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Pobłocka-Olech L, Głód D, Jesionek A, Łuczkiewicz M, Krauze-Baranowska M. Studies on the Polyphenolic Composition and the Antioxidant Properties of the Leaves of Poplar (Populus spp.) Various Species and Hybrids. Chem Biodivers 2021; 18. [PMID: 34138528 DOI: 10.1002/cbdv.202100227] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/27/2021] [Indexed: 11/08/2022]
Abstract
The chemical composition in terms of flavonoid and salicylic compounds of leaves from 6 species and 3 hybrids of poplars (Populus) was identified with the use of TLC and HPLC-DAD/ESI-MS methods. Chromatographic analyses were carried out with 21 standard compounds including salicylic compounds (2), phenolic acids (3) and flavonoids (16). Moreover, on the basis of the obtained chromatographic data from the HPLC-DAD/ESI-MS and TLC separations, the presence of salicortin, tremulacin and chlorogenic acid was confirmed, depending on the analyzed poplar species or hybrid. The content of salicylic compounds was determined by HPLC-UV method and expressed on salicin as free and total fraction. Total flavonoid content was determined by spectroscopic method as quercetin equivalent. Significant qualitative and quantitative differences in the chemical composition of the analyzed leaves were demonstrated. The highest concentration of flavonoids (8.02 mg/g) was found in the leaves of Populus nigra, while the highest content of salicylic compounds (47.14 mg/g) was found in the leaves of P.×berolinensis. The antioxidant and xanthine oxidase inhibition properties of extracts from poplar leaves were investigated by TLC bioautography. It has been shown that the richest set of compounds with antioxidant properties are present in the leaves of P. alba, P.×candicans and P. nigra.
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Affiliation(s)
- Loretta Pobłocka-Olech
- Department of Pharmacognosy with Medicinal Plants Garden, Faculty of Pharmacy, Medical University of Gdańsk, Gen. J. Hallera Str. 107, 80-416, Gdańsk, Poland
| | - Daniel Głód
- Department of Pharmacognosy with Medicinal Plants Garden, Faculty of Pharmacy, Medical University of Gdańsk, Gen. J. Hallera Str. 107, 80-416, Gdańsk, Poland
| | - Anna Jesionek
- Department of Pharmacognosy with Medicinal Plants Garden, Faculty of Pharmacy, Medical University of Gdańsk, Gen. J. Hallera Str. 107, 80-416, Gdańsk, Poland
| | - Maria Łuczkiewicz
- Department of Pharmacognosy with Medicinal Plants Garden, Faculty of Pharmacy, Medical University of Gdańsk, Gen. J. Hallera Str. 107, 80-416, Gdańsk, Poland
| | - Mirosława Krauze-Baranowska
- Department of Pharmacognosy with Medicinal Plants Garden, Faculty of Pharmacy, Medical University of Gdańsk, Gen. J. Hallera Str. 107, 80-416, Gdańsk, Poland
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Boyd MA, Berner LT, Foster AC, Goetz SJ, Rogers BM, Walker XJ, Mack MC. Historic declines in growth portend trembling aspen death during a contemporary leaf miner outbreak in Alaska. Ecosphere 2021. [DOI: 10.1002/ecs2.3569] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Affiliation(s)
- Melissa A. Boyd
- Center for Ecosystem Science and Society and Department of Biological Sciences Northern Arizona University Flagstaff Arizona86011USA
| | - Logan T. Berner
- School of Informatics, Computing, and Cyber Systems Northern Arizona University Flagstaff Arizona86011USA
| | - Adrianna C. Foster
- School of Informatics, Computing, and Cyber Systems Northern Arizona University Flagstaff Arizona86011USA
| | - Scott J. Goetz
- School of Informatics, Computing, and Cyber Systems Northern Arizona University Flagstaff Arizona86011USA
| | - Brendan M. Rogers
- Woodwell Climate Research Center Falmouth Massachusetts02540‐1644USA
| | - Xanthe J. Walker
- Center for Ecosystem Science and Society and Department of Biological Sciences Northern Arizona University Flagstaff Arizona86011USA
| | - Michelle C. Mack
- Center for Ecosystem Science and Society and Department of Biological Sciences Northern Arizona University Flagstaff Arizona86011USA
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Widespread mortality of trembling aspen (Populus tremuloides) throughout interior Alaskan boreal forests resulting from a novel canker disease. PLoS One 2021; 16:e0250078. [PMID: 33831122 PMCID: PMC8032200 DOI: 10.1371/journal.pone.0250078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 03/30/2021] [Indexed: 01/26/2023] Open
Abstract
