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Howe M, Mason CJ, Gratton C, Keefover‐Ring K, Wallin K, Yanchuk A, Zhu J, Raffa KF. Relationships between conifer constitutive and inducible defenses against bark beetles change across levels of biological and ecological scale. OIKOS 2020. [DOI: 10.1111/oik.07242] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Affiliation(s)
- Michael Howe
- Dept of Entomology, Univ. of Wisconsin‐Madison Madison WI 53706 USA
| | - Charles J. Mason
- Dept of Entomology, Pennsylvania State Univ., University Park PA USA
| | - Claudio Gratton
- Dept of Entomology, Univ. of Wisconsin‐Madison Madison WI 53706 USA
| | - Ken Keefover‐Ring
- Depts of Botany and Geography, Univ. of Wisconsin‐Madison Madison WI USA
| | - Kimberly Wallin
- College of Science and Mathematics, North Dakota State Univ. Fargo ND USA
| | - Alvin Yanchuk
- Ministry of Forests, Lands, Natural Resource Operations & Rural Development, Government of British Columbia Victoria BC Canada
| | - Jun Zhu
- Dept of Statistics, Univ. of Wisconsin‐Madison Madison WI USA
| | - Kenneth F. Raffa
- Dept of Entomology, Univ. of Wisconsin‐Madison Madison WI 53706 USA
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Moreira X, Abdala-Roberts L, Bruun HH, Covelo F, De Frenne P, Galmán A, Gaytán Á, Jaatinen R, Pulkkinen P, Ten Hoopen JPJG, Timmermans BGH, Tack AJM, Castagneyrol B. Latitudinal variation in seed predation correlates with latitudinal variation in seed defensive and nutritional traits in a widespread oak species. ANNALS OF BOTANY 2020; 125:881-890. [PMID: 31858135 PMCID: PMC7218813 DOI: 10.1093/aob/mcz207] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 12/17/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND AIMS Classic theory on geographical gradients in plant-herbivore interactions assumes that herbivore pressure and plant defences increase towards warmer and more stable climates found at lower latitudes. However, the generality of these expectations has been recently called into question by conflicting empirical evidence. One possible explanation for this ambiguity is that most studies have reported on patterns of either herbivory or plant defences whereas few have measured both, thus preventing a full understanding of the implications of observed patterns for plant-herbivore interactions. In addition, studies have typically not measured climatic factors affecting plant-herbivore interactions, despite their expected influence on plant and herbivore traits. METHODS Here we tested for latitudinal variation in insect seed predation and seed traits putatively associated with insect attack across 36 Quercus robur populations distributed along a 20° latitudinal gradient. We then further investigated the associations between climatic factors, seed traits and seed predation to test for climate-based mechanisms of latitudinal variation in seed predation. KEY RESULTS We found strong but contrasting latitudinal clines in seed predation and seed traits, whereby seed predation increased whereas seed phenolics and phosphorus decreased towards lower latitudes. We also found a strong direct association between temperature and seed predation, with the latter increasing towards warmer climates. In addition, temperature was negatively associated with seed traits, with populations at warmer sites having lower levels of total phenolics and phosphorus. In turn, these negative associations between temperature and seed traits led to a positive indirect association between temperature and seed predation. CONCLUSIONS These results help unravel how plant-herbivore interactions play out along latitudinal gradients and expose the role of climate in driving these outcomes through its dual effects on plant defences and herbivores. Accordingly, this emphasizes the need to account for abiotic variation while testing concurrently for latitudinal variation in plant traits and herbivore pressure.
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Affiliation(s)
- Xoaquín Moreira
- Misión Biológica de Galicia (MBG-CSIC), Pontevedra, Galicia, Spain
| | - Luis Abdala-Roberts
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Itzimná, Mérida, Yucatán, Mexico
| | - Hans Henrik Bruun
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Felisa Covelo
- Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Sevilla, Spain
| | | | - Andrea Galmán
- Misión Biológica de Galicia (MBG-CSIC), Pontevedra, Galicia, Spain
| | - Álvaro Gaytán
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
| | - Raimo Jaatinen
- Natural Resources Institute Finland, Haapastensyrjä Breeding Station, Läyliäinen, Finland
| | - Pertti Pulkkinen
- Natural Resources Institute Finland, Haapastensyrjä Breeding Station, Läyliäinen, Finland
| | | | - Bart G H Timmermans
- Department of Agriculture, Louis Bolk Institute, LA Driebergen, the Netherlands
| | - Ayco J M Tack
- Department of Ecology, Environment and Plant Sciences, Stockholm University, Stockholm, Sweden
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Martinez-Swatson K, Kjøller R, Cozzi F, Simonsen HT, Rønsted N, Barnes C. Exploring evolutionary theories of plant defence investment using field populations of the deadly carrot. ANNALS OF BOTANY 2020; 125:737-750. [PMID: 31563960 PMCID: PMC7182587 DOI: 10.1093/aob/mcz151] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Accepted: 09/25/2019] [Indexed: 06/10/2023]
Abstract
BACKGROUND AND AIMS There are a number of disparate models predicting variation in plant chemical defences between species, and within a single species over space and time. These can give conflicting predictions. Here we review a number of these theories, before assessing their power to predict the spatial-temporal variation of thapsigargins between and within populations of the deadly carrot (Thapsia garganica). By utilizing multiple models simultaneously (optimum defence theory, growth rate hypothesis, growth-differentiation balance hypothesis, intra-specific framework and resource exchange model of plant defence), we will highlight gaps in their predictions and evaluate the performance of each. METHODS Thapsigargins are potent anti-herbivore compounds that occur in limited richness across the different plant tissues of T. garganica, and therefore represent an ideal system for exploring these models. Thapsia garganica plants were collected from six locations on the island of Ibiza, Spain, and the thapsigargins quantified within reproductive, vegetative and below-ground tissues. The effects of sampling time, location, mammalian herbivory, soil nutrition and changing root-associated fungal communities on the concentrations of thapsigargins within these in situ observations were analysed, and the results were compared with our model predictions. KEY RESULTS The models performed well in predicting the general defence strategy of T. garganica and the above-ground distribution of thapsigargins, but failed to predict the considerable proportion of defences found below ground. Models predicting variation over environmental gradients gave conflicting and less specific predictions, with intraspecific variation remaining less understood. CONCLUSION Here we found that multiple models predicting the general defence strategy of plant species could likely be integrated into a single model, while also finding a clear need to better incorporate below-ground defences into models of plant chemical defences. We found that constitutive and induced thapsigargins differed in their regulation, and suggest that models predicting intraspecific defences should consider them separately. Finally, we suggest that in situ studies be supplemented with experiments in controlled environments to identify specific environmental parameters that regulate variation in defences within species.
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Affiliation(s)
| | - Rasmus Kjøller
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | | | - Henrik Toft Simonsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Nina Rønsted
- Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
- National Tropical Botanical Garden, Kalaheo, Hawaii, USA
| | - Christopher Barnes
- Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark
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Benevenuto RF, Seldal T, Polashock J, Moe SR, Rodriguez‐Saona C, Gillespie MAK, Hegland SJ. Molecular and ecological plant defense responses along an elevational gradient in a boreal ecosystem. Ecol Evol 2020; 10:2478-2491. [PMID: 32184995 PMCID: PMC7069305 DOI: 10.1002/ece3.6074] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 11/28/2019] [Accepted: 01/15/2020] [Indexed: 11/06/2022] Open
Abstract
Plants have the capacity to alter their phenotype in response to environmental factors, such as herbivory, a phenomenon called phenotypic plasticity. However, little is known on how plant responses to herbivory are modulated by environmental variation along ecological gradients. To investigate this question, we used bilberry (Vaccinium myrtillus L.) plants and an experimental treatment to induce plant defenses (i.e., application of methyl jasmonate; MeJA), to observe ecological responses and gene expression changes along an elevational gradient in a boreal system in western Norway. The gradient included optimal growing conditions for bilberry in this region (ca. 500 m a.s.l.), and the plant's range limits at high (ca. 900 m a.s.l.) and low (100 m a.s.l.) elevations. Across all altitudinal sites, MeJA-treated plants allocated more resources to herbivory resistance while reducing growth and reproduction than control plants, but this response was more pronounced at the lowest elevation. High-elevation plants growing under less herbivory pressure but more resource-limiting conditions exhibited consistently high expression levels of defense genes in both MeJA-treated and untreated plants at all times, suggesting a constant state of "alert." These results suggest that plant defense responses at both the molecular and ecological levels are modulated by the combination of climate and herbivory pressure, such that plants under different environmental conditions differentially direct the resources available to specific antiherbivore strategies. Our findings are important for understanding the complex impact of future climate changes on plant-herbivore interactions, as this is a major driver of ecosystem functioning and biodiversity.
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Affiliation(s)
- Rafael Fonseca Benevenuto
- Faculty of Engineering and ScienceWestern Norway University of Applied SciencesSogndalNorway
- Faculty of Environmental Sciences and Natural Resource ManagementNorwegian University of Life SciencesÅsNorway
| | - Tarald Seldal
- Faculty of Engineering and ScienceWestern Norway University of Applied SciencesSogndalNorway
| | - James Polashock
- Genetic Improvement of Fruits and Vegetables LabPhilip E. Marucci Center for Blueberry and Cranberry ResearchUnited States Department of Agriculture‐Agricultural Research ServiceChatsworthNJUSA
| | - Stein R. Moe
- Faculty of Environmental Sciences and Natural Resource ManagementNorwegian University of Life SciencesÅsNorway
| | - Cesar Rodriguez‐Saona
- Department of EntomologyPhilip E. Marucci Center for Blueberry and Cranberry ResearchRutgersThe State University of New JerseyChatsworthNJUSA
| | - Mark A. K. Gillespie
- Faculty of Engineering and ScienceWestern Norway University of Applied SciencesSogndalNorway
| | - Stein Joar Hegland
- Faculty of Engineering and ScienceWestern Norway University of Applied SciencesSogndalNorway
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Kergunteuil A, Humair L, Maire AL, Moreno-Aguilar MF, Godschalx A, Catalán P, Rasmann S. Tritrophic interactions follow phylogenetic escalation and climatic adaptation. Sci Rep 2020; 10:2074. [PMID: 32034273 PMCID: PMC7005781 DOI: 10.1038/s41598-020-59068-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 01/24/2020] [Indexed: 11/29/2022] Open
Abstract
One major goal in plant evolutionary ecology is to address how and why tritrophic interactions mediated by phytochemical plant defences vary across species, space, and time. In this study, we tested three classical hypotheses about plant defences: (i) the resource-availability hypothesis, (ii) the altitudinal/elevational gradient hypothesis and (iii) the defence escalation hypothesis. For this purpose, predatory soil nematodes were challenged to hunt for root herbivores based on volatile cues from damaged or intact roots of 18 Alpine Festuca grass species adapted to distinct climatic niches spanning 2000 meters of elevation. We found that adaptation into harsh, nutrient-limited alpine environments coincided with the production of specific blends of volatiles, highly attractive for nematodes. We also found that recently-diverged taxa exposed to herbivores released higher amounts of volatiles than ancestrally-diverged species. Therefore, our model provides evidence that belowground indirect plant defences associated with tritrophic interactions have evolved under two classical hypotheses in plant ecology. While phylogenetic drivers of volatile emissions point to the defence-escalation hypothesis, plant local adaptation of indirect defences is in line with the resource availability hypothesis.
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Affiliation(s)
- Alan Kergunteuil
- Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland
- INRAE, UMR Laboratoire d'Agronomie et Environnement, Vandoeuvre-lès, 54518, Nancy, France
| | - Laureline Humair
- Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland
| | - Anne-Laure Maire
- Botanical Garden Neuchâtel, Chemin du Pertuis-du-Sault 58, 2000, Neuchâtel, Switzerland
| | - María Fernanda Moreno-Aguilar
- Departamento de Ciencias Agrarias y del Medio Natural, Escuela Politécnica Superior de Huesca, Universidad de Zaragoza, Ctra. Cuarte km 1, 22071, Huesca, Spain
| | - Adrienne Godschalx
- INRAE, UMR Laboratoire d'Agronomie et Environnement, Vandoeuvre-lès, 54518, Nancy, France
| | - Pilar Catalán
- Departamento de Ciencias Agrarias y del Medio Natural, Escuela Politécnica Superior de Huesca, Universidad de Zaragoza, Ctra. Cuarte km 1, 22071, Huesca, Spain
- Grupo de Bioquímica, Biofísica y Biología Computacional (BIFI, UNIZAR), Unidad Asociada al CSIC, Zaragoza, Spain
- Department of Botany, Institute of Biology, Tomsk State University, Lenin Av. 36, Tomsk, 634050, Russia
| | - Sergio Rasmann
- Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland.
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Bittner N, Hundacker J, Achotegui-Castells A, Anderbrant O, Hilker M. Defense of Scots pine against sawfly eggs ( Diprion pini) is primed by exposure to sawfly sex pheromones. Proc Natl Acad Sci U S A 2019; 116:24668-24675. [PMID: 31748269 PMCID: PMC6900732 DOI: 10.1073/pnas.1910991116] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Plants respond to insect infestation with defenses targeting insect eggs on their leaves and the feeding insects. Upon perceiving cues indicating imminent herbivory, such as damage-induced leaf odors emitted by neighboring plants, they are able to prime their defenses against feeding insects. Yet it remains unknown whether plants can amplify their defenses against insect eggs by responding to cues indicating imminent egg deposition. Here, we tested the hypothesis that a plant strengthens its defenses against insect eggs by responding to insect sex pheromones. Our study shows that preexposure of Pinus sylvestris to pine sawfly sex pheromones reduces the survival rate of subsequently laid sawfly eggs. Exposure to pheromones does not significantly affect the pine needle water content, but results in increased needle hydrogen peroxide concentrations and increased expression of defense-related pine genes such as SOD (superoxide dismutase), LOX (lipoxygenase), PAL (phenylalanine ammonia lyase), and PR-1 (pathogenesis related protein 1) after egg deposition. These results support our hypothesis that plant responses to sex pheromones emitted by an herbivorous insect can boost plant defensive responses to insect egg deposition, thus highlighting the ability of a plant to mobilize its defenses very early against an initial phase of insect attack, the egg deposition.
