The Experts below are selected from a list of 240 Experts worldwide ranked by ideXlab platform

John W Kress - One of the best experts on this subject based on the ideXlab platform.

  • Tropical Plant–Herbivore Networks: Reconstructing Species Interactions Using DNA Barcodes
    2016
    Co-Authors: David L. Erickson, Charles L. Staines, Terry L. Erwin, John W Kress
    Abstract:

    Plants and their associated insect Herbivores, represent more than 50 % of all known species on earth. The first step in understanding the mechanisms generating and maintaining this important component of biodiversity is to identify Plant-Herbivore associations. In this study we determined insect-host Plant associations for an entire guild of insect Herbivores using Plant DNA extracted from insect gut contents. Over two years, in a tropical rain forest in Costa Rica (La Selva Biological Station), we recorded the full diet breadth of rolled-leaf beetles, a group of Herbivores that feed on Plants in the order Zingiberales. Field observations were used to determine the accuracy of diet identifications using a three-locus DNA barcode (rbcL, trnH-psbA and ITS2). Using extraction techniques for ancient DNA, we obtained high-quality sequences for two of these loci from gut contents (rbcL and ITS2). Sequences were then compared to a comprehensive DNA barcode library of the Zingiberales. The rbcL locus identified host Plants to family (success/sequence = 58.8%) and genus (success/ sequence = 47%). For all Zingiberales except Heliconiaceae, ITS2 successfully identified host Plants to genus (success/ sequence = 67.1%) and species (success/sequence = 61.6%). Kindt’s sampling estimates suggest that by collecting ca. four individuals representing each Plant-Herbivore Interaction, 99 % of all host associations included in this study can be identified to genus. For Plants that amplified ITS2, 99 % of the hosts can be identified to species after collecting at least four individuals representing each Interaction. Our study demonstrates that host Plant identifications at the species-level usin

  • tropical Plant Herbivore networks reconstructing species Interactions using dna barcodes
    PLOS ONE, 2013
    Co-Authors: Carlos Garciarobledo, Charles L. Staines, Terry L. Erwin, David L. Erickson, John W Kress
    Abstract:

    Plants and their associated insect Herbivores, represent more than 50% of all known species on earth. The first step in understanding the mechanisms generating and maintaining this important component of biodiversity is to identify Plant-Herbivore associations. In this study we determined insect-host Plant associations for an entire guild of insect Herbivores using Plant DNA extracted from insect gut contents. Over two years, in a tropical rain forest in Costa Rica (La Selva Biological Station), we recorded the full diet breadth of rolled-leaf beetles, a group of Herbivores that feed on Plants in the order Zingiberales. Field observations were used to determine the accuracy of diet identifications using a three-locus DNA barcode (rbcL, trnH-psbA and ITS2). Using extraction techniques for ancient DNA, we obtained high-quality sequences for two of these loci from gut contents (rbcL and ITS2). Sequences were then compared to a comprehensive DNA barcode library of the Zingiberales. The rbcL locus identified host Plants to family (success/sequence = 58.8%) and genus (success/sequence = 47%). For all Zingiberales except Heliconiaceae, ITS2 successfully identified host Plants to genus (success/sequence = 67.1%) and species (success/sequence = 61.6%). Kindt's sampling estimates suggest that by collecting ca. four individuals representing each Plant-Herbivore Interaction, 99% of all host associations included in this study can be identified to genus. For Plants that amplified ITS2, 99% of the hosts can be identified to species after collecting at least four individuals representing each Interaction. Our study demonstrates that host Plant identifications at the species-level using DNA barcodes are feasible, cost-effective, and reliable, and that reconstructing Plant-Herbivore networks with these methods will become the standard for a detailed understanding of these Interactions.

Ian T Baldwin - One of the best experts on this subject based on the ideXlab platform.