Over the past several decades, growth declines and mortality of trembling aspen throughout western Canada and the United States have been linked to drought, often interacting with outbreaks of insects and fungal pathogens, resulting in a “sudden aspen decline” throughout much of aspen’s range. In 2015, we noticed an aggressive fungal canker causing widespread mortality of aspen throughout interior Alaska and initiated a study to quantify potential drivers for the incidence, virulence, and distribution of the disease. Stand-level infection rates among 88 study sites distributed across 6 Alaska ecoregions ranged from <1 to 69%, with the proportion of trees with canker that were dead averaging 70% across all sites. The disease is most prevalent north of the Alaska Range within the Tanana Kuskokwim ecoregion. Modeling canker probability as a function of ecoregion, stand structure, landscape position, and climate revealed that smaller-diameter trees in older stands with greater aspen basal area have the highest canker incidence and mortality, while younger trees in younger stands appear virtually immune to the disease. Sites with higher summer vapor pressure deficits had significantly higher levels of canker infection and mortality. We believe the combined effects of this novel fungal canker pathogen, drought, and the persistent aspen leaf miner outbreak are triggering feedbacks between carbon starvation and hydraulic failure that are ultimately driving widespread mortality. Warmer early-season temperatures and prolonged late summer drought are leading to larger and more severe wildfires throughout interior Alaska that are favoring a shift from black spruce to forests dominated by Alaska paper birch and aspen. Widespread aspen mortality fostered by this rapidly spreading pathogen has significant implications for successional dynamics, ecosystem function, and feedbacks to disturbance regimes, particularly on sites too dry for Alaska paper birch.
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Wenninger A, Hollingsworth T, Wagner D. Predatory hymenopteran assemblages in boreal Alaska: associations with forest composition and post-fire succession. ECOSCIENCE 2019. [DOI: 10.1080/11956860.2018.1564484] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Alexandria Wenninger
- Institute of Arctic Biology and Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Teresa Hollingsworth
- USDA Forest Service, Pacific Northwest Research Station, University of Alaska Fairbanks, Fairbanks, AK, USA
| | - Diane Wagner
- Institute of Arctic Biology and Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, USA
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Godschalx AL, Stady L, Watzig B, Ballhorn DJ. Is protection against florivory consistent with the optimal defense hypothesis? BMC PLANT BIOLOGY 2016; 16:32. [PMID: 26822555 PMCID: PMC4730643 DOI: 10.1186/s12870-016-0719-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 01/21/2016] [Indexed: 05/11/2023]
Abstract
BACKGROUND Plant defense traits require resources and energy that plants may otherwise use for growth and reproduction. In order to most efficiently protect plant tissues from herbivory, one widely accepted assumption of the optimal defense hypothesis states that plants protect tissues most relevant to fitness. Reproductive organs directly determining plant fitness, including flowers and immature fruit, as well as young, productive leaf tissue thus should be particularly well-defended. To test this hypothesis, we quantified the cyanogenic potential (HCNp)-a direct, chemical defense-systemically expressed in vegetative and reproductive organs in lima bean (Phaseolus lunatus), and we tested susceptibility of these organs in bioassays with a generalist insect herbivore, the Large Yellow Underwing (Noctuidae: Noctua pronuba). To determine the actual impact of either florivory (herbivory on flowers) or folivory on seed production as a measure of maternal fitness, we removed varying percentages of total flowers or young leaf tissue and quantified developing fruit, seeds, and seed viability. RESULTS We found extremely low HCNp in flowers (8.66 ± 2.19 μmol CN(-) g(-1) FW in young, white flowers, 6.23 ± 1.25 μmol CN(-) g(-1) FW in mature, yellow flowers) and in pods (ranging from 32.05 ± 7.08 to 0.09 ± 0.08 μmol CN(-) g(-1) FW in young to mature pods, respectively) whereas young leaves showed high levels of defense (67.35 ± 3.15 μmol CN(-) g(-1) FW). Correspondingly, herbivores consumed more flowers than any other tissue, which, when taken alone, appears to contradict the optimal defense hypothesis. However, experimentally removing flowers did not significantly impact fitness, while leaf tissue removal significantly reduced production of viable seeds. CONCLUSIONS Even though flowers were the least defended and most consumed, our results support the optimal defense hypothesis due to i) the lack of flower removal effects on fitness and ii) the high defense investment in young leaves, which have high consequences for fitness. These data highlight the importance of considering plant defense interactions from multiple angles; interpreting where empirical data fit within any plant defense hypothesis requires understanding the fitness consequences associated with the observed defense pattern.