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Affiliation(s)
- Norbert Bittner
- Dahlem Centre of Plant Sciences, Institute of Biology, Freie Universität Berlin, 12163 Berlin, Germany
| | - Janik Hundacker
- Dahlem Centre of Plant Sciences, Institute of Biology, Freie Universität Berlin, 12163 Berlin, Germany
| | - Ander Achotegui-Castells
- Centre de Recerca Ecològica i Aplicacions Forestals (CREAF), Barcelona, 08193 Catalonia, Spain
- Global Ecology Unit, CREAF-Consejo Superior de Investigaciones Científicas, Universitat Autònoma de Barcelona, Barcelona, 08193 Catalonia, Spain
| | | | - Monika Hilker
- Dahlem Centre of Plant Sciences, Institute of Biology, Freie Universität Berlin, 12163 Berlin, Germany;
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Galmán A, Abdala-Roberts L, Covelo F, Rasmann S, Moreira X. Parallel increases in insect herbivory and defenses with increasing elevation for both saplings and adult trees of oak (Quercus) species. AMERICAN JOURNAL OF BOTANY 2019; 106:1558-1565. [PMID: 31724166 DOI: 10.1002/ajb2.1388] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Accepted: 10/04/2019] [Indexed: 06/10/2023]
Abstract
PREMISE Herbivory is predicted to increase toward warmer and more stable climates found at lower elevations, and this increase should select for higher plant defenses. Still, a number of recent studies have reported either no evidence of such gradients or reverse patterns. One source of inconsistency may be that plant ontogenetic variation is usually not accounted for and may influence levels of plant defenses and herbivory. METHODS We tested for elevational gradients in insect leaf herbivory and leaf traits putatively associated with herbivore resistance across eight oak (Quercus, Fagaceae) species and compared these patterns for saplings and adult trees. To this end, we surveyed insect leaf herbivory and leaf traits (phenolic compounds, toughness and nutrients) in naturally occurring populations of each oak species at low-, mid- or high-elevation sites throughout the Iberian Peninsula. RESULTS Leaf herbivory and chemical defenses (lignins) were unexpectedly higher at mid- and high-elevation sites than at low-elevation sites. In addition, leaf chemical defenses (lignins and condensed tannins) were higher for saplings than adult trees, whereas herbivory did not significantly differ between ontogenetic stages. Overall, elevational variation in herbivory and plant chemical defenses were consistent across ontogenetic stages (i.e., elevational gradients were not contingent upon tree ontogeny), and herbivory and leaf traits were not associated across elevations. CONCLUSIONS These findings suggest disassociated patterns of elevational variation in herbivory and leaf traits, which, in turn, are independent of plant ontogenetic stage.
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Affiliation(s)
- Andrea Galmán
- Misión Biológica de Galicia (MBG-CSIC), Apartado de correos 28, 36080, Pontevedra, Galicia, Spain
| | - Luis Abdala-Roberts
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Apartado Postal 4-116, Itzimná, 97000, Mérida, Yucatán, México
| | - Felisa Covelo
- Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Carretera de Utrera km. 1, 41013, Sevilla, Spain
| | - Sergio Rasmann
- Institute of Biology, Laboratory of Functional Ecology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland
| | - Xoaquín Moreira
- Misión Biológica de Galicia (MBG-CSIC), Apartado de correos 28, 36080, Pontevedra, Galicia, Spain
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Abdala-Roberts L, Reyes-Hernández M, Quijano-Medina T, Moreira X, Francisco M, Angulo DF, Parra-Tabla V, Virgen A, Rojas JC. Effects of amount and recurrence of leaf herbivory on the induction of direct and indirect defences in wild cotton. PLANT BIOLOGY (STUTTGART, GERMANY) 2019; 21:1063-1071. [PMID: 31237391 DOI: 10.1111/plb.13022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 06/19/2019] [Indexed: 06/09/2023]
Abstract
The induction of defences in response to herbivory is a key mechanism of plant resistance. While a number of studies have investigated the time course and magnitude of plant induction in response to a single event of herbivory, few have looked at the effects of recurrent herbivory. Furthermore, studies measuring the effects of the total amount and recurrence of herbivory on both direct and indirect plant defences are lacking. To address this gap, here we asked whether insect leaf herbivory induced changes in the amount and concentration of extrafloral nectar (an indirect defence) and concentration of leaf phenolic compounds (a direct defence) in wild cotton (Gossypium hirsutum). We conducted a greenhouse experiment where we tested single event or recurrent herbivory effects on defence induction by applying mechanical leaf damage and caterpillar (Spodoptera frugiperda) regurgitant. Single events of 25% and 50% leaf damage did not significantly influence extrafloral nectar production or concentration. Extrafloral nectar traits did, however, increase significantly relative to controls when plants were exposed to recurrent herbivory (two episodes of 25% damage). In contrast, phenolic compounds increased significantly in response to single events of leaf damage but not to recurrent damage. In addition, we found. that local induction of extrafloral nectar production was stronger than systemic induction, whereas the reverse pattern was observed for phenolics. Together, these results reveal seemingly inverse patterns of induction of direct and indirect defences in response to herbivory in wild cotton.
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Affiliation(s)
- L Abdala-Roberts
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
| | - M Reyes-Hernández
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
| | - T Quijano-Medina
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
| | - X Moreira
- Misión Biológica de Galicia (MBG-CSIC), Pontevedra, Spain
| | - M Francisco
- Misión Biológica de Galicia (MBG-CSIC), Pontevedra, Spain
| | - D F Angulo
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
| | - V Parra-Tabla
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Mérida, Yucatán, Mexico
| | - A Virgen
- Departamento de Agricultura, Sociedad y Ambiente, ECOSUR Unidad Tapachula, Tapachula, Chiapas, Mexico
| | - J C Rojas
- Departamento de Agricultura, Sociedad y Ambiente, ECOSUR Unidad Tapachula, Tapachula, Chiapas, Mexico
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McKown AD, Klápště J, Guy RD, Corea ORA, Fritsche S, Ehlting J, El-Kassaby YA, Mansfield SD. A role for SPEECHLESS in the integration of leaf stomatal patterning with the growth vs disease trade-off in poplar. THE NEW PHYTOLOGIST 2019; 223:1888-1903. [PMID: 31081152 DOI: 10.1111/nph.15911] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 04/29/2019] [Indexed: 05/08/2023]
Abstract
Occurrence of stomata on both leaf surfaces (amphistomaty) promotes higher stomatal conductance and photosynthesis while simultaneously increasing exposure to potential disease agents in black cottonwood (Populus trichocarpa). A genome-wide association study (GWAS) with 2.2M single nucleotide polymorphisms generated through whole-genome sequencing found 280 loci associated with variation in adaxial stomatal traits, implicating genes regulating stomatal development and behavior. Strikingly, numerous loci regulating plant growth and response to biotic and abiotic stresses were also identified. The most significant locus was a poplar homologue of SPEECHLESS (PtSPCH1). Individuals possessing PtSPCH1 alleles associated with greater adaxial stomatal density originated primarily from environments with shorter growing seasons (e.g. northern latitudes, high elevations) or with less precipitation. PtSPCH1 was expressed in developing leaves but not developing stem xylem. In developing leaves, RNA sequencing showed patterns of coordinated expression between PtSPCH1 and other GWAS-identified genes. The breadth of our GWAS results suggests that the evolution of amphistomaty is part of a larger, complex response in plants. Suites of genes underpin this response, retrieved through genetic association to adaxial stomata, and show coordinated expression during development. We propose that the occurrence of amphistomaty in P. trichocarpa involves PtSPCH1 and reflects selection for supporting rapid growth over investment in immunity.
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Affiliation(s)
- Athena D McKown
- Department of Forest and Conservation Sciences, Faculty of Forestry, Forest Sciences Centre, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Jaroslav Klápště
- Department of Forest and Conservation Sciences, Faculty of Forestry, Forest Sciences Centre, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
- Department of Genetics and Physiology of Forest Trees, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, Prague, 165 21, Czech Republic
- Scion (New Zealand Forest Research Institute Ltd), Whakarewarewa, Rotorua, 3046, New Zealand
| | - Robert D Guy
- Department of Forest and Conservation Sciences, Faculty of Forestry, Forest Sciences Centre, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Oliver R A Corea
- Department of Biology and Centre for Forest Biology, University of Victoria, Victoria, BC, V8W 3N5, Canada
| | - Steffi Fritsche
- Scion (New Zealand Forest Research Institute Ltd), Whakarewarewa, Rotorua, 3046, New Zealand
- Department of Botany, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Jürgen Ehlting
- Department of Biology and Centre for Forest Biology, University of Victoria, Victoria, BC, V8W 3N5, Canada
| | - Yousry A El-Kassaby
- Department of Forest and Conservation Sciences, Faculty of Forestry, Forest Sciences Centre, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Shawn D Mansfield
- Department of Wood Science, Faculty of Forestry, Forest Sciences Centre, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
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Moreira X, Vázquez-González C, Encinas-Valero M, Covelo F, Castagneyrol B, Abdala-Roberts L. Greater phylogenetic distance from native oaks predicts escape from insect leaf herbivores by non-native oak saplings. AMERICAN JOURNAL OF BOTANY 2019; 106:1202-1209. [PMID: 31449333 DOI: 10.1002/ajb2.1343] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 07/10/2019] [Indexed: 06/10/2023]
Abstract
PREMISE Non-native plant species have been hypothesized to experience lower herbivory in novel environments as a function of their phylogenetic distance from native plant species. Although recent work has found support for this prediction, the plant traits responsible for such patterns have been largely overlooked. METHODS In a common garden experiment in northwestern Spain, we tested whether oak species (Quercus spp.) not native to this region that are phylogenetically more distantly related to native species exhibit less insect leaf herbivory. In addition, we also investigated plant traits potentially correlated with any such effect of phylogenetic distance. RESULTS As expected, phylogenetic distance from native species negatively predicted insect leaf herbivory on non-native oaks. In addition, we found that the leaf traits, namely phosphorus and condensed tannins, were significantly associated with herbivory, suggesting that they are associated with the effect of phylogenetic distance on leaf herbivory on non-native oak species. CONCLUSIONS This study contributes to a better understanding of how evolutionary relationships (relatedness) between native and non-native plant species determine the latter's success in novel environments via locally shared enemies, and encourages more work investigating the plant traits that mediate the effects of phylogenetic distance on enemy escape.
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Affiliation(s)
- Xoaquín Moreira
- Misión Biológica de Galicia (MBG-CSIC), Apdo. 28, 36080, Pontevedra, Galicia, Spain
| | | | | | - Felisa Covelo
- Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Carretera de Utrera km. 1, 41013, Sevilla, Spain
| | | | - Luis Abdala-Roberts
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Apartado Postal 4-116, Itzimná, 97000, Mérida, Yucatán, México
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Abdala-Roberts L, Quijano-Medina T, Moreira X, Vázquez-González C, Parra-Tabla V, Berny Mier Y Terán JC, Grandi L, Glauser G, Turlings TCJ, Benrey B. Bottom-up control of geographic variation in insect herbivory on wild cotton (Gossypium hirsutum) by plant defenses and climate. AMERICAN JOURNAL OF BOTANY 2019; 106:1059-1067. [PMID: 31322738 DOI: 10.1002/ajb2.1330] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Accepted: 05/28/2019] [Indexed: 06/10/2023]
Abstract
PREMISE The occurrence and amount of herbivory are shaped by bottom-up forces, primarily plant traits (e.g., defenses), and by abiotic factors. Addressing these concurrent effects in a spatial context has been useful in efforts to understand the mechanisms governing variation in plant-herbivore interactions. Still, few studies have evaluated the simultaneous influence of multiple sources of bottom-up variation on spatial variation in herbivory. METHODS We tested to what extent chemical (phenolics, production of terpenoid glands) and physical (pubescence) defensive plant traits and climatic factors are associated with variation in herbivory by leaf-chewing insects across populations of wild cotton (Gossypium hirsutum). RESULTS We found substantial population variation in cotton leaf defenses and insect leaf herbivory. Leaf pubescence, but not gossypol gland density or phenolic content, was significantly negatively associated with herbivory by leaf-chewing insects. In addition, there were direct effects of climate on defenses and herbivory, with leaf pubescence increasing toward drier conditions and leaf damage increasing toward wetter and cooler conditions. There was no evidence, however, of indirect effects (via plant defenses) of climate on herbivory. CONCLUSIONS These results suggest that spatial variation in insect herbivory on wild G. hirsutum is predominantly driven by concurrent and independent influences of population variation in leaf pubescence and climatic factors.
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Affiliation(s)
- Luis Abdala-Roberts
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Apartado Postal 4-116, Itzimná, 97000, Mérida, Yucatán, Mexico
| | - Teresa Quijano-Medina
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Apartado Postal 4-116, Itzimná, 97000, Mérida, Yucatán, Mexico
| | - Xoaquín Moreira
- Misión Biológica de Galicia (MBG-CSIC), Apdo. 28, 36080, Pontevedra, Spain
| | | | - Víctor Parra-Tabla
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Apartado Postal 4-116, Itzimná, 97000, Mérida, Yucatán, Mexico
| | | | - Luca Grandi
- Fundamental and Applied Research in Chemical Ecology (FARCE Lab), Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland
| | - Gaétan Glauser
- Neuchâtel Platform of Analytical Chemistry, University of Neuchâtel, Rue Emile Argand 11, 2000, Neuchâtel, Switzerland
| | - Ted C J Turlings
- Fundamental and Applied Research in Chemical Ecology (FARCE Lab), Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland
| | - Betty Benrey
- Laboratory of Evolutionary Entomology, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland
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62
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Agrawal AA, Hastings AP. Trade-offs constrain the evolution of an inducible defense within but not between plant species. Ecology 2019; 100:e02857. [PMID: 31365759 DOI: 10.1002/ecy.2857] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Revised: 07/13/2019] [Accepted: 07/22/2019] [Indexed: 11/05/2022]
Abstract
Inducible defense is a common form of phenotypic plasticity, and inducibility (change in defense after herbivore attack) has long been predicted to trade off with constitutive (or baseline) defense to manage resource allocation. Although such trade-offs likely constrain evolution within species, the extent to which they influence divergence among species is unresolved. We studied cardenolide toxins among genetic families in eight North American Asclepias species, spanning the full range of defense in the genus. Using common environment experiments and chemical assays, we report a consistent trade-off (negative genetic correlation) between concentrations of constitutive cardenolides and their inducibility within each species. However, no trade-off was found in a phylogenetic analysis across species. To investigate factors driving differences in defense allocation among species we used latitude as a proxy for growing season and herbivore pressure and found that divergence into lower latitudes resulted in evolution of higher cardenolides overall. Next we used an enzymatic assay of the cellular target of cardenolides (sodium-potassium ATPase) and confirm that higher cardenolides resulted in stronger toxicity to a sensitive species, but not to specialized monarch butterflies. Thus, plant speciation into biogeographic regions with alternative resources or pest pressure resulted in the macroevolution of cardenolide defense, especially against unspecialized herbivores. Nonetheless, trade-offs persist in the extent to which this defense is allocated constitutively or is inducible among genotypes within each species.
