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Monika Hilker - One of the best experts on this subject based on the ideXlab platform.
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Plant responses to Insect Eggs are not induced by egg-associated microbes, but by a secretion attached to the Eggs.
Plant cell & environment, 2020Co-Authors: Luis R. Paniagua Voirol, Georgios Valsamakis, Vivien Lortzing, Arne Weinhold, Paul R. Johnston, Nina E. Fatouros, Reinhard Kunze, Monika HilkerAbstract:Plants can enhance their defence against herbivorous Insects by responding to Insect egg depositions preceding larval feeding. The similarity of plant responses to Insect Eggs with those to phytopathogens gave rise to the hypothesis that egg-associated microbes might act as elicitors. We tested this hypothesis by investigating first if elimination of microbes in the butterfly Pieris brassicae changes the responses of Brassica nigra and Arabidopsis thaliana to Eggs and larvae of this Insect species. An antibiotic treatment of butterflies mitigated the plant transcriptional response to the Eggs and the egg-mediated enhancement of the plant's defence against larvae. However, application of cultivated microbial isolates from the Eggs onto Arabidopsis thaliana did not enhance the plant's anti-herbivore defence. Instead, application of an egg-associated glandular secretion, which is attaching the Eggs to the leaves, elicited the enhancing effect on the plant's defence against larvae. However, this effect was only achieved when the secretion was applied in similar quantities as released by control butterflies, but not when applied in the reduced quantity as released by antibiotic-treated butterflies. We conclude that glandular secretions rather than egg-associated microbes act in a dose-dependent manner as elicitor of the egg-mediated enhancement of the plant's defence against Insect larvae.
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plant responses to butterfly oviposition partly explain preference performance relationships on different brassicaceous species
bioRxiv, 2019Co-Authors: Eddie Griese, Monika Hilker, Marcel Dicke, Ana Pineda, Foteini G Pashalidou, Eleonora Pizarro Iradi, Nina E. FatourosAbstract:According to the preference-performance hypothesis (PPH), also known as mother-knows-best hypothesis, herbivorous Insects prefer those plants for oviposition, which yield the best offspring performance. Yet, most studies testing the PPH neglect the possibility that plant responses to Insect Eggs may affect both egg survival and larval performance. Here, we tested the PPH by studying responses of seven Brassicaceae plant species to oviposition by two cabbage white species. When including the egg phase, our study supports the mother-knows-best hypothesis: larvae of Pieris rapae (solitary) or P. brassicae (gregarious) gained most weight on those plant species which had received most Eggs (B. nigra or B. montana, respectively). However, our experiments did not reveal any relationship between oviposition preference and egg survival. Brassicaceous species are known to respond to these butterfly Eggs with a hypersensitive response (HR)-like necrosis, which can lower egg survival. Pieris Eggs frequently induced necrosis in five of the tested plant species. Survival of clustered P. brassicae Eggs was unaffected by HR-like in four of the five species. Therefore, our experiments did not reveal any relationship between P. brassicae egg survival and oviposition preference. Females of P. rapae preferred oviposition on plant species which most frequently showed HR-like necrosis. Remarkably, although egg survival was lower on HR-like plants, larval biomass was higher compared to plants without a necrosis. We conclude that egg survival does not seem to be a deciding factor for oviposition choices. However, egg-mediated plant responses might be important to explain the PPH of the two Pieris species.
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resisting the onset of herbivore attack plants perceive and respond to Insect Eggs
Current Opinion in Plant Biology, 2016Co-Authors: Monika Hilker, Nina E. FatourosAbstract:Plants can respond to attack by herbivorous Insects very soon after herbivores start producing a new generation by depositing Eggs onto their leaves. Egg-induced plant responses may result in killing the attacker in its egg stage. However, if the Eggs do survive, they can also prime feeding-induced plant defenses against the larvae hatching from Eggs. In this paper we focus first on egg-induced plant responses that resemble hypersensitive responses (HR) to phytopathogens and lead to egg desiccation or detachment from plants. We then summarize the current knowledge about egg-mediated effects on feeding-induced plant defenses against larvae. Finally, we discuss the Insect species specificity of plant responses to Eggs and the variability of Insect susceptibility to these responses.
