaral, Eduardo P; Barber, Daniel L; Gonzales, Jacqueline; Derrick, Steven C; Shi, Ruiru; Kumar, Nathella Pavan; Wei, Wang; Yuan, Xing; Zhang, Guolong; Cai, Ying; Babu, Subash; Catalfamo, Marta; Salazar, Andres M; Via, Laura E; Barry, Clifton E; Sher, Alan

    2014-07-01

    Tuberculosis remains second only to HIV/AIDS as the leading cause of mortality worldwide due to a single infectious agent. Despite chemotherapy, the global tuberculosis epidemic has intensified because of HIV co-infection, the lack of an effective vaccine and the emergence of multi-drug-resistant bacteria. Alternative host-directed strategies could be exploited to improve treatment efficacy and outcome, contain drug-resistant strains and reduce disease severity and mortality. The innate inflammatory response elicited by Mycobacterium tuberculosis (Mtb) represents a logical host target. Here we demonstrate that interleukin-1 (IL-1) confers host resistance through the induction of eicosanoids that limit excessive type I interferon (IFN) production and foster bacterial containment. We further show that, in infected mice and patients, reduced IL-1 responses and/or excessive type I IFN induction are linked to an eicosanoid imbalance associated with disease exacerbation. Host-directed immunotherapy with clinically approved drugs that augment prostaglandin E2 levels in these settings prevented acute mortality of Mtb-infected mice. Thus, IL-1 and type I IFNs represent two major counter-regulatory classes of inflammatory cytokines that control the outcome of Mtb infection and are functionally linked via eicosanoids. Our findings establish proof of concept for host-directed treatment strategies that manipulate the host eicosanoid network and represent feasible alternatives to conventional chemotherapy. PMID:24990750

  19. Evaluations of melon germplasm reported to exhibit host plant resistance to sweetpotato whitefly

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sweetpotato whitefly (MEAM1 cryptic species of Bemisia tabaci; SPWF) displaced B. tabaci biotype A in 1991 in the lower desert area of southern California and the adjoining areas of Arizona and western Mexico. The search for high-level host plant resistance to this devastating insect has been ongoin...

  20. Effects of elicitors of host plant defenses on pear psylla (Cacopsylla pyricola: Psyllidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pear psylla, Cacopsylla pyricola (Foerster) (Hemiptera: Psyllidae), is a key pest of cultivated pear (Pyrus communis L.) in North America and Europe. We examined the effects of foliar applications of three commercially available chemical elicitors of host-plant defenses, Actigard, Employ, and ODC, ...

  1. Water deficit stress - host plant nutrient accumulations and associations with phytophagous arthropods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In addition to making otherwise arable regions less, or nonarable, from lack of life-sustaining water, water deficit also affects the extent to which crops are afflicted by arthropod pests. This chapter focuses on the effects of water deficit stress on physical and nutritional aspects of host plants...

  2. Host plant resistance in melon (Cucumis melo L.) to sweetpotato whitefly in California and Arizona

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sweetpotato whitefly (MEAM1 cryptic species of Bemisia tabaci; SPWF) feeding severely impacts fall season melon yield and quality in the lower deserts of California and Arizona. Melon accessions PI 313970 and TGR 1551 (PI 482420) have been reported to exhibit host plant resistance (HPR) to SPWF. Pot...

  3. Behavioral model for Homalodisca vitripennis (Hemiptera: Cicadellidae): Optimization of host plant utilization and management implications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We produced a behavioral model which integrates leafhopper behavior and life history strategies with nutritional requirements, as a useful, heuristic tool to understand the patterns of leafhopper host plant utilization, vector behavior and ecology, which also aids the development of better biologica...

  4. Host Plant Associations and Parasitism of South Ecuadorian Eois Species (Lepidoptera: Geometridae) Feeding on Peperomia (Piperaceae)

    PubMed Central

    Seifert, Carlo L.; Bodner, Florian; Brehm, Gunnar; Fiedler, Konrad

    2015-01-01

    The very species-rich tropical moth genus Eois Hübner (Lepidoptera: Geometridae) is a promising model group for studying host plant specialization and adaptive radiation. While most Eois species are assumed to be specialized herbivores on Piper L. species, records on other plant taxa such as Peperomia Ruiz & Pavón (Piperaceae) are still relatively scarce. Moreover, little is known about life history traits of most species, and only a few caterpillars have been described so far. We collected caterpillars associated with Peperomia (Piperaceae) host plants from June 2012 to January 2013 in three elevational bands of montane and elfin rainforests on the eastern slopes of the Andes in southern Ecuador. Caterpillars were systematically searched and reared to the adult stage. We were able to delimitate ten species of Eois on Peperomia by comparison of larval and adult morphology and by using 658 bp fragments of the mitochondrial COI gene (barcode sequences). Three of these species, Eois albosignata (Dognin), Eois bolana (Dognin), and Eois chasca (Dognin), are validly described whereas the other seven taxa represent interim morphospecies, recognized unequivocally by their DNA barcodes, and their larval and adult morphology. We provide information about their host plants, degree of parasitism, and describe the larval stages in their last instar. Additionally, caterpillars and moths are illustrated in color plates. This is the first comparative study dealing with Eois moths whose caterpillars feed on Peperomia hosts. PMID:26286230

  5. Rearing optimization of two races of the Fall armyworm Spodoptera frugiperda feeding natural host plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two ecological races of the Fall armyworm Spodoptera frugiperda were raised under laboratory conditions feeding on natural host plants (corn and bermuda grass). Three rearing containers were used: a plastic container and a vertical cylinder to test fitness when feeding gregariously, and individual ...

  6. Differential regulation of host mRNA translation during obligate pathogen-plant interactions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Virus infection reprograms the plant messenger RNA (mRNA) transcriptome by activating or interfering with a variety of signaling pathways, but the effects on host mRNA translation have not been explored on a genome-wide scale. To address this issue, Arabidopsis thaliana mRNA transcripts were quantif...

  7. Associations between host plant concentrations of selected biochemical nutrients and Mexican rice borer, Eoreuma loftini, infestation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Mexican rice borer, Eoreuma loftini (Dyar) (Lepidoptera: Crambidae), is an economic pest of sugarcane and other graminaceous host crops, and it attacks grassy weeds. Oviposition preference has been known to be for plants with leaves that form folds. This study is the first to associate the nutr...

  8. Host plant resistance in melon to sweetpotato whitefly in California and Arizona

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sweetpotato whitefly biotype B (MEAM1 cryptic species of Bemisia tabaci; SPWF) feeding severely impacts fall season melon (Cucumis melo L.) yield and quality in the lower deserts of California and Arizona. Melon accessions PI 313970 and TGR 1551 (PI 482420) have been reported to exhibit host plant r...

  9. Towards Host Plant Resistance against Psyllid Feeding and Transmission of Ca. Liberibacter spp.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development of host plant resistance against Ca. Liberibacter spp. will be vital for sustainable global production of citrus, potato, tomato, and other crops, because present control methods are very expensive and chemical-intensive. Resistance to the vector’s feeding and/or the bacterial transmiss...

  10. Combining Reflective Mulch and Host Plant Resistance for Sweetpotato Whitefly (Hemiptera: Aleyrodidae) Management in Watermelon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A study was conducted to evaluate the use of reflective mulch and host plant resistance for the management of the B-biotype sweetpotato whitefly, Bemisia tabaci (Gennadius), in watermelon [Citrullus lanatus var. lanatus (Thunberg) Matsum & Nakai]. Whitefly abundance data were collected under both g...

  11. Host Plant Associations and Parasitism of South Ecuadorian Eois Species (Lepidoptera: Geometridae) Feeding on Peperomia (Piperaceae).

    PubMed

    Seifert, Carlo L; Bodner, Florian; Brehm, Gunnar; Fiedler, Konrad

    2015-01-01

    The very species-rich tropical moth genus Eois Hübner (Lepidoptera: Geometridae) is a promising model group for studying host plant specialization and adaptive radiation. While most Eois species are assumed to be specialized herbivores on Piper L. species, records on other plant taxa such as Peperomia Ruiz & Pavón (Piperaceae) are still relatively scarce. Moreover, little is known about life history traits of most species, and only a few caterpillars have been described so far. We collected caterpillars associated with Peperomia (Piperaceae) host plants from June 2012 to January 2013 in three elevational bands of montane and elfin rainforests on the eastern slopes of the Andes in southern Ecuador. Caterpillars were systematically searched and reared to the adult stage. We were able to delimitate ten species of Eois on Peperomia by comparison of larval and adult morphology and by using 658 bp fragments of the mitochondrial COI gene (barcode sequences). Three of these species, Eois albosignata (Dognin), Eois bolana (Dognin), and Eois chasca (Dognin), are validly described whereas the other seven taxa represent interim morphospecies, recognized unequivocally by their DNA barcodes, and their larval and adult morphology. We provide information about their host plants, degree of parasitism, and describe the larval stages in their last instar. Additionally, caterpillars and moths are illustrated in color plates. This is the first comparative study dealing with Eois moths whose caterpillars feed on Peperomia hosts. PMID:26286230

  12. Experimental infection of plants with an herbivore-associated bacterial endosymbiont influences herbivore host selection behavior

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although bacterial endosymbioses are common among phloeophagous herbivores, little is known regarding the effects of symbionts on herbivore host selection and population dynamics. We tested the hypothesis that plant selection and reproductive performance by a phloem-feeding herbivore (potato psyllid...

  13. Volatiles induction in rice stink bug host grasses and rice plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice stink bug (RSB), Oebalus pugnax F., is an important pest of heading rice in the United States. Little is known about plant volatiles production following herbivory by the rice stink bug. RSB feeding induced volatiles production in different RSB host grasses and rice varieties, and may help expl...

  14. Expression of proteins involved in host plant defense against greenbug infestation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The greenbug, Schizaphis graminum (Rondani), has been recognized as a major pest of small grains, including sorghum and wheat. To understand the molecular mechanisms involved in host plant defense against greenbug aphids, a proteomic analysis of greenbug-induced proteins in the seedlings of sorghum...

  15. A dual role for plant quinone reductases in host-fungus interaction.

    PubMed

    Heyno, Eiri; Alkan, Noam; Fluhr, Robert

    2013-11-01

    Quinone reductases (QR, EC 1.5.6.2) are flavoproteins that protect organisms from oxidative stress. The function of plant QRs has not as yet been addressed in vivo despite biochemical evidence for their involvement in redox reactions. Here, using knock-out (KO) and overexpressing lines, we studied the protective role of two groups of Arabidopsis thaliana cytosolic QRs, Nqr (NAD(P)H:quinone oxidoreductase) and Fqr (flavodoxin-like quinone reductase), in response to infection by necrotrophic fungi. The KO lines nqr(-) and fqr1(-) displayed significantly slower development of lesions of Botrytis cinerea and Sclerotinia sclerotium in comparison to the wild type (WT). Consistent with this observation, the overexpressing line FQR1(+) was hypersensitive to the pathogens. Both the nqr(-) and fqr1(-) displayed increased fluorescence of 2',7'-dichlorofluorescein,‬ a reporter for reactive oxygen species in response to B. cinerea. Infection by B. cinerea was accompanied with increased Nqr and Fqr1 protein levels in the WT as revealed by western blotting. In addition, a marked stimulation of salicylic acid-sensitive transcripts and suppression of jasmonate-sensitive transcripts was observed in moderately wounded QR KO mutant leaves, a condition mimicking the early stage of infection. In contrast to the above observations, germination of conidia was accelerated on leaves of QR KO mutants in comparison with the WT and FQR1(+). The same effect was observed in water-soluble leaf surface extracts. It is proposed that the altered interaction between B. cinerea and the QR mutants is a consequence of subtly altered redox state of the host, which perturbs host gene expression in response to environmental stress such as fungal growth.‬‬‬‬‬‬ PMID:23464356

  16. Inferring phylogeny and speciation of Gymnosporangium species, and their coevolution with host plants

    PubMed Central

    Zhao, Peng; Liu, Fang; Li, Ying-Ming; Cai, Lei

    2016-01-01

    Gymnosporangium species (Pucciniaceae, Pucciniales) cause serious diseases and significant economic losses to apple cultivars. Most of the reported species are heteroecious and complete their life cycles on two different plant hosts belonging to two unrelated genera, i.e. Juniperus and Malus. However, the phylogenetic relationships among Gymnosporangium species and the evolutionary history of Gymnosporangium on its aecial and telial hosts were still undetermined. In this study, we recognized species based on rDNA sequence data by using coalescent method of generalized mixed Yule-coalescent (GMYC) and Poisson Tree Processes (PTP) models. The evolutionary relationships of Gymnosporangium species and their hosts were investigated by comparing the cophylogenetic analyses of Gymnosporangium species with Malus species and Juniperus species, respectively. The concordant results of GMYC and PTP analyses recognized 14 species including 12 known species and two undescribed species. In addition, host alternations of 10 Gymnosporangium species were uncovered by linking the derived sequences between their aecial and telial stages. This study revealed the evolutionary process of Gymnosporangium species, and clarified that the aecial hosts played more important roles than telial hosts in the speciation of Gymnosporangium species. Host switch, losses, duplication and failure to divergence all contributed to the speciation of Gymnosporangium species. PMID:27385413

  17. Evaluation of 31 Potential Biofumigant Brassicaceous Plants as Hosts for Three Meloiodogyne Species

    PubMed Central

    Edwards, Scott; Ploeg, Antoon

    2014-01-01

    Brassicaceous cover crops can be used for biofumigation after soil incorporation of the mowed crop. This strategy can be used to manage root-knot nematodes (Meloidogyne spp.), but the fact that many of these crops are host to root-knot nematodes can result in an undesired nematode population increase during the cultivation of the cover crop. To avoid this, cover crop cultivars that are poor or nonhosts should be selected. In this study, the host status of 31 plants in the family Brassicaceae for the three root-knot nematode species M. incognita, M. javanica, and M. hapla were evaluated, and compared with a susceptible tomato host in repeated greenhouse pot trials. The results showed that M. incognita and M. javanica responded in a similar fashion to the different cover cultivars. Indian mustard (Brassica juncea) and turnip (B. rapa) were generally good hosts, whereas most oil radish cultivars (Raphanus. sativus ssp. oleiferus) were poor hosts. However, some oil radish cultivars were among the best hosts for M. hapla. The arugula (Eruca sativa) cultivar Nemat was a poor host for all three nematode species tested. This study provides important information for chosing a cover crop with the purpose of managing root-knot nematodes. PMID:25276003

  18. Evaluation of 31 potential biofumigant brassicaceous plants as hosts for three meloiodogyne species.

    PubMed

    Edwards, Scott; Ploeg, Antoon

    2014-09-01

    Brassicaceous cover crops can be used for biofumigation after soil incorporation of the mowed crop. This strategy can be used to manage root-knot nematodes (Meloidogyne spp.), but the fact that many of these crops are host to root-knot nematodes can result in an undesired nematode population increase during the cultivation of the cover crop. To avoid this, cover crop cultivars that are poor or nonhosts should be selected. In this study, the host status of 31 plants in the family Brassicaceae for the three root-knot nematode species M. incognita, M. javanica, and M. hapla were evaluated, and compared with a susceptible tomato host in repeated greenhouse pot trials. The results showed that M. incognita and M. javanica responded in a similar fashion to the different cover cultivars. Indian mustard (Brassica juncea) and turnip (B. rapa) were generally good hosts, whereas most oil radish cultivars (Raphanus. sativus ssp. oleiferus) were poor hosts. However, some oil radish cultivars were among the best hosts for M. hapla. The arugula (Eruca sativa) cultivar Nemat was a poor host for all three nematode species tested. This study provides important information for chosing a cover crop with the purpose of managing root-knot nematodes. PMID:25276003

  19. Inferring phylogeny and speciation of Gymnosporangium species, and their coevolution with host plants.

    PubMed

    Zhao, Peng; Liu, Fang; Li, Ying-Ming; Cai, Lei

    2016-01-01

    Gymnosporangium species (Pucciniaceae, Pucciniales) cause serious diseases and significant economic losses to apple cultivars. Most of the reported species are heteroecious and complete their life cycles on two different plant hosts belonging to two unrelated genera, i.e. Juniperus and Malus. However, the phylogenetic relationships among Gymnosporangium species and the evolutionary history of Gymnosporangium on its aecial and telial hosts were still undetermined. In this study, we recognized species based on rDNA sequence data by using coalescent method of generalized mixed Yule-coalescent (GMYC) and Poisson Tree Processes (PTP) models. The evolutionary relationships of Gymnosporangium species and their hosts were investigated by comparing the cophylogenetic analyses of Gymnosporangium species with Malus species and Juniperus species, respectively. The concordant results of GMYC and PTP analyses recognized 14 species including 12 known species and two undescribed species. In addition, host alternations of 10 Gymnosporangium species were uncovered by linking the derived sequences between their aecial and telial stages. This study revealed the evolutionary process of Gymnosporangium species, and clarified that the aecial hosts played more important roles than telial hosts in the speciation of Gymnosporangium species. Host switch, losses, duplication and failure to divergence all contributed to the speciation of Gymnosporangium species. PMID:27385413

  20. Critical elements in sediment-hosted deposits (clastic-dominated Zn-Pb-Ag, Mississippi Valley-type Zn-Pb, sedimentary rock-hosted Stratiform Cu, and carbonate-hosted Polymetallic Deposits): A review: Chapter 12

    USGS Publications Warehouse

    Marsh, Erin; Hitzman, Murray W.; Leach, David L.

    2016-01-01

    Some sediment-hosted base metal deposits, specifically the clastic-dominated (CD) Zn-Pb deposits, carbonate-hosted Mississippi Valley-type (MVT) deposits, sedimentary-rock hosted stratiform copper deposits, and carbonate-hosted polymetallic (“Kipushi type”) deposits, are or have been important sources of critical elements including Co, Ga, Ge, and Re. The generally poor data concerning trace element concentrations in these types of sediment-hosted ores suggest that there may be economically important concentrations of critical elements yet to be recognized.

  1. Diversity begets diversity: host expansions and the diversification of plant-feeding insects

    PubMed Central

    Janz, Niklas; Nylin, Sören; Wahlberg, Niklas

    2006-01-01

    Background Plant-feeding insects make up a large part of earth's total biodiversity. While it has been shown that herbivory has repeatedly led to increased diversification rates in insects, there has been no compelling explanation for how plant-feeding has promoted speciation rates. There is a growing awareness that ecological factors can lead to rapid diversification and, as one of the most prominent features of most insect-plant interactions, specialization onto a diverse resource has often been assumed to be the main process behind this diversification. However, specialization is mainly a pruning process, and is not able to actually generate diversity by itself. Here we investigate the role of host colonizations in generating insect diversity, by testing if insect speciation rate is correlated with resource diversity. Results By applying a variant of independent contrast analysis, specially tailored for use on questions of species richness (MacroCAIC), we show that species richness is strongly correlated with diversity of host use in the butterfly family Nymphalidae. Furthermore, by comparing the results from reciprocal sister group selection, where sister groups were selected either on the basis of diversity of host use or species richness, we find that it is likely that diversity of host use is driving species richness, rather than vice versa. Conclusion We conclude that resource diversity is correlated with species richness in the Nymphalidae and suggest a scenario based on recurring oscillations between host expansions – the incorporation of new plants into the repertoire – and specialization, as an important driving force behind the diversification of plant-feeding insects. PMID:16420707

  2. Analysis of the Phialocephala subalpina Transcriptome during Colonization of Its Host Plant Picea abies

    PubMed Central

    Reininger, Vanessa; Schlegel, Markus

    2016-01-01

    Background Phialocephala subalpina belongs to the Phialocephala fortinii s.l.–Acepphala applanata species complex (PAC) forming one of the major groups belonging to the dark septate endophytes (DSE). Depending on the strain, PAC was shown to form neutral to pathogenic associations with its host plant Picea abies. To understand PACs lifestyle we investigated the effect of presence/absence of Picea abies on the transcriptome of strain 6_70_1. Materials and Methods PAC strain 6_70_1 was grown in liquid Pachlewski media either induced by its host plant Picea abies or without host plant as a control. Mycelia were harvested in a time course (1, 2, 3, 4, 7, 11, 18 days) with and without induction by the host plant and the fungal transcriptome revealed by Illumina sequencing. Differential gene expression analysis over the time course comparing control and treatment at each time point using the ‘edgeR glm approach’ and a gene enrichment analysis using GO categories were performed. Results The three main functional groups within differentially expressed genes were ‘metabolism’, ‘transport’ and ‘cell rescue, defense and virulence’. Additionally, genes especially involved in iron metabolism could be detected by gene set enrichment analysis. Conclusion In conclusion, we found PAC strain 6_70_1 to be metabolically very active during colonization of its host plant Picea abies. A major shift in functional groups over the time course of this experiment could not be observed but GO categories which were found to be enriched showed different emphasis depending in the day post induction. PMID:26954682

  3. Common and contrasting themes in host cell-targeted effectors from bacterial, fungal, oomycete and nematode plant symbionts described using the Gene Ontology.

    PubMed

    Torto-Alalibo, Trudy; Collmer, Candace W; Lindeberg, Magdalen; Bird, David; Collmer, Alan; Tyler, Brett M

    2009-01-01

    A wide diversity of plant-associated symbionts, including microbes, produce proteins that can enter host cells, or are injected into host cells in order to modify the physiology of the host to promote colonization. These molecules, termed effectors, commonly target the host defense signaling pathways in order to suppress the defense response. Others target the gene expression machinery or trigger specific modifications to host morphology or physiology that promote the nutrition and proliferation of the symbiont. When recognized by the host's surveillance machinery, which includes cognate resistance (R) gene products, defense responses are engaged to restrict pathogen proliferation. Effectors from diverse symbionts may be delivered into plant cells via varied mechanisms, including whole organism cellular entry (viruses, some bacteria and fungi), type III and IV secretion (in bacteria), physical injection (nematodes and insects) and protein translocation signal sequences (oomycetes and fungi). This mini-review will summarize both similarities and differences in effectors and effector delivery systems found in diverse plant-associated symbionts as well as how these are described with Plant-Associated Microbe Gene Ontology (PAMGO) terms. PMID:19278551

  4. The Multiple Impacts of Tropical Forest Fragmentation on Arthropod Biodiversity and on their Patterns of Interactions with Host Plants

    PubMed Central

    Benítez-Malvido, Julieta; Dáttilo, Wesley; Martínez-Falcón, Ana Paola; Durán-Barrón, César; Valenzuela, Jorge; López, Sara; Lombera, Rafael

    2016-01-01

    Tropical rain forest fragmentation affects biotic interactions in distinct ways. Little is known, however, about how fragmentation affects animal trophic guilds and their patterns of interactions with host plants. In this study, we analyzed changes in biotic interactions in forest fragments by using a multitrophic approach. For this, we classified arthropods associated with Heliconia aurantiaca herbs into broad trophic guilds (omnivores, herbivores and predators) and assessed the topological structure of intrapopulation plant-arthropod networks in fragments and continuous forests. Habitat type influenced arthropod species abundance, diversity and composition with greater abundance in fragments but greater diversity in continuous forest. According to trophic guilds, coleopteran herbivores were more abundant in continuous forest and overall omnivores in fragments. Continuous forest showed a greater diversity of interactions than fragments. Only in fragments, however, did the arthropod community associated with H aurantiaca show a nested structure, suggesting novel and/or opportunistic host-arthropod associations. Plants, omnivores and predators contributed more to nestedness than herbivores. Therefore, Heliconia-arthropod network properties do not appear to be maintained in fragments mainly caused by the decrease of herbivores. Our study contributes to the understanding of the impact of fragmentation on the structure and dynamics of multitrophic arthropod communities associated with a particular plant species of the highly biodiverse tropical forests. Nevertheless, further replication of study sites is needed to strengthen the conclusion that forest fragmentation negatively affects arthropod assemblages. PMID:26731271

  5. The Multiple Impacts of Tropical Forest Fragmentation on Arthropod Biodiversity and on their Patterns of Interactions with Host Plants.

    PubMed

    Benítez-Malvido, Julieta; Dáttilo, Wesley; Martínez-Falcón, Ana Paola; Durán-Barrón, César; Valenzuela, Jorge; López, Sara; Lombera, Rafael

    2016-01-01

    Tropical rain forest fragmentation affects biotic interactions in distinct ways. Little is known, however, about how fragmentation affects animal trophic guilds and their patterns of interactions with host plants. In this study, we analyzed changes in biotic interactions in forest fragments by using a multitrophic approach. For this, we classified arthropods associated with Heliconia aurantiaca herbs into broad trophic guilds (omnivores, herbivores and predators) and assessed the topological structure of intrapopulation plant-arthropod networks in fragments and continuous forests. Habitat type influenced arthropod species abundance, diversity and composition with greater abundance in fragments but greater diversity in continuous forest. According to trophic guilds, coleopteran herbivores were more abundant in continuous forest and overall omnivores in fragments. Continuous forest showed a greater diversity of interactions than fragments. Only in fragments, however, did the arthropod community associated with H aurantiaca show a nested structure, suggesting novel and/or opportunistic host-arthropod associations. Plants, omnivores and predators contributed more to nestedness than herbivores. Therefore, Heliconia-arthropod network properties do not appear to be maintained in fragments mainly caused by the decrease of herbivores. Our study contributes to the understanding of the impact of fragmentation on the structure and dynamics of multitrophic arthropod communities associated with a particular plant species of the highly biodiverse tropical forests. Nevertheless, further replication of study sites is needed to strengthen the conclusion that forest fragmentation negatively affects arthropod assemblages. PMID:26731271

  6. Herbivore Diet Breadth and Host Plant Defense Mediate the Tri-Trophic Effects of Plant Toxins on Multiple Coccinellid Predators

    PubMed Central

    Katsanis, Angelos; Rasmann, Sergio; Mooney, Kailen A.