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Affiliation(s)
- Anurag A Agrawal
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, 14853, USA.,Department of Entomology, Cornell University, Ithaca, New York, 14853, USA
| | - Amy P Hastings
- Department of Ecology and Evolutionary Biology, Cornell University, Ithaca, New York, 14853, USA
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63
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van Boheemen LA, Bou‐Assi S, Uesugi A, Hodgins KA. Rapid growth and defence evolution following multiple introductions. Ecol Evol 2019; 9:7942-7956. [PMID: 31380062 PMCID: PMC6662289 DOI: 10.1002/ece3.5275] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2019] [Revised: 04/23/2019] [Accepted: 05/04/2019] [Indexed: 01/02/2023] Open
Abstract
Rapid adaptation can aid invasive populations in their competitive success. Resource allocation trade-off hypotheses predict higher resource availability or the lack of natural enemies in introduced ranges allow for increased growth and reproduction, thus contributing to invasive success. Evidence for such hypotheses is however equivocal and tests among multiple ranges over productivity gradients are required to provide a better understanding of the general applicability of these theories.Using common gardens, we investigated the adaptive divergence of various constitutive and inducible defence-related traits between the native North American and introduced European and Australian ranges, while controlling for divergence due to latitudinal trait clines, individual resource budgets, and population differentiation, using >11,000 SNPs.Rapid, repeated clinal adaptation in defence-related traits was apparent despite distinct demographic histories. We also identified divergence among ranges in some defence-related traits, although differences in energy budgets among ranges may explain some, but not all, defence-related trait divergence. We do not identify a general reduction in defence in concert with an increase in growth among the multiple introduced ranges as predicted trade-off hypotheses. Synthesis: The rapid spread of invasive species is affected by a multitude of factors, likely including adaptation to climate and escape from natural enemies. Unravelling the mechanisms underlying invasives' success enhances understanding of eco-evolutionary theory and is essential to inform management strategies in the face of ongoing climate change. OPEN RESEARCH BADGES This article has been awarded Open Materials, Open Data, Preregistered Research Designs Badges. All materials and data are publicly accessible via the Open Science Framework at https://doi.org/10.6084/m9.figshare.8028875.v1, https://github.com/lotteanna/defence_adaptation,https://doi.org/10.1101/435271.
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Affiliation(s)
| | - Sarah Bou‐Assi
- School of Biological SciencesMonash UniversityClaytonVictoriaAustralia
| | - Akane Uesugi
- School of Biological SciencesMonash UniversityClaytonVictoriaAustralia
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64
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Damestoy T, Brachi B, Moreira X, Jactel H, Plomion C, Castagneyrol B. Oak genotype and phenolic compounds differently affect the performance of two insect herbivores with contrasting diet breadth. TREE PHYSIOLOGY 2019; 39:615-627. [PMID: 30668790 DOI: 10.1093/treephys/tpy149] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 12/13/2018] [Accepted: 12/19/2018] [Indexed: 05/16/2023]
Abstract
Research on plant-herbivore interactions has long recognized that plant genetic variation plays a central role in driving insect abundance and herbivory, as well as in determining plant defense. However, how plant genes influence herbivore feeding performances, and which plant defensive traits mediate these effects, remain poorly understood. Here we investigated the feeding performances of two insect leaf chewers with contrasting diet breadth (the generalist Lymantria dispar L. and the specialist Thaumetopoea processionea L.) on different genotypes of pedunculate oak (Quercus robur L.) and tested the role of leaf phenolics. We used leaves from four clones of 30 Q. robur full-sibs grown in a common garden to estimate the performance of both herbivores in laboratory feeding trials and to quantify the concentration of constitutive chemical defences (phenolic compounds). We found that tree genetics influenced leaf consumption by T. processionea but not by L. dispar. However genetic variation among trees did not explain growth rate variation in either herbivore nor in leaf phenolics. Interestingly, all phenolic compounds displayed a positive relationship with L. dispar growth rate, and leaf consumption by both herbivores displayed a positive relationship with the concentrations of condensed tannins, suggesting that highly defended leaves could induce a compensatory feeding response. While genetic variation in oaks did not explain herbivore growth rate, we found positive genetic correlations between the two herbivores for leaf consumption and digestion. Overall, we found that oak genotype and phenolic compounds partly and independently contribute to variability in herbivore performance. We challenged the current view of plant-insect interaction and provided little support to the idea that the effect of plant genotype on associated organisms is driven by plant defences. Together, our results point to the existence of genetically determined resistance traits in oaks whose effects differ between herbivores and motivate further research on mechanisms governing oak-herbivore interactions.
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Affiliation(s)
- Thomas Damestoy
- BIOGECO, INRA, Univ. Bordeaux, 69 route d'Arcachon, Cestas Cedex, France
| | - Benjamin Brachi
- BIOGECO, INRA, Univ. Bordeaux, 69 route d'Arcachon, Cestas Cedex, France
| | - Xoaquín Moreira
- Misión Biológica de Galicia (MBG-CSIC), Apartado de correos 28, Pontevedra, Galicia, Spain
| | - Hervé Jactel
- BIOGECO, INRA, Univ. Bordeaux, 69 route d'Arcachon, Cestas Cedex, France
| | - Christophe Plomion
- BIOGECO, INRA, Univ. Bordeaux, 69 route d'Arcachon, Cestas Cedex, France
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65
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Galmán A, Petry WK, Abdala-Roberts L, Butrón A, de la Fuente M, Francisco M, Kergunteuil A, Rasmann S, Moreira X. Inducibility of chemical defences in young oak trees is stronger in species with high elevational ranges. TREE PHYSIOLOGY 2019; 39:606-614. [PMID: 30597091 DOI: 10.1093/treephys/tpy139] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 11/20/2018] [Accepted: 12/01/2018] [Indexed: 06/09/2023]
Abstract
Elevational gradients have been highly useful for understanding the underlying forces driving variation in plant traits and plant-insect herbivore interactions. A widely held view from these studies has been that greater herbivory under warmer and less variable climatic conditions found at low elevations has resulted in stronger herbivore selection on plant defences. However, this prediction has been called into question by conflicting empirical evidence, which could be explained by a number of causes such as an incomplete assessment of defensive strategies (ignoring other axes of defence such as defence inducibility) or unaccounted variation in abiotic factors along elevational clines. We conducted a greenhouse experiment testing for inter-specific variation in constitutive leaf chemical defences (phenolic compounds) and their inducibility in response to feeding by gypsy moth larvae (Lymantria dispar L., Lepidoptera) using saplings of 18 oak (Quercus, Fagaceae) species. These species vary in their elevational distribution and together span >2400 m in elevation, therefore allowing us to test for among-species elevational clines in defences based on the elevational range of each species. In addition, we further tested for elevational gradients in the correlated expression of constitutive defences and their inducibility and for associations between defences and climatic factors potentially underlying elevational gradients in defences. Our results showed that oak species with high elevational ranges exhibited a greater inducibility of phenolic compounds (hydrolysable tannins), but this gradient was not accounted for by climatic predictors. In contrast, constitutive defences and the correlated expression of constitutive phenolics and their inducibility did not exhibit elevational clines. Overall, this study builds towards a more robust and integrative understanding of how multivariate plant defensive phenotypes vary along ecological gradients and their underlying abiotic drivers.
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Affiliation(s)
- Andrea Galmán
- Misión Biológica de Galicia (MBG-CSIC), Apartado de correos 28, Pontevedra, Galicia, Spain
| | - William K Petry
- Institute of Integrative Biology, Eidgenössische Technische Hochschule (ETH) Zürich, Universitätstrasse 16, Zurich, Switzerland
| | - Luis Abdala-Roberts
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Apartado Postal 4-116, Itzimná, Mérida, Yucatán, México
| | - Ana Butrón
- Misión Biológica de Galicia (MBG-CSIC), Apartado de correos 28, Pontevedra, Galicia, Spain
| | - María de la Fuente
- Misión Biológica de Galicia (MBG-CSIC), Apartado de correos 28, Pontevedra, Galicia, Spain
| | - Marta Francisco
- Misión Biológica de Galicia (MBG-CSIC), Apartado de correos 28, Pontevedra, Galicia, Spain
| | - Alan Kergunteuil
- Institute of Biology, Laboratory of Functional Ecology, University of Neuchâtel, Rue Emile-Argand 11, Neuchâtel, Switzerland
| | - Sergio Rasmann
- Institute of Biology, Laboratory of Functional Ecology, University of Neuchâtel, Rue Emile-Argand 11, Neuchâtel, Switzerland
| | - Xoaquín Moreira
- Misión Biológica de Galicia (MBG-CSIC), Apartado de correos 28, Pontevedra, Galicia, Spain
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66
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Monroy P, García-Verdugo C. Testing the hypothesis of loss of defenses on islands across a wide latitudinal gradient of Periploca laevigata populations. AMERICAN JOURNAL OF BOTANY 2019; 106:303-312. [PMID: 30742704 DOI: 10.1002/ajb2.1232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Accepted: 11/19/2018] [Indexed: 06/09/2023]
Abstract
PREMISE OF THE STUDY We tested a hypothesis that predicts loss of chemical defenses on island plant populations (LCDIH) as an evolutionary response to limited herbivore pressures. METHODS Using a common garden approach, we grew 16 populations (N = 286 seedlings) of Periploca laevigata, a Mediterranean shrub for which previous studies suggested that animal browsing elicits defensive responses mediated by tannins. Our experimental setting represented a wide latitudinal gradient (37-15°N) encompassing three island systems, virtually free of large herbivores, and three mainland areas. Putative chemical defenses were estimated from tannin-protein precipitation assays, and inducible responses in growth and chemical traits were assessed between seasons and by subjecting plants to a pruning treatment. KEY RESULTS We failed to find support for the LCDIH, since island populations (Canary Islands, Cape Verde) had increasingly higher constitutive levels of tannins at lower latitudes. Seasonality, but not experimental pruning, induced variation in levels of tannins in a consistent pattern across populations. Thus, net differences in leaf tannin concentration remained similar among geographical areas regardless of the factor considered, with latitude being the best explanatory factor for this trait over seasonal growth patterns. CONCLUSIONS Geographical variation in total tannin pools appears to be mediated by factors other than herbivore pressure in P. laevigata. We hypothesize that abiotic correlates of latitude not considered in our study have promoted high constitutive levels of leaf tannins across Macaronesian populations, which ultimately may explain the pattern of seasonal variation and latitudinal increase from Mediterranean to subtropical Cape Verde populations.
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Affiliation(s)
- Pedro Monroy
- Departamento de Biodiversidad Molecular y Banco de ADN, Jardín Botánico Canario 'Viera y Clavijo' - Unidad Asociada CSIC, Cabildo de Gran Canaria, Camino del Palmeral 15 de Tafira Alta, 35017, Las Palmas de Gran Canaria, Spain
| | - Carlos García-Verdugo
- Departamento de Biodiversidad Molecular y Banco de ADN, Jardín Botánico Canario 'Viera y Clavijo' - Unidad Asociada CSIC, Cabildo de Gran Canaria, Camino del Palmeral 15 de Tafira Alta, 35017, Las Palmas de Gran Canaria, Spain
- Institut Mediterrani d'Estudis Avançats (CSIC-UIB), C/Miquel Marqués 21, 07190, Esporles, Balearic Islands, Spain
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67
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Mason CJ, Keefover-Ring K, Villari C, Klutsch JG, Cook S, Bonello P, Erbilgin N, Raffa KF, Townsend PA. Anatomical defences against bark beetles relate to degree of historical exposure between species and are allocated independently of chemical defences within trees. PLANT, CELL & ENVIRONMENT 2019; 42:633-646. [PMID: 30474119 DOI: 10.1111/pce.13449] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 09/18/2018] [Accepted: 09/18/2018] [Indexed: 06/09/2023]
Abstract
Conifers possess chemical and anatomical defences against tree-killing bark beetles that feed in their phloem. Resins accumulating at attack sites can delay and entomb beetles while toxins reach lethal levels. Trees with high concentrations of metabolites active against bark beetle-microbial complexes, and more extensive resin ducts, achieve greater survival. It is unknown if and how conifers integrate chemical and anatomical components of defence or how these capabilities vary with historical exposure. We compared linkages between phloem chemistry and tree ring anatomy of two mountain pine beetle hosts. Lodgepole pine, a mid-elevation species, has had extensive, continual contact with this herbivore, whereas high-elevation whitebark pines have historically had intermittent exposure that is increasing with warming climate. Lodgepole pine had more and larger resin ducts. In both species, anatomical defences were positively related to tree growth and nutrients. Within-tree constitutive and induced concentrations of compounds bioactive against bark beetles and symbionts were largely unrelated to resin duct abundance and size. Fewer anatomical defences in the semi-naïve compared with the continually exposed host concurs with directional differences in chemical defences. Partially uncoupling chemical and morphological antiherbivore traits may enable trees to confront beetles with more diverse defence permutations that interact to resist attack.
