Volatiles Emission by Crotalaria nitens after Insect Attack.
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ABSTRACT:
SUBMITTER: Prada F
PROVIDER: S-EPMC8618423 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Plants produce volatile organic compounds that are important in communication and defense. While studies have largely focused on volatiles emitted from aboveground plant parts upon exposure to biotic or abiotic stresses, volatile emissions from roots upon aboveground stress are less studied. Here, we investigated if tomato plants under insect herbivore attack exhibited a different root volatilome than non-stressed plants, and whether this was influenced by the plant's genetic background. To this end, we analyzed one domesticated and one wild tomato species, i.e., Solanum lycopersicum cv Moneymaker and Solanum pimpinellifolium, respectively, exposed to leaf herbivory by the insect Spodoptera exigua. Root volatiles were trapped with two sorbent materials, HiSorb and PDMS, at 24 h after exposure to insect stress. Our results revealed that differences in root volatilome were species-, stress-, and material-dependent. Upon leaf herbivory, the domesticated and wild tomato species showed different root volatile profiles. The wild species presented the largest change in root volatile compounds with an overall reduction in monoterpene emission under stress. Similarly, the domesticated species presented a slight reduction in monoterpene emission and an increased production of fatty-acid-derived volatiles under stress. Volatile profiles differed between the two sorbent materials, and both were required to obtain a more comprehensive characterization of the root volatilome. Collectively, these results provide a strong basis to further unravel the impact of herbivory stress on systemic volatile emissions.
| S-EPMC8911868 | biostudies-literature
Project description:Summary Chemical signals mediate major ecological interactions in insects. However, using bioassays only, it is difficult to quantify the bioactivity of complex mixtures, such as volatile defensive secretions emitted by prey insects, and to assess the impact of single compounds on the repellence of the entire mixture. To represent chemical data in a different perceptive mode, we used a process of sonification by parameter mapping of single molecules, which translated chemical signals into acoustic signals. These sounds were then mixed at dB levels reflecting the relative concentrations of the molecules within species-specific secretions. Repellence of single volatiles, as well as mixtures of volatiles, against predators were significantly correlated with the repulsiveness of their respective auditory translates against humans, who mainly reacted to sound pressure. Furthermore, sound pressure and predator response were associated with the number of different molecules in a secretion. Our transmodal approach, from olfactory to auditory perception, offers further prospects for chemo-ecological research and data representation. Highlights • The defensive secretion emitted by insects is often a mixture of volatiles• Volatiles were translated into sounds by sonification using parameter mapping• Chemical signals were repulsive for predators, as were the sounds for humans The bigger picture Insects are often defended against predators by emitting volatile secretions that act as a repellent. Chemical analyses of a secretion provide a list of compounds and their concentrations, but it then remains challenging to study their single and combined bioactivities. Here, we provide a first approach in understanding the bioactivity of single volatiles and volatile mixtures by developing a process of sonification (parameter mapping) to model chemical signals into auditory ones. Our study reveals via bioassays that foraging predators are repelled by volatiles as are human volunteers upon hearing "sonified volatiles". In these audio clips, we could also identify one sound attribute, their maximal loudness, that correlates well with the human response in the modeled world and hence with the predator response in the real world. These findings may help in exploring and understanding the seemingly overabundant diversity of deleterious chemicals present in insects and other organisms. A methodology is described to predict and compare the interspecific repellence of defensive secretions from insects that typically emit volatiles as complex mixtures. Sonification by parameter mapping allowed us to hear single molecules, then their mixtures. Bioassays used insect predators tested against the two sets of stimuli, single and mixed volatiles, as well as humans hearing the corresponding auditory translates. The model based on gathered chemical data can serve as a proxy but quantitative indicator of repellent bioactivities.