    2016-01-01

    Host plant defenses are known to cascade up food chains to influence herbivores and their natural enemies, but how herbivore and predator traits and identity mediate such tri-trophic dynamics is largely unknown. We assessed the influence of plant defense on aphid and coccinellid performance in laboratory trials with low- vs. high-glucosinolate varieties of Brassica napus, a dietary specialist (Brevicoryne brassicae) and generalist (Myzus persicae) aphid, and five species of aphidophagous coccinellids. The performance of the specialist and generalist aphids was similar and unaffected by variation in plant defense. Aphid glucosinolate concentration and resistance to predators differed by aphid species and host plant defense, and these effects acted independently. With respect to aphid species, the dietary generalist aphid (vs. specialist) had 14% lower glucosinolate concentration and coccinellid predators ate three-fold more aphids. With respect to host plant variety, the high-glucosinolate plants (vs. low) increased aphid glucosinolate concentration by 21%, but had relatively weak effects on predation by coccinellids and these effects varied among coccinellid species. In turn, coccinellid performance was influenced by the interactive effects of plant defense and aphid species, as the cascading, indirect effect of plant defense was greater when feeding upon the specialist than generalist aphid. When feeding upon specialist aphids, low- (vs. high-) glucosinolate plants increased coccinellid mass gain by 78% and accelerated development by 14%. In contrast, when feeding upon generalist aphids, low- (vs. high-) glucosinolate plants increased coccinellid mass gain by only 11% and had no detectable effect on development time. These interactive effects of plant defense and aphid diet breadth on predator performance also varied among coccinellid species; the indirect negative effects of plant defenses on predator performance was consistent among the five predators when

  7. Herbivore Diet Breadth and Host Plant Defense Mediate the Tri-Trophic Effects of Plant Toxins on Multiple Coccinellid Predators.

    PubMed

    Katsanis, Angelos; Rasmann, Sergio; Mooney, Kailen A

    2016-01-01

    Host plant defenses are known to cascade up food chains to influence herbivores and their natural enemies, but how herbivore and predator traits and identity mediate such tri-trophic dynamics is largely unknown. We assessed the influence of plant defense on aphid and coccinellid performance in laboratory trials with low- vs. high-glucosinolate varieties of Brassica napus, a dietary specialist (Brevicoryne brassicae) and generalist (Myzus persicae) aphid, and five species of aphidophagous coccinellids. The performance of the specialist and generalist aphids was similar and unaffected by variation in plant defense. Aphid glucosinolate concentration and resistance to predators differed by aphid species and host plant defense, and these effects acted independently. With respect to aphid species, the dietary generalist aphid (vs. specialist) had 14% lower glucosinolate concentration and coccinellid predators ate three-fold more aphids. With respect to host plant variety, the high-glucosinolate plants (vs. low) increased aphid glucosinolate concentration by 21%, but had relatively weak effects on predation by coccinellids and these effects varied among coccinellid species. In turn, coccinellid performance was influenced by the interactive effects of plant defense and aphid species, as the cascading, indirect effect of plant defense was greater when feeding upon the specialist than generalist aphid. When feeding upon specialist aphids, low- (vs. high-) glucosinolate plants increased coccinellid mass gain by 78% and accelerated development by 14%. In contrast, when feeding upon generalist aphids, low- (vs. high-) glucosinolate plants increased coccinellid mass gain by only 11% and had no detectable effect on development time. These interactive effects of plant defense and aphid diet breadth on predator performance also varied among coccinellid species; the indirect negative effects of plant defenses on predator performance was consistent among the five predators when

  8. Jack of all trades masters novel host plants: positive genetic correlations in specialist and generalist insect herbivores expanding their diets to novel hosts

    PubMed Central

    GARCÍA-ROBLEDO, CARLOS; HORVITZ, CAROL C.

    2011-01-01

    One explanation for the widespread host specialization of insect herbivores is the “Jack of all trades-master of none” principle, which states that genotypes with high performance on one host will perform poorly on other hosts. This principle predicts that cross-host correlation in performance of genotypes will be negative. In this study we experimentally explored cross-host correlations and performance among families in four species (two generalist and two specialist) of leaf beetles (Cephaloleia spp.) that are currently expanding their diets from native to exotic plants. All four species displayed similar responses in body size, developmental rates and mortality rates to experimentally controlled diets. When raised on novel hosts, body size of larvae, pupae and adults were reduced. Development times were longer and larval mortality was higher on novel hosts. Genotype × host plant interactions were not detected for most traits. All significant cross-host correlations were positive. These results indicate very different ecological and evolutionary dynamics than those predicted by the “Jack of all trades-master of none” principle. PMID:22022877

  9. The host plants of the Telamonini treehoppers (Hemiptera: Membracidae: Smiliinae) and the first diagnoses of nymphs for 14 species.

    PubMed

    Wallace, Matthew S

    2014-01-01

    Recent research on the treehopper tribe Telamonini has focused on their classification and Nearctic distribution but little has been published on their biology, including detailed information on their host plants as well as data on their nymphal stage. Any studies including host plant data have emphasized adult records (often unreliable due to their movements), largely ignoring the nymphs, which are the predominant feeding stage. This work provides the first comprehensive summary of Telamonini host plants, it documents the first positive identification of the nymphs for several telamonine species (and the genus Helonica), and it provides the first morphological diagnoses for 14 species, thus filling in major gaps in the life history of many species. Host plant records were determined based on accounts in the literature (adults and nymphs), from rearings of nymphs on host plants to the adult stage, and from label data on museum specimens. The Telamonini are known from 22 families, 41 genera, and 80 species of mostly woody, deciduous trees (of which, six species are new host plant records). Nearly half of all telamonines have been collected from more than one plant genus and only 12 species are known from a single host plant species. Telamonine nymphs were reared to the adult stage on 15 plant species. Of 68 telamonine species, 45 have been found on oak (Quercus), and white oak (Q. alba) is the most common telamonine host plant. Telamona monticola has the most recorded host plants with 29. The work includes 23 color illustrations showing both live and preserved nymphs, representing 15 species, all illustrated for the first time (eight are positively identified for the first time). Differences in nymphal morphology among species within Archasia, Glossonotus, Heliria, and Telamona suggest current generic definitions need revision. This study highlights the need for an increased emphasis on nymphal collections when determining treehopper host plants and inferring

  10. Endophytic benefit for a competitive host is neutralized by increasing ratios of infected plants

    NASA Astrophysics Data System (ADS)

    Wu, Lianjie; Ren, Anzhi; Jing, Yuanfang; Zhou, Yong; Wang, Xinyu; Qin, Junhua; Gao, Yubao

    2016-01-01

    Leaf endophytes such as Epichloë can affect the competitive ability of host grasses, but the reported responses are inconsistent. We hypothesized that this inconsistency is caused, at least in part, by the following two aspects. One is that a competitive advantage might occur as a result of an increase in storage compounds for both growth and defense. Another is that the effect of the endophyte might be related to both water availability and host density. In a greenhouse experiment, we compared the competitive abilities of endophyte-infected (EI) and endophyte-free (EF) Leymus chinensis, a dominant grass native to the Inner Mongolia Steppe of China, subjected to ten treatments comprised of a factorial combination of two levels of water availability (well-watered and drought) and five proportions of EI to EF plants (12:0, 4:8, 6:6, 8:4, 0:12). The results showed that the competitive ability of EI plants was higher than that of EF under drought. Here, greater belowground biomass and water use efficiency might contribute to better competitiveness of EI plants. When competing under well-watered conditions, endophyte infection did not provide a benefit to the host plant in biomass accumulation, but more carbon was allocated to defense (total phenolics) in EI plants. This scenario could help EI plants suffer less damage than EF when exposed to herbivores in natural habitats. The competitive ability of EI plants was regulated by EI:EF ratios. Competitive ability of EI plants was higher than that of EF plants in mixtures with lower numbers of EI plants, but the beneficial effect of endophyte infection was neutralized in mixtures with higher numbers of EI plants. Overall, endophyte infection improved the competitive ability of the host under either drought or well-watered conditions but in the presence of herbivore, only this benefit was neutralized by increasing ratios of EI plants. We suspect that both the conditional beneficial effects and stabilizing effects of density

  11. Common Origins and Host-Dependent Diversity of Plant and Animal Viromes

    PubMed Central

    Dolja, Valerian V.; Koonin, Eugene V.

    2012-01-01

    Many viruses infecting animals and plants share common cores of homologous genes involved in the key processes of viral replication. In contrast, genes that mediate virus – host interactions including in many cases capsid protein genes are markedly different. There are three distinct scenarios for the origin of related viruses of plants and animals: i) evolution from a common ancestral virus predating the divergence of plants and animals; ii) horizontal transfer of viruses, for example, through insect vectors; iii) parallel origin from related genetic elements. We present evidence that each of these scenarios contributed, to a varying extent, to the evolution of different groups of viruses. PMID:22408703

  12. Two sugar isomers influence host plant acceptance by a cereal caterpillar pest.

    PubMed

    Juma, G; Thiongo, M; Dutaur, L; Rharrabe, K; Marion-Poll, F; Le Ru, B; Magoma, G; Silvain, J-F; Calatayud, P-A

    2013-02-01

    Plant sugars are often considered as primary feeding stimuli, conditioning host plant acceptance by herbivorous insects. Of the nine sugars identified from methanolic extracts of seven grass species, only turanose, a sucrose isomer, was negatively correlated with the survival and growth of the noctuid larva of cereal stemborer, Busseola fusca. Sucrose was the most abundant sugar, although it did not vary significantly in concentration among the plant species studied. Using Styrofoam™ cylinders impregnated with increasing concentrations of turanose or sucrose, the two sugars had opposing effects: turanose appeared phagodeterrent while sucrose was phagostimulatory. Electrophysiological studies indicated that B. fusca larvae were able to detect both sugars via their styloconic sensilla located on the mouthparts. The findings indicate that, whereas sucrose is a feeding stimulant and positively influences food choice by B. fusca larvae, turanose negatively contributes to larval food choice. The balance in concentrations of both sugars, however, somehow influences the overall host plant choice made by the larvae. This can partly explain host plant suitability and choice by this caterpillar pest in the field. PMID:23168077

  13. Fungal pathogen uses sex pheromone receptor for chemotropic sensing of host plant signals.

    PubMed

    Turrà, David; El Ghalid, Mennat; Rossi, Federico; Di Pietro, Antonio

    2015-11-26

    For more than a century, fungal pathogens and symbionts have been known to orient hyphal growth towards chemical stimuli from the host plant. However, the nature of the plant signals as well as the mechanisms underlying the chemotropic response have remained elusive. Here we show that directed growth of the soil-inhabiting plant pathogen Fusarium oxysporum towards the roots of the host tomato (Solanum lycopersicum) is triggered by the catalytic activity of secreted class III peroxidases, a family of haem-containing enzymes present in all land plants. The chemotropic response requires conserved elements of the fungal cell integrity mitogen-activated protein kinase (MAPK) cascade and the seven-pass transmembrane protein Ste2, a functional homologue of the Saccharomyces cerevisiae sex pheromone α receptor. We further show that directed hyphal growth of F. oxysporum towards nutrient sources such as sugars and amino acids is governed by a functionally distinct MAPK cascade. These results reveal a potentially conserved chemotropic mechanism in root-colonizing fungi, and suggest a new function for the fungal pheromone-sensing machinery in locating plant hosts in a complex environment such as the soil. PMID:26503056

  14. Plants of the fynbos biome harbour host species-specific bacterial communities.

    PubMed

    Miyambo, Tsakani; Makhalanyane, Thulani P; Cowan, Don A; Valverde, Angel

    2016-08-01

    The fynbos biome in South Africa is globally recognised as a plant biodiversity hotspot. However, very little is known about the bacterial communities associated with fynbos plants, despite interactions between primary producers and bacteria having an impact on the physiology of both partners and shaping ecosystem diversity. This study reports on the structure, phylogenetic composition and potential roles of the endophytic bacterial communities located in the stems of three fynbos plants (Erepsia anceps, Phaenocoma prolifera and Leucadendron laureolum). Using Illumina MiSeq 16S rRNA sequencing we found that different subpopulations of Deinococcus-Thermus, Alphaproteobacteria, Acidobacteria and Firmicutes dominated the endophytic bacterial communities. Alphaproteobacteria and Actinobacteria were prevalent in P. prolifera, whereas Deinococcus-Thermus dominated in L. laureolum, revealing species-specific host-bacteria associations. Although a high degree of variability in the endophytic bacterial communities within hosts was observed, we also detected a core microbiome across the stems of the three plant species, which accounted for 72% of the sequences. Altogether, it seems that both deterministic and stochastic processes shaped microbial communities. Endophytic bacterial communities harboured putative plant growth-promoting bacteria, thus having the potential to influence host health and growth. PMID:27190163

  15. The potato pest Russelliana solanicola Tuthill (Hemiptera: Psylloidea): taxonomy and host-plant patterns.

    PubMed

    Serbina, Liliya; Burckhardt, Daniel; Birkhofer, Klaus; Syfert, Mindy M; Halbert, Susan E

    2015-01-01

    The Neotropical jumping plant-louse Russelliana solanicola Tuthill is a potato pest and a probable vector of plant pathogens. Populations morphologically similar to those found on potatoes have been collected on plants of at least ten different families, four of which have been confirmed as hosts by the presence of immatures. This suggests that R. solanicola is either a single polyphagous species or a complex of closely related, monophagous species (host races/cryptic species). Results of our analyses of multiple morphometric characters show for both sexes a grouping of the populations of R. solanicola and a clear separation of the latter from other Russelliana species. On the other hand, within R. solanicola, there is an overlap of populations from different host-plants as well as from different geographical regions. The results of the present study strongly suggest that R. solanicola is a single, polyphagous species and the known distribution indicates that it is native to the Andes. It is likely that R. solanicola has been introduced into eastern Argentina, Brazil and Uruguay. The polyphagy together with the ability to disperse and transmit plant pathogens potentially make this species an economically important pest of potato and other crop species. PMID:26624119

  16. Pea Aphids (Hemiptera: Aphididae) Have Diurnal Rhythms When Raised Independently of a Host Plant.

    PubMed

    Joschinski, Jens; Beer, Katharina; Helfrich-Förster, Charlotte; Krauss, Jochen

    2016-01-01

    Seasonal timing is assumed to involve the circadian clock, an endogenous mechanism to track time and measure day length. Some debate persists, however, and aphids were among the first organisms for which circadian clock involvement was questioned. Inferences about links to phenology are problematic, as the clock itself is little investigated in aphids. For instance, it is unknown whether aphids possess diurnal rhythms at all. Possibly, the close interaction with host plants prevents independent measurements of rhythmicity. We reared the pea aphid Acyrthosiphon pisum(Harris) on an artificial diet, and recorded survival, moulting, and honeydew excretion. Despite their plant-dependent life style, aphids were independently rhythmic under light-dark conditions. This first demonstration of diurnal aphid rhythms shows that aphids do not simply track the host plant's rhythmicity. PMID:27012868

  17. Host genotype and age shape the leaf and root microbiomes of a wild perennial plant.

    PubMed

    Wagner, Maggie R; Lundberg, Derek S; Del Rio, Tijana G; Tringe, Susannah G; Dangl, Jeffery L; Mitchell-Olds, Thomas

    2016-01-01

    Bacteria living on and in leaves and roots influence many aspects of plant health, so the extent of a plant's genetic control over its microbiota is of great interest to crop breeders and evolutionary biologists. Laboratory-based studies, because they poorly simulate true environmental heterogeneity, may misestimate or totally miss the influence of certain host genes on the microbiome. Here we report a large-scale field experiment to disentangle the effects of genotype, environment, age and year of harvest on bacterial communities associated with leaves and roots of Boechera stricta (Brassicaceae), a perennial wild mustard. Host genetic control of the microbiome is evident in leaves but not roots, and varies substantially among sites. Microbiome composition also shifts as plants age. Furthermore, a large proportion of leaf bacterial groups are shared with roots, suggesting inoculation from soil. Our results demonstrate how genotype-by-environment interactions contribute to the complexity of microbiome assembly in natural environments. PMID:27402057

  18. Host genotype and age shape the leaf and root microbiomes of a wild perennial plant

    PubMed Central

    Wagner, Maggie R.; Lundberg, Derek S; del Rio, Tijana G.; Tringe, Susannah G.; Dangl, Jeffery L.; Mitchell-Olds, Thomas

    2016-01-01

    Bacteria living on and in leaves and roots influence many aspects of plant health, so the extent of a plant's genetic control over its microbiota is of great interest to crop breeders and evolutionary biologists. Laboratory-based studies, because they poorly simulate true environmental heterogeneity, may misestimate or totally miss the influence of certain host genes on the microbiome. Here we report a large-scale field experiment to disentangle the effects of genotype, environment, age and year of harvest on bacterial communities associated with leaves and roots of Boechera stricta (Brassicaceae), a perennial wild mustard. Host genetic control of the microbiome is evident in leaves but not roots, and varies substantially among sites. Microbiome composition also shifts as plants age. Furthermore, a large proportion of leaf bacterial groups are shared with roots, suggesting inoculation from soil. Our results demonstrate how genotype-by-environment interactions contribute to the complexity of microbiome assembly in natural environments. PMID:27402057

  19. Oxidative Stress in Fungi: Its Function in Signal Transduction, Interaction with Plant Hosts, and Lignocellulose Degradation

    PubMed Central

    Breitenbach, Michael; Weber, Manuela; Rinnerthaler, Mark; Karl, Thomas; Breitenbach-Koller, Lore

    2015-01-01

    In this review article, we want to present an overview of oxidative stress in fungal cells in relation to signal transduction, interaction of fungi with plant hosts, and lignocellulose degradation. We will discuss external oxidative stress which may occur through the interaction with other microorganisms or plant hosts as well as internally generated oxidative stress, which can for instance originate from NADPH oxidases or “leaky” mitochondria and may be modulated by the peroxiredoxin system or by protein disulfide isomerases thus contributing to redox signaling. Analyzing redox signaling in fungi with the tools of molecular genetics is presently only in its beginning. However, it is already clear that redox signaling in fungal cells often is linked to cell differentiation (like the formation of perithecia), virulence (in plant pathogens), hyphal growth and the successful passage through the stationary phase. PMID:25854186

  20. THE PROPERTIES OF TYPE Ia SUPERNOVA HOST GALAXIES FROM THE SLOAN DIGITAL SKY SURVEY

    SciTech Connect

    Han, Du-Hwan; Park, Myeong-Gu; Park, Changbom; Choi, Yun-Young E-mail: mgp@knu.ac.k E-mail: yychoi@khu.ac.k

    2010-11-20

    We investigate the properties and environments of Type Ia Supernova (SN Ia) host galaxies in the Stripe 82 of the Sloan Digital Sky Survey-II Supernova Survey centered on the celestial equator. Host galaxies are defined as the galaxy nearest to the supernova (SN) in terms of angular distance whose velocity difference from the SN is less than 1000 km s{sup -1}. Eighty seven SN Ia host galaxies are selected from the SDSS Main galaxy sample with the apparent r-band magnitude m{sub r} < 17.77, and compared with the SDSS Main galaxies. The SN Ia rates for early- and late-type galaxies are 0.81 {+-} 0.19 SN (100 yr){sup -1} and 0.99 {+-} 0.21 SN (100 yr){sup -1}, respectively. We find that the host galaxies have a color distribution consistent with that of the Main galaxies, regardless of their morphology. However, host galaxies are on average brighter than the Main galaxies by {approx}0.3 mag over the range of -18.3>M{sub r} > - 21.3. But the brighter ends of their luminosity distributions are similar. The distribution of the distance to the nearest neighbor galaxy shows that SNe Ia are more likely to occur in isolated galaxies without close neighbors. We also find that the SN Ia host galaxies are preferentially located in a region close to massive galaxy clusters compared to the Main galaxies.

  1. Selection for protection in an ant–plant mutualism: host sanctions, host modularity, and the principal–agent game

    PubMed Central

    Edwards, David P; Hassall, Mark; Sutherland, William J; Yu, Douglas W

    2005-01-01

    Retaliation against cheaters can prevent the breakdown of cooperation. Here we ask whether the ant–plant Cordia nodosa is able to apply retaliatory sanctions against its ant symbiont Allomerus octoarticulatus, which patrols new shoots to prevent herbivory. We test the hypothesis that the modular design of C. nodosa physiologically ties the growth of housing (stem swellings known as domatia) to the successful development of the attached leaves. We experimentally simulated herbivory by cutting leaves from patrolled shoots and found that the domatia on such ‘cheated’ shoots suffered higher mortality and lower growth than did controls, evidence for a host sanction. On the other hand, patrolling is costly to the ant, and experiment shows that non-patrollers run a low risk of being sanctioned because most leaves (and the attached domatia) escape heavy herbivory even when patrollers are absent. This suggests that cheaters might enjoy a higher fitness than do mutualists, despite sanctions, but we find that patrolling provides a net fecundity benefit when the colony and plant exceed a minimum size, which requires sustained ant investment in patrolling. These results map directly onto the principal–agent (P–A) game from economics, which we suggest can be used as a framework for studying stability in mutualisms, where high sampling costs and cheating do not allow market effects to select for mutual benefits. PMID:16537131

  2. Herbivore Oral Secreted Bacteria Trigger Distinct Defense Responses in Preferred and Non-Preferred Host Plants.

    PubMed

    Wang, Jie; Chung, Seung Ho; Peiffer, Michelle; Rosa, Cristina; Hoover, Kelli; Zeng, Rensen; Felton, Gary W

    2016-06-01

    Insect symbiotic bacteria affect host physiology and mediate plant-insect interactions, yet there are few clear examples of symbiotic bacteria regulating defense responses in different host plants. We hypothesized that plants would induce distinct defense responses to herbivore- associated bacteria. We evaluated whether preferred hosts (horsenettle) or non-preferred hosts (tomato) respond similarly to oral secretions (OS) from the false potato beetle (FPB, Leptinotarsa juncta), and whether the induced defense triggered by OS was due to the presence of symbiotic bacteria in OS. Both horsenettle and tomato damaged by antibiotic (AB) treated larvae showed higher polyphenol oxidase (PPO) activity than those damaged by non-AB treated larvae. In addition, application of OS from AB treated larvae induced higher PPO activity compared with OS from non-AB treated larvae or water treatment. False potato beetles harbor bacteria that may provide abundant cues that can be recognized by plants and thus mediate corresponding defense responses. Among all tested bacterial isolates, the genera Pantoea, Acinetobacter, Enterobacter, and Serratia were found to suppress PPO activity in tomato, while only Pantoea sp. among these four isolates was observed to suppress PPO activity in horsenettle. The distinct PPO suppression caused by symbiotic bacteria in different plants was similar to the pattern of induced defense-related gene expression. Pantoea inoculated FPB suppressed JA-responsive genes and triggered a SA-responsive gene in both tomato and horsenettle. However, Enterobacter inoculated FPB eliminated JA-regulated gene expression and elevated SA-regulated gene expression in tomato, but did not show evident effects on the expression levels of horsenettle defense-related genes. These results indicate that suppression of plant defenses by the bacteria found in the oral secretions of herbivores may be a more widespread phenomenon than previously indicated. PMID:27294415

  3. Evaluation of Glucose Dehydrogenase and Pyrroloquinoline Quinine (pqq) Mutagenesis that Renders Functional Inadequacies in Host Plants.

    PubMed

    Naveed, Muhammad; Sohail, Younas; Khalid, Nauman; Ahmed, Iftikhar; Mumtaz, Abdul Samad

    2015-08-01

    The rhizospheric zone abutting plant roots usually clutches a wealth of microbes. In the recent past, enormous genetic resources have been excavated with potential applications in host plant interaction and ancillary aspects. Two Pseudomonas strains were isolated and identified through 16S rRNA and rpoD sequence analyses as P. fluorescens QAU67 and P. putida QAU90. Initial biochemical characterization and their root-colonizing traits indicated their potential role in plant growth promotion. Such aerobic systems, involved in gluconic acid production and phosphate solubilization, essentially require the pyrroloquinoline quinine (PQQ)- dependent glucose dehydrogenase (GDH) in the genome. The PCR screening and amplification of GDH and PQQ and subsequent induction of mutagenesis characterized their possible role as antioxidants as well as in growth promotion, as probed in vitro in lettuce and in vivo in rice, bean, and tomato plants. The results showed significant differences (p < or = 0.05) in parameters of plant height, fresh weight, and dry weight, etc., deciphering a clear and in fact complementary role of GDH and PQQ in plant growth promotion. Our study not only provides direct evidence of the in vivo role of GDH and PQQ in host plants but also reveals their functional inadequacy in the event of mutation at either of these loci. PMID:25839331

  4. Host plant use drives genetic differentiation in syntopic populations of Maculinea alcon.

    PubMed

    Tartally, András; Kelager, Andreas; Fürst, Matthias A; Nash, David R

    2016-01-01

    The rare socially parasitic butterfly Maculinea alcon occurs in two forms, which are characteristic of hygric or xeric habitats and which exploit different host plants and host ants. The status of these two forms has been the subject of considerable controversy. Populations of the two forms are usually spatially distinct, but at Răscruci in Romania both forms occur on the same site (syntopically). We examined the genetic differentiation between the two forms using eight microsatellite markers, and compared with a nearby hygric site, Şardu. Our results showed that while the two forms are strongly differentiated at Răscruci, it is the xeric form there that is most similar to the hygric form at Şardu, and Bayesian clustering algorithms suggest that these two populations have exchanged genes relatively recently. We found strong evidence for population substructuring, caused by high within host ant nest relatedness, indicating very limited dispersal of most ovipositing females, but not association with particular host ant species. Our results are consistent with the results of larger scale phylogeographic studies that suggest that the two forms represent local ecotypes specialising on different host plants, each with a distinct flowering phenology, providing a temporal rather than spatial barrier to gene flow. PMID:27069804

  5. Host plant use drives genetic differentiation in syntopic populations of Maculinea alcon

    PubMed Central

    Fürst, Matthias A.