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Affiliation(s)
- Charles J Mason
- Department of Entomology, The Pennsylvania State University, University Park, Pennsylvania
| | - Ken Keefover-Ring
- Departments of Botany and Geography, University of Wisconsin-Madison, Madison, Wisconsin
| | - Caterina Villari
- Department of Plant Pathology, The Ohio State University, Columbus, Ohio
| | - Jennifer G Klutsch
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Stephen Cook
- Department of Entomology, Plant Pathology and Nematology, University of Idaho, Moscow, Idaho
| | - Pierluigi Bonello
- Department of Plant Pathology, The Ohio State University, Columbus, Ohio
| | - Nadir Erbilgin
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, Canada
| | - Kenneth F Raffa
- Department of Entomology, University of Wisconsin-Madison, Madison, Wisconsin
| | - Philip A Townsend
- Departments of Forest and Wildlife Ecology, University of Wisconsin-Madison, Madison, Wisconsin
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68
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Erbilgin N. Phytochemicals as mediators for host range expansion of a native invasive forest insect herbivore. THE NEW PHYTOLOGIST 2019; 221:1268-1278. [PMID: 30291808 DOI: 10.1111/nph.15467] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 09/03/2018] [Indexed: 06/08/2023]
Abstract
Mountain pine beetle (MPB) has recently invaded jack pine forests in western Canada. This invasion signifies a climate change-induced range expansion by a native insect. The mechanism underlying this invasion is unknown, but likely involves phytochemicals that play critical roles in MPB biology. Thus far, studies have investigated the compatibility of jack pine chemistry with beetles and their microbial symbionts. I have identified three phytochemical mechanisms that have likely facilitated the host range expansion of MPB. First, jack pine chemistry is overall similar to that of the historical hosts of MPB. In particular, jack pine chemistry is compatible with beetle pheromone production, aggregation on host trees and larval development. Furthermore, the compatibility of jack pine chemistry maintains beneficial interactions between MPB and its microbial symbionts. Second, compared with historical hosts, the novel host not only has lower concentrations of toxic and repellent defense chemicals, but also contains large concentrations of chemicals promoting host colonization by MPB. These patterns are especially pronounced when comparing novel hosts with well-defended historical hosts. Finally, before MPBs arrived in jack pine forests, they invaded a zone of hybrids of novel and historical hosts that likely improved beetle success on jack pine, as hybrids show chemical characteristics of both hosts. In conclusion, the phytochemistry of jack pine has likely facilitated the biological invasion of this novel host by MPB.
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Affiliation(s)
- Nadir Erbilgin
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, Alberta, T6G 2E3, Canada
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69
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Buckley J, Pashalidou FG, Fischer MC, Widmer A, Mescher MC, De Moraes CM. Divergence in Glucosinolate Profiles between High- and Low-Elevation Populations of Arabidopsis halleri Correspond to Variation in Field Herbivory and Herbivore Behavioral Preferences. Int J Mol Sci 2019; 20:ijms20010174. [PMID: 30621284 PMCID: PMC6337533 DOI: 10.3390/ijms20010174] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 12/26/2018] [Accepted: 12/28/2018] [Indexed: 11/16/2022] Open
Abstract
Variation in local herbivore pressure along elevation gradients is predicted to drive variation in plant defense traits. Yet, the extent of intraspecific variation in defense investment along elevation gradients, and its effects on both herbivore preference and performance, remain relatively unexplored. Using populations of Arabidopsis halleri (Brassicaceae) occurring at different elevations in the Alps, we tested for associations between elevation, herbivore damage in the field, and constitutive chemical defense traits (glucosinolates) assayed under common-garden conditions. Additionally, we examined the feeding preferences and performance of a specialist herbivore, the butterfly Pieris brassicae, on plants from different elevations in the Alps. Although we found no effect of elevation on the overall levels of constitutive glucosinolates in leaves, relative amounts of indole glucosinolates increased significantly with elevation and were negatively correlated with herbivore damage in the field. In oviposition preference assays, P. brassicae females laid fewer eggs on plants from high-elevation populations, although larval performance was similar on populations from different elevations. Taken together, these results support the prediction that species distributed along elevation gradients exhibit genetic variation in chemical defenses, which can have consequences for interactions with herbivores in the field.
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Affiliation(s)
- James Buckley
- Center for Adaptation to a Changing Environment, Institute of Integrative Biology, ETH Zürich, 8092 Zürich, Switzerland.
- Biocommunication Group, Institute of Agricultural Sciences, ETH Zürich, 8092 Zürich, Switzerland.
| | - Foteini G Pashalidou
- Biocommunication Group, Institute of Agricultural Sciences, ETH Zürich, 8092 Zürich, Switzerland.
| | - Martin C Fischer
- Center for Adaptation to a Changing Environment, Institute of Integrative Biology, ETH Zürich, 8092 Zürich, Switzerland.
- Plant Ecological Genetics Group, Institute of Integrative Biology, ETH Zürich, 8092 Zürich, Switzerland.
| | - Alex Widmer
- Plant Ecological Genetics Group, Institute of Integrative Biology, ETH Zürich, 8092 Zürich, Switzerland.
| | - Mark C Mescher
- Evolutionary Biology Group, Institute of Integrative Biology, ETH Zürich, 8092 Zürich, Switzerland.
| | - Consuelo M De Moraes
- Biocommunication Group, Institute of Agricultural Sciences, ETH Zürich, 8092 Zürich, Switzerland.
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López-Goldar X, Villari C, Bonello P, Borg-Karlson AK, Grivet D, Zas R, Sampedro L. Inducibility of Plant Secondary Metabolites in the Stem Predicts Genetic Variation in Resistance Against a Key Insect Herbivore in Maritime Pine. FRONTIERS IN PLANT SCIENCE 2018; 9:1651. [PMID: 30519249 PMCID: PMC6258960 DOI: 10.3389/fpls.2018.01651] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 10/24/2018] [Indexed: 05/20/2023]
Abstract
Resistance to herbivores and pathogens is considered a key plant trait with strong adaptive value in trees, usually involving high concentrations of a diverse array of plant secondary metabolites (PSM). Intraspecific genetic variation and plasticity of PSM are widely known. However, their ecology and evolution are unclear, and even the implication of PSM as traits that provide direct effective resistance against herbivores is currently questioned. We used control and methyl jasmonate (MJ) induced clonal copies of genotypes within families from ten populations of the main distribution range of maritime pine to exhaustively characterize the constitutive and induced profile and concentration of PSM in the stem phloem, and to measure insect herbivory damage as a proxy of resistance. Then, we explored whether genetic variation in resistance to herbivory may be predicted by the constitutive concentration of PSM, and the role of its inducibility to predict the increase in resistance once the plant is induced. We found large and structured genetic variation among populations but not between families within populations in resistance to herbivory. The MJ-induction treatment strongly increased resistance to the weevil in the species, and the genetic variation in the inducibility of resistance was significantly structured among populations, with greater inducibility in the Atlantic populations. Genetic variation in resistance was largely explained by the multivariate concentration and profile of PSM at the genotypic level, rather than by bivariate correlations with individual PSM, after accounting for genetic relatedness among genotypes. While the constitutive concentration of the PSM blend did not show a clear pattern of resistance to herbivory, specific changes in the chemical profile and the increase in concentration of the PSM blend after MJ induction were related to increased resistance. To date, this is the first example of a comprehensive and rigorous approach in which inducibility of PSM in trees and its implication in resistance was analyzed excluding spurious associations due to genetic relatedness, often overlooked in intraspecific studies. Here we provide evidences that multivariate analyses of PSM, rather than bivariate correlations, provide more realistic information about the potentially causal relationships between PSM and resistance to herbivory in pine trees.
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Affiliation(s)
- Xosé López-Goldar
- Misión Biológica de Galicia, Consejo Superior de Investigaciones Científicas, Pontevedra, Spain
- Department of Plant Pathology, The Ohio State University, Columbus, OH, United States
- Ecological Chemistry Group, Department of Chemistry, Royal Institute of Technology, Stockholm, Sweden
- Department of Forest Ecology and Genetics, Forest Research Centre, INIA, Madrid, Spain
| | - Caterina Villari
- Department of Plant Pathology, The Ohio State University, Columbus, OH, United States
- Daniel B. Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, United States
| | - Pierluigi Bonello
- Department of Plant Pathology, The Ohio State University, Columbus, OH, United States
| | - Anna Karin Borg-Karlson
- Ecological Chemistry Group, Department of Chemistry, Royal Institute of Technology, Stockholm, Sweden
| | - Delphine Grivet
- Department of Forest Ecology and Genetics, Forest Research Centre, INIA, Madrid, Spain
- Sustainable Forest Management Research Institute, INIA-University of Valladolid, Palencia, Spain
| | - Rafael Zas
- Misión Biológica de Galicia, Consejo Superior de Investigaciones Científicas, Pontevedra, Spain
| | - Luís Sampedro
- Misión Biológica de Galicia, Consejo Superior de Investigaciones Científicas, Pontevedra, Spain
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71
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Moreira X, Abdala-Roberts L, Berny Mier y Teran JC, Covelo F, de la Mata R, Francisco M, Hardwick B, Pires RM, Roslin T, Schigel DS, ten Hoopen JPJG, Timmermans BGH, van Dijk LJA, Castagneyrol B, Tack AJM. Impacts of urbanization on insect herbivory and plant defences in oak trees. OIKOS 2018. [DOI: 10.1111/oik.05497] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Xoaquín Moreira
- Misión Biológica de Galicia (MBG-CSIC), Apdo. 28, ES-36080 Pontevedra; Galicia Spain
| | - Luis Abdala-Roberts
- Depto de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Univ; Autόnoma de Yucatán Mérida Yucatán México
| | | | - Felisa Covelo
- Depto de Sistemas Físicos, Químicos y Naturales, Univ. Pablo de Olavide; Sevilla Spain
| | - Raúl de la Mata
- Research Inst. of Food Technology and Agriculture-IRTA; Caldes de Montbui Spain
| | - Marta Francisco
- Misión Biológica de Galicia (MBG-CSIC), Apdo. 28, ES-36080 Pontevedra; Galicia Spain
| | - Bess Hardwick
- Dept of Agricultural Sciences, Univ. of Helsinki; Helsinki Finland
| | - Ricardo Matheus Pires
- Inst. de Botânica de São Paulo, Núcleo de Pesquisa em Micologia; São Paulo SP Brasil
| | - Tomas Roslin
- Dept of Agricultural Sciences, Univ. of Helsinki; Helsinki Finland
- Dept of Ecology, Swedish Univ. of Agricultural Sciences; Uppsala Sweden
| | - Dmitry S. Schigel
- Dept of Biosciences, Faculty of Biological and Environmental Sciences, Univ. of Helsinki; Helsinki Finland
| | | | | | - Laura J. A. van Dijk
- Dept of Ecology, Environment and Plant Sciences, Stockholm Univ; Stockholm Sweden
| | | | - Ayco J. M. Tack
- Dept of Ecology, Environment and Plant Sciences, Stockholm Univ; Stockholm Sweden
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72
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Anstett DN, Ahern JR, Johnson MTJ, Salminen JP. Testing for latitudinal gradients in defense at the macroevolutionary scale. Evolution 2018; 72:2129-2143. [PMID: 30101976 DOI: 10.1111/evo.13579] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 08/02/2018] [Indexed: 01/29/2023]
Abstract
Plant defenses against herbivores are predicted to evolve to be greater in warmer climates, such as lower latitudes where herbivore pressure is also thought to be higher. Instead, recent findings are often inconsistent with this expectation, suggesting alternative hypotheses are needed. We tested for latitudinal gradients in plant defense evolution at the macroevolutionary scale by characterizing plant chemical defenses across 80 species of the evening primroses, spanning both North and South America. We quantified phenolics in leaves, flowers, and fruits, using advanced analytical chemistry techniques. Dominant individual ellagitannin compounds, total concentrations of ellagitannins, flavonoids, total phenolics, and compound diversity were quantified. Variation in these compounds was predicted with latitude, temperature, precipitation, and continent using phylogenetic generalized least squares (PGLS) multiple regression models. Latitude did not strongly explain variation in chemical defenses. Instead, fruit total ellagitannins, oenothein A, and total phenolics were greater in species inhabiting regions with colder climates. Using analytical chemistry and 80 species in two continents, we show that contrary to classic predictions, concentrations of secondary metabolites are not greater at lower latitudes or in warmer regions. We propose higher herbivore pressure in colder climates and gradients in resource availability as potential drivers of the observed patterns in Oenothera.
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Affiliation(s)
- Daniel N Anstett
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S 3B2, Canada.,Current Address: Biodiversity Research Centre and Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Jeffrey R Ahern
- Natural Chemistry Research Group, Department of Chemistry, University of Turku, FI-20014 Turku, Finland
| | - Marc T J Johnson
- Department of Biology, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada.,Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Ontario M5S 3B2, Canada
| | - Juha-Pekka Salminen
- Natural Chemistry Research Group, Department of Chemistry, University of Turku, FI-20014 Turku, Finland
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73
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Moreira X, Abdala-Roberts L, Galmán A, Francisco M, Fuente MDL, Butrón A, Rasmann S. Assessing the influence of biogeographical region and phylogenetic history on chemical defences and herbivory in Quercus species. PHYTOCHEMISTRY 2018; 153:64-73. [PMID: 29886158 DOI: 10.1016/j.phytochem.2018.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 05/25/2018] [Accepted: 06/02/2018] [Indexed: 06/08/2023]
Abstract
Biogeographical factors and phylogenetic history are key determinants of inter-specific variation in plant defences. However, few studies have conducted broad-scale geographical comparisons of plant defences while controlling for phylogenetic relationships, and, in doing so, none have separated constitutive from induced defences. This gap has limited our understanding of how historical or large-scale processes mediate biogeographical patterns in plant defences since these may be contingent upon shared evolutionary history and phylogenetic constraints. We conducted a phylogenetically-controlled experiment testing for differences in constitutive leaf chemical defences and their inducibility between Palearctic and Nearctic oak species (Quercus, total 18 species). We induced defences in one-year old plants by inflicting damage by gypsy moth larvae (Lymantria dispar), estimated the amount of leaf area consumed, and quantified various groups of phenolic compounds. There was no detectable phylogenetic signal for constitutive or induced levels of most defensive traits except for constitutive condensed tannins, as well as no phylogenetic signal in leaf herbivory. We did, however, find marked differences in defence levels between oak species from each region: Palearctic species had higher levels of constitutive condensed tannins, but less constitutive lignins and less constitutive and induced hydrolysable tannins compared with Nearctic species. Additionally, Palearctic species had lower levels of leaf damage compared with Nearctic species. These differences in leaf damage, lignins and hydrolysable (but not condensed) tannins were lost after accounting for phylogeny, suggesting that geographical structuring of phylogenetic relationships mediated biogeographical differences in defences and herbivore resistance. Together, these findings suggest that historical processes and large-scale drivers have shaped differences in allocation to constitutive defences (and in turn resistance) between Palearctic and Nearctic oaks. Moreover, although evidence of phylogenetic conservatism in the studied traits is rather weak, shared evolutionary history appears to mediate some of these biogeographical patterns in allocation to chemical defences.