| S-EPMC8600227 | biostudies-literature
Project description:Fungal volatile organic compounds (VOCs) represent promising candidates for biopesticide fumigants to control crop pests and pathogens. Herein, VOCs produced using three strains of the entomopathogenic fungus Metarhizium brunneum were identified via GC-MS and screened for antimicrobial activity. The VOC profiles varied with fungal strain, development state (mycelium, spores) and culture conditions. Selected VOCs were screened against a range of rhizosphere and non-rhizosphere microbes, including three Gram-negative bacteria (Escherichia coli, Pantoea agglomerans, Pseudomonas aeruginosa), five Gram-positive bacteria (Micrococcus luteus, Staphylococcus aureus, Bacillus subtilis, B. megaterium, B. thuringiensis), two yeasts (Candida albicans, Candida glabrata) and three plant pathogenic fungi (Pythium ultimum, Botrytis cinerea, Fusarium graminearum). Microbes differed in their sensitivity to the test compounds, with 1-octen-3-ol and isovaleric acid showing broad-spectrum antimicrobial activity. Yeasts and bacteria were inhibited by the same VOCs. Cryo-SEM showed that both yeasts and bacteria underwent some form of "autolysis", where all components of the cell, including the cell wall, disintegrated with little evidence of their presence in the clear, inhibition zone. The oomycete (P. ultimum) and ascomycete fungi (F. graminearum, B. cinerea) were sensitive to a wider range of VOCs than the bacteria, suggesting that eukaryotic microbes are the main competitors to M. brunneum in the rhizosphere. The ability to alter the VOC profile in response to nutritional cues may assist M. brunneum to survive among the roots of a wide range of plant species. Our VOC studies provided new insights as to how M. brunneum may protect plants from pathogenic microbes and correspondingly promote healthy growth.
| S-EPMC9025432 | biostudies-literature
Project description:Plant defenses against pathogens and insects are regulated differentially by cross-communicating signaling pathways in which salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) play key roles. To understand how plants integrate pathogen- and insect-induced signals into specific defense responses, we monitored the dynamics of SA, JA, and ET signaling in Arabidopsis after attack by a set of microbial pathogens and herbivorous insects with different modes of attack. Arabidopsis plants were exposed to a pathogenic leaf bacterium (Pseudomonas syringae pv. tomato), a pathogenic leaf fungus (Alternaria brassicicola), tissue-chewing caterpillars (Pieris rapae), cell-content-feeding thrips (Frankliniella occidentalis), or phloem-feeding aphids (Myzus persicae). Monitoring the signal signature in each plant-attacker combination showed that the kinetics of SA, JA, and ET production varies greatly in both quantity and timing. Analysis of global gene expression profiles demonstrated that the signal signature characteristic of each Arabidopsis-attacker combination is orchestrated into a surprisingly complex set of transcriptional alterations in which, in all cases, stress-related genes are overrepresented. Comparison of the transcript profiles revealed that consistent changes induced by pathogens and insects with very different modes of attack can show considerable overlap. Of all consistent changes induced by A. brassicicola, P. rapae, and F. occidentalis, more than 50% were also induced consistently by P. syringae. Notably, although these four attackers all stimulated JA biosynthesis, the majority of the changes in JA-responsive gene expression were attacker-specific. All together our study shows that SA, JA, and ET play a primary role in the orchestration of the plant's defense response, but other regulatory mechanisms, such as pathway cross-talk or additional attacker-induced signals, eventually shape the highly complex attacker-specific defense response. In the experimental set up we intended to select for genes that showed a more than 2-fold change in the same direction(up or down)at two time points after pathogen or insect attack. The results are described in the following paper: De Vos, M., Van Oosten, V.R., Van Poecke, R.M.P., Van Pelt, J.A., Pozo, M.J., Mueller, M.J., Buchala, A.J., Metraux, J.-P., Van Loon, L.C., Dicke, M. and Pieterse, C.M.J. (2005). Signal signature and transcriptome changes in Arabidopsis upon pathogen and insect attack. Molecular Plant-Microbe Interactions. Experimenter name = Corne Pieterse Experimenter phone = +31 30 253 3013 Experimenter fax = +31 30 251 8366 Experimenter department = Section Phytopathology Experimenter institute = Utrecht University Experimenter address = Department of Biology Experimenter address = Utrecht University Experimenter address = Sorbonnelaan 16 Experimenter address = Utrecht Experimenter zip/postal_code = 3584CA Experimenter country = The Netherlands Keywords: time_series_design; pathogenicity_design
2006-08-15 | GSE5525 | GEO