    2016-01-01

    The rare socially parasitic butterfly Maculinea alcon occurs in two forms, which are characteristic of hygric or xeric habitats and which exploit different host plants and host ants. The status of these two forms has been the subject of considerable controversy. Populations of the two forms are usually spatially distinct, but at Răscruci in Romania both forms occur on the same site (syntopically). We examined the genetic differentiation between the two forms using eight microsatellite markers, and compared with a nearby hygric site, Şardu. Our results showed that while the two forms are strongly differentiated at Răscruci, it is the xeric form there that is most similar to the hygric form at Şardu, and Bayesian clustering algorithms suggest that these two populations have exchanged genes relatively recently. We found strong evidence for population substructuring, caused by high within host ant nest relatedness, indicating very limited dispersal of most ovipositing females, but not association with particular host ant species. Our results are consistent with the results of larger scale phylogeographic studies that suggest that the two forms represent local ecotypes specialising on different host plants, each with a distinct flowering phenology, providing a temporal rather than spatial barrier to gene flow. PMID:27069804

  6. Virus versus Host Plant MicroRNAs: Who Determines the Outcome of the Interaction?

    PubMed Central

    Maghuly, Fatemeh; Ramkat, Rose C.; Laimer, Margit

    2014-01-01

    Considering the importance of microRNAs (miRNAs) in the regulation of essential processes in plant pathogen interactions, it is not surprising that, while plant miRNA sequences counteract viral attack via antiviral RNA silencing, viruses in turn have developed antihost defense mechanisms blocking these RNA silencing pathways and establish a counter-defense. In the current study, computational and stem-loop Reverse Transcription – Polymerase Chain Reaction (RT-PCR) approaches were employed to a) predict and validate virus encoded mature miRNAs (miRs) in 39 DNA-A sequences of the bipartite genomes of African cassava mosaic virus (ACMV) and East African cassava mosaic virus-Uganda (EACMV-UG) isolates, b) determine whether virus encoded miRs/miRs* generated from the 5′/3′ harpin arms have the capacity to bind to genomic sequences of the host plants Jatropha or cassava and c) investigate whether plant encoded miR/miR* sequences have the potential to bind to the viral genomes. Different viral pre-miRNA hairpin sequences and viral miR/miR* length variants occurring as isomiRs were predicted in both viruses. These miRNAs were located in three Open Reading Frames (ORFs) and in the Intergenic Region (IR). Moreover, various target genes for miRNAs from both viruses were predicted and annotated in the host plant genomes indicating that they are involved in biotic response, metabolic pathways and transcription factors. Plant miRs/miRs* from conserved and highly expressed families were identified, which were shown to have potential targets in the genome of both begomoviruses, representing potential plant miRNAs mediating antiviral defense. This is the first assessment of predicted viral miRs/miRs* of ACMV and EACMV-UG and host plant miRNAs, providing a reference point for miRNA identification in pathogens and their hosts. These findings will improve the understanding of host- pathogen interaction pathways and the function of viral miRNAs in Euphorbiaceous crop plants. PMID

  7. Hyperparasitoids Use Herbivore-Induced Plant Volatiles to Locate Their Parasitoid Host

    PubMed Central

    Poelman, Erik H.; Bruinsma, Maaike; Zhu, Feng; Weldegergis, Berhane T.; Boursault, Aline E.; Jongema, Yde; van Loon, Joop J. A.; Vet, Louise E. M.; Harvey, Jeffrey A.; Dicke, Marcel

    2012-01-01

    Plants respond to herbivory with the emission of induced plant volatiles. These volatiles may attract parasitic wasps (parasitoids) that attack the herbivores. Although in this sense the emission of volatiles has been hypothesized to be beneficial to the plant, it is still debated whether this is also the case under natural conditions because other organisms such as herbivores also respond to the emitted volatiles. One important group of organisms, the enemies of parasitoids, hyperparasitoids, has not been included in this debate because little is known about their foraging behaviour. Here, we address whether hyperparasitoids use herbivore-induced plant volatiles to locate their host. We show that hyperparasitoids find their victims through herbivore-induced plant volatiles emitted in response to attack by caterpillars that in turn had been parasitized by primary parasitoids. Moreover, only one of two species of parasitoids affected herbivore-induced plant volatiles resulting in the attraction of more hyperparasitoids than volatiles from plants damaged by healthy caterpillars. This resulted in higher levels of hyperparasitism of the parasitoid that indirectly gave away its presence through its effect on plant odours induced by its caterpillar host. Here, we provide evidence for a role of compounds in the oral secretion of parasitized caterpillars that induce these changes in plant volatile emission. Our results demonstrate that the effects of herbivore-induced plant volatiles should be placed in a community-wide perspective that includes species in the fourth trophic level to improve our understanding of the ecological functions of volatile release by plants. Furthermore, these findings suggest that the impact of species in the fourth trophic level should also be considered when developing Integrated Pest Management strategies aimed at optimizing the control of insect pests using parasitoids. PMID:23209379

  8. Depth and type of substrate influence the ability of Nasonia vitripennis to locate a host.

    PubMed

    Frederickx, Christine; Dekeirsschieter, Jessica; Verheggen, François J; Haubruge, Eric

    2014-01-01

    The foraging behaviour of a parasitoid insect species includes the host's habitat and subsequent location of the host. Habitats substrate, substrate moisture, and light levels can affect the host searching of different species of parasitoids. However, the depth at which parasitoids concentrate their search effort is another important ecological characteristic and plays an important role in locating a host. Here, we investigated the ability of a pupal parasitoid, Nasonia vitripennis Walker (Hymenoptera: Pteromalidae), to penetrate and kill fly pupae located at different depths of the substrate. Three different types of substrate were tested: loam soil, compost, and vermiculite substrate. In both loam soil and compost, all of the parasitism activity was restricted to pupae placed directly on the surface. Parasitism activity in vermiculite showed that the average number of pupae parasitized decreased with depth of substrate. These results suggest that fly pupae situated deeper in the substrate are less subjected to parasitism by N. vitripennis. PMID:25373205

  9. Depth and Type of Substrate Influence the Ability of Nasonia vitripennis to Locate a Host

    PubMed Central

    Frederickx, Christine; Dekeirsschieter, Jessica; Verheggen, François J.; Haubruge, Eric

    2014-01-01

    The foraging behaviour of a parasitoid insect species includes the host's habitat and subsequent location of the host. Habitats substrate, substrate moisture, and light levels can affect the host searching of different species of parasitoids. However, the depth at which parasitoids concentrate their search effort is another important ecological characteristic and plays an important role in locating a host. Here, we investigated the ability of a pupal parasitoid, Nasonia vitripennis Walker (Hymenoptera: Pteromalidae), to penetrate and kill fly pupae located at different depths of the substrate. Three different types of substrate were tested: loam soil, compost, and vermiculite substrate. In both loam soil and compost, all of the parasitism activity was restricted to pupae placed directly on the surface. Parasitism activity in vermiculite showed that the average number of pupae parasitized decreased with depth of substrate. These results suggest that fly pupae situated deeper in the substrate are less subjected to parasitism by N. vitripennis. PMID:25373205

  10. Fungal nutrient allocation in common mycorrhizal networks is regulated by the carbon source strength of individual host plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    • The common mycorrhizal networks (CMN) of arbuscular mycorrhizal (AM) fungi in the soil provide multiple host plants with nutrients, but the mechanisms by which the nutrient transport to individual host plants within one CMN is controlled, are currently unknown. • We followed by radioactive and st...

  11. Haplotypes of the potato psyllid, Bactericera cockerelli, on the wild host plant, Solanum dulcamara, in the Pacific Northwestern United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    ‘Candidatus Liberibacter solanacearum’ (Lso) is a bacterium that infects solanaceous crops and causes plant decline and yield losses, especially in potato and tomato. Lso is transmitted to these hosts by the potato psyllid (Bactericera cockerelli Sulc.) vector. B. cockerelli host plants are not li...

  12. Arbuscular mycorrhizal symbiosis increases host plant acceptance and population growth rates of the two-spotted spider mite Tetranychus urticae.

    PubMed

    Hoffmann, Daniela; Vierheilig, Horst; Riegler, Petra; Schausberger, Peter

    2009-01-01

    Most terrestrial plants live in symbiosis with arbuscular mycorrhizal (AM) fungi. Studies on the direct interaction between plants and mycorrhizal fungi are numerous whereas studies on the indirect interaction between such fungi and herbivores feeding on aboveground plant parts are scarce. We studied the impact of AM symbiosis on host plant choice and life history of an acarine surface piercing-sucking herbivore, the polyphagous two-spotted spider mite Tetranychus urticae. Experiments were performed on detached leaflets taken from common bean plants (Phaseolus vulgaris) colonized or not colonized by the AM fungus Glomus mosseae. T. urticae females were subjected to choice tests between leaves from mycorrhizal and non-mycorrhizal plants. Juvenile survival and development, adult female survival, oviposition rate and offspring sex ratio were measured in order to estimate the population growth parameters of T. urticae on either substrate. Moreover, we analyzed the macro- and micronutrient concentration of the aboveground plant parts. Adult T. urticae females preferentially resided and oviposited on mycorrhizal versus non-mycorrhizal leaflets. AM symbiosis significantly decreased embryonic development time and increased the overall oviposition rate as well as the proportion of female offspring produced during peak oviposition. Altogether, the improved life history parameters resulted in significant changes in net reproductive rate, intrinsic rate of increase, doubling time and finite rate of increase. Aboveground parts of colonized plants showed higher concentrations of P and K whereas Mn and Zn were both found at lower levels. This is the first study documenting the effect of AM symbiosis on the population growth rates of a herbivore, tracking the changes in life history characteristics throughout the life cycle. We discuss the AM-plant-herbivore interaction in relation to plant quality, herbivore feeding type and site and the evolutionary implications in a multi

  13. The Influence of Host Plant Volatiles on the Attraction of Longhorn Beetles to Pheromones.

    PubMed

    Collignon, R Maxwell; Swift, Ian P; Zou, Yunfan; McElfresh, J Steven; Hanks, Lawrence M; Millar, Jocelyn G

    2016-03-01

    Host plant volatiles have been shown to strongly synergize the attraction of some longhorn beetle species (Coleoptera: Cerambycidae) to their pheromones. This synergism is well documented among species that infest conifers, but less so for angiosperm-infesting species. To explore the extent of this phenomenon in the Cerambycidae, we first tested the responses of a cerambycid community to a generic pheromone blend in the presence or absence of chipped material from host plants as a source of host volatiles. In the second phase, blends of oak and conifer volatiles were reconstructed, and tested at low, medium, and high release rates with the pheromone blend. For conifer-infesting species in the subfamilies Spondylidinae and Lamiinae, conifer volatiles released at the high rate synergized attraction of some species to the pheromone blend. When comparing high-release rate conifer blend with high-release rate α-pinene as a single component, species responses varied, with Asemum nitidum LeConte being most attracted to pheromones plus α-pinene, whereas Neospondylis upiformis (Mannerheim) were most attracted to pheromones plus conifer blend and ethanol. For oak-infesting species in the subfamily Cerambycinae, with the exception of Phymatodes grandis Casey, which were most attracted to pheromones plus ethanol, neither synthetic oak blend nor ethanol increased attraction to pheromones. The results indicate that the responses to combinations of pheromones with host plant volatiles varied from synergistic to antagonistic, depending on beetle species. Release rates of host plant volatiles also were important, with some high release rates being antagonistic for oak-infesting species, but acting synergistically for conifer-infesting species. PMID:26980612

  14. Behaviorally plastic host-plant use by larval Lepidoptera in tri-trophic food webs.

    PubMed

    Singer, Michael S

    2016-04-01

    Plant-insect interactions research emphasizes adaptive plasticity of plants and carnivores, such as parasitoids, implying a relatively passive role of herbivores. Current work is addressing this deficit, with exciting studies of behavioral plasticity of larval Lepidoptera (caterpillars). Here I use select examples to illustrate the diversity of behaviorally plastic host-plant use by caterpillars, including anti-predator tactics, self-medication, and evasion of dynamic plant defenses, as proof of the agency of caterpillar behavior in plant-insect interactions. I emphasize the significance of adaptive behavioral plasticity of caterpillars in the context of tri-trophic interactions. Recent research on trait-mediated indirect interactions places adaptive behavioral plasticity of herbivores at the center of community and food web dynamics, with far-reaching consequences of issues such as community stability. PMID:27436647

  15. Drought stress affects plant metabolites and herbivore preference but not host location by its parasitoids.

    PubMed

    Weldegergis, Berhane T; Zhu, Feng; Poelman, Erik H; Dicke, Marcel

    2015-03-01

    One of the main abiotic stresses that strongly affects plant survival and the primary cause of crop loss around the world is drought. Drought stress leads to sequential morphological, physiological, biochemical and molecular changes that can have severe effects on plant growth, development and productivity. As a consequence of these changes, the interaction between plants and insects can be altered. Using cultivated Brassica oleracea plants, the parasitoid Microplitis mediator and its herbivorous host Mamestra brassicae, we studied the effect of drought stress on (1) the emission of plant volatile organic compounds (VOCs), (2) plant hormone titres, (3) preference and performance of the herbivore, and (4) preference of the parasitoid. Higher levels of jasmonic acid (JA) and abscisic acid (ABA) were recorded in response to herbivory, but no significant differences were observed for salicylic acid (SA) and indole-3-acetic acid (IAA). Drought significantly impacted SA level and showed a significant interactive effect with herbivory for IAA levels. A total of 55 VOCs were recorded and the difference among the treatments was influenced largely by herbivory, where the emission rate of fatty acid-derived volatiles, nitriles and (E)-4,8-dimethylnona-1,3,7-triene [(E)-DMNT] was enhanced. Mamestra brassicae moths preferred to lay eggs on drought-stressed over control plants; their offspring performed similarly on plants of both treatments. VOCs due to drought did not affect the choice of M. mediator parasitoids. Overall, our study reveals an influence of drought on plant chemistry and insect-plant interactions. PMID:25370387

  16. Checklist of available generic names for Microsporidia with type species and type host

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The science of microsporidiology encompasses a diverse assemblage of pathogens from a large and varied group of hosts. Many members of this group have been studied and exploited for their role in the control of insect pests and vectors as well as their detrimental impact on vertebrates including ma...

  17. Selective destruction of a host blood cell type by a parasitoid wasp.

    PubMed

    Rizki, R M; Rizki, T M

    1984-10-01

    Foreign objects that enter the hemocoel of Drosophila melanogaster larvae are encapsulated by one type of blood cell, the lamellocyte, yet eggs of the parasitoid wasp Leptopilina heterotoma remain unencapsulated in D. melanogaster larval hosts that have many lamellocytes. Here we demonstrate that shortly after a female wasp oviposits in the hemocoel the lamellocytes undergo morphological changes and lose their adhesiveness. These affected blood cells are eventually destroyed as the parasitoid egg continues its development. The factor responsible for lamellocyte destruction, lamellolysin, is contained in an accessory gland of the female reproductive system and is injected along with the egg into the host hemocoel. Lamellolysin does not alter the morphology or the defense functions of the other types of blood cells in the host. PMID:6435126

  18. Electroantennographic and behavioral responses of the sphinx moth Manduca sexta to host plant headspace volatiles.

    PubMed

    Fraser, Ann M; Mechaber, Wendy L; Hildebrand, John G

    2003-08-01

    Coupled gas chromatography with electroantennographic detection (GC-EAD) using antennae of adult female Manduca sexta was employed to screen for olfactory stimulants present in headspace collections from four species of larval host plants belonging to two families: Solanaceae--Lycopersicon esculentum (tomato), Capiscum annuum (bell pepper), and Datura wrightii; and Martyniaceae--Pronboscideaparviflora. Headspace volatiles were collected from undamaged foliage of potted, living plants. GC-EAD revealed 23 EAD-active compounds, of which 15 were identified by GC-mass spectrometry. Identified compounds included aliphatic, aromatic, and terpenoid compounds bearing a range of functional groups. Nine EAD-active compounds were common to all four host plant species: (Z)-3-hexenyl acetate, nonanal, decanal, phenylacetaldehyde, methyl salicylate, benzyl alcohol, geranyl acetone, (E)-nerolidol, and one unidentified compound. Behavioral responses of female moths to an eight-component synthetic blend of selected tomato headspace volatiles were tested in a laboratory wind tunnel. Females were attracted to the blend. A comparison of responses from antennae of males and females to bell pepper headspace volatiles revealed that males responded to the same suite of volatiles as females, except for (Z)-3-hexenyl benzoate. EAD responses of males also were lower for (Z)-and (E)-nerolidol and one unidentified compound. Electroantennogram EAG dose-response curves for the 15 identified EAD-active volatiles were recorded. At the higher test doses (10-100 microg), female antennae yielded larger EAG responses to terpenoids and to aliphatic and aromatic esters. Male antennae did respond to the higher doses of (Z)-3-hexenyl benzoate, indicating that they can detect this compound. On the basis of ubiquity of the EAD-active volatiles identified to date in host plant headspace collections, we suggest that M. sexta uses a suite of volatiles to locate and identify appropriate host plants. PMID

  19. Parasitoids select plants more heavily infested with their caterpillar hosts: a new approach to aid interpretation of plant headspace volatiles

    PubMed Central

    Girling, Robbie D.; Stewart-Jones, Alex; Dherbecourt, Julie; Staley, Joanna T.; Wright, Denis J.; Poppy, Guy M.

    2011-01-01

    Plants produce volatile organic compounds (VOCs) in response to herbivore attack, and these VOCs can be used by parasitoids of the herbivore as host location cues. We investigated the behavioural responses of the parasitoid Cotesia vestalis to VOCs from a plant–herbivore complex consisting of cabbage plants (Brassica oleracea) and the parasitoids host caterpillar, Plutella xylostella. A Y-tube olfactometer was used to compare the parasitoids' responses to VOCs produced as a result of different levels of attack by the caterpillar and equivalent levels of mechanical damage. Headspace VOC production by these plant treatments was examined using gas chromatography–mass spectrometry. Cotesia vestalis were able to exploit quantitative and qualitative differences in volatile emissions, from the plant–herbivore complex, produced as a result of different numbers of herbivores feeding. Cotesia vestalis showed a preference for plants with more herbivores and herbivore damage, but did not distinguish between different levels of mechanical damage. Volatile profiles of plants with different levels of herbivores/herbivore damage could also be separated by canonical discriminant analyses. Analyses revealed a number of compounds whose emission increased significantly with herbivore load, and these VOCs may be particularly good indicators of herbivore number, as the parasitoid processes cues from its external environment. PMID:21270031

  20. Conventional and PCR Detection of Aphelenchoides fragariae in Diverse Ornamental Host Plant Species

    PubMed Central

    McCuiston, Jamie L.; Hudson, Laura C.; Subbotin, Sergei A.; Davis, Eric L.; Warfield, Colleen Y.

    2007-01-01

    A PCR-based diagnostic assay was developed for early detection and identification of Aphelenchoides fragariae directly in host plant tissues using the species-specific primers AFragFl and AFragRl that amplify a 169-bp fragment in the internal transcribed spacer (ITS1) region of ribosomal DNA. These species-specific primers did not amplify DNA from Aphelenchoides besseyi or Aphelenchoides ritzemabosi. The PCR assay was sensitive, detecting a single nematode in a background of plant tissue extract. The assay accurately detected A. fragariae in more than 100 naturally infected, ornamental plant samples collected in North Carolina nurseries, garden centers and landscapes, including 50 plant species not previously reported as hosts of Aphelenchoides spp. The detection sensitivity of the PCR-based assay was higher for infected yet asymptomatic plants when compared to the traditional, water extraction method for Aphelenchoides spp. detection. The utility of using NaOH extraction for rapid preparation of total DNA from plant samples infected with A. fragariae was demonstrated. PMID:19259510

  1. Multitasking antimicrobial peptides in plant development and host defense against biotic/abiotic stress.

    PubMed

    Goyal, Ravinder K; Mattoo, Autar K

    2014-11-01

    Crop losses due to pathogens are a major threat to global food security. Plants employ a multilayer defense against a pathogen including the use of physical barriers (cell wall), induction of hypersensitive defense response (HR), resistance (R) proteins, and synthesis of antimicrobial peptides (AMPs). Unlike a complex R gene-mediated immunity, AMPs directly target diverse microbial pathogens. Many a times, R-mediated immunity breaks down and plant defense is compromised. Although R-gene dependent pathogen resistance has been well studied, comparatively little is known about the interactions of AMPs with host defense and physiology. AMPs are ubiquitous, low molecular weight peptides that display broad spectrum resistance against bacteria, fungi and viruses. In plants, AMPs are mainly classified into cyclotides, defensins, thionins, lipid transfer proteins, snakins, and hevein-like vicilin-like and knottins. Genetic distance lineages suggest their conservation with minimal effect of speciation events during evolution. AMPs provide durable resistance in plants through a combination of membrane lysis and cellular toxicity of the pathogen. Plant hormones - gibberellins, ethylene, jasmonates, and salicylic acid, are among the physiological regulators that regulate the expression of AMPs. Transgenically produced AMP-plants have become a means showing that AMPs are able to mitigate host defense responses while providing durable resistance against pathogens. PMID:25438794

  2. Contributions of host cellular trafficking and organization to the outcomes of plant-pathogen interactions.

    PubMed

    Underwood, William

    2016-08-01

    In recent years it has become increasingly apparent that dynamic changes in protein localization, membrane trafficking pathways, and cellular organization play a major role in determining the outcome of interactions between plants and pathogenic microorganisms. Plants have evolved sophisticated perception systems to recognize the presence of potentially pathogenic microorganisms via the detection of non-self or modified-self elicitor molecules, pathogen virulence factors, or the activities of such virulence factors. Dynamic changes to host cellular organization and membrane trafficking pathways play pivotal roles in detection and signaling by plant immune receptors and are vital for the execution of spatially targeted defense responses to thwart invasion by potential pathogens. Conversely, from the perspective of the pathogen, the ability to manipulate plant cellular organization and trafficking processes to establish infection structures and deliver virulence factors is a major determinant of pathogen success. This review summarizes selected topics that illustrate how dynamic changes in host cellular trafficking and organization shape the outcomes of diverse plant-pathogen interactions and addresses ways in which our rapidly expanding knowledge of the cell biological processes that contribute to immunity or infection may influence efforts to improve plant disease resistance. PMID:27216829

  3. Deletion of the Fungal Gene soft Disrupts Mutualistic Symbiosis between the Grass Endophyte Epichloë festucae and the Host Plant

    PubMed Central

    Charlton, Nikki D.; Shoji, Jun-Ya; Ghimire, Sita R.; Nakashima, Jin

    2012-01-01

    Hyphal anastomosis, or vegetative hyphal fusion, establishes the interconnection of individual hyphal strands into an integrated network of a fungal mycelium. In contrast to recent advances in the understanding of the molecular basis for hyphal anastomosis, knowledge of the physiological role of hyphal anastomosis in the natural habitats of filamentous fungi is still very limited. To investigate the role of hyphal anastomosis in fungal endophyte-plant interactions, we generated mutant strains lacking the Epichloë festucae soft (so) gene, an ortholog of the hyphal anastomosis gene so in the endophytic fungus E. festucae. The E. festucae Δso mutant strains grew similarly to the wild-type strain in culture but with reduced aerial hyphae and completely lacked hyphal anastomosis. The most striking phenotype of the E. festucae Δso mutant strain was that it failed to establish a mutualistic symbiosis with the tall fescue plant host (Lolium arundinaceum); instead, it killed the host plant within 2 months after the initial infection. Microscopic examination revealed that the death of the tall fescue plant host was associated with the distortion and disorganization of plant cells. This study suggests that hyphal anastomosis may have an important role in the establishment/maintenance of fungal endophyte-host plant mutualistic symbiosis. PMID:23042130

  4. A Small Secreted Virulence-Related Protein Is Essential for the Necrotrophic Interactions of Sclerotinia sclerotiorum with Its Host Plants

    PubMed Central

    Lyu, Xueliang; Shen, Cuicui; Fu, Yanping; Xie, Jiatao; Jiang, Daohong; Li, Guoqing; Cheng, Jiasen

    2016-01-01

    indicate novel roles of small secreted proteins in the interactions between host-non-specific necrotrophic fungi and plants, and highlight the significance to illuminate the pathogenic mechanisms of this type of interaction. PMID:26828434

  5. Effect of mechanical damage on emission of volatile organic compounds from plant leaves and implications for evaluation of host plant specificity of prospective biological control agents of weeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Assessment of host plant specificity is a critical step in the evaluation of classical biological control agents of weeds, which is necessary for avoiding possible damage to nontarget plants. Volatile organic compounds (VOC) emitted by plants likely play an important role in determining which plant...

  6. Exploitation of Herbivore-Induced Plant Odors by Host-Seeking Parasitic Wasps

    NASA Astrophysics Data System (ADS)

    Turlings, T. C. J.; Tumlinson, J. H.; Lewis, W. J.

    1990-11-01

    Corn seedlings release large amounts of terpenoid volatiles after they have been fed upon by caterpillars. Artificially damaged seedlings do not release these volatiles in significant amounts unless oral secretions from the caterpillars are applied to the damaged sites. Undamaged leaves, whether or not they are treated with oral secretions, do not release detectable amounts of the terpenoids. Females of the parasitic wasp Cotesia marginiventris (Cresson) learn to take advantage of those plant-produced volatiles to locate hosts when exposed to these volatiles in association with hosts or host by-products. The terpenoids may be produced in defense against herbivores but may also serve a secondary function in attracting the natural enemies of these herbivores.

  7. Attraction of two lacewing species to volatiles produced by host plants and aphid prey

    NASA Astrophysics Data System (ADS)

    Zhu, J.; Obrycki, J. J.; Ochieng, Samuel A.; Baker, Thomas C.; Pickett, J. A.; Smiley, D.

    2005-06-01

    It is well documented that host-related odors enable many species of parasitoids and predatory insects to locate their prey and prey habitats. This study reports the first characterization of prey and prey host odor reception in two species of lacewings, Chrysoperla carnea (Say) and Chrysopa oculata L. 2-Phenylethanol, one of the volatiles emitted from their prey’s host plants (alfalfa and corn) evoked a significant EAG response from antennae of C. carnea. Traps baited with this compound attracted high numbers of adult C. carnea, which were predominantly females. One of the sex pheromone components (1R,4aS,7S,7aR)-nepetalactol of an aphid species, Acyrthosiphon pisum (Harris) attracted only C. oculata adults. Single sensillum recordings showed that the olfactory neurons of C. carnea responded to both 2-phenylethanol and aphid sex pheromone components, but those of C. oculata only responded to the latter.