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Affiliation(s)
- Adrienne L Godschalx
- Department of Biology, Portland State University, 1719 SW 10th Ave, Portland, OR, 97201, USA.
| | - Lauren Stady
- Department of Biology, Portland State University, 1719 SW 10th Ave, Portland, OR, 97201, USA.
| | - Benjamin Watzig
- Department of Biology, Portland State University, 1719 SW 10th Ave, Portland, OR, 97201, USA.
| | - Daniel J Ballhorn
- Department of Biology, Portland State University, 1719 SW 10th Ave, Portland, OR, 97201, USA.
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Doak P, Wagner D. The role of interference competition in a sustained population outbreak of the aspen leaf miner in Alaska. Basic Appl Ecol 2015. [DOI: 10.1016/j.baae.2015.04.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Chedgy RJ, Köllner TG, Constabel CP. Functional characterization of two acyltransferases from Populus trichocarpa capable of synthesizing benzyl benzoate and salicyl benzoate, potential intermediates in salicinoid phenolic glycoside biosynthesis. PHYTOCHEMISTRY 2015; 113:149-59. [PMID: 25561400 DOI: 10.1016/j.phytochem.2014.10.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 10/07/2014] [Accepted: 10/16/2014] [Indexed: 05/19/2023]
Abstract
Salicinoids are phenolic glycosides (PGs) characteristic of the Salicaceae and are known defenses against insect herbivory. Common examples are salicin, salicortin, tremuloidin, and tremulacin, which accumulate to high concentrations in the leaves and bark of willows and poplars. Although their biosynthetic pathway is not known, recent work has suggested that benzyl benzoate may be a potential biosynthetic intermediate. Two candidate genes, named PtACT47 and PtACT49, encoding BAHD-type acyl transferases were identified and are predicted to produce such benzylated secondary metabolites. Herein described are the cDNA cloning, heterologous expression and in vitro functional characterization of these two BAHD acyltransferases. Recombinant PtACT47 exhibited low substrate selectivity and could utilize acetyl-CoA, benzoyl-CoA, and cinnamoyl-CoA as acyl donors with a variety of alcohols as acyl acceptors. This enzyme showed the greatest Km/Kcat ratio (45.8 nM(-1) s(-1)) and lowest Km values (45.1 μM) with benzoyl-CoA and salicyl alcohol, and was named benzoyl-CoA: salicyl alcohol O-benzoyltransferase (PtSABT). Recombinant PtACT49 utilized a narrower range of substrates, including benzoyl-CoA and acetyl-CoA and a limited number of alcohols. Its highest Km/Kcat (31.8 nM(-1) s(-1)) and lowest Km (55.3 μM) were observed for benzoyl-CoA and benzyl alcohol, and it was named benzoyl-CoA: benzyl alcohol O-benzoyltransferase (PtBEBT). Both enzymes were also capable of synthesizing plant volatile alcohol esters, such as hexenyl benzoate, at trace levels. Although the activities demonstrated are consistent with roles in salicinoid biosynthesis, direct tests of this hypothesis using transgenic poplar must still be performed.