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pre exposure of arabidopsis to the abiotic or biotic environmental stimuli chilling or Insect Eggs exhibits different transcriptomic responses to herbivory
Scientific Reports, 2016Co-Authors: Vivien Firtzlaff, Monika Hilker, Jana Oberlander, Sven Geiselhardt, Reinhard KunzeAbstract:Plants can retain information about environmental stress and thus, prepare themselves for impending stress. In nature, it happens that environmental stimuli like ‘cold’ and ‘Insect egg deposition’ precede Insect herbivory. Both these stimuli are known to elicit transcriptomic changes in Arabidposis thaliana. It is unknown, however, whether they affect the plant’s anti-herbivore defence and feeding-induced transcriptome when they end prior to herbivory. Here we investigated the transcriptomic response of Arabidopsis to feeding by Pieris brassicae larvae after prior exposure to cold or oviposition. The transcriptome of plants that experienced a five-day-chilling period (4 °C) was not fully reset to the pre-chilling state after deacclimation (20 °C) for one day and responded differently to herbivory than that of chilling-inexperienced plants. In contrast, when after a five-day-lasting oviposition period the Eggs were removed, one day later the transcriptome and, consistently, also its response to herbivory resembled that of egg-free plants. Larval performance was unaffected by previous exposure of plants to cold and to Eggs, thus indicating P. brassicae tolerance to cold-mediated plant transcriptomic changes. Our results show strong differences in the persistence of the plant’s transcriptomic state after removal of different environmental cues and consequently differential effects on the transcriptomic response to later herbivory.
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elm leaves warned by Insect egg deposition reduce survival of hatching larvae by a shift in their quantitative leaf metabolite pattern
Plant Cell and Environment, 2016Co-Authors: Nadine Austel, Torsten Meiners, Elisabeth J Eilers, Monika HilkerAbstract:Plants may take Insect Eggs on their leaves as a warning of future herbivory and intensify their defence against feeding larvae. Responsible agents are, however, largely unknown, and little knowledge is available on this phenomenon in perennial plants. We investigated how egg deposition affects the anti-herbivore defence of elm against the multivoltine elm leaf beetle. Prior egg deposition caused changes in the quality of feeding-damaged leaves that resulted in increased larval mortality and reduced reproductive capacity of the herbivore by harming especially female larvae. Chemical analyses of primary and secondary leaf metabolites in feeding-damaged, egg-free (F) and feeding-damaged, egg-deposited (EF)-leaves revealed only small differences in concentrations when comparing metabolites singly. However, a pattern-focused analysis showed clearly separable patterns of (F) and (EF)-leaves because of concentration differences in especially nitrogen and phenolics, of which robinin was consumed in greater amounts by larvae on (EF) than on (F)-leaves. Our study shows that Insect egg deposition mediates a shift in the quantitative nutritional pattern of feeding-damaged leaves, and thus might limit the herbivore's population growth by reducing the number of especially female herbivores. This may be a strategy that pays off in a long run particularly in perennial plants against multivoltine herbivores.
Arthur H Woods - One of the best experts on this subject based on the ideXlab platform.
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subtle direct effects of rising atmospheric co2 on Insect Eggs
Physiological Entomology, 2013Co-Authors: Emily D Kerr, Conan Phelan, Arthur H WoodsAbstract:Ocean acidification is an important consequence of rising levels of atmospheric CO2. The chemistry of acidification is, however, general and may disturb pH in terrestrial systems. The present study examines the effects of rising CO2 on Insect Eggs, which may be vulnerable to acidification because they are small, have (at least initially) poorly developed physiological systems, and support important developmental events. Newly-laid Eggs of the moth Manduca sexta are exposed to levels of CO2 between 0 and 2200 p.p.m., in air, and effects on yolk pH, total developmental time, and survival are measured. Altered CO2 has no effect, over several hours, on the pH of egg yolk, suggesting that yolk fluids are well buffered. By contrast, there is a large developmental change in yolk pH. Eggs exposed to eight different levels of CO2 for the duration of development show a small but significant parabolic response in development time. Eggs develop fastest at intermediate levels of CO2, between 400 and 1200 p.p.m., and slower at 0, 1600 and 2000 p.p.m. These results suggest that future rises in CO2 may not have strong direct effects on Insect development.