  8. Root microbiome relates to plant host evolution in maize and other Poaceae.

    PubMed

    Bouffaud, Marie-Lara; Poirier, Marie-Andrée; Muller, Daniel; Moënne-Loccoz, Yvan

    2014-09-01

    Prokaryote-eukaryote interactions are primordial, but host selection of its bacterial community remains poorly understood. Because eukaryote evolution affects numerous traits shaping the ecology of their microbiome, we can expect that many evolutionary changes in the former will have the potential to impact on the composition of the latter. Consequently, the more phylogenetically distant the eukaryotic hosts, the more distinct their associated bacterial communities should be. We tested this with plants, by comparing the bacterial communities associated with maize genotypes or other Poaceae. 16S rRNA taxonomic microarray analysis showed that the genetic distance between rhizobacterial communities correlated significantly with the phylogenetic distance (derived from chloroplastic sequences) between Poaceae genotypes. This correlation was also significant when considering specific bacterial populations from all main bacterial divisions, instead of the whole rhizobacterial community. These results indicate that eukaryotic host's evolutionary history can be a significant factor shaping directly the assembly and composition of its associated bacterial compartment. PMID:24588973

  9. Inoculation of Transgenic Resistant Potato by Phytophthora infestans Affects Host Plant Choice of a Generalist Moth.

    PubMed

    Abreha, Kibrom B; Alexandersson, Erik; Vossen, Jack H; Anderson, Peter; Andreasson, Erik

    2015-01-01

    Pathogen attack and the plant's response to this attack affect herbivore oviposition preference and larval performance. Introduction of major resistance genes against Phytophthora infestans (Rpi-genes), the cause of the devastating late blight disease, from wild Solanum species into potato changes the plant-pathogen interaction dynamics completely, but little is known about the effects on non-target organisms. Thus, we examined the effect of P. infestans itself and introduction of an Rpi-gene into the crop on host plant preference of the generalist insect herbivore, Spodoptera littoralis (Lepidoptera: Noctuidae). In two choice bioassays, S. littoralis preferred to oviposit on P. infestans-inoculated plants of both the susceptible potato (cv. Desiree) and an isogenic resistant clone (A01-22: cv. Desiree transformed with Rpi-blb1), when compared to uninoculated plants of the same genotype. Both cv. Desiree and clone A01-22 were equally preferred for oviposition by S. littoralis when uninoculated plants were used, while cv. Desiree received more eggs compared to the resistant clone when both were inoculated with the pathogen. No significant difference in larval and pupal weight was found between S. littoralis larvae reared on leaves of the susceptible potato plants inoculated or uninoculated with P. infestans. Thus, the herbivore's host plant preference in this system was not directly associated with larval performance. The results indicate that the Rpi-blb1 based resistance in itself does not influence insect behavior, but that herbivore oviposition preference is affected by a change in the plant-microbe interaction. PMID:26053171

  10. Food preference and performance of the larvae of a specialist herbivore: variation among and within host-plant populations

    NASA Astrophysics Data System (ADS)

    Leimu, Roosa; Riipi, Marianna; Stærk, Dan

    2005-11-01

    Specialist herbivores are suggested to be unaffected by or attracted to the defense compounds of their host-plants, and can even prefer higher levels of certain chemicals. Abrostola asclepiadis is a specialist herbivore whose larvae feed on the leaves of Vincetoxicum hirundinaria, which contains toxic alkaloids and is unpalatable to most generalist herbivores. The food choice, leaf consumption and growth of A. asclepiadis larvae were studied to determine whether there is variation among and within host-plant populations in their suitability for this specialist herbivore. There was significant variation in food preference and leaf consumption among host-plant populations, but no differences were found in larval growth and feeding on different host-plant populations. A. asclepiadis larvae preferred host-plant populations with higher alkaloid concentrations, but did not consume more leaf material from plants originating from such populations in a no-choice experiment. There was also some variation in food preference of larvae among host-plant individuals belonging to the same population, suggesting that there was variability in leaf chemistry also within populations. Such variation in larval preference among host-plant genotypes and populations may create potential for coevolutionary dynamics in a spatial mosaic.

  11. Identification of cotton fleahopper (Hemiptera: Miridae) host plants in Central Texas and compendium of reported hosts in the United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The cotton fleahopper is an early-season pest of developing cotton in Central Texas and other regions of the Cotton Belt. Cotton fleahopper populations develop on spring weed hosts and move to cotton as weed hosts senesce, or if other weed hosts are not readily available. To identify temporally av...

  12. Host-plant dependent population genetics of the invading weevil Hypera postica.

    PubMed

    Iwase, S-I; Nakahira, K; Tuda, M; Kagoshima, K; Takagi, M

    2015-02-01

    Population genetics of invading pests can be informative for understanding their ecology. In this study, we investigated population genetics of the invasive alfalfa weevil Hypera postica in Fukuoka Prefecture, Japan. We analyzed mitochondrial tRNALeu-COII, nuclear EF-1α gene fragments, and Wolbachia infection in relation to three leguminous host plants: Vicia angustifolia, Vicia villosa, and a new host Astragalus sinicus cultivated as a honey source and green manure crop. A parsimony network generated from mitochondrial gene sequences uncovered two major haplotypic groups, Western and Egyptian. In contrast to reported Wolbachia infection of the Western strain in the United States, none of our analyzed individuals were infected. The absence of Wolbachia may contribute to the stable coexistence of mitochondrial strains through inter-strain reproductive compatibility. Hypera postica genetic variants for the mitochondrial and nuclear genes were associated neither with host plant species nor with two geographic regions (Hisayama and Kama) within Fukuoka. Mitochondrial haplogroups were incongruent with nuclear genetic variants. Genetic diversity at the nuclear locus was the highest for the populations feeding on V. angustifolia. The nuclear data for A. sinicus-feeding populations indicated past sudden population growth and extended Bayesian skyline plot analysis based on the mitochondrial and nuclear data showed that the growth of A. sinicus-feeding population took place within the past 1000 years. These results suggest a shorter history of A. sinicus as a host plant compared with V. angustifolia and a recent rapid growth of H. postica population using the new host A. sinicus. PMID:25336385

  13. Flagellin typing of Bordetella bronchiseptica strains originating from different host species.

    PubMed

    Khayer, Bernadett; Magyar, Tibor; Wehmann, Enikő

    2014-10-10

    Bordetella bronchiseptica is a widespread Gram-negative pathogen occurring in different mammal species. It is known to play a role in the aetiology of infectious atrophic rhinitis of swine, canine kennel cough, respiratory syndromes of cats, rabbits and guinea pigs, and sporadic human cases have also been reported. In this study, 93 B. bronchiseptica strains were examined from a broad range of host species and different geographical regions using restriction fragment length polymorphism analysis of polymerase chain reaction products of flaA to reveal the possible host-specificity of the flagellin. Eight types (A-H) of flaA were identified, including five newly described ones (D-H). All but one of the 22 B. bronchiseptica strains from swine showed type B fragment pattern. The eighteen Hungarian isolates of canine origin were uniform (type A) while in other countries type B and D were also present in dogs. The sequence and phylogenetic analysis of 36 representative strains of flaA types revealed four clusters. These clusters correlated with flaA PCR-RFLP types and host species, especially in pigs and dogs. The revealed diversity of the strains isolated from human cases indicated possible zoonotic transmissions from various animal sources. PMID:25153650

  14. AN ODORANT-BINDING PROTEIN INVOLVED IN PERCEPTION OF HOST PLANT ODORANTS IN LOCUST Locusta migratoria.

    PubMed

    Li, Jia; Zhang, Long; Wang, Xiaoqi

    2016-04-01

    Locusts, Locusta migratoria (Orthoptera: Acrididae), are extremely destructive agricultural pests, but very little is known of their molecular aspects of perception to host plant odorants including related odorant-binding proteins (OBPs), though several OBPs have been identified in locust. To elucidate the function of LmigOBP1, the first OBP identified from locust, RNA interference was employed in this study to silence LmigOBP1, which was achieved by injection of dsRNA targeting LmigOBP1 into the hemolymph of male nymphs. Compared with LmigOBP1 normal nymphs, LmigOBP1 knockdown nymphs significantly decreased food (maize leaf, Zea mays) consumption and electro-antennography responses to five maize leaf volatiles, ((Z)-3-hexenol, linalool, nonanal, decanal, and (Z)-3-hexenyl acetate). These suggest that LmigOBP1 is involved in perception of host plant odorants. PMID:26864243

  15. A study of the early detection of insect infestations and density/distribution of host plants

    NASA Technical Reports Server (NTRS)

    Hart, W. G.; Ingle, S. J.; Davis, M. R. (Principal Investigator)

    1974-01-01

    The author has identified the following significant results. Significant results have been obtained in the identification of citrus, sugarcane, winter vegetables, irrigated pastures, and unimproved pastures which contain brush. Land without vegetation, lakes, roads, and waterways can also be determined. Different densities of vegetation covering some cultivated areas are apparent. The practical applications of these results are many. The abundance of host plants of pests can be determined. Avenues of entry of pests can be plotted, facilitating control or preventing entry of pest species. The boundaries of areas to be quarantined can be accurately established after viewing the S-190B data. Better cultural methods can be employed such as planning where to plant certain crops that indirectly are detrimental to those already growing. This would relate to such factors as pesticide drift or alternate hosts of major pests.

  16. Pea Aphids (Hemiptera: Aphididae) Have Diurnal Rhythms When Raised Independently of a Host Plant

    PubMed Central

    Joschinski, Jens; Beer, Katharina; Helfrich-Förster, Charlotte; Krauss, Jochen

    2016-01-01

    Seasonal timing is assumed to involve the circadian clock, an endogenous mechanism to track time and measure day length. Some debate persists, however, and aphids were among the first organisms for which circadian clock involvement was questioned. Inferences about links to phenology are problematic, as the clock itself is little investigated in aphids. For instance, it is unknown whether aphids possess diurnal rhythms at all. Possibly, the close interaction with host plants prevents independent measurements of rhythmicity. We reared the pea aphid Acyrthosiphon pisum (Harris) on an artificial diet, and recorded survival, moulting, and honeydew excretion. Despite their plant-dependent life style, aphids were independently rhythmic under light–dark conditions. This first demonstration of diurnal aphid rhythms shows that aphids do not simply track the host plant’s rhythmicity. PMID:27012868

  17. Hoverfly preference for high honeydew amounts creates enemy-free space for aphids colonizing novel host plants.

    PubMed

    Vosteen, Ilka; Gershenzon, Jonathan; Kunert, Grit

    2016-09-01

    The existence of an enemy-free space can play an important role in aphid host race formation processes, but little is known about the mechanisms that create an area of low predation pressure on particular host plants. In this paper, we identify a mechanism generating lower predation pressure that promotes the maintenance of the different host races of the pea aphid (Acyrthosiphon pisum) complex, a well-studied model for ecological speciation. The pea aphid consists of at least 15 genetically distinct host races which are native to specific host plants of the legume family, but can all develop on the universal host plant Vicia faba. Previous work showed that hoverfly (Episyrphus balteatus) oviposition preferences contribute to the enemy-free space that helps to maintain the different pea aphid host races, and that higher amounts of honeydew are more attractive to ovipositing hoverflies. Here we demonstrated that aphid honeydew is produced in large amounts when aphid reproduction rate was highest, and is an important oviposition cue for hoverflies under field conditions. However, on less suitable host plants, where honeydew production is reduced, pea aphids enjoy lower predation rates. A reduction in enemy pressure can mitigate the performance disadvantages of aphids colonizing a novel host and probably plays an important role in pea aphid host race formation. PMID:27328648

  18. Host plant-specific remodeling of midgut physiology in the generalist insect herbivore Trichoplusia ni.

    PubMed

    Herde, Marco; Howe, Gregg A

    2014-07-01

    Species diversity in terrestrial ecosystems is influenced by plant defense compounds that alter the behavior, physiology, and host preference of insect herbivores. Although it is established that insects evolved the ability to detoxify specific allelochemicals, the mechanisms by which polyphagous insects cope with toxic compounds in diverse host plants are not well understood. Here, we used defended and non-defended plant genotypes to study how variation in chemical defense affects midgut responses of the lepidopteran herbivore Trichoplusia ni, which is a pest of a wide variety of native and cultivated plants. The genome-wide midgut transcriptional response of T. ni larvae to glucosinolate-based defenses in the crucifer Arabidopsis thaliana was characterized by strong induction of genes encoding Phase I and II detoxification enzymes. In contrast, the response of T. ni to proteinase inhibitors and other jasmonate-regulated defenses in tomato (Solanum lycopersicum) was dominated by changes in the expression of digestive enzymes and, strikingly, concomitant repression of transcripts encoding detoxification enzymes. Unbiased proteomic analyses of T. ni feces demonstrated that tomato defenses remodel the complement of T.ni digestive enzymes, which was associated with increased amounts of serine proteases and decreased lipase protein abundance upon encountering tomato defense chemistry. These collective results indicate that T. ni adjusts its gut physiology to the presence of host plant-specific chemical defenses, and further suggest that plants may exploit this digestive flexibility as a defensive strategy to suppress the production of enzymes that detoxify allelochemicals. PMID:24727019

  19. Competitive displacement between two invasive whiteflies: insecticide application and host plant effects.

    PubMed

    Sun, Di-Bing; Liu, Yin-Quan; Qin, Li; Xu, Jing; Li, Fang-Fang; Liu, Shu-Sheng

    2013-06-01

    The cryptic species Middle East-Asia Minor 1 (MEAM1), formerly referred to as 'B biotype', of the whitefly Bemisia tabaci complex entered China in the mid 1990s, and the Mediterranean (MED) cryptic species, formerly referred to as 'Q biotype', of the same whitefly complex entered China around 2003. Field surveys in China after 2003 indicate that in many regions MED has been replacing the earlier invader MEAM1. The factors underlying this displacement are unclear. We conducted laboratory experiments and field sampling to examine the effects of insecticide application on the competitive interactions between MEAM1 and MED. In the laboratory, on cotton, a plant showing similar levels of suitability to both whitefly species, MEAM1 displaced MED in five generations when initial populations of the two species were equal and no insecticide was applied. In contrast, MED displaced MEAM1 in seven and two generations, respectively, when 12.5 and 50.0 mg l⁻¹ imidacloprid was applied to the plants via soil drench. Field sampling indicated that in a single season MED displaced MEAM1 on crops heavily sprayed with neonicotinoid insecticides but the relative abundance of the two species changed little on crops without insecticide spray. We also examined the effects of host plants on the competitive interactions between the two species in the laboratory. When cohorts with equal abundance of MEAM1 and MED were set up on different host plants, MEAM1 displaced MED on cabbage and tomato in five and seven generations, respectively, but MED displaced MEAM1 on pepper in two generations. As field populations of MED have lower susceptibility than those of MEAM1 to nearly all commonly used insecticides including imidacloprid, insecticide application seems to have played a major role in shifting the species competitive interaction effects in favour of MED in the field across China. Host plants may also shape competition between the two species depending on the relative levels of plant

  20. Sexual dimorphism dominates divergent host plant use in stick insect trophic morphology

    PubMed Central

    2013-01-01

    Background Clear examples of ecological speciation exist, often involving divergence in trophic morphology. However, substantial variation also exists in how far the ecological speciation process proceeds, potentially linked to the number of ecological axes, traits, or genes subject to divergent selection. In addition, recent studies highlight how differentiation might occur between the sexes, rather than between populations. We examine variation in trophic morphology in two host-plant ecotypes of walking-stick insects (Timema cristinae), known to have diverged in morphological traits related to crypsis and predator avoidance, and to have reached an intermediate point in the ecological speciation process. Here we test how host plant use, sex, and rearing environment affect variation in trophic morphology in this species using traditional multivariate, novel kernel density based and Bayesian morphometric analyses. Results Contrary to expectations, we find limited host-associated divergence in mandible shape. Instead, the main predictor of shape variation is sex, with secondary roles of population of origin and rearing environment. Conclusion Our results show that trophic morphology does not strongly contribute to host-adapted ecotype divergence in T. cristinae and that traits can respond to complex selection regimes by diverging along different intraspecific lines, thereby impeding progress toward speciation. PMID:23819550

  1. Midgut serine proteases and alternative host plant utilization in Pieris brassicae L.

    PubMed Central

    Kumar, Rakesh; Bhardwaj, Usha; Kumar, Pawan; Mazumdar-Leighton, Sudeshna

    2015-01-01

    Pieris brassicae L. is a serious pest of cultivated crucifers in several parts of the world. Larvae of P. brassicae also feed prolifically on garden nasturtium (Tropaeolum majus L., of the family Tropaeolaceae). Proteolytic digestion was studied in larvae feeding on multiple hosts. Fourth instars were collected from cauliflower fields before transfer onto detached, aerial tissues of selected host plants in the lab. Variable levels of midgut proteases were detected in larvae fed on different hosts using protein substrates (casein and recombinant RBCL cloned from cauliflower) and diagnostic, synthetic substrates. Qualitative changes in midgut trypsin activities and quantitative changes in midgut chymotrypsin activities were implicated in physiological adaptation of larvae transferred to T. majus. Midgut proteolytic activities were inhibited to different extents by serine protease inhibitors, including putative trypsin inhibitors isolated from herbivore-attacked and herbivore-free leaves of cauliflower (CfTI) and T. majus (TpTI). Transfer of larvae to T. majus significantly influenced feeding parameters but not necessarily when transferred to different tissues of the same host. Results obtained are relevant for devising sustainable pest management strategies, including transgenic approaches using genes encoding plant protease inhibitors. PMID:25873901

  2. Demonstration Using Field Collections that Argentina Fall Armyworm Populations Exhibit Strain-specific Host Plant Preferences.

    PubMed

    Murúa, M Gabriela; Nagoshi, Rodney N; Dos Santos, Daniel A; Hay-Roe, Mirian M; Meagher, Robert L; Vilardi, J C

    2015-10-01

    Spodoptera frugiperda, the fall armyworm, is a major economic pest throughout the Western Hemisphere of corn (maize), cotton, sorghum, and a variety of agricultural grasses and vegetable crops. Studies in the United States, the Caribbean, and Brazil demonstrated the existence of two subpopulations (previously designated "host strains") that differ in their choice of plant host. Specifically, the corn strain is preferentially found in corn and sorghum, while the rice strain is dominant in rice, turf grass, and alfalfa. However, inconsistent results were reported in surveys of fall armyworm in Argentina, with some indicating that the host plant preferences of the two strains might be compromised or even nonexistent. If correct, this would complicate efforts to control this pest by considerably expanding the range of habitats that would have to be considered as potential sources for fall armyworm infestations in specific crops. A reexamination of Argentine fall armyworm, this time with field collections rather than the laboratory colonies used in previous studies, confirmed the existence of the two strains and their host preferences. Specifically, the corn strain was consistently the majority population infesting corn and was usually so in sorghum, while the rice strain was predominant in pasture/turf grasses and alfalfa. The one outlier was a collection from rice, which had a corn strain majority. Overall, the data were generally consistent with strain behaviors observed in other areas of the Western Hemisphere. PMID:26453719

  3. Global GPP based on Plant Functional Types

    NASA Astrophysics Data System (ADS)

    Veroustraete, Frank; Balzarolo, Manuela

    2016-04-01

    Vegetation variables like Gross Primary productivity (GPP) and the Normalized Difference Vegetation Index (NDVI) are key variables in vegetation carbon exchange studies. Field measurements of the NDVI are time consuming due to landscape heterogeneity across time. Typically a sampling protocol adopted during field campaigns is based on the VALERI protocol in that case toe estimate LAI. Field campaign GPP or NDVI measurements can be scaled up to using in-situ FLUXNET radiation raster maps. Regression analysis can then be applied to construct transfer functions for the determination of GPP raster maps raster imagery from Normalized Difference Vegetation Index (NDVI) raster maps derived from in-situ FLUXNET radiation raster maps. Subsequently, in the VALERI approach the scaling up of raster maps is performed by aggregation of high resolution in-situ FLUXNET radiation raster maps data into high resolution raster maps and subsequently aggregating these to 1x1 km MODIS NDVI raster maps by calculating average NDVI values for the low resolution data. The up-scaled 1x1 km pixels are then used to validate the MODIS GPP and NVI products. Hence up scaling based on in-situ FLUXNET radiation measurements are not a luxury for large and heterogeneous sites. Therefore this paper tackles the problem of up scaling using in-situ FLUXNET radiation measurements. Key Words: FLUXNET, GPP, Plant Functional Types, Up-scaling

  4. Exogenous RNA interference exposes contrasting roles for sugar exudation in host-finding by plant pathogens.

    PubMed

    Warnock, Neil D; Wilson, Leonie; Canet-Perez, Juan V; Fleming, Thomas; Fleming, Colin C; Maule, Aaron G; Dalzell, Johnathan J

    2016-07-01

    Plant parasitic nematodes (PPN) locate host plants by following concentration gradients of root exudate chemicals in the soil. We present a simple method for RNA interference (RNAi)-induced knockdown of genes in tomato seedling roots, facilitating the study of root exudate composition, and PPN responses. Knockdown of sugar transporter genes, STP1 and STP2, in tomato seedlings triggered corresponding reductions of glucose and fructose, but not xylose, in collected root exudate. This corresponded directly with reduced infectivity and stylet thrusting of the promiscuous PPN Meloidogyne incognita, however we observed no impact on the infectivity or stylet thrusting of the selective Solanaceae PPN Globodera pallida. This approach can underpin future efforts to understand the early stages of plant-pathogen interactions in tomato and potentially other crop plants. PMID:27033013

  5. Native and introduced host plants of Anastrepha fraterculus and Ceratitis capitata (Diptera: Tephritidae) in northwestern Argentina.

    PubMed

    Ovruski, Sergio; Schliserman, Pablo; Aluja, Martín

    2003-08-01

    Wild or commercially grown, native and exotic fruit were collected in 30 localities in the Tucumán province (NW Argentina) from January 1990 to December 1995 to determine their status as hosts of Anastrepha fraterculus (Wiedemann) and/or Ceratitis capitata (Wiedemann), the only two fruit fly species of economic and quarantine importance in Argentina. A total of 84,094 fruit (3,466.1 kg) representing 33 species (7 native and 26 exotic) in 15 plant families were sampled. We determined the following 17 host plant associations: Annona cherimola Miller (Annonaceae), Citrus paradisi Macfadyn (Rutaceae), Diospyros kaki L. (Ebenaceae), Eugenia uniflora L., Psidium guajava L., Myrcianthes pungens (Berg) Legrand (Myrtaceae), Ficus carica L. (Moraceae), Juglans australis Grisebach (Juglandaceae), Mangifera indica L. (Anacardiaceae), Eriobotrya japonica (Thunb.) Lindl., Prunus armeniaca L., P. domestica L., and P. persica (L.) Batsch (Rosaceae) were infested by both A. fraterculus and C. capitata. Citrus aurantium L., Citrus reticulata Blanco, Citrus sinensis (L.) Osbeck (Rutaceae), and Passiflora caerulea L. (Passifloraceae) were only infested by Ceratitis capitata. Out of a total of 99,627 adults that emerged from pupae, 69,180 (approximately 69.5%) were Anastrepha fraterculus, 30,138 (approximately 30.2%) were C. capitata, and 309 (approximately 0.3%) were an unidentified Anastrepha species. Anastrepha fraterculus predominated in native plant species while C. capitata did so in introduced species. Infestation rates (number of larvae/kg of fruit) varied sharply from year to year and between host plant species (overall there was a significant negative correlation between fruit size and infestation level). We provide information on fruiting phenology of all the reported hosts and discuss our findings in light of their practical (e.g., management of A. fraterculus and C. capitata in citrus groves) implications. PMID:14503581

  6. Tackling Unwanted Proteolysis in Plant Production Hosts Used for Molecular Farming

    PubMed Central

    Mandal, Manoj K.; Ahvari, Houtan; Schillberg, Stefan; Schiermeyer, Andreas

    2016-01-01

    Although the field of molecular farming has significantly matured over the last years, some obstacles still need to be resolved. A major limiting factor for a broader application of plant hosts for the production of valuable recombinant proteins is the low yield of intact recombinant proteins. These low yields are at least in part due to the action of endogenous plant proteases on the foreign recombinant proteins. This mini review will present the current knowledge of the proteolytic enzymes involved in the degradation of different target proteins and strategies that are applied to suppress undesirable proteolytic activities in order to safeguard recombinant proteins during the production process. PMID:27014293

  7. Tackling Unwanted Proteolysis in Plant Production Hosts Used for Molecular Farming.

    PubMed

    Mandal, Manoj K; Ahvari, Houtan; Schillberg, Stefan; Schiermeyer, Andreas

    2016-01-01

    Although the field of molecular farming has significantly matured over the last years, some obstacles still need to be resolved. A major limiting factor for a broader application of plant hosts for the production of valuable recombinant proteins is the low yield of intact recombinant proteins. These low yields are at least in part due to the action of endogenous plant proteases on the foreign recombinant proteins. This mini review will present the current knowledge of the proteolytic enzymes involved in the degradation of different target proteins and strategies that are applied to suppress undesirable proteolytic activities in order to safeguard recombinant proteins during the production process. PMID:27014293

  8. VIGS, HIGS and FIGS: small RNA silencing in the interactions of viruses or filamentous organisms with their plant hosts.

    PubMed

    Baulcombe, David C

    2015-08-01

    Recent evidence indicates two-way traffic of silencing RNA between filamentous organisms and their plant hosts. There are also indications that suppressors of RNA silencing are transferred from filamentous organisms into host plant cells where they influence the innate immune system. Here I use virus disease as a template for interpretation of RNA silencing in connection with filamentous organisms and infected plant cells. I propose that host plant interactions of these organisms are influenced by RNA silencing networks in which there are: small interfering RNAs from the host that are transported into the filamentous organism and vice versa; silencing suppressors from the organism that are transported into the host; endogenous small interfering RNAs and micro RNAs that target components of the innate immune system or endogenous suppressors of the innate immune system. PMID:26247121

  9. Female butterflies adapt and allocate their progeny to the host-plant quality of their own larval experience.

    PubMed

    Cahenzli, Fabian; Wenk, Barbara A; Erhardt, Andreas

    2015-07-01

    Recent studies with diverse taxa have shown that parents can utilize their experience of the environment to adapt their offspring's phenotype to the same environmental conditions. Thus, offspring would then perform best under environmental conditions experienced by their parents due to transgenerational phenotypic plasticity. Such an effect has been dubbed transgenerational acclimatization. However, evidence that parents can subsequently ensure the appropriate environmental conditions in order that offspring benefit from transgenerational acclimatization has never been demonstrated. We reared Pieris rapae larvae in the parental generation on high-nitrogen and low-nitrogen host plants, and reared the offspring (F1) of both treatments again on high- and low-nitrogen plants. Furthermore, we tested if females prefer to oviposit on high- or low-nitrogen host plants in two-way choice tests. We here show not only that females adapt their offspring's phenotype to the host-plant quality that they themselves experienced, but that females also mainly oviposit on the host quality to which they adapt their offspring. Moreover, effects of larval host plant on oviposition preference of females increased across two generations in F1-females acclimatized to low-nitrogen host plants, showing an adaptive host shift from one generation to the next. These findings may have profound implications for host-race formation and sympatric speciation. PMID:26378318

  10. Population dynamics of Dichelops melacanthus (Dallas) (Heteroptera: Pentatomidae) on Host Plants.

    PubMed

    Silva, J J; Ventura, M U; Silva, F A C; Panizzi, A R

    2013-04-01

    The stink bug Dichelops melacanthus (Dallas) has become one of the major pests of corn and wheat in Brasil, mainly after a shift from the conventional tillage system to the no tillage cultivation system. This fact may be due to the simultaneous occurrence of second planting corn with wheat cultivation, and the presence of wild hosts. This study aimed to evaluate the population dynamics of D. melacanthus on wild hosts adjacent to areas cultivated with corn, wheat, and soybean during the season and off-season of soybean cultivation. Weekly surveys were conducted in the region of Londrina, PR, Brasil from the beginning of July 2007 up to the end of June 2008 using the square meter method. Corn (Zea mays), soybean (Glycine max), tropical spiderwort (Commelina benghalensis), hairy indigo (Indigofera hirsuta), crotalaria (Crotalaria pallida), wheat (Triticum aestivum), and signal grass (Brachiaria decumbens) were identified as hosts of D. melacanthus. Signal grass was the host in which stink bug adults were found in higher numbers, while nymphs and adults were consistently collected on tropical spiderwort. Although nymphs completed their development on tropical spiderwort seeds, this host was found less suitable than soybean seeds. PMID:23949747

  11. Caterpillar-induced plant volatiles remain a reliable signal for foraging wasps during dual attack with a plant pathogen or non-host insect herbivore.