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Affiliation(s)
- Xoaquín Moreira
- Misión Biológica de Galicia (MBG-CSIC), Apartado de correos 28, 36080 Pontevedra, Galicia, Spain.
| | - Luis Abdala-Roberts
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Apartado Postal 4-116, Itzimná, 97000 Mérida, Yucatán, Mexico
| | - Andrea Galmán
- Misión Biológica de Galicia (MBG-CSIC), Apartado de correos 28, 36080 Pontevedra, Galicia, Spain
| | - Marta Francisco
- Misión Biológica de Galicia (MBG-CSIC), Apartado de correos 28, 36080 Pontevedra, Galicia, Spain
| | - María de la Fuente
- Misión Biológica de Galicia (MBG-CSIC), Apartado de correos 28, 36080 Pontevedra, Galicia, Spain
| | - Ana Butrón
- Misión Biológica de Galicia (MBG-CSIC), Apartado de correos 28, 36080 Pontevedra, Galicia, Spain
| | - Sergio Rasmann
- Institute of Biology, Laboratory of Functional Ecology, University of Neuchâtel, Rue Emile-Argand 11, 2000 Neuchâtel, Switzerland
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74
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Moreira X, Abdala-Roberts L, Gols R, Francisco M. Plant domestication decreases both constitutive and induced chemical defences by direct selection against defensive traits. Sci Rep 2018; 8:12678. [PMID: 30140028 PMCID: PMC6107632 DOI: 10.1038/s41598-018-31041-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 08/10/2018] [Indexed: 11/27/2022] Open
Abstract
Studies reporting domestication effects on plant defences have focused on constitutive, but not on induced defences. However, theory predicts a trade-off between constitutive (CD) and induced defences (ID), which intrinsically links both defensive strategies and argues for their joint consideration in plant domestications studies. We measured constitutive and induced glucosinolates in wild cabbage (Brassica oleracea ssp. oleracea) and two domesticated varieties (B. oleracea var. acephala and B. oleracea var. capitata) in which the leaves have been selected to grow larger. We also estimated leaf area (proxy of leaf size) to assess size-defence trade-offs and whether domestication effects on defences are indirect via selection for larger leaves. Both CD and ID were lower in domesticated than in wild cabbage and they were negatively correlated (i.e. traded off) in all of the cabbage lines studied. Reductions in CD were similar in magnitude for leaves and stems, and CD and leaf size were uncorrelated. We conclude that domestication of cabbage has reduced levels not only constitutive defences but also their inducibility, and that reductions in CD may span organs not targeted by breeding. This reduction in defences in domesticated cabbage is presumably the result of direct selection rather than indirect effects via trade-offs between size and defences.
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Affiliation(s)
- Xoaquín Moreira
- Misión Biológica de Galicia (MBG-CSIC), Apartado de correos 28, 36080, Pontevedra, Galicia, Spain.
| | - Luis Abdala-Roberts
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Apartado Postal 4-116, Itzimná, 97000, Mérida, Yucatán, Mexico
| | - Rieta Gols
- Laboratory of Entomology, Wageningen University, PO Box 16, 6700 AA, Wageningen, The Netherlands
| | - Marta Francisco
- Misión Biológica de Galicia (MBG-CSIC), Apartado de correos 28, 36080, Pontevedra, Galicia, Spain.
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75
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Abdala-Roberts L, Galmán A, Petry WK, Covelo F, de la Fuente M, Glauser G, Moreira X. Interspecific variation in leaf functional and defensive traits in oak species and its underlying climatic drivers. PLoS One 2018; 13:e0202548. [PMID: 30125315 PMCID: PMC6101385 DOI: 10.1371/journal.pone.0202548] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 08/06/2018] [Indexed: 11/19/2022] Open
Abstract
Plants exhibit a diverse set of functional traits and ecological strategies which reflect an adaptation process to the biotic and abiotic components of the environment. The Plant Economic Spectrum organizes these traits along a continuum from conservative to acquisitive resource use strategies and shows how the abiotic environment governs a species' position along the continuum. However, this framework does not typically account for leaf traits associated with herbivore resistance, despite fundamental metabolic links (and therefore co-variance) between resource use traits and defensive traits. Here we analyzed a suite of leaf traits associated with either resource use (specific leaf area [SLA], nutrients and water content) or defenses (phenolic compounds) for saplings of 11 species of oaks (Quercus spp.), and further investigated whether climatic variables underlie patterns of trait interspecific variation. An ordination of leaf traits revealed the primary axis of trait variation to be leaf economic spectrum traits associated with resource use (SLA, nitrogen, water content) in conjunction with a defensive trait (condensed tannins). Secondary and tertiary axes of trait variation were mainly associated with other defensive traits (lignins, flavonoids, and hydrolysable tannins). Within the primary axis we found a trade-off between resource use traits and both water content and condensed tannins; species with high SLA and leaf N values invested less in condensed tannins and viceversa. Moreover, temperature and precipitation mediated the trait space occupied by species, such that species distributed in warmer and drier climates had less leaf N, lower SLA, and more defenses (condensed tannins, lignins and flavonoids), whereas opposite values were observed for species distributed in colder and wetter climates. These results emphasize the role of abiotic controls over all-inclusive axes of trait variation and contribute to a more complete understanding of interspecific variation in plant functional strategies.
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Affiliation(s)
- Luis Abdala-Roberts
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Itzimná, Mérida, Yucatán, México
| | - Andrea Galmán
- Misión Biológica de Galicia (MBG-CSIC), Pontevedra, Galicia, Spain
| | - William K. Petry
- Institute of Integrative Biology, Eidgenössische Technische Hochschule (ETH) Zürich, Universitätstrasse 16, Zurich, Switzerland
| | - Felisa Covelo
- Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Sevilla, Spain
| | | | - Gaétan Glauser
- Neuchâtel Platform of Analytical Chemistry, University of Neuchâtel, Neuchâtel, Switzerland
| | - Xoaquín Moreira
- Misión Biológica de Galicia (MBG-CSIC), Pontevedra, Galicia, Spain
- * E-mail:
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76
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Jones E, Long JD. Geographic variation in the sensitivity of an herbivore-induced seaweed defense. Ecology 2018; 99:1748-1758. [PMID: 29846935 DOI: 10.1002/ecy.2407] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 04/07/2018] [Accepted: 05/14/2018] [Indexed: 11/11/2022]
Abstract
Intraspecific variation in primary producer induced defenses may affect how these defenses contribute to population and community regulation. For instance, inducible defenses may play larger roles in primary producer populations that are sensitive to low levels of grazing than populations that only respond to high levels of grazing. Although the incidence of herbivore-induced defenses is well documented, and there are examples of geographic variation in these defenses, we have limited knowledge of the factors that affect sensitivity to grazing (i.e., the minimum grazer density needed to elicit these responses) within and among populations. Filling this gap is necessary to understand the importance of these defenses under different conditions. To address whether the sensitivity of seaweed induced defenses varies geographically, we exposed Northern and Southern California populations of the seaweed Silvetia compressa to five densities of the snail Tegula funebralis, under ambient, regional environmental conditions. Southern seaweeds required high levels of grazing to induce defenses, while all levels of herbivory decreased Northern seaweed palatability. To better understand these different responses to low levels of grazing, we conducted common garden experiments to directly test the roles of experimental environment and herbivore source. Consistent with initial experiments, Northern Silvetia responded to low levels of grazing, regardless of environmental conditions, while Southern Silvetia never responded to low levels of grazing, even after being acclimated to Northern environmental conditions for 24 d. Additionally, Southern Silvetia did not respond to grazing by Northern snails, suggesting that herbivore source did not explain this geographic pattern in inducible seaweed defenses. Together, these observations suggest that the seaweed source explains this geographic pattern in sensitivity. Trade-offs with constitutive defenses did not help explain this pattern, as Southern Silvetia had weaker constitutive defenses than Northern seaweeds. This may be due to a combination of low grazing pressure and low predictability of attack in the South. Thus, population variation in sensitivity may be due to long-term differences in environmental histories, resulting in local adaptation or legacy effects from exposure to local conditions. Overall, our results indicate that these herbivore-induced responses may be more important in Northern Silvetia populations than Southern ones.
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Affiliation(s)
- Emily Jones
- Coastal and Marine Institute, San Diego State University, 4165 Spruance Road, San Diego, California, 92106, USA
- Bodega Marine Laboratory, University of California, Davis, 2099 Westshore Road, Bodega Bay, California, 94923, USA
| | - Jeremy D Long
- Coastal and Marine Institute, San Diego State University, 4165 Spruance Road, San Diego, California, 92106, USA
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77
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Lloret F, Kitzberger T. Historical and event-based bioclimatic suitability predicts regional forest vulnerability to compound effects of severe drought and bark beetle infestation. GLOBAL CHANGE BIOLOGY 2018; 24:1952-1964. [PMID: 29316042 DOI: 10.1111/gcb.14039] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 11/30/2017] [Accepted: 12/13/2017] [Indexed: 06/07/2023]
Abstract
Vulnerability to climate change, and particularly to climate extreme events, is expected to vary across species ranges. Thus, we need tools to standardize the variability in regional climatic legacy and extreme climate across populations and species. Extreme climate events (e.g., droughts) can erode populations close to the limits of species' climatic tolerance. Populations in climatic-core locations may also become vulnerable because they have developed a greater demand for resources (i.e., water) that cannot be enough satisfied during the periods of scarcity. These mechanisms can become exacerbated in tree populations when combined with antagonistic biotic interactions, such as insect infestation. We used climatic suitability indices derived from Species Distribution Models (SDMs) to standardize the climatic conditions experienced across Pinus edulis populations in southwestern North America, during a historical period (1972-2000) and during an extreme event (2001-2007), when the compound effect of hot drought and bark beetle infestation caused widespread die-off and mortality. Pinus edulis climatic suitability diminished dramatically during the die-off period, with remarkable variation between years. P. edulis die-off occurred mainly not just in sites that experienced lower climatic suitability during the drought but also where climatic suitability was higher during the historical period. The combined effect of historically high climatic suitability and a marked decrease in the climatic suitability during the drought best explained the range-wide mortality. Lagged effects of climatic suitability loss in previous years and co-occurrence of Juniperus monosperma also explained P. edulis die-off in particular years. Overall, the study shows that past climatic legacy, likely determining acclimation, together with competitive interactions plays a major role in responses to extreme drought. It also provides a new approach to standardize the magnitude of climatic variability across populations using SDMs, improving our capacity to predict population's or species' vulnerability to climatic change.
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Affiliation(s)
- Francisco Lloret
- CREAF Cerdanyola del Vallès, Bellaterra, Spain
- Univ Autònoma Barcelona, Cerdanyola del Vallès, Spain
| | - Thomas Kitzberger
- Laboratorio Ecotono, INIBIOMA-CONICET, Universidad Nacional del Comahue, Bariloche, Argentina
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78
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Knappová J, Židlická D, Kadlec T, Knapp M, Haisel D, Hadincová V, Münzbergová Z. Population differentiation related to climate of origin affects the intensity of plant–herbivore interactions in a clonal grass. Basic Appl Ecol 2018. [DOI: 10.1016/j.baae.2018.02.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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79
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Bullington LS, Lekberg Y, Sniezko R, Larkin B. The influence of genetics, defensive chemistry and the fungal microbiome on disease outcome in whitebark pine trees. MOLECULAR PLANT PATHOLOGY 2018; 19:1847-1858. [PMID: 29388309 PMCID: PMC6638087 DOI: 10.1111/mpp.12663] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 01/02/2018] [Accepted: 01/26/2018] [Indexed: 05/23/2023]
Abstract
The invasive fungal pathogen Cronartium ribicola infects and kills whitebark pine (Pinus albicaulis) throughout western North America. Whitebark pine has been proposed for listing under the Endangered Species Act in the USA, and the loss of this species is predicted to have severe impacts on ecosystem composition and function in high-elevation forests. Numerous fungal endophytes live inside whitebark pine tissues and may influence the severity of C. ribicola infection, either directly by inhibition of pathogen growth or indirectly by the induction of chemical defensive pathways in the tree. Terpenes, a form of chemical defence in pine trees, can also influence disease. In this study, we characterized fungal endophyte communities in whitebark pine seedlings before and after experimental inoculation with C. ribicola, monitored disease progression and compared fungal community composition in susceptible vs. resistant seedlings in a common garden. We analysed the terpene composition of these same seedlings. Seed family identity or maternal genetics influenced both terpenes and endophyte communities. Terpene and endophyte composition correlated with disease severity, and terpene concentrations differed in resistant vs. susceptible seedlings. These results suggest that the resistance to C. ribicola observed in natural whitebark pine populations is caused by the combined effects of genetics, endophytes and terpenes within needle tissue, in which initial interactions between microbes and hosts take place. Tree genotype, terpene and microbiome combinations associated with healthy trees could help to predict or reduce disease severity and improve outcomes of future tree breeding programmes.