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Affiliation(s)
- Russell J Chedgy
- Centre for Forest Biology, Department of Biology, University of Victoria, P.O. Box 3020, STN CSC, Victoria, BC V8W 3N5, Canada
| | - Tobias G Köllner
- Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany
| | - C Peter Constabel
- Centre for Forest Biology, Department of Biology, University of Victoria, P.O. Box 3020, STN CSC, Victoria, BC V8W 3N5, Canada.
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Pentzold S, Zagrobelny M, Rook F, Bak S. How insects overcome two-component plant chemical defence: plant β-glucosidases as the main target for herbivore adaptation. Biol Rev Camb Philos Soc 2015; 89:531-51. [PMID: 25165798 DOI: 10.1111/brv.12066] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Insect herbivory is often restricted by glucosylated plant chemical defence compounds that are activated by plant β-glucosidases to release toxic aglucones upon plant tissue damage. Such two-component plant defences are widespread in the plant kingdom and examples of these classes of compounds are alkaloid, benzoxazinoid, cyanogenic and iridoid glucosides as well as glucosinolates and salicinoids. Conversely, many insects have evolved a diversity of counteradaptations to overcome this type of constitutive chemical defence. Here we discuss that such counter-adaptations occur at different time points, before and during feeding as well as during digestion, and at several levels such as the insects’ feeding behaviour, physiology and metabolism. Insect adaptations frequently circumvent or counteract the activity of the plant β-glucosidases, bioactivating enzymes that are a key element in the plant’s two-component chemical defence. These adaptations include host plant choice, non-disruptive feeding guilds and various physiological adaptations as well as metabolic enzymatic strategies of the insect’s digestive system. Furthermore, insect adaptations often act in combination, may exist in both generalists and specialists, and can act on different classes of defence compounds. We discuss how generalist and specialist insects appear to differ in their ability to use these different types of adaptations: in generalists, adaptations are often inducible, whereas in specialists they are often constitutive. Future studies are suggested to investigate in detail how insect adaptations act in combination to overcome plant chemical defences and to allow ecologically relevant conclusions.
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Yamawo A. Relatedness of Neighboring Plants Alters the Expression of Indirect Defense Traits in an Extrafloral Nectary-Bearing Plant. Evol Biol 2014. [DOI: 10.1007/s11692-014-9295-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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10
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Randriamanana TR, Nybakken L, Lavola A, Aphalo PJ, Nissinen K, Julkunen-Tiitto R. Sex-related differences in growth and carbon allocation to defence in Populus tremula as explained by current plant defence theories. TREE PHYSIOLOGY 2014; 34:471-87. [PMID: 24852570 DOI: 10.1093/treephys/tpu034] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Plant defence theories have recently evolved in such a way that not only the quantity but also the quality of mineral nutrients is expected to influence plant constitutive defence. Recently, an extended prediction derived from the protein competition model (PCM) suggested that nitrogen (N) limitation is more important for the production of phenolic compounds than phosphorus (P). We aimed at studying sexual differences in the patterns of carbon allocation to growth and constitutive defence in relation to N and P availability in Populus tremula L. seedlings. We compared the gender responses in photosynthesis, growth and whole-plant allocation to phenolic compounds at different combination levels of N and P, and studied how they are explained by the main plant defence theories. We found no sexual differences in phenolic concentrations, but interestingly, slow-growing females had higher leaf N concentration than did males, and genders differed in their allocation priority. There was a trade-off between growth and the production of flavonoid-derived phenylpropanoids on one hand, and between the production of salicylates and flavonoid-derived phenylpropanoids on the other. Under limited nutrient conditions, females prioritized mineral nutrient acquisition, flavonoid and condensed tannin (CT) production, while males invested more in above-ground biomass. Salicylate accumulation followed the growth differentiation balance hypothesis as low N mainly decreased the production of leaf and stem salicylate content while the combination of both low N and low P increased the amount of flavonoids and CTs allocated to leaves and to a lesser extent stems, which agrees with the PCM. We suggest that such a discrepancy in the responses of salicylates and flavonoid-derived CTs is linked to their clearly distinct biosynthetic origins and/or their metabolic costs.