    PubMed

    Ponzio, Camille; Gols, Rieta; Weldegergis, Berhane T; Dicke, Marcel

    2014-08-01

    Plants respond to herbivory with the emission of plant volatiles, which can be used by the herbivores' natural enemies to locate their hosts or prey. In nature, plants are often simultaneously confronted with insect herbivores and phytopathogens, potentially interfering with the attraction of the herbivores' enemies as a result of modifications of the induced volatile blend. Here, we investigated parasitoid (Cotesia glomerata) attraction to volatiles of plants challenged by different attackers, either alone or in combination with Pieris brassicae caterpillars, hosts of C. glomerata. We used a natural system consisting of Brassica nigra plants, eggs and larvae of P. brassicae, Brevicoryne brassicae aphids and the bacterial phytopathogen Xanthomonas campestris pv. campestris. In all cases, parasitoids successfully located host-infested plants, and wasp foraging behaviour was unaffected by the simultaneous presence of a non-host attacker or host eggs. Analysis of the volatile emissions show that the volatile blends of caterpillar-infested treatments were different from those without caterpillars. Furthermore, dually attacked plants could not be separated from those with only caterpillars, regardless of non-host identity, supporting the behavioural data. Our results suggest that, in this system, indirect plant defences may be more resistant to interference than is generally assumed, with volatiles induced during dual attack remaining reliable indicators of host presence for parasitoids. PMID:24697624

  12. Host plant affects the sexual attractiveness of the female white-spotted longicorn beetle, Anoplophora malasiaca.

    PubMed

    Yasui, Hiroe; Fujiwara-Tsujii, Nao

    2016-01-01

    Anoplophora malasiaca (Coleoptera: Cerambycidae) is a serious pest that destroys various landscape and crop trees in Japan. We evaluated the precopulatory responses of three different A. malasiaca populations collected from mandarin orange, willow and blueberry trees. Most of the males accepted mates from within the same host plant population as well as females from the willow and blueberry populations. However, significant number of males from the blueberry and willow populations rejected females from the mandarin orange population immediately after touching them with their antennae. Because all three of the female populations produced contact sex pheromones on their elytra, the females of the mandarin orange population were predicted to possess extra chemicals that repelled the males of the other two populations. β-Elemene was identified as a key component that was only found in mandarin orange-fed females and induced a rejection response in willow-fed males. Our results represent the first example of a female-acquired repellent against conspecific males of different host plant populations, indicating that the host plant greatly affects the female's sexual attractiveness. PMID:27412452

  13. Host plant affects the sexual attractiveness of the female white-spotted longicorn beetle, Anoplophora malasiaca

    PubMed Central

    Yasui, Hiroe; Fujiwara-Tsujii, Nao

    2016-01-01

    Anoplophora malasiaca (Coleoptera: Cerambycidae) is a serious pest that destroys various landscape and crop trees in Japan. We evaluated the precopulatory responses of three different A. malasiaca populations collected from mandarin orange, willow and blueberry trees. Most of the males accepted mates from within the same host plant population as well as females from the willow and blueberry populations. However, significant number of males from the blueberry and willow populations rejected females from the mandarin orange population immediately after touching them with their antennae. Because all three of the female populations produced contact sex pheromones on their elytra, the females of the mandarin orange population were predicted to possess extra chemicals that repelled the males of the other two populations. β-Elemene was identified as a key component that was only found in mandarin orange-fed females and induced a rejection response in willow-fed males. Our results represent the first example of a female-acquired repellent against conspecific males of different host plant populations, indicating that the host plant greatly affects the female’s sexual attractiveness. PMID:27412452

  14. The Irish Potato Famine Pathogen Phytophthora infestans Translocates the CRN8 Kinase into Host Plant Cells

    PubMed Central

    van Damme, Mireille; Bozkurt, Tolga O.; Cakir, Cahid; Schornack, Sebastian; Sklenar, Jan; Jones, Alexandra M. E.; Kamoun, Sophien

    2012-01-01

    Phytopathogenic oomycetes, such as Phytophthora infestans, secrete an arsenal of effector proteins that modulate plant innate immunity to enable infection. We describe CRN8, a host-translocated effector of P. infestans that has kinase activity in planta. CRN8 is a modular protein of the CRN effector family. The C-terminus of CRN8 localizes to the host nucleus and triggers cell death when the protein is expressed in planta. Cell death induction by CRN8 is dependent on its localization to the plant nucleus, which requires a functional nuclear localization signal (NLS). The C-terminal sequence of CRN8 has similarity to a serine/threonine RD kinase domain. We demonstrated that CRN8 is a functional RD kinase and that its auto-phosphorylation is dependent on an intact catalytic site. Co-immunoprecipitation experiments revealed that CRN8 forms a dimer or multimer. Heterologous expression of CRN8 in planta resulted in enhanced virulence by P. infestans. In contrast, in planta expression of the dominant-negative CRN8R469A;D470A resulted in reduced P. infestans infection, further implicating CRN8 in virulence. Overall, our results indicate that similar to animal parasites, plant pathogens also translocate biochemically active kinase effectors inside host cells. PMID:22927814

  15. Rhizobium meliloti produces a family of sulfated lipooligosaccharides exhibiting different degrees of plant host specificity.

    PubMed Central

    Schultze, M; Quiclet-Sire, B; Kondorosi, E; Virelizer, H; Glushka, J N; Endre, G; Géro, S D; Kondorosi, A

    1992-01-01

    We have shown that a Rhizobium meliloti strain overexpressing nodulation genes excreted high amounts of a family of N-acylated and 6-O-sulfated N-acetyl-beta-1,4-D-glucosamine penta-, tetra-, and trisaccharide Nod factors. Either a C(16:2) or a C(16:3) acyl chain is attached to the nonreducing end subunit, whereas the sulfate group is bound to the reducing glucosamine. One of the tetrasaccharides is identical to the previously described NodRm-1 factor. The two pentasaccharides as well as NodRm-1 were purified and tested for biological activity. In the root hair deformation assay the pentasaccharides show similar activities on the host plants Medicago sativa and Melilotus albus and on the non-host plant Vicia sativa at a dilution of up to 0.01-0.001 microM, in contrast to NodRm-1, which displays a much higher specific activity for Medicago and Melilotus than for Vicia. The active concentration range of the pentasaccharides is more narrow on Medicago than on Melilotus and Vicia. In addition to root hair deformation, the different Nod factors were shown to induce nodule formation on M. sativa. We suggest that the production of a series of active signal molecules with different degrees of specificity might be important in controlling the symbiosis of R. meliloti with several different host plants or under different environmental conditions. Images PMID:1729688

  16. Does host plant influence parasitism and parasitoid species composition in Lygus rugulipennis? A molecular approach.

    PubMed

    Gariepy, T D; Kuhlmann, U; Gillott, C; Erlandson, M

    2008-06-01

    Lygus Hahn plant bugs (Hemiptera: Miridae) are serious pests of a wide variety of economically important crops in North America. European Peristenus digoneutis Loan and P. relictus Ruthe (Hymenoptera: Braconidae) are being considered for release in Canada as part of a classical biological control program for Lygus. The attractiveness of different host plants to European Peristenus has not been addressed, but may be an important consideration prior to parasitoid release. Lygus rugulipennis Poppius nymphs were collected in the Northern Temperate Atlantic (NTA) ecoregion on red clover (Trifolium pratense L.; Fabaceae) and chamomile (Matricaria recutita L.; Asteraceae), and in the Western European Broadleaf Forest (WEBF) ecoregion on red clover and alfalfa (Medicago sativa L.; Fabaceae). Parasitism levels and parasitoid species were determined using a multiplex PCR assay for P. digoneutis, P. relictus, and P. pallipes Curtis. Mean parasitism levels in L. rugulipennis were 45-49% in the NTA ecoregion and 25-32% in the WEBF ecoregion. However, in neither ecoregion were parasitism levels and parasitoid species compositions significantly different in nymphs from different host plant species. Furthermore, multiparasitism was low despite the fact that P. digoneutis and P. relictus share the same host species. PMID:18439339

  17. Ectomycorrhizal fungal communities coinvading with Pinaceae host plants in Argentina: Gringos bajo el bosque.

    PubMed

    Hayward, Jeremy; Horton, Thomas R; Nuñez, Martin A

    2015-10-01

    Coinvasive ectomycorrhizal (ECM) fungi allow Pinaceae species to invade regions otherwise lacking compatible symbionts, but ECM fungal communities permitting Pinaceae invasions are poorly understood. In the context of Pinaceae invasions on Isla Victoria, Nahuel Huapi National Park, Argentina, we asked: what ECM fungi are coinvading with Pinaceae hosts on Isla Victoria; are some ECM fungal species or genera more prone to invade than others; and are all ECM fungal species that associate with Northern Hemisphere hosts also nonnative, or are some native fungi compatible with nonnative plants? We sampled ECMs from 226 Pinaceae host plant individuals, both planted individuals and recruits, growing inside and invading from plantations. We used molecular techniques to examine ECM fungal communities associating with these trees. A distinctive subset of the ECM fungal community predominated far from plantations, indicating differences between highly invasive and less invasive ECM fungi. Some fungal invaders reported here have been detected in other locations around the world, suggesting strong invasion potential. Fungi that were frequently detected far from plantations are often found in early-successional sites in the native range, while fungi identified as late-successional species in the native range are rarely found far from plantations, suggesting a means for predicting potential fungal coinvaders. PMID:25963605

  18. A Binary Host Plant Volatile Lure Combined With Acetic Acid to Monitor Codling Moth (Lepidoptera: Tortricidae).

    PubMed

    Knight, A L; Basoalto, E; Katalin, J; El-Sayed, A M

    2015-10-01

    Field studies were conducted in the United States, Hungary, and New Zealand to evaluate the effectiveness of septa lures loaded with ethyl (E,Z)-2,4-decadienoate (pear ester) and (E)-4,8-dimethyl-1,3,7-nonatriene (nonatriene) alone and in combination with an acetic acid co-lure for both sexes of codling moth, Cydia pomonella (L.). Additional studies were conducted to evaluate these host plant volatiles and acetic acid in combination with the sex pheromone, (E,E)-8,10-dodecadien-1-ol (codlemone). Traps baited with pear ester/nonatriene + acetic acid placed within orchards treated either with codlemone dispensers or left untreated caught significantly more males, females, and total moths than similar traps baited with pear ester + acetic acid in some assays. Similarly, traps baited with codlemone/pear ester/nonatriene + acetic acid caught significantly greater numbers of moths than traps with codlemone/pear ester + acetic acid lures in some assays in orchards treated with combinational dispensers (dispensers loaded with codlemone/pear ester). These data suggest that monitoring of codling moth can be marginally improved in orchards under variable management plans using a binary host plant volatile lure in combination with codlemone and acetic acid. These results are likely to be most significant in orchards treated with combinational dispensers. Significant increases in the catch of female codling moths in traps with the binary host plant volatile blend plus acetic acid should be useful in developing more effective mass trapping strategies. PMID:26314018

  19. Co-evolution of plant LTR-retrotransposons and their host genomes.

    PubMed

    Zhao, Meixia; Ma, Jianxin

    2013-07-01

    Transposable elements (TEs), particularly, long terminal repeat retrotransposons (LTR-RTs), are the most abundant DNA components in all plant species that have been investigated, and are largely responsible for plant genome size variation. Although plant genomes have experienced periodic proliferation and/or recent burst of LTR-retrotransposons, the majority of LTR-RTs are inactivated by DNA methylation and small RNA-mediated silencing mechanisms, and/or were deleted/truncated by unequal homologous recombination and illegitimate recombination, as suppression mechanisms that counteract genome expansion caused by LTR-RT amplification. LTR-RT DNA is generally enriched in pericentromeric regions of the host genomes, which appears to be the outcomes of preferential insertions of LTR-RTs in these regions and low effectiveness of selection that purges LTR-RT DNA from these regions relative to chromosomal arms. Potential functions of various TEs in their host genomes remain blurry; nevertheless, LTR-RTs have been recognized to play important roles in maintaining chromatin structures and centromere functions and regulation of gene expressions in their host genomes. PMID:23794032

  20. Host plants of the tranished plant bug, Lygus Lineolaris (Palisot De Beauvois)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), is a highly polyphagous mirid that damages economically important plants across much of the new world including vegetables, fruits, nuts, nursery stock, and fiber. It is a primary pest of cotton across the mid-south of the United State...

  1. Grasshopper host-plant selection influences seedling recruitment of native plants in an exotic dominated grassland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crested wheatgrass (Agropyron cristatum) is the most common exotic grass in western North America. Areas planted to crested wheatgrass are resistant to colonization by native plant species and often remain relatively stable for decades, imposing problems for the restoration of native grasslands. Gra...

  2. Plant-ants feed their host plant, but above all a fungal symbiont to recycle nitrogen

    PubMed Central

    Defossez, Emmanuel; Djiéto-Lordon, Champlain; McKey, Doyle; Selosse, Marc-André; Blatrix, Rumsaïs

    2011-01-01

    In ant–plant symbioses, plants provide symbiotic ants with food and specialized nesting cavities (called domatia). In many ant–plant symbioses, a fungal patch grows within each domatium. The symbiotic nature of the fungal association has been shown in the ant-plant Leonardoxa africana and its protective mutualist ant Petalomyrmex phylax. To decipher trophic fluxes among the three partners, food enriched in 13C and 15N was given to the ants and tracked in the different parts of the symbiosis up to 660 days later. The plant received a small, but significant, amount of nitrogen from the ants. However, the ants fed more intensively the fungus. The pattern of isotope enrichment in the system indicated an ant behaviour that functions specifically to feed the fungus. After 660 days, the introduced nitrogen was still present in the system and homogeneously distributed among ant, plant and fungal compartments, indicating efficient recycling within the symbiosis. Another experiment showed that the plant surface absorbed nutrients (in the form of simple molecules) whether or not it is coated by fungus. Our study provides arguments for a mutualistic status of the fungal associate and a framework for investigating the previously unsuspected complexity of food webs in ant–plant mutualisms. PMID:20980297

  3. Real-time imaging of type III secretion: Salmonella SipA injection into host cells.

    PubMed

    Schlumberger, Markus C; Müller, Andreas J; Ehrbar, Kristin; Winnen, Brit; Duss, Iwan; Stecher, Bärbel; Hardt, Wolf-Dietrich

    2005-08-30

    Many pathogenic and symbiotic Gram-negative bacteria employ type III secretion systems to inject "effector" proteins into eukaryotic host cells. These effectors manipulate signaling pathways to initiate symbiosis or disease. By using time-lapse microscopy, we have imaged delivery of the Salmonella type III effector protein SipA/SspA into animal cells in real time. SipA delivery mostly began 10-90 sec after docking and proceeded for 100-600 sec until the bacterial SipA pool (6 +/- 3 x 10(3) molecules) was exhausted. Similar observations were made for the effector protein SopE. This visualization of type III secretion in real time explains the efficiency of host cell manipulation by means of this virulence system. PMID:16107539

  4. Ecological costs on local adaptation of an insect herbivore imposed by host plants and enemies.

    PubMed

    Zovi, Daniel; Stastny, Michael; Battisti, Andrea; Larsson, Stig

    2008-05-01

    Herbivore populations may become adapted to the defenses of their local hosts, but the traits that maximize host exploitation may also carry ecological costs. We investigated the patterns and costs of local adaptation in the pine processionary moth, Thaumetopoea pityocampa, to its host plants, Pinus nigra and P. sylvestris. The two hosts differ in needle toughness, a major feeding impediment for leaf-eating insects. We observed a west-to-east gradient of increasing progeny size in the Italian Alps, matching the pattern in toughness of their respective local host plant. Eastern populations that feed on the native P. nigra with tough needles had larger eggs, and neonate larvae with larger head capsules, than western populations that feed on the native P. sylvestris and the introduced P. nigra with softer foliage. In a reciprocal transfer experiment that involved the eastern-most and the western-most populations of T. pityocampa from this region, and excluded natural enemies, we found evidence for local adaptation to the host plant. Specifically, larvae from the western population only performed well when raised on their local hosts with soft needles, and they suffered near-complete mortality on the tough foliage at the eastern site. In contrast, larvae from the eastern population survived equally well at both sites. Local adaptation involved a trade-off between progeny size and the number of offspring. We hypothesized that an additional cost, imposed by natural enemies, may be associated with increased egg size: we also observed a west-to-east gradient of increased egg parasitism. We tested this hypothesis in a common garden by exposing eggs of both populations to parasitism by two native egg parasitoids, Ooencyrtus pityocampae and Baryscapus servadeii. The eastern population suffered a higher level of parasitoid attack by O. pityocampae than the western population, and performance of hatched adults of both parasitoids was enhanced in large eggs. Thus, increased

  5. Type III Protein Secretion Systems in Bacterial Pathogens of Animals and Plants

    PubMed Central

    Hueck, Christoph J.

    1998-01-01

    Various gram-negative animal and plant pathogens use a novel, sec-independent protein secretion system as a basic virulence mechanism. It is becoming increasingly clear that these so-called type III secretion systems inject (translocate) proteins into the cytosol of eukaryotic cells, where the translocated proteins facilitate bacterial pathogenesis by specifically interfering with host cell signal transduction and other cellular processes. Accordingly, some type III secretion systems are activated by bacterial contact with host cell surfaces. Individual type III secretion systems direct the secretion and translocation of a variety of unrelated proteins, which account for species-specific pathogenesis phenotypes. In contrast to the secreted virulence factors, most of the 15 to 20 membrane-associated proteins which constitute the type III secretion apparatus are conserved among different pathogens. Most of the inner membrane components of the type III secretion apparatus show additional homologies to flagellar biosynthetic proteins, while a conserved outer membrane factor is similar to secretins from type II and other secretion pathways. Structurally conserved chaperones which specifically bind to individual secreted proteins play an important role in type III protein secretion, apparently by preventing premature interactions of the secreted factors with other proteins. The genes encoding type III secretion systems are clustered, and various pieces of evidence suggest that these systems have been acquired by horizontal genetic transfer during evolution. Expression of type III secretion systems is coordinately regulated in response to host environmental stimuli by networks of transcription factors. This review comprises a comparison of the structure, function, regulation, and impact on host cells of the type III secretion systems in the animal pathogens Yersinia spp., Pseudomonas aeruginosa, Shigella flexneri, Salmonella typhimurium, enteropathogenic Escherichia coli

  6. Growth Performance and Biometric Characteristics of Spodoptera litura (Lepidoptera: Noctuidae) Reared on Different Host Plants.

    PubMed

    Tuan, Shu-Jen; Li, Nian-Jhen; Yeh, Chih-Chun

    2015-10-01

    Spodoptera litura (F.), an important polyphagous insect pest, attacks ca. 300 economic crops in dozens of countries. Investigations into its growth and development performance on different host plants can provide an understanding of the potential for increase of S. litura population in the field. We measured the development time, body weight, and head capsule width of S. litura larvae reared on cabbage, taro, peanut, and sesbania, a green manure. Larvae reared on cabbage ingested a significantly higher amount of protein and completed the immature stages in a shorter period than those reared on the other three plants. The relationship between head capsule width and larval instars on these four crops fitted well with Dyar's rule, and the Dyar's ratios ranged from 1.4554 to 1.6786, although a few supernumerary instar individuals on sesbania, peanut, and taro showed lower ratios (1.0103 to 1.1330). The head capsule width among cohorts fed on different host plants varied significantly and overlapped between late instars, which could lead to a misjudgment of instar stage in the field. The growth index of S. litura on cabbage was significantly higher than on the other host plants. Larvae fed on sesbania showed the highest feeding index and a better growth index than on taro and peanut. We therefore suggest that the area-wide pest management against S. litura should take into consideration its occurrence on sesbania in intercropping seasons. Additionally, the effective management of this pest during cropping windows between all these four plants should not be ignored. PMID:26453712

  7. The Host Galaxies of Type Ia Supernovae Discovered by the Palomar Transient Factory

    NASA Technical Reports Server (NTRS)

    Pan, Y.-C.; Sullivan, M.; McGuire, K.; Hook, I. M.; Nugent, P. E.; Howell, D. A.; Arcavi, I.; Botyanszki, J.; Cenko, Stephen Bradley; DeRose, J.

    2013-01-01

    We present spectroscopic observations of the host galaxies of 82 low-redshift type Ia supernovae (SNe Ia) discovered by the Palomar Transient Factory (PTF). We determine star-formation rates, gas-phase stellar metallicities, and stellar masses and ages of these objects. As expected, strong correlations between the SN Ia light-curve width (stretch) and the host age mass metallicity are found: fainter, faster-declining events tend to be hosted by older massive metal-rich galaxies. There is some evidence that redder SNe Ia explode in higher metallicity galaxies, but we found no relation between the SN colour and host galaxy extinction based on the Balmer decrement, suggesting that the colour variation of these SNe does not primarily arise from this source. SNe Ia in higher-mass metallicity galaxies also appear brighter after stretch colour corrections than their counterparts in lower mass hosts, and the stronger correlation is with gas-phase metallicity suggesting this may be the more important variable. We also compared the host stellar mass distribution to that in galaxy targeted SN surveys and the high-redshift untargeted Supernova Legacy Survey (SNLS). SNLS has many more low mass galaxies, while the targeted searches have fewer. This can be explained by an evolution in the galaxy stellar mass function, coupled with a SN delay-time distribution proportional to t1. Finally, we found no significant difference in the mass--metallicity relation of our SN Ia hosts compared to field galaxies, suggesting any metallicity effect on the SN Ia rate is small.

  8. Infection of host plants by Cucumber mosaic virus increases the susceptibility of Myzus persicae aphids to the parasitoid Aphidius colemani

    PubMed Central

    Mauck, Kerry E.; De Moraes, Consuelo M.; Mescher, Mark C.

    2015-01-01

    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 parasitism on infected plants compared to healthy plants. Subsequent experiments revealed that this difference is not explained by different attack rates on plants differing in infection status, but rather by the fact that parasitoid larvae successfully complete their development more often when aphid hosts feed on infected plants. This suggests that the reduced nutritional quality of infected plants as host for aphids—documented in previous studies—compromises their ability to mount effective defenses against parasitism. Furthermore, our current findings indicate that the aphid diet during parasitoid development (rather than prior to wasp oviposition) is a key factor influencing resistance. These findings complement our previous work showing that CMV-induced changes in host plant chemistry alter patterns of aphid recruitment and dispersal in ways conducive to virus transmission. PMID:26043237

  9. THE FUNDAMENTAL METALLICITY RELATION REDUCES TYPE Ia SN HUBBLE RESIDUALS MORE THAN HOST MASS ALONE

    SciTech Connect

    Hayden, Brian T.; Garnavich, Peter M.; Gupta, Ravi R.; Sako, Masao; Mannucci, Filippo; Nichol, Robert C.

    2013-02-20

    Type Ia supernova Hubble residuals have been shown to correlate with host galaxy mass, imposing a major obstacle for their use in measuring dark energy properties. Here, we calibrate the fundamental metallicity relation (FMR) of Mannucci et al. for host mass and star formation rates measured from broadband colors alone. We apply the FMR to the large number of hosts from the SDSS-II sample of Gupta et al. and find that the scatter in the Hubble residuals is significantly reduced when compared with using only stellar mass (or the mass-metallicity relation) as a fit parameter. Our calibration of the FMR is restricted to only star-forming galaxies and in the Hubble residual calculation we include only hosts with log(SFR) > - 2. Our results strongly suggest that metallicity is the underlying source of the correlation between Hubble residuals and host galaxy mass. Since the FMR is nearly constant between z = 2 and the present, use of the FMR along with light-curve width and color should provide a robust distance measurement method that minimizes systematic errors.

  10. Dictyophara europaea (Hemiptera: Fulgoromorpha: Dictyopharidae): description of immatures, biology and host plant associations.