  • real time genetic manipulation a new tool for ecological field studies
    Plant Journal, 2013
    Co-Authors: Martin Schafer, Ian T Baldwin, Christoph Brutting, Klaus Gase, Michael Reichelt, Stefan Meldau
    Abstract:

    Field experiments with transgenic Plants often reveal the functional significance of genetic traits that are important for the performance of the Plants in their natural environments. Until now, only constitutive overexpression, ectopic expression and gene silencing methods have been used to analyze gene-related phenotypes in natural habitats. These methods do not allow sufficient control over gene expression for the study of ecological Interactions in real time, of genetic traits that play essential roles in development, or of dose-dependent effects. We applied the sensitive dexamethasone (DEX)-inducible pOp6/LhGR expression system to the ecological model Plant Nicotiana attenuata and established a lanolin-based DEX application method to facilitate ectopic gene expression and RNA interference-mediated gene silencing in the field and under challenging conditions (e.g. high temperature, wind and UV radiation). Fully established field-grown Plants were used to silence phytoene desaturase and thereby cause photobleaching only in specific Plant sectors, and to activate expression of the cytokinin (CK) biosynthesis gene isopentenyl transferase (ipt). We used ipt expression to analyze the role of CKs in both the glasshouse and the field to understand resistance to the native Herbivore Tupiocoris notatus, which attacks Plants at small spatial scales. By spatially restricting ipt expression and elevating CK levels in single leaves, damage by T. notatus increased, demonstrating the role of CKs in this Plant-Herbivore Interaction at a small scale. As the arena of most ecological Interactions is highly constrained in time and space, these tools will advance the genetic analysis of dynamic traits that matter for Plant performance in nature.

  • pithy protection nicotiana attenuata s jasmonic acid mediated defenses are required to resist stem boring weevil larvae
    Plant Physiology, 2011
    Co-Authors: Celia Diezel, Danny Kessler, Ian T Baldwin
    Abstract:

    Folivory is the best studied Plant-Herbivore Interaction, but it is unclear whether the signaling and resistance traits important for the defense of leaves are also important for other Plant parts. Larvae of the tobacco stem weevil, Trichobaris mucorea, burrow into stems of Nicotiana attenuata and feed on the pith. Transgenic N. attenuata lines silenced in signaling and foliar defense traits were evaluated in a 2-year field study for resistance against attack by naturally occurring T. mucorea larva. Plants silenced in early jasmonic acid (JA) biosynthesis (antisense [as]-lipoxygenase3 [lox3]; inverted repeat [ir]-allene oxide cyclase), JA perception (as-coronatine insensitive1), proteinase inhibitors (ir-pi), and nicotine (ir-putrescine methyl-transferase) direct defenses and lignin (ir-cad) biosynthesis were infested more frequently than wild-type Plants. Plants unable to emit C 6 aldehydes (as-hpl) had lower infestation rates, while Plants silenced in late steps in JA biosynthesis (ir-acyl-coenzyme A oxidase, ir-opr) and silenced in diterpene glycoside production (ir-geranylgeranyl pyrophosphate synthase) did not differ from wild type. Pith choice assays revealed that ir-putrescine methyl-transferase, ir-coronatine insensitive1, and ir-lox3 pith, which all had diminished nicotine levels, were preferred by larvae compared to wild-type pith. The lack of preference for ir-lox2 and ir-cad piths, suggest that oviposition attraction and vascular defense, rather than pith palatability accounts for the higher attack rates observed for these Plants. We conclude that traits that influence a Plant’s apparency, stem hardness, and pith direct defenses all contribute to resistance against this Herbivore whose attack can be devastating to N. attenuata’s fitness.