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Affiliation(s)
- Tendry R Randriamanana
- Natural Products Research Laboratories, Department of Biology, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland
| | - Line Nybakken
- Natural Products Research Laboratories, Department of Biology, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland Department of Ecology and Natural Resource Management, Norwegian University of Life Sciences, Ås, Norway
| | - Anu Lavola
- Natural Products Research Laboratories, Department of Biology, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland
| | - Pedro J Aphalo
- Department of Biosciences, University of Helsinki, Helsinki, Finland
| | - Katri Nissinen
- Natural Products Research Laboratories, Department of Biology, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland
| | - Riitta Julkunen-Tiitto
- Natural Products Research Laboratories, Department of Biology, University of Eastern Finland, P.O. Box 111, 80101 Joensuu, Finland
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Mortensen B, Wagner D, Doak P. Parental resource and offspring liability: the influence of extrafloral nectar on oviposition by a leaf-mining moth. Oecologia 2012; 172:767-77. [PMID: 23223861 DOI: 10.1007/s00442-012-2525-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 10/30/2012] [Indexed: 11/29/2022]
Abstract
For many insect herbivores, maternal host selection is a critical determinant of offspring survival; however, maternal fitness is also affected by adult resources such as food availability. Consequently, adult resources may promote oviposition in sub-optimal locations when measured in terms of offspring performance. We tested whether oviposition site preference is primarily shaped by proximity to adult food resources or offspring performance in the aspen leaf miner (Phyllocnistis populiella). Quaking aspen (Populus tremuloides) produce extrafloral nectaries (EFNs) on a subset of their leaves. EFN expression on leaves is associated with decreased P. populiella damage and larval performance; however, P. populiella adults feed from EFNs. We reduced extrafloral nectar availability on entire aspen ramets and excluded crawling predators in a full factorial experiment at two sites in interior Alaska, USA. Patterns of egg deposition by P. populiella appeared to be primarily affected by offspring survival rather than adult resource availability. While oviposition was unaffected by nectar availability, adult moths laid fewer eggs on leaves with than without EFNs. By avoiding leaves with EFNs, moths increased offspring survival. Both moths and predators distinguished between leaves with and without EFNs even when nectar and visual cues were obscured, and therefore may respond to chemical cues associated with EFN expression.
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Affiliation(s)
- Brent Mortensen
- Department of Biology and Wildlife, Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000, USA.
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Li T, Holopainen JK, Kokko H, Tervahauta AI, Blande JD. Herbivore-induced aspen volatiles temporally regulate two different indirect defences in neighbouring plants. Funct Ecol 2012. [DOI: 10.1111/j.1365-2435.2012.01984.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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13
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Boeckler GA, Gershenzon J, Unsicker SB. Phenolic glycosides of the Salicaceae and their role as anti-herbivore defenses. PHYTOCHEMISTRY 2011; 72:1497-509. [PMID: 21376356 DOI: 10.1016/j.phytochem.2011.01.038] [Citation(s) in RCA: 184] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Revised: 01/26/2011] [Accepted: 01/28/2011] [Indexed: 05/21/2023]
Abstract
Since the 19th century the phytochemistry of the Salicaceae has been systematically investigated, initially for pharmaceutical and later for ecological reasons. The result of these efforts is a rich knowledge about the phenolic components, especially a series of glycosylated and esterified derivatives of salicyl alcohol known as "phenolic glycosides". These substances have received extensive attention with regard to their part in plant-herbivore interactions. The negative impact of phenolic glycosides on the performance of many generalist herbivores has been reported in numerous studies. Other more specialized feeders are less susceptible and have even been reported to sequester phenolic glycosides for their own defense. In this review, we attempt to summarize our current knowledge about the role of phenolic glycosides in mediating plant-herbivore interactions. As background, we first review what is known about their basic chemistry and occurrence in plants.