    PubMed

    Krstić, O; Cvrković, T; Mitrović, M; Toševski, I; Jović, J

    2016-06-01

    The European lantern fly Dictyophara europaea (Linnaeus, 1767), is a polyphagous dictyopharid planthopper of Auchenorrhyncha commonly found throughout the Palaearctic. Despite abundant data on its distribution range and reports on its role in the epidemiology of plant-pathogenic phytoplasmas (Flavescence dorée, FD-C), literature regarding the biology and host plants of this species is scarce. Therefore, the aims of our study were to investigate the seasonal occurrence, host plant associations, oviposition behaviour and immature stages of this widespread planthopper of economic importance. We performed a 3-year field study to observe the spatio-temporal distribution and feeding sources of D. europaea. The insects's reproductive strategy, nymphal molting and behaviour were observed under semi-field cage conditions. Measurement of the nymphal vertex length was used to determine the number of instars, and the combination of these data with body length, number of pronotal rows of sensory pits and body colour pattern enabled the discrimination of each instar. We provide data showing that D. europaea has five instars with one generation per year and that it overwinters in the egg stage. Furthermore, our study confirmed highly polyphagous feeding nature of D. europaea, for all instars and adults, as well as adult horizontal movement during the vegetation growing season to the temporarily preferred feeding plants where they aggregate during dry season. We found D. europaea adult aggregation in late summer on Clematis vitalba L. (Ranunculaceae), a reservoir plant of FD-C phytoplasma strain; however, this appears to be a consequence of forced migration due to drying of herbaceous vegetation rather than to a high preference of C. vitalba as a feeding plant. Detailed oviposition behaviour and a summary of the key discriminatory characteristics of the five instars are provided. Emphasis is placed on the economic importance of D. europaea because of its involvement in

  11. A fungal endophyte induces transcription of genes encoding a redundant fungicide pathway in its host plant

    PubMed Central

    2013-01-01

    Background Taxol is an anti-cancer drug harvested from Taxus trees, proposed ecologically to act as a fungicide. Taxus is host to fungal endophytes, defined as organisms that inhabit plants without causing disease. The Taxus endophytes have been shown to synthesize Taxol in vitro, providing Taxus with a second potential biosynthetic route for this protective metabolite. Taxol levels in plants vary 125-fold between individual trees, but the underlying reason has remained unknown. Results Comparing Taxus trees or branches within a tree, correlations were observed between Taxol content, and quantity of its resident Taxol-producing endophyte, Paraconiothyrium SSM001. Depletion of fungal endophyte in planta by fungicide reduced plant Taxol accumulation. Fungicide treatment of intact plants caused concomitant decreases in transcript and/or protein levels corresponding to two critical genes required for plant Taxol biosynthesis. Taxol showed fungicidal activity against fungal pathogens of conifer wood, the natural habitat of the Taxol-producing endophyte. Consistent with other Taxol-producing endophytes, SSM001 was resistant to Taxol. Conclusions These results suggest that the variation in Taxol content between intact Taxus plants and/or tissues is at least in part caused by varying degrees of transcriptional elicitation of plant Taxol biosynthetic genes by its Taxol-producing endophyte. As Taxol is a fungicide, and the endophyte is resistant to Taxol, we discuss how this endophyte strategy may be to prevent colonization by its fungal competitors but at minimal metabolic cost to itself. PMID:23802696

  12. Use of refuse in host plant resistance systems for the control of virulent biotype adaptation in the soybean aphid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Host plant resistant (HPR) soybean varieties have the potential to offer economic control of the soybean aphid (Aphis glycines). However, virulent aphid biotypes capable of overcoming plant resistance have caused challenges for the integration of HPR. The widespread planting of HPR soybean would inc...

  13. Host genotype determines cytoplasmic incompatibility type in the haplodiploid genus Nasonia.

    PubMed Central

    Bordenstein, Seth R; Uy, Julieanne J; Werren, John H

    2003-01-01

    In haplodiploid species, Wolbachia-induced cytoplasmic incompatibility (CI) can be expressed in one of two ways: as a "conversion" of diploid fertilized eggs into haploid males or as embryonic mortality. Here we describe CI-type variation within the parasitic wasp genus Nasonia and genetically analyze the basis of this variation. We reach four main conclusions: (i) CI is expressed primarily as conversion in N. vitripennis, but as embryonic mortality in the sibling species N. giraulti and N. longicornis; (ii) the difference in CI type between N. giraulti (mortality) and N. vitripennis (conversion) is determined by host nuclear genotype rather than by Wolbachia differences; (iii) N. vitripennis "conversion genes" are recessive in hybrid females; and (iv) a difference in CI level between the sibling species N. giraulti and N. longicornis is due to the different Wolbachia infections in the species rather than to the host genotype. These results show that host nuclear genes can influence the type of CI present in a species. On the basis of these findings, we propose a model for how different CI types evolve in haplodiploids due to selection on nuclear genes modifying CI. PMID:12750334

  14. Agrobacterium tumefaciens recognizes its host environment using ChvE to bind diverse plant sugars as virulence signals

    PubMed Central

    Hu, Xiaozhen; Zhao, Jinlei; DeGrado, William F.; Binns, Andrew N.

    2013-01-01

    Agrobacterium tumefaciens is a broad host range plant pathogen that combinatorially recognizes diverse host molecules including phenolics, low pH, and aldose monosaccharides to activate its pathogenic pathways. Chromosomal virulence gene E (chvE) encodes a periplasmic-binding protein that binds several neutral sugars and sugar acids, and subsequently interacts with the VirA/VirG regulatory system to stimulate virulence (vir) gene expression. Here, a combination of genetics, X-ray crystallography, and isothermal calorimetry reveals how ChvE binds the different monosaccharides and also shows that binding of sugar acids is pH dependent. Moreover, the potency of a sugar for vir gene expression is modulated by a transport system that also relies on ChvE. These two circuits tune the overall system to respond to sugar concentrations encountered in vivo. Finally, using chvE mutants with restricted sugar specificities, we show that there is host variation in regard to the types of sugars that are limiting for vir induction. PMID:23267119

  15. Genome plasticity in filamentous plant pathogens contributes to the emergence of novel effectors and their cellular processes in the host.

    PubMed

    Dong, Yanhan; Li, Ying; Qi, Zhongqiang; Zheng, Xiaobo; Zhang, Zhengguang

    2016-02-01

    Plant diseases cause extensive yield loss of crops worldwide, and secretory 'warfare' occurs between plants and pathogenic organisms all the time. Filamentous plant pathogens have evolved the ability to manipulate host processes and facilitate colonization through secreting effectors inside plant cells. The stresses from hosts and environment can drive the genome dynamics of plant pathogens. Remarkable advances in plant pathology have been made owing to these adaptable genome regions of several lineages of filamentous phytopathogens. Characterization new effectors and interaction analyses between pathogens and plants have provided molecular insights into the plant pathways perturbed during the infection process. In this mini-review, we highlight promising approaches of identifying novel effectors based on the genome plasticity. We also discuss the interaction mechanisms between plants and their filamentous pathogens and outline the possibilities of effector gene expression under epigenetic control that will be future directions for research. PMID:26228744

  16. Molecular characterization of Chilli leaf curl viruses infecting new host plant Petunia hybrida in India.

    PubMed

    Nehra, Chitra; Gaur, R K

    2015-02-01

    Petunia hybrida is an important ornamental plant grown in many countries including India. It is a good model plant for the study of genetics and molecular biology. During a survey in 2013-2014, severe leaf curling was observed on most of the P. hybrida grown in the Sikar district, Rajasthan. The infected plants were analyzed for begomovirus infection by rolling circular amplification (RCA) and sequenced. Full length sequences confirmed the association of monopartite begomovirus with betasatellites. Phylogenetic analysis showed the highest percentage of identity with Chilli leaf curl virus (ChLCuV) and therefore considered to be an isolate of ChLCuV. Recombination analysis showed that ChLCuV has broadened its host range by recombination process. To the best our knowledge, this is the first report of natural occurrence of ChLCuV on P. hybrida in India. PMID:25294775

  17. A «Repertoire for Repertoire» Hypothesis: Repertoires of Type Three Effectors are Candidate Determinants of Host Specificity in Xanthomonas

    PubMed Central

    Hajri, Ahmed; Brin, Chrystelle; Hunault, Gilles; Lardeux, Frédéric; Lemaire, Christophe; Manceau, Charles

    2009-01-01

    Background The genetic basis of host specificity for animal and plant pathogenic bacteria remains poorly understood. For plant pathogenic bacteria, host range is restricted to one or a few host plant species reflecting a tight adaptation to specific hosts. Methodology/Principal Findings Two hypotheses can be formulated to explain host specificity: either it can be explained by the phylogenetic position of the strains, or by the association of virulence genes enabling a pathological convergence of phylogenically distant strains. In this latter hypothesis, host specificity would result from the interaction between repertoires of bacterial virulence genes and repertoires of genes involved in host defences. To challenge these two hypotheses, we selected 132 Xanthomonas axonopodis strains representative of 18 different pathovars which display different host range. First, the phylogenetic position of each strain was determined by sequencing the housekeeping gene rpoD. This study showed that many pathovars of Xanthomonas axonopodis are polyphyletic. Second, we investigated the distribution of 35 type III effector genes (T3Es) in these strains by both PCR and hybridization methods. Indeed, for pathogenic bacteria T3Es were shown to trigger and to subvert host defences. Our study revealed that T3E repertoires comprise core and variable gene suites that likely have distinct roles in pathogenicity and different evolutionary histories. Our results showed a correspondence between composition of T3E repertoires and pathovars of Xanthomonas axonopodis. For polyphyletic pathovars, this suggests that T3E genes might explain a pathological convergence of phylogenetically distant strains. We also identified several DNA rearrangements within T3E genes, some of which correlate with host specificity of strains. Conclusions/Significance These data provide insight into the potential role played by T3E genes for pathogenic bacteria and support a “repertoire for repertoire” hypothesis

  18. Importance of protein quality versus quantity in alternative host plants for a leaf-feeding insect.

    PubMed

    Barbehenn, Raymond V; Niewiadomski, Julie; Kochmanski, Joseph

    2013-09-01

    The nutritional value of alternative host plants for leaf-feeding insects such as caterpillars is commonly measured in terms of protein quantity. However, nutritional value might also depend on the quality of the foliar protein [i.e., the composition of essential amino acids (EAAs)]. A lack of comparative work on the EAA compositions of herbivores and their host plants has hampered the testing of this hypothesis. We tested the "protein quality hypothesis" using the tree-feeding caterpillars of Lymantria dispar (gypsy moth) and two taxonomically unrelated host plants, red oak (Quercus rubra) and sugar maple (Acer saccharum). Because L. dispar has higher fitness on oak than on maple, support for the hypothesis would be found if protein were of higher quality from oak than from maple. The whole-body EAA composition of L. dispar larvae was measured to estimate its optimum dietary protein composition, which was compared with the EAA compositions of oak and maple leaves. Contrary to the protein quality hypothesis, the EAA compositions of oak and maple were not significantly different in the spring. The growth-limiting EAAs in both tree species were histidine and methionine. Similar results were observed in the summer, with the exception that the histidine composition of oak was between 10 and 15 % greater than in maple leaves. The two main factors that affected the nutritional value of protein from the tree species were the quantities of EAAs, which were consistently higher in oak, and the efficiency of EAA utilization, which decreased from 80 % in May to <50 % in August. We conclude that the relative nutritional value of red oak and sugar maple for L. dispar is more strongly affected by protein quantity than quality. Surveys of many wild herbaceous species also suggest that leaf-feeding insects would be unlikely to specialize on plants based on protein quality. PMID:23297046

  19. Rapid adaptive radiation and host plant conservation in the Hawaiian picture wing Drosophila (Diptera: Drosophilidae).

    PubMed

    Magnacca, Karl N; Price, Donald K

    2015-11-01

    The Hawaiian picture wing Drosophila are a striking example of adaptive radiation in specialist saprophages on an island system. We use DNA sequences from five nuclear genes with a total of 4260 nucleotides to provide a comprehensive phylogeny and biogeographic analysis of 90 species in the Hawaiian Drosophila picture wing clade. The current analysis indicates that the evolution of the picture wing clade took place more recently than previously suggested. The relationships of several morphologically anomalous taxa are resolved with strong support. Biogeography and host plant analyses show two periods of rapid divergence occurred when Kauai and Oahu were the main high islands, indicating that a combination of complex topographical features of islands and development of novel host plant associations was key to the rapid diversification of these lineages. For the past 2 million years, host associations within lineages have been largely stable, and speciation has occurred primarily due to the establishment of populations on newer islands as they arose followed by divergence by isolation. The existence of several apparently relictual taxa suggests that extinction has also played a major role in assembly of the present Hawaiian Drosophila fauna. PMID:26151218

  20. Host-Plant Species Conservatism and Ecology of a Parasitoid Fig Wasp Genus (Chalcidoidea; Sycoryctinae; Arachonia)

    PubMed Central

    McLeish, Michael J.; Beukman, Gary; van Noort, Simon; Wossler, Theresa C.

    2012-01-01

    Parasitoid diversity in terrestrial ecosystems is enormous. However, ecological processes underpinning their evolutionary diversification in association with other trophic groups are still unclear. Specialisation and interdependencies among chalcid wasps that reproduce on Ficus presents an opportunity to investigate the ecology of a multi-trophic system that includes parasitoids. Here we estimate the host-plant species specificity of a parasitoid fig wasp genus that attacks the galls of non-pollinating pteromalid and pollinating agaonid fig wasps. We discuss the interactions between parasitoids and the Ficus species present in a forest patch of Uganda in context with populations in Southern Africa. Haplotype networks are inferred to examine intraspecific mitochondrial DNA divergences and phylogenetic approaches used to infer putative species relationships. Taxonomic appraisal and putative species delimitation by molecular and morphological techniques are compared. Results demonstrate that a parasitoid fig wasp population is able to reproduce on at least four Ficus species present in a patch. This suggests that parasitoid fig wasps have relatively broad host-Ficus species ranges compared to fig wasps that oviposit internally. Parasitoid fig wasps did not recruit on all available host plants present in the forest census area and suggests an important ecological consequence in mitigating fitness trade-offs between pollinator and Ficus reproduction. The extent to which parasitoid fig wasps exert influence on the pollination mutualism must consider the fitness consequences imposed by the ability to interact with phenotypes of multiple Ficus and fig wasps species, but not equally across space and time. PMID:22970309

  1. Oxaloacetate acetylhydrolase gene mutants of Sclerotinia sclerotiorum do not accumulate oxalic acid, but do produce limited lesions on host plants.

    PubMed

    Liang, Xiaofei; Liberti, Daniele; Li, Moyi; Kim, Young-Tae; Hutchens, Andrew; Wilson, Ron; Rollins, Jeffrey A

    2015-08-01

    The oxaloacetate acetylhydrolase (OAH, EC 3.7.1.1)-encoding gene Ss-oah1 was cloned and functionally characterized from Sclerotinia sclerotiorum. Ss-oah1 transcript accumulation mirrored oxalic acid (OA) accumulation with neutral pH induction dependent on the pH-responsive transcriptional regulator Ss-Pac1. Unlike previously characterized ultraviolet (UV)-induced oxalate-deficient mutants ('A' mutants) which retain the capacity to accumulate OA, gene deletion Δss-oah1 mutants did not accumulate OA in culture or during plant infection. This defect in OA accumulation was fully restored on reintroduction of the wild-type (WT) Ss-oah1 gene. The Δss-oah1 mutants were also deficient in compound appressorium and sclerotium development and exhibited a severe radial growth defect on medium buffered at neutral pH. On a variety of plant hosts, the Δss-oah1 mutants established very restricted lesions in which the infectious hyphae gradually lost viability. Cytological comparisons of WT and Δss-oah1 infections revealed low and no OA accumulation, respectively, in subcuticular hyphae. Both WT and mutant hyphae exhibited a transient association with viable host epidermal cells at the infection front. In summary, our experimental data establish a critical requirement for OAH activity in S. sclerotiorum OA biogenesis and pathogenesis, but also suggest that factors independent of OA contribute to the establishment of primary lesions. PMID:25285668

  2. When History Repeats Itself: Exploring the Genetic Architecture of Host-Plant Adaptation in Two Closely Related Lepidopteran Species

    PubMed Central

    Alexandre, Hermine; Ponsard, Sergine; Bourguet, Denis; Vitalis, Renaud; Audiot, Philippe; Cros-Arteil, Sandrine; Streiff, Réjane

    2013-01-01

    The genus Ostrinia includes two allopatric maize pests across Eurasia, namely the European corn borer (ECB, O. nubilalis) and the Asian corn borer (ACB, O. furnacalis). A third species, the Adzuki bean borer (ABB, O. scapulalis), occurs in sympatry with both the ECB and the ACB. The ABB mostly feeds on native dicots, which probably correspond to the ancestral host plant type for the genus Ostrinia. This situation offers the opportunity to characterize the two presumably independent adaptations or preadaptations to maize that occurred in the ECB and ACB. In the present study, we aimed at deciphering the genetic architecture of these two adaptations to maize, a monocot host plant recently introduced into Eurasia. To this end, we performed a genome scan analysis based on 684 AFLP markers in 12 populations of ECB, ACB and ABB. We detected 2 outlier AFLP loci when comparing French populations of the ECB and ABB, and 9 outliers when comparing Chinese populations of the ACB and ABB. These outliers were different in both countries, and we found no evidence of linkage disequilibrium between any two of them. These results suggest that adaptation or preadaptation to maize relies on a different genetic architecture in the ECB and ACB. However, this conclusion must be considered in light of the constraints inherent to genome scan approaches and of the intricate evolution of adaptation and reproductive isolation in the Ostrinia spp. complex. PMID:23874914

  3. Host-Parasite Interactions from the Inside: Plant Reproductive Ontogeny Drives Specialization in Parasitic Insects

    PubMed Central

    Boivin, Thomas; Gidoin, Cindy; von Aderkas, Patrick; Safrana, Jonathan; Candau, Jean-Noël; Chalon, Alain; Sondo, Marion; El Maâtaoui, Mohamed

    2015-01-01

    Host plant interactions are likely key drivers of evolutionary processes involved in the diversification of phytophagous insects. Granivory has received substantial attention for its crucial role in shaping the interaction between plants and their seed parasites, but fine-scale mechanisms explaining the role of host plant reproductive biology on specialization of seed parasites remain poorly described. In a comparative approach using plant histological techniques, we tested the hypotheses that different seed parasite species synchronize their life cycles to specific stages in seed development, and that the stage they target depends on major differences in seed development programs. In a pinaceous system, seed storage products are initiated before ovule fertilization and the wasps target the ovule’s nucellus during megagametogenesis, a stage at which larvae may benefit from the by-products derived from both secreting cells and dying nucellar cells. In a cupressaceous system, oviposition activity peaks later, during embryogenesis, and the wasps target the ovule’s megagametophyte where larvae may benefit from cell disintegration during embryogenesis. Our cytohistological approach shows for the first time how, despite divergent oviposition targets, different parasite species share a common strategy that consists of first competing for nutrients with developing plant structures, and then consuming these developed structures to complete their development. Our results support the prediction that seed developmental program is an axis for specialization in seed parasites, and that it could be an important parameter in models of their ecological and taxonomic divergence. This study provides the basis for further investigating the possibility of the link between plant ontogeny and pre-dispersal seed parasitism. PMID:26441311

  4. Competitive Exclusion among Fig Wasps Achieved via Entrainment of Host Plant Flowering Phenology

    PubMed Central

    Chen, Yan; Zhang, Jian; Compton, Stephen G.; Chen, Xiao-Yong

    2014-01-01

    Molecular techniques are revealing increasing numbers of morphologically similar but co-existing cryptic species, challenging the niche theory. To understand the co-existence mechanism, we studied phenologies of morphologically similar species of fig wasps that pollinate the creeping fig (F. pumila) in eastern China. We compared phenologies of fig wasp emergence and host flowering at sites where one or both pollinators were present. At the site where both pollinators were present, we used sticky traps to capture the emerged fig wasps and identified species identity using mitochondrial DNA COI gene. We also genotyped F. pumila individuals of the three sites using polymorphic microsatellites to detect whether the host populations were differentiated. Male F. pumila produced two major crops annually, with figs receptive in spring and summer. A small partial third crop of receptive figs occurred in the autumn, but few of the second crop figs matured at that time. Hence, few pollinators were available to enter third crop figs and they mostly aborted, resulting in two generations of pollinating wasps each year, plus a partial third generation. Receptive figs were produced on male plants in spring and summer, timed to coincide with the release of short-lived adult pollinators from the same individual plants. Most plants were pollinated by a single species. Plants pollinated by Wiebesia sp. 1 released wasps earlier than those pollinated by Wiebesia sp. 3, with little overlap. Plants occupied by different pollinators were not spatially separated, nor genetically distinct. Our findings show that these differences created mismatches with the flight periods of the other Wiebesia species, largely ‘reserving’ individual plants for the resident pollinator species. This pre-emptive competitive displacement may prevent long term co-existence of the two pollinators. PMID:24849458

  5. Within-Host Niche Differences and Fitness Trade-offs Promote Coexistence of Plant Viruses.

    PubMed

    Mordecai, Erin A; Gross, Kevin; Mitchell, Charles E

    2016-01-01

    Pathogens live in diverse, competitive communities, yet the processes that maintain pathogen diversity remain elusive. Here, we use a species-rich, well-studied plant virus system, the barley yellow dwarf viruses, to examine the mechanisms that regulate pathogen diversity. We empirically parameterized models of three viruses, their two aphid vectors, and one perennial grass host. We found that high densities of both aphids maximized virus diversity and that competition limited the coexistence of two closely related viruses. Even limited ability to simultaneously infect (coinfect) host individuals strongly promoted virus coexistence; preventing coinfection led to priority effects. Coinfection generated stabilizing niche differences by allowing viruses to share hosts. However, coexistence also required trade-offs between vector generalist and specialist life-history strategies. Our predicted outcomes broadly concur with previous field observations. These results show how competition within individual hosts and vectors may lead to unexpected population-level outcomes between pathogens, including coexistence, competitive exclusion, and priority effects, and how contemporary coexistence theory can help to predict these outcomes. PMID:27277413

  6. Systematic Effects in Type-1a Supernovae Surveys from Host Galaxy Spectra

    SciTech Connect

    Strauss, Michael A.

    2013-08-23

    The physical relation between the properties of Type Ia supernovae and their host galaxies is investigated. Such supernovae are used to constrain the properties of dark energy, making it crucial to understand their physical properties and to check for systematic effects relating to the stellar populations of the progenitor stars from which these supernovae arose. This grant found strong evidence for two distinct populations of supernovae, and correlations between the progenitor stellar populations and the nature of the supernova light curves.

  7. Plant-derived nanostructures: types and applications

    EPA Science Inventory

    Plant-derived nanostructures and nanoparticles (NPs) have functional applications in numerous disciplines such as health care, food and feed, cosmetics, biomedical science, energy science, drug-gene delivery, environmental health, and so on. Consequently, it is imperative for res...

  8. Early stage phytohormone and fatty acid profiles of plants associated with host and non-host resistance to hessian fly (Diptera: Cecidomyiidae) infestation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Phytohormones and fatty acids play important roles in plant resistance to insects and pathogens. In this study, we investigated the similarities and differences in the accumulations of phytohormones and fatty acids in the resistant wheat (Triticum aestivum L.) ‘Molly’ and the non-host rice (Oryza sa...

  9. Predicting the host range of Nystalea ebalea: secondary plant chemistry and host selection by a surrogate biological control agent of Schinus terebinthifolia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The safety of weed biological control depends upon the selection and utilization of the target weed by the agent while causing minimal harm to non-target species. Selection of weed species by biological control agents is determined by the presence of behavioral cues, generally host secondary plant c...

  10. Gas-chromatography and electroantennogram analysis of saturated hydrocarbons of cruciferous host plants and host larval body extracts of Plutella xylostella for behavioural manipulation of Cotesia plutellae.

    PubMed

    Seenivasagan, T; Paul, A V Navarajan

    2011-05-01

    Saturated hydrocarbons (SHC) of five cruciferous host plants viz., cabbage, cauliflower, broccoli, knol khol and Brussels sprout and the larvae of diamondback moth (DBM), Plutella xylostella reared on these host plants were identified through gas-chromatography. The hydrocarbon profile of host plants and larval body extract of DBM reared on respective host plants revealed a wide variation in quantity as well as quality. Long chain hydrocarbons C26-C30 were detected in all the extracts. In electroantennogram (EAG) studies, SHCs at 10(-3) g dose elicited differential EAG response in the antennal receptors of gravid Cotesia plutellae females. Tricosane (C23) and hexacosane (C26) elicited 10-fold increased EAG response compared to control stimulus. Long chain hydrocarbons C27, C28 and C29 elicited, 6-7 fold increased responses. The sensitivity of antenna was 4-5 folds for C25, C14, C24, C15 and C30, while the short chain hydrocarbons elicited 2-3 fold increased EAG responses. Dual choice flight orientation experiments in a wind tunnel revealed that the gravid C. plutellae females preferred the odour of C16, C26, C29, C15, C21, C23, C30, C27, C24 and C22 as 60-70% females oriented and landed on SHC treated substrate compared to control odour, while the odour of eicosane (C20), pentacosane (C25) and octacosane (C28) were not preferred by the females. PMID:21615063

  11. Host Plant Use by and New Host Records of Apple Maggot, Western Cherry Fruit Fly, and Other Rhagoletis Species (Diptera: Tephritidae). I. Central Washington State

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Host plant use by apple maggot fly, Rhagoletis pomonella (Walsh), western cherry fruit fly, Rhagoletis indifferens Curran, and other Rhagoletis species (Diptera: Tephritidae) in five cities or towns and several habitats of difference commercial importance within south central Washington state was de...

  12. Orbital Decay of Hot Jupiters Due to Nonlinear Tidal Dissipation within Solar-type Hosts

    NASA Astrophysics Data System (ADS)

    Essick, Reed; Weinberg, Nevin N.

    2016-01-01

    We study the orbital evolution of hot Jupiters due to the excitation and damping of tidally driven g-modes within solar-type host stars. Linearly resonant g-modes (the dynamical tide) are driven to such large amplitudes in the stellar core that they excite a sea of other g-modes through weakly nonlinear interactions. By solving the dynamics of large networks of nonlinearly coupled modes, we show that the nonlinear dissipation rate of the dynamical tide is several orders of magnitude larger than the linear dissipation rate. We find stellar tidal quality factors {Q}*' ≃ 105-106 for systems with planet mass {M}p≳ 0.5{M}{{J}} and orbital period P≲ 2 {days}, which implies that such systems decay on timescales that are small compared to the main-sequence lifetime of their solar-type hosts. According to our results, there are ≃ 10 currently known exoplanetary systems, including WASP-19b and HAT-P-36-b, with orbital decay timescales shorter than a Gyr. Rapid, tidally induced orbital decay may explain the observed paucity of planets with {M}p≳ {M}{{J}} and P<2 {days} around solar-type hosts and could generate detectable transit-timing variations in the near future.

  13. Molecular content of a Type Ia supernova host galaxy at z = 0.6

    NASA Astrophysics Data System (ADS)

    Melchior, A.-L.; Combes, F.

    2007-11-01

    We study the properties and the molecular content of the host of a Type Ia supernova (SN1997ey). This z = 0.575 host is the brightest submillimetre source of the sample of Type Ia supernova hosts observed at 450 and 850 μm by Farrah et al. Observations were performed at the Institut de Radioastronomie Millimétrique 30 m telescope (IRAM 30m) to search for CO(2-1) and CO(3-2) lines in good weather conditions but no signal was detected. The star formation rate cannot exceed 50Msolaryr-1. These negative results are confronted with an optical analysis of a Keck spectrum and other data archives. We reach the conclusion that this galaxy is a late-type system (0.7LB*), with a small residual star formation activity (0.2Msolaryr-1) detected in the optical. No source of heating (active galactic nucleus or starburst) is found to explain the submillimetre-continuum flux and the non-CO detection excludes the presence of a large amount of cold gas. We thus suggest that either the star formation activity is hidden in the nucleus (with AV ~ 4) or this galaxy is passive or anemic, and this flux might be associated with a background galaxy.