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Insect Eggs protected from high temperatures by limited homeothermy of plant leaves
The Journal of Experimental Biology, 2009Co-Authors: Kristen A Potter, Goggy Davidowitz, Arthur H WoodsAbstract:SUMMARY Virtually all aspects of Insect biology are affected by body temperature, and many taxa have evolved sophisticated temperature-control mechanisms. All Insects, however, begin life as Eggs and lack the ability to thermoregulate. Eggs laid on leaves experience a thermal environment, and thus a body temperature, that is strongly influenced by the leaves themselves. Because plants can maintain leaf temperatures that differ from ambient, e.g. by evapotranspiration, plant hosts may protect Eggs from extreme ambient temperatures. We examined the degree to which leaves buffer ambient thermal variation and whether that buffering benefits leaf-associated Insect Eggs. In particular, we: (1) measured temperature variation at oviposition sites in the field, (2) manipulated temperatures in the laboratory to determine the effect of different thermal conditions on embryo development time and survival, and (3) tested embryonic metabolic rates over increasing temperatures. Our results show that Datura wrightii leaves buffer Manduca sexta Eggs from fatally high ambient temperatures in the southwestern USA. Moreover, small differences in temperature profiles among leaves can cause large variation in egg metabolic rate and development time. Specifically, large leaves were hotter than small leaves during the day, reaching temperatures that are stressfully high for Eggs. This study provides the first mechanistic demonstration of how this type of leaf-constructed thermal refuge interacts with egg physiology.
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Insect Eggs at a transition between diffusion and reaction limitation temperature oxygen and water
Journal of Theoretical Biology, 2006Co-Authors: Arthur H Woods, Roger T BonnecazeAbstract:In diverse animal taxa, Eggs and embryos are incapable of transporting oxygen by convection. In such cases, internal oxygen distributions are determined jointly by rates of oxygen consumption and diffusive transport. Here we develop a mathematical model of oxygen consumption and transport in Insect Eggs, with the goal of understanding-for Eggs in variable-temperature environments-the interactive effects of the two processes on development. We fit the model to previously published data on development time of Eggs of a sphingid moth, Manduca sexta. The fitted coefficients suggest that Eggs develop at a transition point between reaction- and diffusion-limitation. We test then this conclusion with independent data on development times of Eggs distributed across a set of temperatures generated by a thermal gradient bar. Finally, we develop an extension of the model that considers tradeoffs between oxygen transfer to Eggs versus water loss from them. The model results provide both a rationale for why development is often mass-transfer limited and a set of new predictions about oxygen-water tradeoffs.
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Insect Eggs exert rapid control over an oxygen water tradeoff
Proceedings of The Royal Society B: Biological Sciences, 2006Co-Authors: Brandy Zrubek, Arthur H WoodsAbstract:In terrestrial environments, the exchange of respiratory gases exacts a water cost: obtaining oxygen or carbon dioxide requires losing water. Insect Eggs should be especially sensitive to this trad...