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Affiliation(s)
- G Andreas Boeckler
- Max Planck Institute for Chemical Ecology, Department of Biochemistry, Hans-Knöll Str. 8, 07745 Jena, Germany
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Mortensen B, Wagner D, Doak P. Defensive effects of extrafloral nectaries in quaking aspen differ with scale. Oecologia 2010; 165:983-93. [PMID: 20931234 DOI: 10.1007/s00442-010-1799-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 09/14/2010] [Indexed: 11/25/2022]
Abstract
The effects of plant defenses on herbivory can differ among spatial scales. This may be particularly common with indirect defenses, such as extrafloral nectaries (EFNs), that attract predatory arthropods and are dependent on predator distribution, abundance, and behavior. We tested the defensive effects of EFNs in quaking aspen (Populus tremuloides Michx.) against damage by a specialist herbivore, the aspen leaf miner (Phyllocnistis populiella Cham.), at the scale of individual leaves and entire ramets (i.e., stems). Experiments excluding crawling arthropods revealed that the effects of aspen EFNs differed at the leaf and ramet scales. Crawling predators caused similar reductions in the percent leaf area mined on individual leaves with and without EFNs. However, the extent to which crawling predators increased leaf miner mortality and, consequently, reduced mining damage increased with EFN expression at the ramet scale. Thus, aspen EFNs provided a diffuse defense, reducing damage to leaves across a ramet regardless of leaf-scale EFN expression. We detected lower leaf miner damage and survival unassociated with crawling predators on EFN-bearing leaves, suggesting that direct defenses (e.g., chemical defenses) were stronger on leaves with than without EFNs. Greater direct defenses on EFN-bearing leaves may reduce the probability of losing these leaves and thus weakening ramet-scale EFN defense. Aspen growth was not related to EFN expression or the presence of crawling predators over the course of a single season. Different effects of aspen EFNs at the leaf and ramet scales suggest that future studies may benefit from examining indirect defenses simultaneously at multiple scales.
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Affiliation(s)
- Brent Mortensen
- Department of Biology and Wildlife, Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775-7000, USA
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15
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Young B, Wagner D, Doak P, Clausen T. Induction of phenolic glycosides by quaking aspen (Populus tremuloides) leaves in relation to extrafloral nectaries and epidermal leaf mining. J Chem Ecol 2010; 36:369-77. [PMID: 20354896 DOI: 10.1007/s10886-010-9763-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2009] [Revised: 01/24/2010] [Accepted: 02/10/2010] [Indexed: 11/27/2022]
Abstract
We studied the effect of epidermal leaf mining on the leaf chemistry of quaking aspen, Populus tremuloides, during an outbreak of the aspen leaf miner, Phyllocnistis populiella, in the boreal forest of interior Alaska. Phyllocnistis populiella feeds on the epidermal cells of P. tremuloides leaves. Eleven days after the onset of leaf mining, concentrations of the phenolic glycosides tremulacin and salicortin were significantly higher in aspen leaves that had received natural levels of leaf mining than in leaves sprayed with insecticide to reduce mining damage. In a second experiment, we examined the time course of induction in more detail. The levels of foliar phenolic glycosides in naturally mined ramets increased relative to the levels in insecticide-treated ramets on the ninth day following the onset of leaf mining. Induction occurred while some leaf miner larvae were still feeding and when leaves had sustained mining over 5% of the leaf surface. Leaves with extrafloral nectaries (EFNs) had significantly higher constitutive and induced levels of phenolic glycosides than leaves lacking EFNs, but there was no difference in the ability of leaves with and without EFNs to induce phenolic glycosides in response to mining. Previous work showed that the extent of leaf mining damage was negatively related to the total foliar phenolic glycoside concentration, suggesting that phenolic glycosides deter or reduce mining damage. The results presented here demonstrate that induction of phenolic glycosides can be triggered by relatively small amounts of mining damage confined to the epidermal tissue, and that these changes in leaf chemistry occur while a subset of leaf miners are still feeding within the leaf.
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Affiliation(s)
- Brian Young
- Institute of Arctic Biology, Department of Biology & Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775-7000, USA.
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