  • independently silencing two photosynthetic proteins in nicotiana attenuata has different effects on Herbivore resistance
    Plant Physiology, 2008
    Co-Authors: Sirsha Mitra, Ian T Baldwin
    Abstract:

    Insect attack frequently down-regulates photosynthetic proteins. To understand how this influences the Plant-insect Interaction, we transformed Nicotiana attenuata to independently silence ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBPCase) activase (RCA) and RuBPCase and selected lines whose photosynthetic capacity was similarly reduced. Decreases in Plant growth mirrored the decreases in photosynthesis, but the effects on Herbivore performance differed. Both generalist (Spodoptera littoralis) and specialist (Manduca sexta) larvae grew larger on RCA-silenced Plants, which was consistent with decreased levels of trypsin protease inhibitors and diterpene glycosides and increased levels of RuBPCase, the larvae's main dietary protein. RCA-silenced Plants were impaired in their attack-elicited jasmonate (JA)-isoleucine (Ile)/leucine levels, but RuBPCase-silenced Plants were not, a deficiency that could not be restored by supplementation with Ile or attributed to lower transcript levels of JAR4/6, the key enzyme for JA-Ile conjugation. From these results, we infer that JA-Ile/leucine signaling and the Herbivore resistance traits elicited by JA-Ile are influenced by adenylate charge, or more generally, carbon availability in RCA- but not RuBPCase-silenced Plants. Growth of generalist larvae on RuBPCase-silenced Plants did not differ from growth on empty vector controls, but the specialist larvae grew faster on RuBPCase-silenced Plants, which suggests that the specialist can better tolerate the protein deficiency resulting from RuBPCase silencing than the generalist can. We conclude that the Plant-Herbivore Interaction is more influenced by the particular mechanisms that reduce photosynthetic capacity after Herbivore attack than by the magnitude of the decrease, which highlights the value of understanding defense mechanisms in evaluating growth-defense tradeoffs.

Carlos Garciarobledo - One of the best experts on this subject based on the ideXlab platform.

  • tropical Plant Herbivore networks reconstructing species Interactions using dna barcodes
    PLOS ONE, 2013
    Co-Authors: Carlos Garciarobledo, Charles L. Staines, Terry L. Erwin, David L. Erickson, John W Kress
    Abstract:

    Plants and their associated insect Herbivores, represent more than 50% of all known species on earth. The first step in understanding the mechanisms generating and maintaining this important component of biodiversity is to identify Plant-Herbivore associations. In this study we determined insect-host Plant associations for an entire guild of insect Herbivores using Plant DNA extracted from insect gut contents. Over two years, in a tropical rain forest in Costa Rica (La Selva Biological Station), we recorded the full diet breadth of rolled-leaf beetles, a group of Herbivores that feed on Plants in the order Zingiberales. Field observations were used to determine the accuracy of diet identifications using a three-locus DNA barcode (rbcL, trnH-psbA and ITS2). Using extraction techniques for ancient DNA, we obtained high-quality sequences for two of these loci from gut contents (rbcL and ITS2). Sequences were then compared to a comprehensive DNA barcode library of the Zingiberales. The rbcL locus identified host Plants to family (success/sequence = 58.8%) and genus (success/sequence = 47%). For all Zingiberales except Heliconiaceae, ITS2 successfully identified host Plants to genus (success/sequence = 67.1%) and species (success/sequence = 61.6%). Kindt's sampling estimates suggest that by collecting ca. four individuals representing each Plant-Herbivore Interaction, 99% of all host associations included in this study can be identified to genus. For Plants that amplified ITS2, 99% of the hosts can be identified to species after collecting at least four individuals representing each Interaction. Our study demonstrates that host Plant identifications at the species-level using DNA barcodes are feasible, cost-effective, and reliable, and that reconstructing Plant-Herbivore networks with these methods will become the standard for a detailed understanding of these Interactions.

Ek Delval - One of the best experts on this subject based on the ideXlab platform.