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oxygen and water flux across Eggshells of manduca sexta
The Journal of Experimental Biology, 2005Co-Authors: Arthur H Woods, Roger T Bonnecaze, Brandy ZrubekAbstract:Insect Eggs must obtain oxygen across the Eggshell to support embryonic development. Because Eggs are small, obtaining enough oxygen would seem trivial. Recent work, however, has shown that Eggs of a moth, Manduca sexta, are oxygen limited at high but realistic temperatures (32‐37°C) and that PO∑ drops steeply across the Eggshell. Here we use theoretical and experimental approaches to partition the total resistance to oxygen flux among several steps in the oxygen cascade from environment to embryo. Standard mass-transfer analysis suggests that boundary layers of air around Eggs, and around substrates to which they are attached, offer negligible resistance. Likewise, a mathematical model, parameterized using published and newly obtained morphological data, predicts that air-filled parts of the chorion also do not resist oxygen flux. This prediction was confirmed by experiments that measured rates of carbon dioxide emission from batches of Eggs subjected simultaneously to hypoxia and inert gas substitution: depression of metabolic rate by hypoxia was not rescued when the diffusion coefficient of oxygen in air was doubled by substituting helium for nitrogen. The model did predict, however, that a set of subchoral layers (a crystalline chorionic layer, a wax layer and the vitelline membrane) could account for most or all of the total resistance to oxygen flux. Support for this prediction was obtained from two sequential experiments. First, Eggs extracted with chloroform:methanol had highly elevated rates of water loss, suggesting that indeed Eggs of M. sexta are waterproofed by wax. Second, rates of water loss and carbon dioxide emission from batches of Eggs, measured from laying to hatching, changed in parallel over development. These data suggest that a single layer, likely a wax layer or a combination of wax and other subchoral layers, provides the main resistance to water efflux and oxygen influx.
Gary W Felton - One of the best experts on this subject based on the ideXlab platform.
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Insect Eggs Can Enhance Wound Response in Plants: A Study System of Tomato Solanum lycopersicum L. and
2016Co-Authors: Helicoverpa Zea Boddie, John F Tooker, Consuelo M De Moraes, Douglas S Luthe, Jinwon Kim, Gary W FeltonAbstract:Insect oviposition on plants frequently precedes herbivory. Accumulating evidence indicates that plants recognize Insect oviposition and elicit direct or indirect defenses to reduce the pressure of future herbivory. Most of the oviposition-triggered plant defenses described thus far remove Eggs or keep them away from the host plant or their desirable feeding sites. Here, we report induction of antiherbivore defense by Insect oviposition which targets newly hatched larvae, not the Eggs, in the system of tomato Solanum lycopersicum L., and tomato fruitworm moth Helicoverpa zea Boddie. When tomato plants were oviposited by H. zeamoths, pin2, a highly inducible gene encoding protease inhibitor2, which is a representative defense protein against herbivorous arthropods, was expressed at significantly higher level at the oviposition site than surrounding tissues, and expression decreased with distance away from the site of oviposition. Moreover, more Eggs resulted in higher pin2 expression in leaves, and both fertilized and unfertilized Eggs induced pin2 expression. Notably, when quantified daily following deposition of Eggs, pin2 expression at the oviposition site was highest just before the emergence of larvae. Furthermore, H. zea oviposition primed the wound-induced increase of pin2 transcription and a burst of jasmonic acid (JA); tomato plants previously exposed to H. zea oviposition showed significantly stronger induction of pin2 and higher production of JA upon subsequent simulated herbivory than without oviposition. Our results suggest that tomato plants recognize H. zea oviposition as a signal of impending future herbivory and induce defenses to prepare for thi
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Insect Eggs can enhance wound response in plants a study system of tomato solanum lycopersicum l and helicoverpa zea boddie
PLOS ONE, 2012Co-Authors: John F Tooker, Consuelo M De Moraes, Douglas S Luthe, Gary W FeltonAbstract:Insect oviposition on plants frequently precedes herbivory. Accumulating evidence indicates that plants recognize Insect oviposition and elicit direct or indirect defenses to reduce the pressure of future herbivory. Most of the oviposition-triggered plant defenses described thus far remove Eggs or keep them away from the host plant or their desirable feeding sites. Here, we report induction of antiherbivore defense by Insect oviposition which targets newly hatched larvae, not the Eggs, in the system of tomato Solanum lycopersicum L., and tomato fruitworm moth Helicoverpa zea Boddie. When tomato plants were oviposited by H. zea moths, pin2, a highly inducible gene encoding protease inhibitor2, which is a representative defense protein against herbivorous arthropods, was expressed at significantly higher level at the oviposition site than surrounding tissues, and expression decreased with distance away from the site of oviposition. Moreover, more Eggs resulted in higher pin2 expression in leaves, and both fertilized and unfertilized Eggs induced pin2 expression. Notably, when quantified daily following deposition of Eggs, pin2 expression at the oviposition site was highest just before the emergence of larvae. Furthermore, H. zea oviposition primed the wound-induced increase of pin2 transcription and a burst of jasmonic acid (JA); tomato plants previously exposed to H. zea oviposition showed significantly stronger induction of pin2 and higher production of JA upon subsequent simulated herbivory than without oviposition. Our results suggest that tomato plants recognize H. zea oviposition as a signal of impending future herbivory and induce defenses to prepare for this herbivory by newly hatched neonate larvae.