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Affiliation(s)
- Lorinda S. Bullington
- MPG RanchFlorenceMT 59833USA
- Interdisciplinary Sciences, University of MontanaMissoulaMT 59801USA
| | - Ylva Lekberg
- MPG RanchFlorenceMT 59833USA
- College of Forestry and ConservationUniversity of MontanaMissoulaMT 59801USA
| | - Richard Sniezko
- USDA Forest Service, Dorena Genetic Resource CenterCottage GroveOR 97424USA
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80
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Roslin T, Hardwick B, Novotny V, Petry WK, Andrew NR, Asmus A, Barrio IC, Basset Y, Boesing AL, Bonebrake TC, Cameron EK, Dáttilo W, Donoso DA, Drozd P, Gray CL, Hik DS, Hill SJ, Hopkins T, Huang S, Koane B, Laird-Hopkins B, Laukkanen L, Lewis OT, Milne S, Mwesige I, Nakamura A, Nell CS, Nichols E, Prokurat A, Sam K, Schmidt NM, Slade A, Slade V, Suchanková A, Teder T, van Nouhuys S, Vandvik V, Weissflog A, Zhukovich V, Slade EM. Higher predation risk for insect prey at low latitudes and elevations. Science 2018; 356:742-744. [PMID: 28522532 DOI: 10.1126/science.aaj1631] [Citation(s) in RCA: 201] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 04/06/2017] [Indexed: 11/02/2022]
Abstract
Biotic interactions underlie ecosystem structure and function, but predicting interaction outcomes is difficult. We tested the hypothesis that biotic interaction strength increases toward the equator, using a global experiment with model caterpillars to measure predation risk. Across an 11,660-kilometer latitudinal gradient spanning six continents, we found increasing predation toward the equator, with a parallel pattern of increasing predation toward lower elevations. Patterns across both latitude and elevation were driven by arthropod predators, with no systematic trend in attack rates by birds or mammals. These matching gradients at global and regional scales suggest consistent drivers of biotic interaction strength, a finding that needs to be integrated into general theories of herbivory, community organization, and life-history evolution.
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Affiliation(s)
- Tomas Roslin
- Spatial Foodweb Ecology Group, Department of Ecology, Swedish University of Agricultural Sciences, Post Office Box 7044, SE-750 07 Uppsala, Sweden. .,Spatial Foodweb Ecology Group, Department of Agricultural Sciences, Post Office Box 27, FI-00014 University of Helsinki, Finland
| | - Bess Hardwick
- Spatial Foodweb Ecology Group, Department of Agricultural Sciences, Post Office Box 27, FI-00014 University of Helsinki, Finland
| | - Vojtech Novotny
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences (CAS), Branisovska 31, 37005 Ceske Budejovice, Czech Republic.,Department of Zoology, Faculty of Science, University of South Bohemia, Branisovska 1760, 37005 Ceske Budejovice, Czech Republic.,The New Guinea Binatang Research Center, Post Office Box 604, Madang, Papua New Guinea
| | - William K Petry
- Department of Ecology and Evolutionary Biology, University of California-Irvine, 321 Steinhaus Hall, Irvine, CA 92697-2525, USA.,Institute of Integrative Biology, Eidgenössische Technische Hochschule (ETH) Zürich, Universitätstrasse 16, 8092 Zurich, Switzerland
| | - Nigel R Andrew
- Insect Ecology Lab, Centre of Excellence for Behavioural and Physiological Ecology, University of New England, NSW, Australia, 2351, Australia
| | - Ashley Asmus
- Department of Biology, The University of Texas at Arlington, Arlington, TX 76019, USA
| | - Isabel C Barrio
- Department of Biological Sciences, University of Alberta, Edmonton, T6G 2E9 Alberta, Canada.,Institute of Life and Environmental Sciences, University of Iceland, Sturlugata 7 IS-101 Reykjavik, Iceland
| | - Yves Basset
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences (CAS), Branisovska 31, 37005 Ceske Budejovice, Czech Republic.,Department of Zoology, Faculty of Science, University of South Bohemia, Branisovska 1760, 37005 Ceske Budejovice, Czech Republic.,Smithsonian Tropical Research Institute, Apartado 0843-03092, Panama City, Republic of Panama
| | - Andrea Larissa Boesing
- Department of Ecology, University of São Paulo, Rua do Matão 321, T-14, CEP 05508-900, São Paulo, SP, Brazil
| | - Timothy C Bonebrake
- School of Biological Sciences, The University of Hong Kong, Pok Fu Lam Rd, Hong Kong SAR, People's Republic of China
| | - Erin K Cameron
- Metapopulation Research Centre, Department of Biosciences, Post Office Box 65, FI-00014, University of Helsinki, Finland.,Center for Macroecology, Evolution and Climate Change, Natural History Museum of Denmark, University of Copenhagen, Universitetsparken 15, København, Denmark
| | - Wesley Dáttilo
- Red de Ecoetología, Instituto de Ecología, CP 91070, Xalapa, Veracruz, Mexico
| | - David A Donoso
- Instituto de Ciencias Biológicas, Escuela Politécnica Nacional, Ladrón de Guevara E11-253, Quito, Ecuador
| | - Pavel Drozd
- University of Ostrava, Faculty of Science-Department of Biology and Ecology, Chittussiho 10, 710 00 Slezská Ostrava, Czech Republic
| | - Claudia L Gray
- Evolutionarily Distinct and Globally Endangered (EDGE) of Existence, Conservation Programmes, Zoological Society of London, Regent's Park, London NW1 4RY, UK.,Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - David S Hik
- Department of Biological Sciences, University of Alberta, Edmonton, T6G 2E9 Alberta, Canada
| | - Sarah J Hill
- Insect Ecology Lab, Centre of Excellence for Behavioural and Physiological Ecology, University of New England, NSW, Australia, 2351, Australia
| | - Tapani Hopkins
- Zoological Museum, Biodiversity Unit, FI-20014 University of Turku, Finland
| | - Shuyin Huang
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303 Yunnan, People's Republic of China
| | - Bonny Koane
- The New Guinea Binatang Research Center, Post Office Box 604, Madang, Papua New Guinea
| | - Benita Laird-Hopkins
- Smithsonian Tropical Research Institute, Apartado 0843-03092, Panama City, Republic of Panama
| | | | - Owen T Lewis
- Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
| | - Sol Milne
- University of Aberdeen, Zoology Building, Tillydrone Avenue, Aberdeen AB24 2TZ, UK
| | - Isaiah Mwesige
- Makerere University Biological Field Station, Post Office Box 409, Fort Portal, Uganda
| | - Akihiro Nakamura
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, 666303 Yunnan, People's Republic of China
| | - Colleen S Nell
- Department of Ecology and Evolutionary Biology, University of California-Irvine, 321 Steinhaus Hall, Irvine, CA 92697-2525, USA
| | - Elizabeth Nichols
- Department of Ecology, University of São Paulo, Rua do Matão 321, T-14, CEP 05508-900, São Paulo, SP, Brazil.,Department of Biology, Swarthmore College, 500 College Avenue, Swarthmore, PA 19081, USA
| | - Alena Prokurat
- State Institution of Education, Zditovo High School, Zditovo, Belarus
| | - Katerina Sam
- Institute of Entomology, Biology Centre of the Czech Academy of Sciences (CAS), Branisovska 31, 37005 Ceske Budejovice, Czech Republic.,Department of Zoology, Faculty of Science, University of South Bohemia, Branisovska 1760, 37005 Ceske Budejovice, Czech Republic
| | - Niels M Schmidt
- Arctic Research Centre, Aarhus University, Ny Munkegade 114, DK-8000 Aarhus C, Denmark.,Department of Bioscience, Aarhus University, Frederiksborgvej 399, DK-4000 Roskilde, Denmark
| | - Alison Slade
- 40 Town End Lane, Lepton, Huddersfield, HD8 ONA, UK
| | - Victor Slade
- 40 Town End Lane, Lepton, Huddersfield, HD8 ONA, UK
| | - Alžběta Suchanková
- University of Ostrava, Faculty of Science-Department of Biology and Ecology, Chittussiho 10, 710 00 Slezská Ostrava, Czech Republic
| | - Tiit Teder
- Department of Zoology, Institute of Ecology and Earth Sciences, University of Tartu, EE-51014 Tartu, Estonia
| | - Saskya van Nouhuys
- Metapopulation Research Centre, Department of Biosciences, Post Office Box 65, FI-00014, University of Helsinki, Finland
| | - Vigdis Vandvik
- Department of Biology, University of Bergen, Post Office Box 7800, 5020 Bergen, Norway
| | - Anita Weissflog
- Department of Plant Ecology, University of Bayreuth, 95440 Bayreuth, Germany
| | - Vital Zhukovich
- State Institution of Education, Zditovo High School, Zditovo, Belarus
| | - Eleanor M Slade
- Spatial Foodweb Ecology Group, Department of Agricultural Sciences, Post Office Box 27, FI-00014 University of Helsinki, Finland.,Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK.,Lancaster Environment Centre, University of Lancaster, Lancaster, UK
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81
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Schaeffer RN, Wang Z, Thornber CS, Preisser EL, Orians CM. Two invasive herbivores on a shared host: patterns and consequences of phytohormone induction. Oecologia 2018; 186:973-982. [PMID: 29362885 DOI: 10.1007/s00442-018-4063-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Accepted: 01/08/2018] [Indexed: 01/10/2023]
Abstract
Herbivore-induced changes in host quality mediate indirect interactions between herbivores. The nature of these indirect interactions can vary depending on the identity of herbivores involved, species-specific induction of defense-signaling pathways, and sequence of attack. However, our understanding of the role of these signaling pathways in the success of multiple exotic herbivores is less known. Eastern hemlock (Tsuga canadensis) is attacked by two invasive herbivores [elongate hemlock scale (EHS; Fiorinia externa) and hemlock woolly adelgid (HWA; Adelges tsugae)] throughout much of its range, but prior attack by EHS is known to deter HWA. The potential role of phytohormones in this interaction is poorly understood. We measured endogenous levels of phytohormones in eastern hemlock in response to attack by these invasive herbivores. We also used exogenous application of methyl jasmonate (MJ) and acibenzolar-S-methyl (ASM), a salicylic acid (SA) pathway elicitor, to test the hypothesis that defense-signaling phytohormones typically induced by herbivores could deter HWA. Resistance to adelgid attack was assessed using a behavioral assay. Adelgid feeding significantly elevated both abscisic acid (ABA) and SA in local tissues, while EHS feeding had no detectable effect on either phytohormone. HWA progrediens and sistens crawlers preferred to settle on ASM-treated foliage. In contrast, HWA crawlers actively avoided settlement on MJ-treated foliage. We suggest that induction of ABA- and SA-signaling pathways, in concert with defense-signaling interference, may aid HWA invasion success, and that defense-signaling interference, induced by exotic competitors, may mediate resistance of native hosts.
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Affiliation(s)
- Robert N Schaeffer
- Department of Biology, Tufts University, Medford, MA, 02155, USA. .,Department of Entomology, Washington State University, Pullman, WA, 99164, USA.
| | - Zhou Wang
- Department of Biology, Tufts University, Medford, MA, 02155, USA
| | - Carol S Thornber
- Department of Biological Sciences, University of Rhode Island, Kingston, RI, 02881, USA.,Department of Natural Resources Science, University of Rhode Island, Kingston, RI, 02881, USA
| | - Evan L Preisser
- Department of Biological Sciences, University of Rhode Island, Kingston, RI, 02881, USA
| | - Colin M Orians
- Department of Biology, Tufts University, Medford, MA, 02155, USA
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82
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Abdala-Roberts L, Covelo F, Parra-Tabla V, Terán JCBMY, Mooney KA, Moreira X. Intra-Specific Latitudinal Clines in Leaf Carbon, Nitrogen, and Phosphorus and their Underlying Abiotic Correlates in Ruellia Nudiflora. Sci Rep 2018; 8:596. [PMID: 29330375 PMCID: PMC5766631 DOI: 10.1038/s41598-017-18875-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 12/18/2017] [Indexed: 11/10/2022] Open
Abstract
While plant intra-specific variation in the stoichiometry of nutrients and carbon is well documented, clines for such traits have been less studied, despite their potential to reveal the mechanisms underlying such variation. Here we analyze latitudinal variation in the concentration of leaf nitrogen (N), phosphorus (P), carbon (C) and their ratios across 30 populations of the perennial herb Ruellia nudiflora. In addition, we further determined whether climatic and soil variables underlie any such latitudinal clines in leaf traits. The sampled transect spanned 5° latitude (ca. 900 km) and exhibited a four-fold precipitation gradient and 2 °C variation in mean annual temperature. We found that leaf P concentration increased with precipitation towards lower latitudes, whereas N and C did not exhibit latitudinal clines. In addition, N:P and C:P decreased towards lower latitudes and latitudinal variation in the former was weakly associated with soil conditions (clay content and cation exchange capacity); C:N did not exhibit a latitudinal gradient. Overall, these results emphasize the importance of addressing and disentangling the simultaneous effects of abiotic factors associated with intra-specific clines in plant stoichiometric traits, and highlight the previously underappreciated influence of abiotic factors on plant nutrients operating under sharp abiotic gradients over smaller spatial scales.
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Affiliation(s)
- Luis Abdala-Roberts
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Apartado Postal 4-116, Itzimná, 97000 Mérida, Yucatán, Mexico.
| | - Felisa Covelo
- Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Carretera de Utrera km. 1, 41013, Sevilla, Spain
| | - Víctor Parra-Tabla
- Departamento de Ecología Tropical, Campus de Ciencias Biológicas y Agropecuarias, Universidad Autónoma de Yucatán, Apartado Postal 4-116, Itzimná, 97000 Mérida, Yucatán, Mexico
| | - Jorge C Berny Mier Y Terán
- Department of Plant Sciences, University of California-Davis, One Shields Avenue, Davis, California, 95616, USA
| | - Kailen A Mooney
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California, 92697, USA
| | - Xoaquín Moreira
- Misión Biológica de Galicia (MBG-CSIC), Apdo. 28, 36080, Pontevedra, Spain.