Project description:Plant defenses against pathogens and insects are regulated differentially by cross-communicating signaling pathways in which salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) play key roles. To understand how plants integrate pathogen- and insect-induced signals into specific defense responses, we monitored the dynamics of SA, JA, and ET signaling in Arabidopsis after attack by a set of microbial pathogens and herbivorous insects with different modes of attack. Arabidopsis plants were exposed to a pathogenic leaf bacterium (Pseudomonas syringae pv. tomato), a pathogenic leaf fungus (Alternaria brassicicola), tissue-chewing caterpillars (Pieris rapae), cell-content-feeding thrips (Frankliniella occidentalis), or phloem-feeding aphids (Myzus persicae). Monitoring the signal signature in each plant-attacker combination showed that the kinetics of SA, JA, and ET production varies greatly in both quantity and timing. Analysis of global gene expression profiles demonstrated that the signal signature characteristic of each Arabidopsis-attacker combination is orchestrated into a surprisingly complex set of transcriptional alterations in which, in all cases, stress-related genes are overrepresented. Comparison of the transcript profiles revealed that consistent changes induced by pathogens and insects with very different modes of attack can show considerable overlap. Of all consistent changes induced by A. brassicicola, P. rapae, and F. occidentalis, more than 50% were also induced consistently by P. syringae. Notably, although these four attackers all stimulated JA biosynthesis, the majority of the changes in JA-responsive gene expression were attacker-specific. All together our study shows that SA, JA, and ET play a primary role in the orchestration of the plant's defense response, but other regulatory mechanisms, such as pathway cross-talk or additional attacker-induced signals, eventually shape the highly complex attacker-specific defense response. In the experimental set up we intended to select for genes that showed a more than 2-fold change in the same direction(up or down)at two time points after pathogen or insect attack. The results are described in the following paper:; De Vos, M., Van Oosten, V.R., Van Poecke, R.M.P., Van Pelt, J.A., Pozo, M.J., Mueller, M.J., Buchala, A.J., Metraux, J.-P., Van Loon, L.C., Dicke, M. and Pieterse, C.M.J. (2005). Signal signature and transcriptome changes in Arabidopsis upon pathogen and insect attack. Molecular Plant-Microbe Interactions. Experimenter name = Corne Pieterse; Experimenter phone = +31 30 253 3013; Experimenter fax = +31 30 251 8366; Experimenter department = Section Phytopathology; Experimenter institute = Utrecht University; Experimenter address = Department of Biology; Experimenter address = Utrecht University; Experimenter address = Sorbonnelaan 16; Experimenter address = Utrecht; Experimenter zip/postal_code = 3584CA; Experimenter country = The Netherlands Experiment Overall Design: 14 samples were used in this experiment
2008-06-13 | E-GEOD-5525 | biostudies-arrayexpress
Project description:Plants can perceive a wide range of biotic attackers and respond with targeted induced defenses. Specificity in plant non-self-recognition occurs either directly by perception of pest-derived elicitors or indirectly through resistance protein recognition of host targets that are inappropriately proteolyzed. Indirect plant perception can occur during interactions with pathogens, yet evidence for analogous events mediating the detection of insect herbivores remains elusive. Here we report indirect perception of herbivory in cowpea (Vigna unguiculata) plants attacked by fall armyworm (Spodoptera frugiperda) larvae. We isolated and identified a disulfide-bridged peptide (+ICDINGVCVDA-), termed inceptin, from S. frugiperda larval oral secretions that promotes cowpea ethylene production at 1 fmol leaf(-1) and triggers increases in the defense-related phytohormones salicylic acid and jasmonic acid. Inceptins are proteolytic fragments of chloroplastic ATP synthase gamma-subunit regulatory regions that mediate plant perception of herbivory through the induction of volatile, phenylpropanoid, and protease inhibitor defenses. Only S. frugiperda larvae that previously ingested chloroplastic ATP synthase gamma-subunit proteins and produced inceptins significantly induced cowpea defenses after herbivory. Digestive fragments of an ancient and essential plant enzyme, inceptin functions as a potent indirect signal initiating specific plant responses to insect attack.
| S-EPMC1482674 | biostudies-literature
Project description:Plants are often attacked by multiple insect herbivores. How plants deal with an increasing richness of attackers from a single or multiple feeding guilds is poorly understood. We subjected black mustard (Brassica nigra) plants to 51 treatments representing attack by an increasing species richness (one, two or four species) of either phloem feeders, leaf chewers, or a mix of both feeding guilds when keeping total density of attackers constant and studied how this affects plant resistance to subsequent attack by caterpillars of the diamondback moth (Plutella xylostella). Increased richness in phloem-feeding attackers compromised resistance to P. xylostella. By contrast, leaf chewers induced a stronger resistance to subsequent attack by caterpillars of P. xylostella while species richness did not play a significant role for chewing herbivore induced responses. Attack by a mix of herbivores from different feeding guilds resulted in plant resistance similar to resistance levels of plants that were not previously exposed to herbivory. We conclude that B. nigra plants channel their defence responses stronger towards a feeding-guild specific response when under multi-species attack by herbivores of the same feeding guild, but integrate responses when simultaneously confronted with a mix of herbivores from different feeding guilds.