John F Tooker - One of the best experts on this subject based on the ideXlab platform.
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Insect Eggs Can Enhance Wound Response in Plants: A Study System of Tomato Solanum lycopersicum L. and
2016Co-Authors: Helicoverpa Zea Boddie, John F Tooker, Consuelo M De Moraes, Douglas S Luthe, Jinwon Kim, Gary W FeltonAbstract:Insect oviposition on plants frequently precedes herbivory. Accumulating evidence indicates that plants recognize Insect oviposition and elicit direct or indirect defenses to reduce the pressure of future herbivory. Most of the oviposition-triggered plant defenses described thus far remove Eggs or keep them away from the host plant or their desirable feeding sites. Here, we report induction of antiherbivore defense by Insect oviposition which targets newly hatched larvae, not the Eggs, in the system of tomato Solanum lycopersicum L., and tomato fruitworm moth Helicoverpa zea Boddie. When tomato plants were oviposited by H. zeamoths, pin2, a highly inducible gene encoding protease inhibitor2, which is a representative defense protein against herbivorous arthropods, was expressed at significantly higher level at the oviposition site than surrounding tissues, and expression decreased with distance away from the site of oviposition. Moreover, more Eggs resulted in higher pin2 expression in leaves, and both fertilized and unfertilized Eggs induced pin2 expression. Notably, when quantified daily following deposition of Eggs, pin2 expression at the oviposition site was highest just before the emergence of larvae. Furthermore, H. zea oviposition primed the wound-induced increase of pin2 transcription and a burst of jasmonic acid (JA); tomato plants previously exposed to H. zea oviposition showed significantly stronger induction of pin2 and higher production of JA upon subsequent simulated herbivory than without oviposition. Our results suggest that tomato plants recognize H. zea oviposition as a signal of impending future herbivory and induce defenses to prepare for thi
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Insect Eggs can enhance wound response in plants a study system of tomato solanum lycopersicum l and helicoverpa zea boddie
PLOS ONE, 2012Co-Authors: John F Tooker, Consuelo M De Moraes, Douglas S Luthe, Gary W FeltonAbstract:Insect oviposition on plants frequently precedes herbivory. Accumulating evidence indicates that plants recognize Insect oviposition and elicit direct or indirect defenses to reduce the pressure of future herbivory. Most of the oviposition-triggered plant defenses described thus far remove Eggs or keep them away from the host plant or their desirable feeding sites. Here, we report induction of antiherbivore defense by Insect oviposition which targets newly hatched larvae, not the Eggs, in the system of tomato Solanum lycopersicum L., and tomato fruitworm moth Helicoverpa zea Boddie. When tomato plants were oviposited by H. zea moths, pin2, a highly inducible gene encoding protease inhibitor2, which is a representative defense protein against herbivorous arthropods, was expressed at significantly higher level at the oviposition site than surrounding tissues, and expression decreased with distance away from the site of oviposition. Moreover, more Eggs resulted in higher pin2 expression in leaves, and both fertilized and unfertilized Eggs induced pin2 expression. Notably, when quantified daily following deposition of Eggs, pin2 expression at the oviposition site was highest just before the emergence of larvae. Furthermore, H. zea oviposition primed the wound-induced increase of pin2 transcription and a burst of jasmonic acid (JA); tomato plants previously exposed to H. zea oviposition showed significantly stronger induction of pin2 and higher production of JA upon subsequent simulated herbivory than without oviposition. Our results suggest that tomato plants recognize H. zea oviposition as a signal of impending future herbivory and induce defenses to prepare for this herbivory by newly hatched neonate larvae.