  • resilience in Plant Herbivore networks during secondary succession
    PLOS ONE, 2012
    Co-Authors: Edith Villagalaviz, Karina Boege, Ek Delval
    Abstract:

    Extensive land-use change in the tropics has produced a mosaic of successional forests within an agricultural and cattle-pasture matrix. Post-disturbance biodiversity assessments have found that regeneration speed depends upon propagule availability and the intensity and duration of disturbance. However, reestablishment of species Interactions is still poorly understood and this limits our understanding of the anthropogenic impacts upon ecosystem resilience. This is the first investigation that evaluates Plant-Herbivore Interaction networks during secondary succession. In particular we investigated succession in a Mexican tropical dry forest using data of caterpillar associations with Plants during 2007–2010. Plant-Herbivore networks showed high resilience. We found no differences in most network descriptors between secondary and mature forest and only recently abandoned fields were found to be different. No significant nestedness or modularity network structure was found. Plant-Herbivore network properties appear to quickly reestablish after perturbation, despite differences in species richness and composition. This study provides some valuable guidelines for the implement of restoration efforts that can enhance ecological processes such as the Interaction between Plants and their Herbivores.

Jose Roberto Trigo - One of the best experts on this subject based on the ideXlab platform.

  • the geographical and seasonal mosaic in a Plant Herbivore Interaction patterns of defences and herbivory by a specialist and a non specialist
    Scientific Reports, 2019
    Co-Authors: Diomar Vercosa, Rodrigo Cogni, Marcos Nopper Alves, Jose Roberto Trigo
    Abstract:

    In order to evaluate the geographic mosaic theory of coevolution, it is crucial to investigate geographical variation on the outcome of ecological Interactions and the functional traits which dictate these outcomes. Plant populations are attacked by specialist and non-specialist Herbivores and may have different types of chemical and biotic defences. We investigated geographical and seasonal variation in the Interaction between the Plant Crotalaria pallida and its two major Herbivores (the specialist Utetheisa ornatrix and the non-specialist Etiella zinckenella). We first showed that attack by the two Herbivores and a chemical and a biotic defence vary greatly in time and space. Second, we performed a common garden experiment that revealed genetic variation among populations in Herbivore resistance and a chemical defence, but no genetic variation in a biotic defence. Third, we sampled 20 populations on a much larger geographical scale and showed great variation in attack rates by the two Herbivores and a chemical defence. Finally, we showed that herbivory is not correlated with a chemical defence in the 20 field populations. Our study shows that to understand the evolution of ecological Interactions it is crucial to investigate how the outcome of the Interaction and the important species traits vary geographically and seasonally.

  • varying Herbivore population structure correlates with lack of local adaptation in a geographic variable Plant Herbivore Interaction
    PLOS ONE, 2011
    Co-Authors: Rodrigo Cogni, Jose Roberto Trigo, Douglas J Futuyma
    Abstract:

    Local adaptation of parasites to their hosts due to coevolution is a central prediction of many theories in evolutionary biology. However, empirical studies looking for parasite local adaptation show great variation in outcomes, and the reasons for such variation are largely unknown. In a previous study, we showed adaptive differentiation in the arctiid moth Utetheisa ornatrix to its host Plant, the pyrrolizidine alkaloid-bearing legume Crotalaria pallida, at the continental scale, but found no differentiation at the regional scale. In the present study, we sampled the same sites to investigate factors that may contribute to the lack of differentiation at the regional scale. We performed field observations that show that specialist and non-specialist polyphagous Herbivore incidence varies among populations at both scales. With a series of common-garden experiments we show that some Plant traits that may affect herbivory (pyrrolizidine alkaloids and extrafloral nectaries) vary at the regional scale, while other traits (trichomes and nitrogen content) just vary at the continental scale. These results, combined with our previous evidence for Plant population differentiation based on larval performance on fresh fruits, suggest that U. ornatrix is subjected to divergent selection even at the regional scale. Finally, with a microsatellite study we investigated population structure of U. ornatrix. We found that population structure is not stable over time: we found population differentiation at the regional scale in the first year of sampling, but not in the second year. Unstable population structure of the Herbivore is the most likely cause of the lack of regional adaptation.