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83
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Rosado-Sánchez S, Parra-Tabla V, Betancur-Ancona D, Moreira X, Abdala-Roberts L. Tree species diversity alters plant defense investment in an experimental forest plantation in southern Mexico. Biotropica 2017. [DOI: 10.1111/btp.12527] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Silvia Rosado-Sánchez
- Departamento de Ecología Tropical; Campus de Ciencias Biológicas y Agropecuarias; Universidad Autónoma de Yucatán; Carretera Mérida-Xmatkuil Km 15.5 C.P. 97100 Mérida Yuc. México
| | - Víctor Parra-Tabla
- Departamento de Ecología Tropical; Campus de Ciencias Biológicas y Agropecuarias; Universidad Autónoma de Yucatán; Carretera Mérida-Xmatkuil Km 15.5 C.P. 97100 Mérida Yuc. México
| | - David Betancur-Ancona
- Facultad de Ingeniería Química; Universidad Autónoma de Yucatán; Periférico Nte. Km. 33.5, Tablaje Catastral 13615, Col. Chuburná de Hidalgo Inn. C.P. 97203 Mérida Yuc. México
| | - Xoaquín Moreira
- Misión Biológica de Galicia (MBG-CSIC); Apdo. 28 36080 Pontevedra, Galicia Spain
| | - Luis Abdala-Roberts
- Departamento de Ecología Tropical; Campus de Ciencias Biológicas y Agropecuarias; Universidad Autónoma de Yucatán; Carretera Mérida-Xmatkuil Km 15.5 C.P. 97100 Mérida Yuc. México
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84
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Ferrenberg S, Langenhan JM, Loskot SA, Rozal LM, Mitton JB. Resin monoterpene defenses decline within three widespread species of pine (Pinus) along a 1530-m elevational gradient. Ecosphere 2017. [DOI: 10.1002/ecs2.1975] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Affiliation(s)
- Scott Ferrenberg
- Department of Biology; New Mexico State University; Las Cruces New Mexico 88003 USA
| | | | - Steven A. Loskot
- Department of Chemistry; Seattle University; Seattle Washington 98122 USA
| | - Leonardo M. Rozal
- Department of Chemistry; Seattle University; Seattle Washington 98122 USA
| | - Jeffry B. Mitton
- Department of Ecology and Evolutionary Biology; University of Colorado; Boulder Colorado 80309 USA
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85
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Zamora Nasca LB, Relva MA, Núñez MA. Ungulates can control tree invasions: experimental evidence from nonnative conifers and sheep herbivory. Biol Invasions 2017. [DOI: 10.1007/s10530-017-1558-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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86
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Raffa KF, Mason CJ, Bonello P, Cook S, Erbilgin N, Keefover-Ring K, Klutsch JG, Villari C, Townsend PA. Defence syndromes in lodgepole - whitebark pine ecosystems relate to degree of historical exposure to mountain pine beetles. PLANT, CELL & ENVIRONMENT 2017; 40:1791-1806. [PMID: 28543133 DOI: 10.1111/pce.12985] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 04/21/2017] [Accepted: 04/28/2017] [Indexed: 06/07/2023]
Abstract
Warming climate is allowing tree-killing bark beetles to expand their ranges and access naïve and semi-naïve conifers. Conifers respond to attack using complex mixtures of chemical defences that can impede beetle success, but beetles exploit some compounds for host location and communication. Outcomes of changing relationships will depend on concentrations and compositions of multiple host compounds, which are largely unknown. We analysed constitutive and induced chemistries of Dendroctonus ponderosae's primary historical host, Pinus contorta, and Pinus albicaulis, a high-elevation species whose encounters with this beetle are transitioning from intermittent to continuous. We quantified multiple classes of terpenes, phenolics, carbohydrates and minerals. Pinus contorta had higher constitutive allocation to, and generally stronger inducibility of, compounds that resist these beetle-fungal complexes. Pinus albicaulis contained higher proportions of specific monoterpenes that enhance pheromone communication, and lower induction of pheromone inhibitors. Induced P. contorta increased insecticidal and fungicidal compounds simultaneously, whereas P. albicaulis responses against these agents were inverse. Induced terpene accumulation was accompanied by decreased non-structural carbohydrates, primarily sugars, in P. contorta, but not P. albicaulis, which contained primarily starches. These results show some host species with continuous exposure to bark beetles have more thoroughly integrated defence syndromes than less-continuously exposed host species.
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Affiliation(s)
- Kenneth F Raffa
- Department of Entomology, University of Wisconsin - Madison, Madison, WI, 53706, USA
| | - Charles J Mason
- Department of Entomology, University of Wisconsin - Madison, Madison, WI, 53706, USA
- Department of Entomology, Pennsylvania State University, State College, PA, 16802, USA
| | - Pierluigi Bonello
- Department of Plant Pathology, The Ohio State University, Columbus, OH, 43210, USA
| | - Stephen Cook
- Department of Plant, Soil and Entomological Science, University of Idaho, Moscow, ID, 83844, USA
| | - Nadir Erbilgin
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, T6G 2E3, Canada
| | - Ken Keefover-Ring
- Departments of Botany and Geography, University of Wisconsin - Madison, Madison, WI, 53706, USA
| | - Jennifer G Klutsch
- Department of Renewable Resources, University of Alberta, Edmonton, Alberta, T6G 2E3, Canada
| | - Caterina Villari
- Department of Plant Pathology, The Ohio State University, Columbus, OH, 43210, USA
- Warnell School of Forestry and Natural Resources, University of Georgia - Athens, Athens, GA, 30602, USA
| | - Philip A Townsend
- Department of Forest and Wildlife Ecology, University of Wisconsin - Madison, Madison, WI, 53706, USA
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87
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de la Mata R, Hood S, Sala A. Insect outbreak shifts the direction of selection from fast to slow growth rates in the long-lived conifer Pinus ponderosa. Proc Natl Acad Sci U S A 2017; 114:7391-7396. [PMID: 28652352 PMCID: PMC5514711 DOI: 10.1073/pnas.1700032114] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Long generation times limit species' rapid evolution to changing environments. Trees provide critical global ecosystem services, but are under increasing risk of mortality because of climate change-mediated disturbances, such as insect outbreaks. The extent to which disturbance changes the dynamics and strength of selection is unknown, but has important implications on the evolutionary potential of tree populations. Using a 40-y-old Pinus ponderosa genetic experiment, we provide rare evidence of context-dependent fluctuating selection on growth rates over time in a long-lived species. Fast growth was selected at juvenile stages, whereas slow growth was selected at mature stages under strong herbivory caused by a mountain pine beetle (Dendroctonus ponderosae) outbreak. Such opposing forces led to no net evolutionary response over time, thus providing a mechanism for the maintenance of genetic diversity on growth rates. Greater survival to mountain pine beetle attack in slow-growing families reflected, in part, a host-based life-history trade-off. Contrary to expectations, genetic effects on tree survival were greatest at the peak of the outbreak and pointed to complex defense responses. Our results suggest that selection forces in tree populations may be more relevant than previously thought, and have implications for tree population responses to future environments and for tree breeding programs.
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Affiliation(s)
- Raul de la Mata
- Division of Biological Sciences, University of Montana, Missoula, MT 59812;
- Department of Renewable Resources, University of Alberta, Edmonton, AB, Canada T6G 2H1
| | - Sharon Hood
- Division of Biological Sciences, University of Montana, Missoula, MT 59812
- Rocky Mountain Research Station, Fire, Fuel, and Smoke Science Program, US Department of Agriculture Forest Service, Missoula, MT 59808
| | - Anna Sala
- Division of Biological Sciences, University of Montana, Missoula, MT 59812
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88
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Abstract
Plant ontogenetic stage and features of surrounding plant neighbourhoods can strongly influence herbivory and defences on focal plants. However, the effects of both factors have been assessed independently in previous studies. Here we tested for the independent and interactive effects of neighbourhood type (low vs. high frequency of our focal plant species in heterospecific stands) and ontogeny on leaf herbivory, physical traits and chemical defences of the English oak Quercus robur. We further tested whether plant traits were associated with neighbourhood and ontogenetic effects on herbivory. We found that leaf herbivory decreased in stands with a low frequency of Q. robur, and that saplings received less herbivory than adult trees. Interestingly, we also found interactive effects of these factors where a difference in damage between saplings and adult trees was only observed in stands with a high frequency of Q. robur. We also found strong ontogenetic differences in leaf traits where saplings had more defended leaves than adult trees, and this difference in turn explained ontogenetic differences in herbivory. Plant trait variation did not explain the neighbourhood effect on herbivory. This study builds towards a better understanding of the concurrent effects of plant individual- and community-level characteristics influencing plant-herbivore interactions.
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89
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Moreira X, Pearse IS. Leaf habit does not determine the investment in both physical and chemical defences and pair-wise correlations between these defensive traits. PLANT BIOLOGY (STUTTGART, GERMANY) 2017; 19:354-359. [PMID: 28008702 DOI: 10.1111/plb.12537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Accepted: 12/16/2016] [Indexed: 06/06/2023]
Abstract
Plant life-history strategies associated with resource acquisition and economics (e.g. leaf habit) are thought to be fundamental determinants of the traits and mechanisms that drive herbivore pressure, resource allocation to plant defensive traits, and the simultaneous expression (positive correlations) or trade-offs (negative correlations) between these defensive traits. In particular, it is expected that evergreen species - which usually grow slower and support constant herbivore pressure in comparison with deciduous species - will exhibit higher levels of both physical and chemical defences and a higher predisposition to the simultaneous expression of physical and chemical defensive traits. Here, by using a dataset which included 56 oak species (Quercus genus), we investigated whether leaf habit of plant species governs the investment in both physical and chemical defences and pair-wise correlations between these defensive traits. Our results showed that leaf habit does not determine the production of most leaf physical and chemical defences. Although evergreen oak species had higher levels of leaf toughness and specific leaf mass (physical defences) than deciduous oak species, both traits are essentially prerequisites for evergreenness. Similarly, our results also showed that leaf habit does not determine pair-wise correlations between defensive traits because most physical and chemical defensive traits were simultaneously expressed in both evergreen and deciduous oak species. Our findings indicate that leaf habit does not substantially contribute to oak species differences in plant defence investment.
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Affiliation(s)
- X Moreira
- Misión Biológica de Galicia (MBG-CSIC), Pontevedra, Galicia, Spain
| | - I S Pearse
- Illinois Natural History Survey, Champaign, IL, USA
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90
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Erbilgin N, Cale JA, Hussain A, Ishangulyyeva G, Klutsch JG, Najar A, Zhao S. Weathering the storm: how lodgepole pine trees survive mountain pine beetle outbreaks. Oecologia 2017; 184:469-478. [PMID: 28421324 DOI: 10.1007/s00442-017-3865-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 04/04/2017] [Indexed: 11/29/2022]
Abstract
Recent mountain pine beetle outbreaks in western North America killed millions of lodgepole pine trees, leaving few survivors. However, the mechanism underlying the ability of trees to survive bark beetle outbreaks is unknown, but likely involve phytochemicals such as monoterpenes and fatty acids that can drive beetle aggregation and colonization on their hosts. Thus, we conducted a field survey of beetle-resistant lodgepole pine (Pinus contorta) trees to retrospectively deduce whether these phytochemicals underlie their survival by comparing their chemistry to that of non-attacked trees in the same stands. We also compared beetle attack characteristics between resistant and beetle-killed trees. Beetle-killed trees had more beetle attacks and longer ovipositional galleries than resistant trees, which also lacked the larval establishment found in beetle-killed trees. Resistant trees contained high amounts of toxic and attraction-inhibitive compounds and low amounts of pheromone-precursor and synergist compounds. During beetle host aggregation and colonization, these compounds likely served three critical roles in tree survival. First, low amounts of pheromone-precursor (α-pinene) and synergist (mycrene, terpinolene) compounds reduced or prevented beetles from attracting conspecifics to residual trees. Second, high amounts of 4-allyanisole further inhibited beetle attraction to its pheromone. Finally, high amounts of toxic limonene, 3-carene, 4-allyanisole, α-linolenic acid, and linoleic acid inhibited beetle gallery establishment and oviposition. We conclude that the variation of chemotypic expression of local plant populations can have profound ecological consequences including survival during insect outbreaks.
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Affiliation(s)
- Nadir Erbilgin
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada.
| | - Jonathan A Cale
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada
| | - Altaf Hussain
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada
| | - Guncha Ishangulyyeva
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada
| | - Jennifer G Klutsch
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada
| | - Ahmed Najar
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada
| | - Shiyang Zhao
- Department of Renewable Resources, University of Alberta, 442 Earth Sciences Building, Edmonton, AB, T6G 2E3, Canada
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91
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Colicchio J. Transgenerational effects alter plant defence and resistance in nature. J Evol Biol 2017; 30:664-680. [PMID: 28102915 PMCID: PMC5382043 DOI: 10.1111/jeb.13042] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 01/09/2017] [Accepted: 01/12/2017] [Indexed: 12/17/2022]
Abstract
Trichomes, or leaf hairs, are epidermal extensions that take a variety of forms and perform many functions in plants, including herbivore defence. In this study, I document genetically determined variation, within-generation plasticity, and a direct role of trichomes in herbivore defence for Mimulus guttatus. After establishing the relationship between trichomes and herbivory, I test for transgenerational effects of wounding on trichome density and herbivore resistance. Patterns of interannual variation in herbivore density and the high cost of plant defence makes plant-herbivore interactions a system in which transgenerational phenotypic plasticity (TPP) is apt to evolve. Here, I demonstrate that parental damage alters offspring trichome density and herbivore resistance in nature. Moreover, this response varies between populations. This is among the first studies to demonstrate that TPP contributes to variation in nature, and also suggests that selection can modify TPP in response to local conditions.
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Affiliation(s)
- J Colicchio
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, USA
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92
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Zadworny M, McCormack ML, Żytkowiak R, Karolewski P, Mucha J, Oleksyn J. Patterns of structural and defense investments in fine roots of Scots pine (Pinus sylvestris L.) across a strong temperature and latitudinal gradient in Europe. GLOBAL CHANGE BIOLOGY 2017; 23:1218-1231. [PMID: 27670838 DOI: 10.1111/gcb.13514] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 09/06/2016] [Accepted: 09/09/2016] [Indexed: 05/05/2023]
Abstract
Plant functional traits may be altered as plants adapt to various environmental constraints. Cold, low fertility growing conditions are often associated with root adjustments to increase acquisition of limiting nutrient resources, but they may also result in construction of roots with reduced uptake potential but higher tissue persistence. It is ultimately unclear whether plants produce fine roots of different structure in response to decreasing temperatures and whether these changes represent a trade-off between root function or potential root persistence. We assessed patterns of root construction based on various root morphological, biochemical and defense traits including root diameter, specific root length (SRL), root tissue density (RTD), C:N ratio, phenolic compounds, and number of phellem layers across up to 10 root orders in diverse populations of Scots pine along a 2000-km climatic gradient in Europe. Our results showed that different root traits are related to mean annual temperature (MAT) and expressed a pattern of higher root diameter and lower SRL and RTD in northern sites with lower MAT. Among absorptive roots, we observed a gradual decline in chemical defenses (phenolic compounds) with decreasing MAT. In contrast, decreasing MAT resulted in an increase of structural protection (number of phellem layers) in transport fine roots. This indicated that absorptive roots with high capacity for nutrient uptake, and transport roots with low uptake capacity, were characterized by distinct and contrasting trade-offs. Our observations suggest that diminishing structural and chemical investments into the more distal, absorptive roots in colder climates is consistent with building roots of higher absorptive capacity. At the same time, roots that play a more prominent role in transport of nutrients and water within the root system saw an increase in structural investment, which can increase persistence and reduce long-term costs associated with their frequent replacement.