  14. Host plant effects on development and reproduction of the glassy-winged sharpshooter, Homalodisca vitripennis (Homoptera: Cicadellidae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development, survivorship, longevity, reproduction and life table parameters of the glassy-winged sharpshooter, Homalodisca vitripennis (Germar), were examined in the laboratory using three host plants, sunflower (Helianthus annuus L.), Chrysanthemum morifolium L. and euonymus (Euonymus japonica Thu...

  15. Genetic and behavioral discrimination of host plant populations of the leafbeetle, Psylliodes chalcomera, for biological control of yellow starthistle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Molecular genetic techniques clearly distinguish three separate populations within the flea beetle "species" Psylliodes chalcomera that are associated with three different host plants (yellow starthistle, Scotch thistle and musk thistle). Preliminary studies have not revealed any reliable morpholog...

  16. Accomplishments of a 10-year initiative to develop host plant resistance to root-knot and reniform nematodes in cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2003 Cotton Incorporated initiated a Beltwide research program to develop host plant resistance against root-knot (Meloidogyne incognita) and reniform (Rotylenchulus reniformis) nematodes. Objectives formulated at a coordinating meeting in 2003 that included participants from public institutions...

  17. MEDHOST: An encyclopedic bibliography of the host plants of the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), version 1.1

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This monograph is a compendium of all plant species reported as hosts of C. capitata (or potential hosts based on mere appearance on some lists). There are 353 species (312 have valid genera and species names and 41 have species identified as "sp." or "spp.") included in the monograph; 79 species ha...

  18. The genetic architecture of a complex ecological trait: host plant use in the specialist moth, HELIOTHIS SUBFLEXA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The study of the genetic basis of ecological adaptation remains in its infancy, and most studies have focused on phenotypically simple traits. Host plant use by herbivorous insects is phenotypically complex. While research has illuminated the evolutionary determinants of host use, knowledge of its...

  19. SEASONAL ECOLOGY OF BEMISIA TABACI IN ARIZONA: LOW TEMPERATURE AND HOST PLANT EFFECTS ON FIELD POPULATIONS AND ASSOCIATED MORTALITY FACTORS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The current ongoing study has examined seasonality and mortality patterns of B. tabaci on different hosts during the year. Plots of six representative host plants (broccoli, cantaloupe, cotton, alfalfa, Lantana and various weeds) were established at the Yuma, Maricopa and Marana Agricultural Centers...

  20. Arsenal of plant cell wall degrading enzymes reflects host preference among plant pathogenic fungi

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Discovery and development of novel plant cell wall degrading enzymes is a key step towards more efficient depolymerization of polysaccharides to fermentable sugars for production of liquid transportation biofuels and other bioproducts. The industrial fungus Trichoderma reesei is known to be highly c...

  1. HOST PLANTS OF THE TARNISHED PLANT BUG (HETEROPTERA: MIRIDAE) IN CENTRAL TEXAS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The tarnished plant bug, Lygus lineolaris, has taken on added importance as a pest of cotton in the Cotton Belt following successful eradication efforts for the boll weevil. Because the Southern Blacklands region of Central Texas is in advanced stages of boll weevil eradication, blooming weeds and ...

  2. The Use of High Pressure Freezing and Freeze Substitution to Study Host-Pathogen Interactions in Fungal Diseases of Plants

    NASA Astrophysics Data System (ADS)

    Mims, C. W.; Celio, Gail J.; Richardson, Elizabeth A.

    2003-12-01

    This article reports on the use of high pressure freezing followed by freeze substitution (HPF/FS) to study ultrastructural details of host pathogen interactions in fungal diseases of plants. The specific host pathogen systems discussed here include a powdery mildew infection of poinsettia and rust infections of daylily and Indian strawberry. The three pathogens considered here all attack the leaves of their hosts and produce specialized hyphal branches known as haustoria that invade individual host cells without killing them. We found that HPF/FS provided excellent preservation of both haustoria and host cells for all three host pathogen systems. Preservation of fungal and host cell membranes was particularly good and greatly facilitated the detailed study of host pathogen interfaces. In some instances, HPF/FS provided information that was not available in samples prepared for study using conventional chemical fixation. On the other hand, we did encounter various problems associated with the use of HPF/FS. Examples included freeze damage of samples, inconsistency of fixation in different samples, separation of plant cell cytoplasm from cell walls, breakage of cell walls and membranes, and splitting of thin sections. However, we believe that the outstanding preservation of ultrastructural details afforded by HPF/FS significantly outweighs these problems and we highly recommend the use of this fixation protocol for future studies of fungal host-plant interactions.

  3. Intra-host competition between nef-defective escape mutants and wild-type human immunodeficiency virus type 1.

    PubMed Central

    Altes, H K; Jansen, V A

    2000-01-01

    Various forms of nef genes with deletions at conserved positions along the sequence have been reported to persist in human immunodeficiency virus type 1 infected patients. We investigate the forces maintaining such variants in the proviral population. The main selection pressures are preservation of function and host immune response. The crippled Nef protein might have fewer epitopes, and as such be less visible to the specific immune response, but it will lose some function. Does a trade-off between avoidance of the immune response and loss of function explain the dynamics of the crippled virus found in the patients? To answer this question, we formulated a deterministic model of the virus-host interactions. We found that when the crippled protein presents few epitopes and suffers little loss of function, the two viral types can coexist. Otherwise, the wild-type comes to prevail. The mutant form might initially dominate, but as the selective pressure by the CD84+ T cells decreases over the course of infection, the advantage for the crippled form of losing epitopes disappears. Hence, we go from a situation of coexistence of wild-type and mutant, to a situation of only full-length nef. The results are discussed in the context of the suggested use of live attenuated vaccines having deletions in nef. PMID:10687825

  4. Supernovae and their host galaxies - II. The relative frequencies of supernovae types in spirals

    NASA Astrophysics Data System (ADS)

    Hakobyan, A. A.; Nazaryan, T. A.; Adibekyan, V. Zh.; Petrosian, A. R.; Aramyan, L. S.; Kunth, D.; Mamon, G. A.; de Lapparent, V.; Bertin, E.; Gomes, J. M.; Turatto, M.

    2014-11-01

    We present an analysis of the relative frequencies of different supernova (SN) types in spirals with various morphologies and in barred or unbarred galaxies. We use a well-defined and homogeneous sample of spiral host galaxies of 692 SNe from the Sloan Digital Sky Survey in different stages of galaxy-galaxy interaction and activity classes of nucleus. We propose that the underlying mechanisms shaping the number ratios of SNe types can be interpreted within the framework of interaction-induced star formation, in addition to the known relations between morphologies and stellar populations. We find a strong trend in behaviour of the NIa/NCC ratio depending on host morphology, such that early spirals include more Type Ia SNe. The NIbc/NII ratio is higher in a broad bin of early-type hosts. The NIa/NCC ratio is nearly constant when changing from normal, perturbed to interacting galaxies, then declines in merging galaxies, whereas it jumps to the highest value in post-merging/remnant galaxies. In contrast, the NIbc/NII ratio jumps to the highest value in merging galaxies and slightly declines in post-merging/remnant subsample. The interpretation is that the star formation rates and morphologies of galaxies, which are strongly affected in the final stages of interaction, have an impact on the number ratios of SNe types. The NIa/NCC (NIbc/NII) ratio increases (decreases) from star-forming to active galactic nuclei (AGN) classes of galaxies. These variations are consistent with the scenario of an interaction-triggered starburst evolving into AGN during the later stages of interaction, accompanied with the change of star formation and transformation of the galaxy morphology into an earlier type.

  5. Response of a gall wasp community to genetic variation in the host plant Quercus crispula: a test using half-sib families

    NASA Astrophysics Data System (ADS)

    Ito, Masato; Ozaki, Kenichi

    2005-02-01

    The structure of a herbivore community may change consistently along the genetic cline of a host plant, change at particular points along the cline, or respond independently of the cline. To reveal such relationships between a gall wasp community and genetic variation in the host plant Quercus crispula, we examined patterns in the species richness and abundance of gall wasps along a genetic cline of the host plant, using 12 half-sib families from six different regions. The genetic relationships among the half-sib families of Q. crispula were quantified on the basis of leaf morphology, which represented a morphological cline from leaves typical of Q. crispula to leaves resembling another oak species, Q. dentata. The morphological cline could be regarded as a genetic cline caused by a history of hybridization with Q. dentata. The mean numbers of gall types varied among the half-sib families, but did not show a consistent increase or decrease along the genetic cline. This pattern could be explained by the fact that responses to host plant variation differed among the gall wasp species. The half-sib families were classified into three groups based on an ordination analysis of the species composition of the gall wasp community that to some extent also reflected the genetic cline of Q. crispula. This suggests that the species composition of gall wasps changed intermittently along the genetic cline, rather than gradually and consistently along the cline.

  6. Endophytic Fungal Communities Associated with Vascular Plants in the High Arctic Zone Are Highly Diverse and Host-Plant Specific.

    PubMed

    Zhang, Tao; Yao, Yi-Feng

    2015-01-01

    This study assessed the diversity and distribution of endophytic fungal communities associated with the leaves and stems of four vascular plant species in the High Arctic using 454 pyrosequencing with fungal-specific primers targeting the ITS region. Endophytic fungal communities showed high diversity. The 76,691 sequences obtained belonged to 250 operational taxonomic units (OTUs). Of these OTUs, 190 belonged to Ascomycota, 50 to Basidiomycota, 1 to Chytridiomycota, and 9 to unknown fungi. The dominant orders were Helotiales, Pleosporales, Capnodiales, and Tremellales, whereas the common known fungal genera were Cryptococcus, Rhizosphaera, Mycopappus, Melampsora, Tetracladium, Phaeosphaeria, Mrakia, Venturia, and Leptosphaeria. Both the climate and host-related factors might shape the fungal communities associated with the four Arctic plant species in this region. These results suggested the presence of an interesting endophytic fungal community and could improve our understanding of fungal evolution and ecology in the Arctic terrestrial ecosystems. PMID:26067836

  7. Endophytic Fungal Communities Associated with Vascular Plants in the High Arctic Zone Are Highly Diverse and Host-Plant Specific

    PubMed Central

    Zhang, Tao; Yao, Yi-Feng

    2015-01-01

    This study assessed the diversity and distribution of endophytic fungal communities associated with the leaves and stems of four vascular plant species in the High Arctic using 454 pyrosequencing with fungal-specific primers targeting the ITS region. Endophytic fungal communities showed high diversity. The 76,691 sequences obtained belonged to 250 operational taxonomic units (OTUs). Of these OTUs, 190 belonged to Ascomycota, 50 to Basidiomycota, 1 to Chytridiomycota, and 9 to unknown fungi. The dominant orders were Helotiales, Pleosporales, Capnodiales, and Tremellales, whereas the common known fungal genera were Cryptococcus, Rhizosphaera, Mycopappus, Melampsora, Tetracladium, Phaeosphaeria, Mrakia, Venturia, and Leptosphaeria. Both the climate and host-related factors might shape the fungal communities associated with the four Arctic plant species in this region. These results suggested the presence of an interesting endophytic fungal community and could improve our understanding of fungal evolution and ecology in the Arctic terrestrial ecosystems. PMID:26067836

  8. [Host plants of Aphis gossypii (Aphididae), vector of virus of Cucumis melo melon (Cucurbitaceae) in Costa Rica].

    PubMed

    Sánchez, M V; Agüero, R; Rivera, C

    2001-03-01

    Plant species associated with commercial melon crops and surrounding areas were examined to identity the natural host plants of Aphis gossypii Glover. The study was conducted in two farms located in different melon production areas and plant life zones of Costa Rica. Plant species diversity, percent coverage and distribution over time were recorded during one year. Differences between locations were observed. A total of 86 plant species (49 families) and 72 plant species (40 families) were identified associated to the crop in farms A and B, respectively. In both farms a total of 24 species plants (16 families) were colonized by A. gossypii and 16 (10 families) are new reports of host plant species for this aphid. The new reports are: Justicia comata, Tetramerium nervosum, Alternanthera pubiflora, Cassia massoni, C. reticulata, Cleome viscosa, C. spinosa, Croton argenteus, Caperonia palustris, Chamaesyce gyssopilopia, Phyllantus amarus, Sida decumbens, Ludwigia erecta, Passiflora foetida, Guazuma ulmifolia and Corchorus orinocensis. PMID:11795159

  9. Host plants of Brevipalpus californicus, B. obovatus, and B. phoenicis (Acari: Tenuipalpidae) and their potential involvement in the spread of viral diseases vectored by these mites.

    PubMed

    Childers, Carl C; Rodrigues, Jose Carlos V; Welbourn, Warren C

    2003-01-01

    The family Tenuipalpidae has over 622 species in 30 genera described worldwide. A total of 928 plant species in 513 genera within 139 families are recorded hosts of one or more of the following species: Brevipalpus californicus (Banks), B. obovatus Donnadieu, and B. phoenicis (Geijskes). B. californicus has 316 plant species reported as hosts compared with 451 and 486 host plants for B. obovatus and B. phoenicis, respectively. There are 67 genera of plants within 33 families that are reported hosts of only B. californicus, 119 genera within 55 plant families that are hosts of only B. obovatus, and 118 genera of plants within 64 families that are hosts of only B. phoenicis. There are 14 genera of plants within 12 families that are hosts to both B. californicus and B. obovatus, while there are 40 genera of host plants within 26 families that are hosts for both B. californicus and B. phoenicis. A total of 70 genera of host plants within 39 families have been reported as hosts of both B. obovatus and B. phoenicis, while 77 genera of plants within 44 families have been reported as hosts of all three Brevipalpus species. Geographical differences in the three species of Brevipalpus identified on different plant species within the same genus are common. PMID:14756412

  10. Plant-mediated pheromone emission by a hemipteran seed feeder increases the apparency of an unreliable but rewarding host.

    PubMed

    Stanton, Mariana A; Preβler, Jens; Paetz, Christian; Boland, Wilhelm; Svatoš, Aleš; Baldwin, Ian T

    2016-07-01

    The defensive chemistry and persistence of plant tissues determine their suitability and apparency - the likelihood of being discovered - to insect herbivores. As consumers of plant tissues with transient apparency, florivores and seed-feeders must frequently migrate between host plants to synchronize colonization with plant phenology. Aggregation pheromones could provide information-based solutions to finding ephemeral hosts, but little is known about plant-influenced variation in this form of chemical communication. Combining analytical chemistry, de novo synthesis and field ecology, we investigated the change in colonization of two sympatric host plants, Nicotiana attenuata and Nicotiana obtusifolia, which differ in apparency-related life history traits, by a heteropteran seed-feeder, Corimelaena extensa. We identified a novel pheromone released by C. extensa males - (5Z,8Z)-tetradeca-5,8-dienal - and performed field assays with the synthetic pheromone, showing that it stimulates the formation of feeding aggregations on the post-fire annual N. attenuata. Corimelaena extensa pheromone emission was 40-fold higher when feeding on N. attenuata compared with the perennial N. obtusifolia, as were adult fecundity and seed capsule content of the putative biosynthetic precursor, linoleic acid. Higher pheromone emission increases the apparency and colonization of the ephemeral, high-quality host N. attenuata. This plant-specific variation in insect signaling could facilitate host-finding by seed-feeders migrating between plant patches. PMID:26915986

  11. Genetic Determinism and Evolutionary Reconstruction of a Host Jump in a Plant Virus.

    PubMed

    Vassilakos, Nikon; Simon, Vincent; Tzima, Aliki; Johansen, Elisabeth; Moury, Benoît

    2016-02-01

    In spite of their widespread occurrence, only few host jumps by plant viruses have been evidenced and the molecular bases of even fewer have been determined. A combination of three independent approaches, 1) experimental evolution followed by reverse genetics analysis, 2) positive selection analysis, and 3) locus-by-locus analysis of molecular variance (AMOVA) allowed reconstructing the Potato virus Y (PVY; genus Potyvirus, family Potyviridae) jump to pepper (Capsicum annuum), probably from other solanaceous plants. Synthetic chimeras between infectious cDNA clones of two PVY isolates with contrasted levels of adaptation to C. annuum showed that the P3 and, to a lower extent, the CI cistron played important roles in infectivity toward C. annuum. The three analytical approaches pinpointed a single nonsynonymous substitution in the P3 and P3N-PIPO cistrons that evolved several times independently and conferred adaptation to C. annuum. In addition to increasing our knowledge of host jumps in plant viruses, this study illustrates also the efficiency of locus-by-locus AMOVA and combined approaches to identify adaptive mutations in the genome of RNA viruses. PMID:26503941

  12. Field Biology of the Beetle Aegopsis bolboceridus in Brazil, with a List of Host Plants

    PubMed Central

    Oliveira, Charles M.; Frizzas, Marina R.

    2013-01-01

    The white grub, Aegopsis bolboceridus (Thomson) (Coleoptera: Melolonthidae), is an important vegetable and corn pest in central Brazil. The objective of this study was to examine the biology of A. bolboceridus in the field and to update the list of its host plants. The study was conducted in an area with vegetable crops and corn located in the Federal District of Brazil. Samplings were taken to observe the biological stages of A. bolboceridus, preferred oviposition sites, and the adult swarming period. A. bolboceridus exhibited a univoltine cycle that lasted approximately 12 months from egg to active adults. Its eggs were found from October to November. The larval stage lasted approximately eight months, occurring between October and May. Pre-pupae were observed between April and June, and pupae were found between May and July. Inactive adults were observed in July and August, and the swarming period was between September and October. The females preferred to oviposit in sites with taller plants. Four new plant species were identified as hosts for this pest, and two new locations were recorded for its occurrence. This study is the first to describe the biology of a representative of the tribe Agaocephalini in Brazil. PMID:23909396

  13. The neural bases of host plant selection in a Neuroecology framework

    PubMed Central

    Reisenman, Carolina E.; Riffell, Jeffrey A.

    2015-01-01

    Understanding how animals make use of environmental information to guide behavior is a fundamental problem in the field of neuroscience. Similarly, the field of ecology seeks to understand the role of behavior in shaping interactions between organisms at various levels of organization, including population-, community- and even ecosystem-level scales. Together, the newly emerged field of “Neuroecology” seeks to unravel this fundamental question by studying both the function of neurons at many levels of the sensory pathway and the interactions between organisms and their natural environment. The interactions between herbivorous insects and their host plants are ideal examples of Neuroecology given the strong ecological and evolutionary forces and the underlying physiological and behavioral mechanisms that shaped these interactions. In this review we focus on an exemplary herbivorous insect within the Lepidoptera, the giant sphinx moth Manduca sexta, as much is known about the natural behaviors related to host plant selection and the involved neurons at several level of the sensory pathway. We also discuss how herbivore-induced plant odorants and secondary metabolites in floral nectar in turn can affect moth behavior, and the underlying neural mechanisms. PMID:26321961

  14. Predation and aggressiveness in host plant protection: a generalization using ants from the genus Azteca

    NASA Astrophysics Data System (ADS)

    Dejean, Alain; Grangier, Julien; Leroy, Céline; Orivel, Jerôme

    2009-01-01

    In studying the ant genus Azteca, a Neotropical group of arboreal species, we aimed to determine the extent to which the ants use predation and/or aggressiveness to protect their host plants from defoliating insects. We compared a territorially dominant, carton-nester, Azteca chartifex, and three plant-ant species. Azteca alfari and Azteca ovaticeps are associated with the myrmecophyte Cecropia (Cecropiaceae) and their colonies shelter in its hollow branches; whereas Azteca bequaerti is associated with Tococa guianensis (Melastomataceae) and its colonies shelter in leaf pouches situated at the base of the laminas. Whereas A. bequaerti workers react to the vibrations transmitted by the lamina when an alien insect lands on a leaf making it unnecessary for them to patrol their plant, the workers of the three other species rather discover prey by contact. The workers of all four species use a predatory behaviour involving spread-eagling alien insects after recruiting nestmates at short range, and, in some cases, at long range. Because A. alfari and A. ovaticeps discard part of the insects they kill, we deduced that the workers’ predatory behaviour and territorial aggressiveness combine in the biotic defence of their host tree.

  15. The neural bases of host plant selection in a Neuroecology framework.

    PubMed

    Reisenman, Carolina E; Riffell, Jeffrey A

    2015-01-01

    Understanding how animals make use of environmental information to guide behavior is a fundamental problem in the field of neuroscience. Similarly, the field of ecology seeks to understand the role of behavior in shaping interactions between organisms at various levels of organization, including population-, community- and even ecosystem-level scales. Together, the newly emerged field of "Neuroecology" seeks to unravel this fundamental question by studying both the function of neurons at many levels of the sensory pathway and the interactions between organisms and their natural environment. The interactions between herbivorous insects and their host plants are ideal examples of Neuroecology given the strong ecological and evolutionary forces and the underlying physiological and behavioral mechanisms that shaped these interactions. In this review we focus on an exemplary herbivorous insect within the Lepidoptera, the giant sphinx moth Manduca sexta, as much is known about the natural behaviors related to host plant selection and the involved neurons at several level of the sensory pathway. We also discuss how herbivore-induced plant odorants and secondary metabolites in floral nectar in turn can affect moth behavior, and the underlying neural mechanisms. PMID:26321961

  16. Data on litter quality of host grass plants with and without fungal endophytes.

    PubMed

    Gundel, P E; Helander, M; Garibaldi, L A; Vázquez-de-Aldana, B R; Zabalgogeazcoa, I; Saikkonen, K

    2016-06-01

    Certain Pooideae species form persistent symbiosis with fungal endophytes of Epichloë genus. Although endophytes are known to impact the ecology and evolution of host species, their effects on parameters related with quality of plant biomass has been elusive. This article provides information about parameters related with the quality of plant litter biomass of two important grass species (Schedonorus phoenix and Schedonorus pratensis) affected by the symbiosis with fungal endophytes (Epichloë coenophiala and Epichloë uncinata, respectively). Four population origins of S. phoenix and one of S. pratensis were included. Mineral, biochemical and structural parameters were obtained from three samples per factors combination [species (and population origin)×endophyte]. This data can be potentially used in other studies which, by means of 'data reanalyzing' or meta-analysis, attempt to find generalizations about endophyte effects on host plant litter biomass. The present data is associated with the research article "Role of foliar fungal endophytes on litter decomposition among species and population origins" (Gundel et al., In preparation) [1]. PMID:27182541

  17. Data on litter quality of host grass plants with and without fungal endophytes

    PubMed Central

    Gundel, P.E.; Helander, M.; Garibaldi, L.A.; Vázquez-de-Aldana, B.R.; Zabalgogeazcoa, I.; Saikkonen, K.

    2016-01-01

    Certain Pooideae species form persistent symbiosis with fungal endophytes of Epichloë genus. Although endophytes are known to impact the ecology and evolution of host species, their effects on parameters related with quality of plant biomass has been elusive. This article provides information about parameters related with the quality of plant litter biomass of two important grass species (Schedonorus phoenix and Schedonorus pratensis) affected by the symbiosis with fungal endophytes (Epichloë coenophiala and Epichloë uncinata, respectively). Four population origins of S. phoenix and one of S. pratensis were included. Mineral, biochemical and structural parameters were obtained from three samples per factors combination [species (and population origin)×endophyte]. This data can be potentially used in other studies which, by means of ‘data reanalyzing’ or meta-analysis, attempt to find generalizations about endophyte effects on host plant litter biomass. The present data is associated with the research article “Role of foliar fungal endophytes on litter decomposition among species and population origins” (Gundel et al., In preparation) [1]. PMID:27182541

  18. Olfactory Response and Host Plant Feeding of the Central American Locust Schistocerca piceifrons piceifrons Walker to Common Plants in a Gregarious Zone.

    PubMed

    Poot-Pech, M A; Ruiz-Sánchez, E; Ballina-Gómez, H S; Gamboa-Angulo, M M; Reyes-Ramírez, A

    2016-08-01

    The Central American locust (CAL) Schistocerca piceifrons piceifrons Walker is one of the most harmful plant pests in the Yucatan Peninsula, where an important gregarious zone is located. The olfactory response and host plant acceptance by the CAL have not been studied in detail thus far. In this work, the olfactory response of the CAL to odor of various plant species was evaluated using an olfactometer test system. In addition, the host plant acceptance was assessed by the consumption of leaf area. Results showed that the CAL was highly attracted to odor of Pisonia aculeata. Evaluation of host plant acceptance showed that the CAL fed on Leucaena glauca and Waltheria americana, but not on P. aculeata or Guazuma ulmifolia. Analysis of leaf thickness, and leaf content of nitrogen (N) and carbon (C) showed that the CAL was attracted to plant species with low leaf C content. PMID:26957085

  19. Oviposition Preference of Pea Weevil, Bruchus pisorum L. Among Host and Non-host Plants and its Implication for Pest Management

    PubMed Central

    Mendesil, Esayas; Rämert, Birgitta; Marttila, Salla; Hillbur, Ylva; Anderson, Peter

    2016-01-01

    The pea weevil, Bruchus pisorum L. is a major insect pest of field pea, Pisum sativum L. worldwide and current control practices mainly depend on the use of chemical insecticides that can cause adverse effects on environment and human health. Insecticides are also unaffordable by many small-scale farmers in developing countries, which highlights the need for investigating plant resistance traits and to develop alternative pest management strategies. The aim of this study was to determine oviposition preference of pea weevil among P. sativum genotypes with different level of resistance (Adet, 32410-1 and 235899-1) and the non-host leguminous plants wild pea (Pisum fulvum Sibth. et Sm.) and grass pea (Lathyrus sativus L.), in no-choice and dual-choice tests. Pod thickness and micromorphological traits of the pods were also examined. In the no-choice tests significantly more eggs were laid on the susceptible genotype Adet than on the other genotypes. Very few eggs were laid on P. fulvum and L. sativus. In the dual-choice experiments Adet was preferred by the females for oviposition. Furthermore, combinations of Adet with either 235899-1 or non-host plants significantly reduced the total number of eggs laid by the weevil in the dual-choice tests. Female pea weevils were also found to discriminate between host and non-host plants during oviposition. The neoplasm (Np) formation on 235899-1 pods was negatively correlated with oviposition by pea weevil. Pod wall thickness and trichomes might have influenced oviposition preference of the weevils. These results on oviposition behavior of the weevils can be used in developing alternative pest management strategies such as trap cropping using highly attractive genotype and intercropping with the non-host plants. PMID:26779220

  20. Oviposition Preference of Pea Weevil, Bruchus pisorum L. Among Host and Non-host Plants and its Implication for Pest Management.