| S-EPMC8451852 | biostudies-literature
Project description:Insect and gastropod herbivores are major plant consumers and their importance in the evolution of plant defensive traits is broadly recognized. However, their respective effects on plant responses have rarely been compared. Here we focused on plant volatile emissions (VOCs) following herbivory and compared the effects of herbivory by caterpillars of the generalist insect Spodoptera littoralis and by generalist slugs of the genus Arion on the VOCs emissions of 14 cultivated plant species. Results revealed that plants consistently produced higher amounts of volatiles and responded more specifically to caterpillar than to slug herbivory. Specifically, plants released on average 6.0 times more VOCs (total), 8.9 times more green leaf volatiles, 4.2 times more terpenoids, 6.0 times more aromatic hydrocarbons, and 5.7 times more other VOCs in response to 1 cm2 of insect damage than to 1 cm2 of slug damage. Interestingly, four of the plant species tested produced a distinct blend of volatiles following insect damage but not slug damage. These findings may result from different chemical elicitors or from physical differences in herbivory by the two herbivores. This study is an important step toward a more inclusive view of plant responses to different types of herbivores.
| S-EPMC8654843 | biostudies-literature
Project description:Rice dwarf virus (RDV) is transmitted by insect vectors Nephotettix virescens and Nephotettix cincticeps (Hemiptera: Cicadellidae) that threatens rice yield and results in substantial economic losses. RDV induces two volatiles ((E)-β-caryophyllene (EBC) and 2-heptanol) to emit from RDV-infected rice plants. However, the effects of the two volatiles on the olfactory behavior of both non-viruliferous and viruliferous N. virescens are unknown, and whether the two volatiles could facilitate the spread and dispersal of RDV remains elusive. Combining the methods of insect behavior, chemical ecology, and molecular biology, we found that EBC and 2-heptanol influenced the olfactory behavior of non-viruliferous and viruliferous N. virescens, independently. EBC attracted non-viruliferous N. virescens towards RDV-infected rice plants, promoting virus acquisition by non-viruliferous vectors. The effect was confirmed by using oscas1 mutant rice plants (repressed EBC synthesis), but EBC had no effects on viruliferous N. virescens. 2-heptanol did not attract or repel non-viruliferous N. virescens. However, spraying experiments showed that 2-heptanol repelled viruliferous N. virescens to prefer RDV-free rice plants, which would be conducive to the transmission of the virus. These novel results reveal that rice plant volatiles modify the behavior of N. virescens vectors to promote RDV acquisition and transmission. They will provide new insights into virus-vector-plant interactions, and promote the development of new prevention and control strategies for disease management.
| S-EPMC9860585 | biostudies-literature
Project description:Background and aimsMounting concerns about balancing food security with the environmental impacts of agro-chemical use underpin the need to better understand the mechanisms by which crop plants, particularly during the vulnerable seedling stage, attract or repel herbivores.MethodsThe feeding preferences of the mollusc Helix aspersa were determined for several oilseed rape (Brassica napus) cultivars and a rank order of acceptability was established. This was compared with glucosinolate concentrations and volatile organic compound (VOC) profiles to determine whether seedling acceptability to molluscs was linked to either form of defence.Key resultsWhile VOC profiles for each oilseed rape cultivar could be separated by canonical discriminant analysis and associated with mollusc feeding preferences, glucosinolate profiles were unrelated to snail feeding behaviour. A mixture of monoterpenes (?-pinene, ?-myrcene and ?-3-carene) was identified as a putative attractant, while a blend of the green leaf volatiles 3-hexen-1-ol, 3-hexen-1-ol acetate and the monoterpene ?-terpinene was identified as a putative repellent mix. Added to the VOC profile of oilseed rape seedlings, the 'repellent' mix reduced mollusc selection, while the 'attractant' mix had no effect.ConclusionsDespite the widespread assumption that seedling selection by generalist herbivores is governed by chemical defence and taste, we show that olfactory cues may be more important. Oilseed rape may be atypical of wild plants, but our ability to identify repellent volatile organic compounds that can influence snail olfactory selection points to new methods for crop protection using modified VOC profiles during the vulnerable seedling stage.
| S-EPMC4866317 | biostudies-literature