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Jasmonate, Salicylate, and Benzoate in Insect Eggs
Journal of Chemical Ecology, 2006Co-Authors: John F Tooker, Consuelo M De MoraesAbstract:Jasmonic acid (JA) and salicylic acid (SA) are key molecules in the initiation of plant defensive responses to attack by herbivores and pathogens, respectively. Our previous work has shown that JA occurs at high concentrations in Eggs and neonates of lepidopteran species. Here, we extend our analyses to Eggs of 15 non-lepidopteran Insect species spanning eight orders, again screening for JA, but also including SA and one of its metabolic precursors, benzoic acid. We detected all three compounds in Eggs of almost all the species examined. Moreover, concentrations of these compounds were variable across species, suggesting that species accumulate and/or utilize the compounds differently. Eggs of the fruit-feeding fly Rhagoletis pomonella contained the greatest concentrations of all three compounds, which appear to be common in fruit. The presence of these plant-derived compounds in Eggs may serve defensive or other functions for Insects, and could conceivably trigger plant defensive responses after oviposition.
Philippe Reymond - One of the best experts on this subject based on the ideXlab platform.
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arabidopsis myc transcription factors are the target of hormonal salicylic acid jasmonic acid cross talk in response to pieris brassicae egg extract
Plant Physiology, 2016Co-Authors: Andre Schmiesing, Aurelia Emonet, Caroline Gouhierdarimont, Philippe ReymondAbstract:Arabidopsis (Arabidopsis thaliana) plants recognize Insect Eggs and activate the salicylic acid (SA) pathway. As a consequence, expression of defense genes regulated by the jasmonic acid (JA) pathway is suppressed and larval performance is enhanced. Cross talk between defense signaling pathways is common in plant-pathogen interactions, but the molecular mechanism mediating this phenomenon is poorly understood. Here, we demonstrate that egg-induced SA/JA antagonism works independently of the APETALA2/ETHYLENE RESPONSE FACTOR (AP2/ERF) transcription factor ORA59, which controls the ERF branch of the JA pathway. In addition, treatment with egg extract did not enhance expression or stability of JASMONATE ZIM-domain transcriptional repressors, and SA/JA cross talk did not involve JASMONATE ASSOCIATED MYC2-LIKEs, which are negative regulators of the JA pathway. Investigating the stability of MYC2, MYC3, and MYC4, three basic helix-loop-helix transcription factors that additively control jasmonate-related defense responses, we found that egg extract treatment strongly diminished MYC protein levels in an SA-dependent manner. Furthermore, we identified WRKY75 as a novel and essential factor controlling SA/JA cross talk. These data indicate that Insect Eggs target the MYC branch of the JA pathway and uncover an unexpected modulation of SA/JA antagonism depending on the biological context in which the SA pathway is activated.
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Insect Eggs induce a systemic acquired resistance in Arabidopsis.