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Affiliation(s)
- Marcin Zadworny
- Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035, Kórnik, Poland
| | - M Luke McCormack
- Department of Plant Biology, University of Minnesota, St. Paul, Minnesota, 55108, USA
| | - Roma Żytkowiak
- Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035, Kórnik, Poland
| | - Piotr Karolewski
- Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035, Kórnik, Poland
| | - Joanna Mucha
- Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035, Kórnik, Poland
| | - Jacek Oleksyn
- Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035, Kórnik, Poland
- Department of Forest Resources, University of Minnesota, St. Paul, Minnesota, 55108, USA
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93
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Bentz BJ, Hood SM, Hansen EM, Vandygriff JC, Mock KE. Defense traits in the long-lived Great Basin bristlecone pine and resistance to the native herbivore mountain pine beetle. THE NEW PHYTOLOGIST 2017; 213:611-624. [PMID: 27612209 PMCID: PMC5213150 DOI: 10.1111/nph.14191] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Accepted: 08/05/2016] [Indexed: 05/11/2023]
Abstract
Mountain pine beetle (MPB, Dendroctonus ponderosae) is a significant mortality agent of Pinus, and climate-driven range expansion is occurring. Pinus defenses in recently invaded areas, including high elevations, are predicted to be lower than in areas with longer term MPB presence. MPB was recently observed in high-elevation forests of the Great Basin (GB) region, North America. Defense and susceptibility in two long-lived species, GB bristlecone pine (Pinus longaeva) and foxtail pine (P. balfouriana), are unclear, although they are sympatric with a common MPB host, limber pine (P. flexilis). We surveyed stands with sympatric GB bristlecone-limber pine and foxtail-limber pine to determine relative MPB attack susceptibility and constitutive defenses. MPB-caused mortality was extensive in limber, low in foxtail and absent in GB bristlecone pine. Defense traits, including constitutive monoterpenes, resin ducts and wood density, were higher in GB bristlecone and foxtail than in limber pine. GB bristlecone and foxtail pines have relatively high levels of constitutive defenses which make them less vulnerable to climate-driven MPB range expansion relative to other high-elevation pines. Long-term selective herbivore pressure and exaptation of traits for tree longevity are potential explanations, highlighting the complexity of predicting plant-insect interactions under climate change.
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Affiliation(s)
- Barbara J. Bentz
- USDA Forest Service Rocky Mountain Research StationLoganUT84321USA
| | - Sharon M. Hood
- USDA Forest Service Rocky Mountain Research StationMissoulaMT59808USA
| | | | | | - Karen E. Mock
- Department of Wildland Resources and Ecology CenterUtah State UniversityLoganUT84321USA
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94
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Reese AT, Ames GM, Wright JP. Variation in Plant Response to Herbivory Underscored by Functional Traits. PLoS One 2016; 11:e0166714. [PMID: 27936155 PMCID: PMC5147848 DOI: 10.1371/journal.pone.0166714] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Accepted: 11/02/2016] [Indexed: 11/19/2022] Open
Abstract
The effects of herbivory can shape plant communities and evolution. However, the many forms of herbivory costs and the wide variation in herbivory pressure, including across latitudinal gradients, can make predicting the effects of herbivory on different plant species difficult. Functional trait approaches may aid in contextualizing and standardizing the assessment of herbivory impacts. Here we assessed the response of 26 old-field plant species to simulated defoliation in a greenhouse setting by measuring whole plant and leaf level traits in control and treated individuals. Simulated defoliation had no significant effects on any plant traits measured. However, the baseline leaf level traits of healthy plants consistently predicted the log response ratio for these species whole plant response to defoliation. The latitudinal mid-point of species' distributions was also significantly correlated with aboveground biomass and total leaf area responses, with plants with a more northern distribution being more negatively impacted by treatment. These results indicate that even in the absence of significant overall impacts, functional traits may aid in predicting variability in plant responses to defoliation and in identifying the underlying limitations driving those responses.
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Affiliation(s)
- Aspen T. Reese
- Department of Biology, Duke University, Durham, NC, United States of America
- * E-mail:
| | - Gregory M. Ames
- Department of Biology, Duke University, Durham, NC, United States of America
| | - Justin P. Wright
- Department of Biology, Duke University, Durham, NC, United States of America
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95
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Zvereva EL, Hunter MD, Zverev V, Kozlov MV. Factors affecting population dynamics of leaf beetles in a subarctic region: The interplay between climate warming and pollution decline. THE SCIENCE OF THE TOTAL ENVIRONMENT 2016; 566-567:1277-1288. [PMID: 27266523 DOI: 10.1016/j.scitotenv.2016.05.187] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 05/26/2016] [Accepted: 05/26/2016] [Indexed: 06/06/2023]
Abstract
Understanding the mechanisms by which abiotic drivers, such as climate and pollution, influence population dynamics of animals is important for our ability to predict the population trajectories of individual species under different global change scenarios. We monitored four leaf beetle species (Coleoptera: Chrysomelidae) feeding on willows (Salix spp.) in 13 sites along a pollution gradient in subarctic forests of north-western Russia from 1993 to 2014. During a subset of years, we also measured the impacts of natural enemies and host plant quality on the performance of one of these species, Chrysomela lapponica. Spring and fall temperatures increased by 2.5-3°C during the 21-year observation period, while emissions of sulfur dioxide and heavy metals from the nickel-copper smelter at Monchegorsk decreased fivefold. However, contrary to predictions of increasing herbivory with climate warming, and in spite of discovered increase in host plant quality with increase in temperatures, none of the beetle species became more abundant during the past 20years. No directional trends were observed in densities of either Phratora vitellinae or Plagiodera versicolora, whereas densities of both C. lapponica and Gonioctena pallida showed a simultaneous rapid 20-fold decline in the early 2000s, remaining at very low levels thereafter. Time series analysis and model selection indicated that these abrupt population declines were associated with decreases in aerial emissions from the smelter. Observed declines in the population densities of C. lapponica can be explained by increases in mortality from natural enemies due to the combined action of climate warming and declining pollution. This pattern suggests that at least in some tri-trophic systems, top-down factors override bottom-up effects and govern the impacts of environmental changes on insect herbivores.
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Affiliation(s)
- Elena L Zvereva
- Section of Ecology, Department of Biology, University of Turku, Turku 20014, Finland.
| | - Mark D Hunter
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI 48109-1048, USA
| | - Vitali Zverev
- Section of Ecology, Department of Biology, University of Turku, Turku 20014, Finland
| | - Mikhail V Kozlov
- Section of Ecology, Department of Biology, University of Turku, Turku 20014, Finland
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96
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Anstett DN, Nunes KA, Baskett C, Kotanen PM. Sources of Controversy Surrounding Latitudinal Patterns in Herbivory and Defense. Trends Ecol Evol 2016; 31:789-802. [DOI: 10.1016/j.tree.2016.07.011] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 05/09/2016] [Accepted: 07/21/2016] [Indexed: 12/23/2022]
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97
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Bixenmann RJ, Coley PD, Weinhold A, Kursar TA. High herbivore pressure favors constitutive over induced defense. Ecol Evol 2016; 6:6037-49. [PMID: 27648224 PMCID: PMC5016630 DOI: 10.1002/ece3.2208] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 05/05/2016] [Indexed: 11/13/2022] Open
Abstract
UNLABELLED Theoretical and empirical studies show that, when past or current herbivory is a reliable cue of future attack and defenses are costly, defenses can be induced only when needed and thereby permit investment in other functions such as growth or reproduction. Theory also states that, in environments where herbivory is constantly high, constitutive defenses should be favored. Here, we present data to support the second aspect of the induced resistance hypothesis. We examined herbivore-induced responses for four species of Inga (Fabaceae), a common canopy tree in Neotropical forests. We quantified chemical defenses of expanding leaves, including phenolic, saponin and toxic amino acids, in experimental field treatments with and without caterpillars. Because young leaves lack fiber and are higher in protein than mature leaves, they typically lose >25% of their leaf area during the few weeks of expansion. We predicted that the high rates of attack would select for investment in constitutive defenses over induction. Our data show that chemical defenses were quite unresponsive to herbivory. We demonstrated that expanding leaves showed no or only small increases in investment in secondary metabolites, and no qualitative changes in the phenolic compound profile in response to herbivory. The proteinogenic amino acid tyrosine, which can be toxic at high concentrations, showed the greatest levels of induction. SYNTHESIS These results provide some of the first support for theoretical predictions that the evolution of induced vs. constitutive defenses depends on the risk of herbivory. In habitats with constant and high potential losses to herbivores, such as tropical rainforests, high investments in constitutive defenses are favored over induction.
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Affiliation(s)
- Ryan J. Bixenmann
- Department of BiologyUniversity of Utah257S 1400ESalt Lake CityUtah84112
| | - Phyllis D. Coley
- Department of BiologyUniversity of Utah257S 1400ESalt Lake CityUtah84112
- Smithsonian Tropical Research InstituteBox 0843‐03092BalboaRepublic of Panama
| | - Alexander Weinhold
- Department of BiologyUniversity of Utah257S 1400ESalt Lake CityUtah84112
- German Centre for Integrative Biodiversity Research (iDiv), Halle‐Jena‐LeipzigDeutscher Platz 5eLeipzig04103Germany
| | - Thomas A. Kursar
- Department of BiologyUniversity of Utah257S 1400ESalt Lake CityUtah84112
- Smithsonian Tropical Research InstituteBox 0843‐03092BalboaRepublic of Panama
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98
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Latitudinal Gradients in Induced and Constitutive Resistance against Herbivores. J Chem Ecol 2016; 42:772-781. [PMID: 27501815 DOI: 10.1007/s10886-016-0735-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 04/11/2016] [Accepted: 07/25/2016] [Indexed: 01/14/2023]
Abstract
Plants are hypothesized to evolve increased defense against herbivores at lower latitudes, but an increasing number of studies report evidence that contradicts this hypothesis. Few studies have examined the evolution of constitutive and induced resistance along latitudinal gradients. When induction is not considered, underlying patterns of latitudinal clines in resistance can be obscured because plant resistance represents a combination of induced and constitutive resistance, which may show contrasting patterns with latitude. Here, we asked if there are latitudinal gradients in constitutive versus induced resistance by using genotypes of Oenothera biennis (Onagraceae) sampled along an 18° latitudinal gradient. We conducted two bioassay experiments to compare the resistance of plant genotypes against one generalist (Spodoptera exigua) and one specialist (Acanthoscelidius acephalus) herbivore. These insects were assayed on: i) undamaged control plants, ii) plants that had been induced with jasmonic acid, and iii) plants induced with herbivore damage. Additionally, we examined latitudinal gradients of constitutive and induced chemical resistance by measuring the concentrations of total phenolics, the concentration of oxidized phenolics, and the percentage of phenolics that were oxidized. Spodoptera exigua showed lower performance on plants from lower latitudes, whereas A. acephalus showed no latitudinal pattern. Constitutive total phenolics were greater in plants from lower latitudes, but induced plants showed higher total phenolics at higher latitudes. Oxidative activity was greatest at higher latitudes regardless of induction. Overall, both latitude and induction have an impact on different metrics of plant resistance to herbivory. Further studies should consider the effect of induction and herbivore specialization more explicitly, which may help to resolve the controversy in latitudinal gradients in herbivory and defense.
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99
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Dudeque Zenni R, Lacerda da Cunha W, Sena G. Rapid increase in growth and productivity can aid invasions by a non-native tree. AOB PLANTS 2016; 8:plw048. [PMID: 27339051 PMCID: PMC4972472 DOI: 10.1093/aobpla/plw048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 06/10/2016] [Indexed: 05/31/2023]
Abstract
Research on biological invasions has produced detailed theories describing range expansions of introduced populations. However, current knowledge of evolutionary factors associated with invasive range expansions, especially those related to rapid evolution of long-lived organisms, is still rudimentary. Here, we used a system of six 40-year-old invasive pine populations that originated from replicated introduction events to study evolution in productivity, growth, and chemical defence traits. We tested the hypotheses that invasive populations were undergoing rapid phenotypic change as populations spread, that populations exhibit trade-offs between evolution in growth and chemical defences, and that rates of rapid evolution in plant growth and productivity effect rates of invasion. Although all invasions started from replicated pools of genetic material and equal propagule pressure, we found divergence in mean values for the six invasive populations in the six traits measured. Not only were there between-population variations but also invasive populations were also rapidly changing along each invasive population expansion. Two populations displayed greater leaf areas (LAs) and smaller specific LAs (SLAs) during range expansion. Four populations had faster growth rates at the leading edge of the invasion front in comparison with plants at the rear edge. In terms of total plant defences, non-volatile resin increased in plants along one invasion gradient and decreased in a second, total needle phenolics increased in plants along one invasion gradient and total wood phenolics increased in plants along the one invasion gradient and decreased in a second. We found no trade-offs between investments in growth and chemical defence. Also, faster rates of change in growth rate and LA were positively associated with greater dispersal distances of invasive populations, suggesting rapid evolution may increase invasiveness. Understanding the roles of both natural and human-mediated ecological and evolutionary processes in population-level dynamics is key to understanding the ability of non-native species to invade.
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Affiliation(s)
- Rafael Dudeque Zenni
- Department of Ecology, University of Brasília, Campus Universitário Darcy Ribeiro, Brasília CEP 70910-900, Brazil
| | - Wanderson Lacerda da Cunha
- Department of Ecology, University of Brasília, Campus Universitário Darcy Ribeiro, Brasília CEP 70910-900, Brazil
| | - Guilherme Sena
- Department of Ecology, University of Brasília, Campus Universitário Darcy Ribeiro, Brasília CEP 70910-900, Brazil
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100
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A Framework for Predicting Intraspecific Variation in Plant Defense. Trends Ecol Evol 2016; 31:646-656. [DOI: 10.1016/j.tree.2016.05.007] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 05/17/2016] [Accepted: 05/19/2016] [Indexed: 01/01/2023]
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