    PubMed

    Mendesil, Esayas; Rämert, Birgitta; Marttila, Salla; Hillbur, Ylva; Anderson, Peter

    2015-01-01

    The pea weevil, Bruchus pisorum L. is a major insect pest of field pea, Pisum sativum L. worldwide and current control practices mainly depend on the use of chemical insecticides that can cause adverse effects on environment and human health. Insecticides are also unaffordable by many small-scale farmers in developing countries, which highlights the need for investigating plant resistance traits and to develop alternative pest management strategies. The aim of this study was to determine oviposition preference of pea weevil among P. sativum genotypes with different level of resistance (Adet, 32410-1 and 235899-1) and the non-host leguminous plants wild pea (Pisum fulvum Sibth. et Sm.) and grass pea (Lathyrus sativus L.), in no-choice and dual-choice tests. Pod thickness and micromorphological traits of the pods were also examined. In the no-choice tests significantly more eggs were laid on the susceptible genotype Adet than on the other genotypes. Very few eggs were laid on P. fulvum and L. sativus. In the dual-choice experiments Adet was preferred by the females for oviposition. Furthermore, combinations of Adet with either 235899-1 or non-host plants significantly reduced the total number of eggs laid by the weevil in the dual-choice tests. Female pea weevils were also found to discriminate between host and non-host plants during oviposition. The neoplasm (Np) formation on 235899-1 pods was negatively correlated with oviposition by pea weevil. Pod wall thickness and trichomes might have influenced oviposition preference of the weevils. These results on oviposition behavior of the weevils can be used in developing alternative pest management strategies such as trap cropping using highly attractive genotype and intercropping with the non-host plants. PMID:26779220

  1. High-brightness blue organic light emitting diodes with different types of guest-host systems

    NASA Astrophysics Data System (ADS)

    Wang, Xiao; Zhang, Jing-shuang; Peng, Cui-yun; Guo, Kun-ping; Wei, Bin; Zhang, Hao

    2016-03-01

    We demonstrate high-brightness blue organic light emitting diodes (OLEDs) using two types of guest-host systems. A series of blue OLEDs were fabricated using three organic emitters of dibenz anthracene (perylene), di(4-fluorophenyl) amino-di (styryl) biphenyl (DSB) and 4,4'-bis[2-(9-ethyl-3-carbazolyl)vinyl]biphenyl (BCzVBi) doped into two hosting materials of 4,4'-bis(9-carbazolyl) biphenyl (CBP) and 2-(4-biphenylyl)-5(4-tert-butyl-phenyl)-1,3,4-oxadiazole (PBD) as blue emitting layers, respectively. We achieve three kinds of devices with colors of deep-blue, pure-blue and sky-blue with the Commission Internationale de L'Eclairage (CIE) coordinates of (0.16, 0.10), (0.15, 0.15) and (0.17, 0.24), respectively, by employing PBD as host material. In addition, we present a microcavity device using the PBD guest-host system and achieve high-purity blue devices with narrowed spectrum.

  2. Correlating Type Ia Supernova Properties with Their Local Environment Using HST Snapshots of Host Galaxies

    NASA Astrophysics Data System (ADS)

    Rose, Benjamin; Garnavich, Peter M.

    2016-01-01

    Type Ia supernovae (SN Ia) are important tools for precision cosmology. But there are still uncertainties about how the host galaxy properties and local environment influence the luminosity, color and Hubble residuals of SN Ia. We investigate these questions by analyzing high angular resolution Hubble Space Telescope (HST) imaging of SDSS-II host galaxies. These are "snapshot" images obtained while the telescope was slewing to new targets, so the total exposure times are less than 30 minutes. ACS images were obtained in F475W and F625W filters, similar to SDSS g and r-bands. In total, we observed 61 host galaxies in Stripe 82 that had SN Ia discovered by the SDSS-II SN Survey. HST's resolution and low background allow for detailed analysis of both the region around the SN Ia and the galaxy as a whole. Co-added SDSS-II images of the hosts are used to supplement the HST data in regions of low surface brightness. From this data set we estimate the fractional pixel rank and photometric color of the SN Ia's location and correlate the local environment variables with SN Ia luminosity, light curve width, color and Hubble residual. We assess the impact of these correlations on the accuracy of SN Ia distance estimates and possible biases in measuring the Hubble constant and dark energy parameters.

  3. Retinoid X receptor α attenuates host antiviral response by suppressing type I interferon

    PubMed Central

    Ma, Feng; Liu, Su-Yang; Razani, Bahram; Arora, Neda; Li, Bing; Kagechika, Hiroyuki; Tontonoz, Peter; Núñez, Vanessa; Ricote, Mercedes; Cheng, Genhong

    2015-01-01

    The retinoid X receptor α (RXRα), a key nuclear receptor in metabolic processes, is down-regulated during host antiviral response. However, the roles of RXRα in host antiviral response are unknown. Here we show that RXRα overexpression or ligand activation increases host susceptibility to viral infections in vitro and in vivo, while Rxra −/− or antagonist treatment reduces infection by the same viruses. Consistent with these functional studies, ligand activation of RXR inhibits the expression of antiviral genes including type I interferon (IFN) and Rxra −/− macrophages produce more IFNβ than WT macrophages in response to polyI:C stimulation. Further results indicate that ligand activation of RXR suppresses the nuclear translocation of β-catenin, a co-activator of IFNβ enhanceosome. Thus, our studies have uncovered a novel RXR-dependent innate immune regulatory pathway, suggesting that the downregulation of RXR expression or RXR antagonist treatment benefits host antiviral response, whereas RXR agonist treatment may increase the risk of viral infections. PMID:25417649

  4. Down-regulation of gibberellic acid in poplar has negligible effects on host-plant suitability and insect pest response

    SciTech Connect

    Buhl, Christine; Strauss, Steven H.; Lindroth, Richard L.

    2015-01-06

    Abstract Endogenous levels and signaling of gibberellin plant hormones such as gibberellic acid (GA) have been genetically down-regulated to create semi-dwarf varieties of poplar. The potential benefits of semi-dwarf stature include reduced risk of wind damage, improved stress tolerance, and improved wood quality. Despite these benefits, modification of growth traits may have consequences for non-target traits that confer defense against insect herbivores. According to the growth-differentiation balance hypothesis, reductions in growth may shift allocation of carbon from growth to chemical resistance traits, thereby altering plant defense. To date, host-plant suitability and pest response have not been comprehensively evaluated in GA down-regulated plants. We quantified chemical resistance and nitrogen (an index of protein) in GA down-regulated and wild-type poplar (Populus alba × P. tremula) genotypes. We also evaluated performance of both generalist (Lymantria dispar) and specialist (Chrysomela scripta) insect pests reared on these genotypes. Our evaluation of resistance traits in four GA down-regulated genotypes revealed increased phenolic glycosides in one modified genotype and reduced lignin in two modified genotypes relative to the non-transgenic wild type. Nitrogen levels did not vary significantly among the experimental genotypes. Generalists reared on the four GA down-regulated genotypes exhibited reduced performance on only one modified genotype relative to the wild type. Specialists, however, performed similarly across all genotypes. Results from this study indicate that although some non-target traits varied among GA down-regulated genotypes, the differences in poplar pest susceptibility were modest and highly genotype-specific.

  5. Down-regulation of gibberellic acid in poplar has negligible effects on host-plant suitability and insect pest response

    DOE PAGESBeta

    Buhl, Christine; Strauss, Steven H.; Lindroth, Richard L.

    2015-01-06

    Abstract Endogenous levels and signaling of gibberellin plant hormones such as gibberellic acid (GA) have been genetically down-regulated to create semi-dwarf varieties of poplar. The potential benefits of semi-dwarf stature include reduced risk of wind damage, improved stress tolerance, and improved wood quality. Despite these benefits, modification of growth traits may have consequences for non-target traits that confer defense against insect herbivores. According to the growth-differentiation balance hypothesis, reductions in growth may shift allocation of carbon from growth to chemical resistance traits, thereby altering plant defense. To date, host-plant suitability and pest response have not been comprehensively evaluated in GAmore » down-regulated plants. We quantified chemical resistance and nitrogen (an index of protein) in GA down-regulated and wild-type poplar (Populus alba × P. tremula) genotypes. We also evaluated performance of both generalist (Lymantria dispar) and specialist (Chrysomela scripta) insect pests reared on these genotypes. Our evaluation of resistance traits in four GA down-regulated genotypes revealed increased phenolic glycosides in one modified genotype and reduced lignin in two modified genotypes relative to the non-transgenic wild type. Nitrogen levels did not vary significantly among the experimental genotypes. Generalists reared on the four GA down-regulated genotypes exhibited reduced performance on only one modified genotype relative to the wild type. Specialists, however, performed similarly across all genotypes. Results from this study indicate that although some non-target traits varied among GA down-regulated genotypes, the differences in poplar pest susceptibility were modest and highly genotype-specific.« less

  6. Antipredator defense of biological control agent Oxyops vitiosa is mediated by plant volatiles sequestered from the host plant Melaleuca quinquenervia.

    PubMed

    Wheeler, G S; Massey, L M; Southwell, I A

    2002-02-01

    The weevil Oxyops vitiosa is an Australian species imported to Florida, USA, for the biological control of the invasive weed species Melaleuca quinquenervia. Larvae of this species feed on leaves of their host and produce a shiny orange secretion that covers the integument. When this secretion is applied at physiological concentrations to dog food bait, fire ant consumption and visitation are significantly reduced. Gas chromatographic analysis indicates that the larval secretion qualitatively and quantitatively resembles the terpenoid composition of the host foliage. When the combination of 10 major terpenoids from the O. vitiosa secretion was applied to dog food bait, fire ant consumption and visitation were reduced. When these 10 terpenoids were tested individually, the sesquiterpene viridiflorol was the most active component in decreasing fire ant consumption. Fire ant visitation was initially (15 min after initiation of the study) decreased for dog food bait treated with viridiflorol and the monoterpenes 1,8-cineole and alpha-terpineol. Fire ants continued to avoid the bait treated with viridiflorol at 18 microg/mg dog food for up to 6 hr after the initiation of the experiment. Moreover, ants avoided bait treated with 1.8 microg/mg for up to 3 hr. The concentrations of viridiflorol, 1,8-cineole, and alpha-terpineol in larval washes were about twice that of the host foliage, suggesting that the larvae sequester these plant-derived compounds for defense against generalist predators. PMID:11925069

  7. Sequestration of host plant glucosinolates in the defensive hemolymph of the sawfly Athalia rosae.

    PubMed

    Müller, C; Agerbirk, N; Olsen, C E; Boevé, J L; Schaffner, U; Brakefield, P M

    2001-12-01

    Interactions between insects and glucosinolate-containing plant species have been investigated for a long time. Although the glucosinolate-myrosinase system is believed to act as a defense mechanism against generalist herbivores and fungi, several specialist insects use these secondary metabolites for host plant finding and acceptance and can handle them physiologically. However, sequestration of glucosinolates in specialist herbivores has been less well studied. Larvae of the tumip sawfly Athalia rosae feed on several glucosinolate-containing plant species. When larvae are disturbed by antagonists, they release one or more small droplets of hemolymph from their integument. This "reflex bleeding" is used as a defense mechanism. Specific glucosinolate analysis, by conversion to desulfoglucosinolates and analysis of these by high-performance liquid chromatography coupled to diode array UV spectroscopy and mass spectrometry, revealed that larvae incorporate and concentrate the plant's characteristic glucosinolates from their hosts. Extracts of larvae that were reared on Sinapis alba contained sinalbin, even when the larvae were first starved for 22 hr and, thus, had empty guts. Hemolymph was analyzed from larvae that were reared on either S. alba, Brassica nigra, or Barbarea stricta. Leaves were analyzed from the same plants the larvae had fed on. Sinalbin (from S. alba), sinigrin (B. nigra), or glucobarbarin and glucobrassicin (B. stricta) were present in leaves in concentrations less than 1 micromol/g fresh weight, while the same glucosinolates could be detected in the larvae's hemolymph in concentrations between 10 and 31 micromol/g fresh weight, except that glucobrassicin was present only as a trace. In larval feces, only trace amounts of glucosinolates (sinalbin and sinigrin) could be detected. The glucosinolates were likewise found in freshly emerged adults, showing that the sequestered phytochemicals were transferred through the pupal stage. PMID:11789955

  8. Type I Interferons Increase Host Susceptibility to Trypanosoma cruzi Infection▿†

    PubMed Central

    Chessler, Anne-Danielle C.; Caradonna, Kacey L.; Da'dara, Akram; Burleigh, Barbara A.

    2011-01-01

    Trypanosoma cruzi, the protozoan parasite that causes human Chagas' disease, induces a type I interferon (IFN) (IFN-α/β) response during acute experimental infection in mice and in isolated primary cell types. To examine the potential impact of the type I IFN response in shaping outcomes in experimental T. cruzi infection, groups of wild-type (WT) and type I IFN receptor-deficient (IFNAR−/−) 129sv/ev mice were infected with two different T. cruzi strains under lethal and sublethal conditions and several parameters were measured during the acute stage of infection. The results demonstrate that type I IFNs are not required for early host protection against T. cruzi. In contrast, under conditions of lethal T. cruzi challenge, WT mice succumbed to infection whereas IFNAR−/− mice were ultimately able to control parasite growth and survive. T. cruzi clearance in and survival of IFNAR−/− mice were accompanied by higher levels of IFN-γ production by isolated splenocytes in response to parasite antigen. The suppression of IFN-γ in splenocytes from WT mice was independent of IL-10 levels. While the impact of type I IFNs on the production of IFN-γ and other cytokines/chemokines remains to be fully determined in the context of T. cruzi infection, our data suggest that, under conditions of high parasite burden, type I IFNs negatively impact IFN-γ production, initiating a detrimental cycle that contributes to the ultimate failure to control infection. These findings are consistent with a growing theme in the microbial pathogenesis field in which type I IFNs can be detrimental to the host in a variety of nonviral pathogen infection models. PMID:21402764

  9. Museum specimens reveal loss of pollen host plants as key factor driving wild bee decline in The Netherlands.

    PubMed

    Scheper, Jeroen; Reemer, Menno; van Kats, Ruud; Ozinga, Wim A; van der Linden, Giel T J; Schaminée, Joop H J; Siepel, Henk; Kleijn, David

    2014-12-01

    Evidence for declining populations of both wild and managed bees has raised concern about a potential global pollination crisis. Strategies to mitigate bee loss generally aim to enhance floral resources. However, we do not really know whether loss of preferred floral resources is the key driver of bee decline because accurate assessment of host plant preferences is difficult, particularly for species that have become rare. Here we examine whether population trends of wild bees in The Netherlands can be explained by trends in host plants, and how this relates to other factors such as climate change. We determined host plant preference of bee species using pollen loads on specimens in entomological collections that were collected before the onset of their decline, and used atlas data to quantify population trends of bee species and their host plants. We show that decline of preferred host plant species was one of two main factors associated with bee decline. Bee body size, the other main factor, was negatively related to population trend, which, because larger bee species have larger pollen requirements than smaller species, may also point toward food limitation as a key factor driving wild bee loss. Diet breadth and other potential factors such as length of flight period or climate change sensitivity were not important in explaining twentieth century bee population trends. These results highlight the species-specific nature of wild bee decline and indicate that mitigation strategies will only be effective if they target the specific host plants of declining species. PMID:25422416

  10. Fungal nutrient allocation in common mycorrhizal networks is regulated by the carbon source strength of individual host plants.

    PubMed

    Fellbaum, Carl R; Mensah, Jerry A; Cloos, Adam J; Strahan, Gary E; Pfeffer, Philip E; Kiers, E Toby; Bücking, Heike

    2014-07-01

    Common mycorrhizal networks (CMNs) of arbuscular mycorrhizal (AM) fungi in the soil simultaneously provide multiple host plants with nutrients, but the mechanisms by which the nutrient transport to individual host plants within one CMN is controlled are unknown. Using radioactive and stable isotopes, we followed the transport of phosphorus (P) and nitrogen (N) in the CMNs of two fungal species to plants that differed in their carbon (C) source strength, and correlated the transport to the expression of mycorrhiza-inducible plant P (MtPt4) and ammonium (1723.m00046) transporters in mycorrhizal roots. AM fungi discriminated between host plants that shared a CMN and preferentially allocated nutrients to high-quality (nonshaded) hosts. However, the fungus also supplied low-quality (shaded) hosts with nutrients and maintained a high colonization rate in these plants. Fungal P transport was correlated to the expression of MtPt4. The expression of the putative ammonium transporter 1723.m00046 was dependent on the fungal nutrient supply and was induced when the CMN had access to N. Biological market theory has emerged as a tool with which the strategic investment of competing partners in trading networks can be studied. Our work demonstrates how fungal partners are able to retain bargaining power, despite being obligately dependent on their hosts. PMID:24787049

  11. Functional Characterizations of Chemosensory Proteins of the Alfalfa Plant Bug Adelphocoris lineolatus Indicate Their Involvement in Host Recognition

    PubMed Central

    Zhang, Xue-Ying; Ji, Ping; Liu, Jing-Tao; Wang, Gui-Rong; Wu, Kong-Ming; Guo, Yu-Yuan; Zhou, Jing-Jiang; Zhang, Yong-Jun

    2012-01-01

    Insect chemosensory proteins (CSPs) have been proposed to capture and transport hydrophobic chemicals from air to olfactory receptors in the lymph of antennal chemosensilla. They may represent a new class of soluble carrier protein involved in insect chemoreception. However, their specific functional roles in insect chemoreception have not been fully elucidated. In this study, we report for the first time three novel CSP genes (AlinCSP1-3) of the alfalfa plant bug Adelphocoris lineolatus (Goeze) by screening the antennal cDNA library. The qRT-PCR examinations of the transcript levels revealed that all three genes (AlinCSP1-3) are mainly expressed in the antennae. Interestingly, these CSP genes AlinCSP1-3 are also highly expressed in the 5th instar nymphs, suggesting a proposed function of these CSP proteins (AlinCSP1-3) in the olfactory reception and in maintaining particular life activities into the adult stage. Using bacterial expression system, the three CSP proteins were expressed and purified. For the first time we characterized the types of sensilla in the antennae of the plant bug using scanning electron microscopy (SEM). Immunocytochemistry analysis indicated that the CSP proteins were expressed in the pheromone-sensitive sensilla trichodea and general odorant-sensitive sensilla basiconica, providing further evidence of their involvement in chemoreception. The antennal activity of 55 host-related semiochemicals and sex pheromone compounds in the host location and mate selection behavior of A. lineolatus was investigated using electroantennogram (EAG), and the binding affinities of these chemicals to the three CSPs (AlinCSP1-3) were measured using fluorescent binding assays. The results showed several host-related semiochemicals, (Z)-3-hexen-1-ol, (E)-2-hexen-1-al and valeraldehyde, have a high binding affinity with AlinCSP1-3 and can elicit significant high EAG responses of A. lineolatus antennae. Our studies indicate the three antennae-biased CSPs may

  12. Functional characterizations of chemosensory proteins of the alfalfa plant bug Adelphocoris lineolatus indicate their involvement in host recognition.

    PubMed

    Gu, Shao-Hua; Wang, Song-Ying; Zhang, Xue-Ying; Ji, Ping; Liu, Jing-Tao; Wang, Gui-Rong; Wu, Kong-Ming; Guo, Yu-Yuan; Zhou, Jing-Jiang; Zhang, Yong-Jun

    2012-01-01

    Insect chemosensory proteins (CSPs) have been proposed to capture and transport hydrophobic chemicals from air to olfactory receptors in the lymph of antennal chemosensilla. They may represent a new class of soluble carrier protein involved in insect chemoreception. However, their specific functional roles in insect chemoreception have not been fully elucidated. In this study, we report for the first time three novel CSP genes (AlinCSP1-3) of the alfalfa plant bug Adelphocoris lineolatus (Goeze) by screening the antennal cDNA library. The qRT-PCR examinations of the transcript levels revealed that all three genes (AlinCSP1-3) are mainly expressed in the antennae. Interestingly, these CSP genes AlinCSP1-3 are also highly expressed in the 5(th) instar nymphs, suggesting a proposed function of these CSP proteins (AlinCSP1-3) in the olfactory reception and in maintaining particular life activities into the adult stage. Using bacterial expression system, the three CSP proteins were expressed and purified. For the first time we characterized the types of sensilla in the antennae of the plant bug using scanning electron microscopy (SEM). Immunocytochemistry analysis indicated that the CSP proteins were expressed in the pheromone-sensitive sensilla trichodea and general odorant-sensitive sensilla basiconica, providing further evidence of their involvement in chemoreception. The antennal activity of 55 host-related semiochemicals and sex pheromone compounds in the host location and mate selection behavior of A. lineolatus was investigated using electroantennogram (EAG), and the binding affinities of these chemicals to the three CSPs (AlinCSP1-3) were measured using fluorescent binding assays. The results showed several host-related semiochemicals, (Z)-3-hexen-1-ol, (E)-2-hexen-1-al and valeraldehyde, have a high binding affinity with AlinCSP1-3 and can elicit significant high EAG responses of A. lineolatus antennae. Our studies indicate the three antennae-biased CSPs may

  13. Variation in Fitness of the Longhorned Beetle, Dectes texanus, as a Function of Host Plant

    PubMed Central

    Michaud, J.P.; Grant, Angela K.

    2010-01-01

    Dectes texanus LeConte (Coleoptera: Cerambycidae) has become a serious pest of two different crops in the American Midwest, sunflower, Helianthus annuus L. and soybean, Glycines max (L.). Laboratory and field studies were used to compare the effects of these two host plants on D. texanus life history and behavior. Insects from soybean were 40–60% smaller than those from sunflower and larval weight at collection was strongly correlated with survival to adulthood, whereas it was not in sunflower, suggesting that body size was more limiting to immature survival in soybean. Pupal weights increased more rapidly with increasing stem diameter in soybean than in sunflower and the correlation was stronger, indicating that body size was more limited by plant size in soybean. Adults collected as larvae from soybean had shorter longevities when starved, fed soybean, or fed an alternating diet of soybean and cultivated sunflower, than did those collected from sunflower, suggesting a negative larval legacy of soybean on adult fitness. Adult beetles that developed in soybean lived longer when fed soybean than when starved, but an adult diet of sunflower doubled longevity compared to soybean for beetles that developed in sunflower, and tripled it for those that developed in soybean. An adult diet of wild H. annuus yielded survivorship equivalent to cultivated H. annuus in one trial, and slightly lower in another. Larval host plant did not influence the numbers of ovipunctures or eggs laid by females in field trials, but adult diet did. Sunflower-fed females punctured more, and laid more eggs, on sunflowers than on soybeans in field cages and the reverse trend was evident, but not significant, in soybean-fed females. It can be concluded that H. annuus is a superior food source to G. max for both larval and adult D. texanus, and that wild sunflowers may represent a valuable food for adults during the pre-reproductive period, prior to invasion of soybean fields, even though they

  14. Apparent Acquired Resistance by a Weevil to Its Parasitoid Is Influenced by Host Plant.

    PubMed

    Goldson, Stephen L; Tomasetto, Federico

    2016-01-01

    Field parasitism rates of the Argentine stem weevil Listronotus bonariensis (Kuschel; Coleoptera: Curculionidae) by Microctonus hyperodae Loan (Hymenoptera: Braconidae) are known to vary according to different host Lolium species that also differ in ploidy. To further investigate this, a laboratory study was conducted to examine parasitism rates on tetraploid Italian Lolium multiflorum, diploid Lolium perenne and diploid hybrid L. perenne ×L. multiflorum; none of which were infected by Epichloë endophyte. At the same time, the opportunity was taken to compare the results of this study with observations made during extensive laboratory-based research and parasitoid-rearing in the 1990s using the same host plant species. This made it possible to determine whether there has been any change in weevil susceptibility to the parasitoid over a 20 year period when in the presence of the tetraploid Italian, diploid perennial and hybrid host grasses that were commonly in use in the 1990's. The incidence of parasitism in cages, in the presence of these three grasses mirrored what has recently been observed in the field. When caged, weevil parasitism rates in the presence of a tetraploid Italian ryegrass host were significantly higher (75%) than rates that occurred in the presence of either the diploid perennial (46%) or the diploid hybrid (52%) grass, which were not significantly different from each other. This is very different to laboratory parasitism rates in the 1990s when in the presence of both of the latter grasses high rates of parasitism (c. 75%) were recorded. These high rates are typical of those still found in weevils in the presence of both field and caged tetraploid Italian grasses. In contrast, the abrupt decline in weevil parasitism rates points to the possibility of evolved resistance by the weevil to the parasitoid in the diploid and hybrid grasses, but not so in the tetraploid. The orientation of plants in the laboratory cages had no significant effect on

  15. Apparent Acquired Resistance by a Weevil to Its Parasitoid Is Influenced by Host Plant

    PubMed Central

    Goldson, Stephen L.; Tomasetto, Federico

    2016-01-01

    Field parasitism rates of the Argentine stem weevil Listronotus bonariensis (Kuschel; Coleoptera: Curculionidae) by Microctonus hyperodae Loan (Hymenoptera: Braconidae) are known to vary according to different host Lolium species that also differ in ploidy. To further investigate this, a laboratory study was conducted to examine parasitism rates on tetraploid Italian Lolium multiflorum, diploid Lolium perenne and diploid hybrid L. perenne ×L. multiflorum; none of which were infected by Epichloë endophyte. At the same time, the opportunity was taken to compare the results of this study with observations made during extensive laboratory-based research and parasitoid-rearing in the 1990s using the same host plant species. This made it possible to determine whether there has been any change in weevil susceptibility to the parasitoid over a 20 year period when in the presence of the tetraploid Italian, diploid perennial and hybrid host grasses that were commonly in use in the 1990’s. The incidence of parasitism in cages, in the presence of these three grasses mirrored what has recently been observed in the field. When caged, weevil parasitism rates in the presence of a tetraploid Italian ryegrass host were significantly higher (75%) than rates that occurred in the presence of either the diploid perennial (46%) or the diploid hybrid (52%) grass, which were not significantly different from each other. This is very different to laboratory parasitism rates in the 1990s when in the presence of both of the latter grasses high rates of parasitism (c. 75%) were recorded. These high rates are typical of those still found in weevils in the presence of both field and caged tetraploid Italian grasses. In contrast, the abrupt decline in weevil parasitism rates points to the possibility of evolved resistance by the weevil to the parasitoid in the diploid and hybrid grasses, but not so in the tetraploid. The orientation of