The Plant Journal, 2014Co-Authors: Olivier Hilfiker, Raphael Groux, Friederike Bruessow, Karin Kiefer, Jürgen Zeier, Philippe ReymondAbstract:Although they constitute an inert stage of the Insect's life, Eggs trigger plant defences that lead to egg mortality or attraction of egg parasitoids. We recently found that salicylic acid (SA) accumulates in response to oviposition by the Large White butterfly Pieris brassicae, both in local and systemic leaves, and that plants activate a response that is similar to the recognition of pathogen-associated molecular patterns (PAMPs), which are involved in PAMP-triggered immunity (PTI). Here we discovered that natural oviposition by P. brassicae or treatment with egg extract inhibit growth of different Pseudomonas syringae strains in Arabidopsis through the activation of a systemic acquired resistance (SAR). This egg-induced SAR involves the metabolic SAR signal pipecolic acid, depends on ALD1 and FMO1, and is accompanied by a stronger induction of defence genes upon secondary infection. Although P. brassicae larvae showed a reduced performance when feeding on Pseudomonas syringae-infected plants, this effect was less pronounced when infected plants had been previously oviposited. Altogether, our results indicate that egg-induced SAR might have evolved as a strategy to prevent the detrimental effect of bacterial pathogens on feeding larvae.
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Insect Eggs suppress plant defence against chewing herbivores
Plant Journal, 2010Co-Authors: Friederike Bruessow, Caroline Gouhierdarimont, Antony Buchala, Jeanpierre Metraux, Philippe ReymondAbstract:Plants activate direct and indirect defences in response to Insect egg deposition. However, whether Eggs can manipulate plant defence is unknown. In Arabidopsis thaliana, oviposition by the butterfly Pieris brassicae triggers cellular and molecular changes that are similar to the changes caused by biotrophic pathogens. In the present study, we found that the plant defence signal salicylic acid (SA) accumulates at the site of oviposition. This is unexpected, as the SA pathway controls defence against fungal and bacterial pathogens and negatively interacts with the jasmonic acid (JA) pathway, which is crucial for the defence against herbivores. Application of P. brassicae or Spodoptera littoralis egg extract onto leaves reduced the induction of Insect-responsive genes after challenge with caterpillars, suggesting that egg-derived elicitors suppress plant defence. Consequently, larval growth of the generalist herbivore S. littoralis, but not of the specialist P. brassicae, was significantly higher on plants treated with egg extract than on control plants. In contrast, suppression of gene induction and enhanced S. littoralis performance were not seen in the SA-deficient mutant sid2-1, indicating that it is SA that mediates this phenomenon. These data reveal an intriguing facet of the cross-talk between SA and JA signalling pathways, and suggest that Insects have evolved a way to suppress the induction of defence genes by laying Eggs that release elicitors. We show here that egg-induced SA accumulation negatively interferes with the JA pathway, and provides an advantage for generalist herbivores.
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oviposition by pierid butterflies triggers defense responses in arabidopsis
Plant Physiology, 2006Co-Authors: Dawn Little, Friederike Bruessow, Caroline Gouhierdarimont, Philippe ReymondAbstract:Insect Eggs represent a threat for the plant as hatching larvae rapidly start with their feeding activity. Using a whole-genome microarray, we studied the expression profile of Arabidopsis (Arabidopsis thaliana) leaves after oviposition by two pierid butterflies. For Pieris brassicae, the deposition of egg batches changed the expression of hundreds of genes over a period of 3 d after oviposition. The transcript signature was similar to that observed during a hypersensitive response or in lesion-mimic mutants, including the induction of defense and stress-related genes and the repression of genes involved in growth and photosynthesis. Deposition of single Eggs by Pieris rapae caused a similar although much weaker transcriptional response. Analysis of the jasmonic acid and salicylic acid mutants coi1-1 and sid2-1 indicated that the response to egg deposition is mostly independent of these signaling pathways. Histochemical analyses showed that egg deposition is causing a localized cell death, accompanied by the accumulation of callose, and the production of reactive oxygen species. In addition, activation of the pathogenesis-related1∷β-glucuronidase reporter gene correlated precisely with the site of egg deposition and was also triggered by crude egg extract. This study provides molecular evidence for the detection of egg deposition by Arabidopsis plants and suggests that oviposition causes a localized response with strong similarity to a hypersensitive response.