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1
de Bobadilla, Maite Fernández, Roel Van Wiechen, Gerrit Gort e Erik H. Poelman. "Plasticity in induced resistance to sequential attack by multiple herbivores in Brassica nigra". Oecologia 198, n. 1 (13 ottobre 2021): 11–20. http://dx.doi.org/10.1007/s00442-021-05043-1.
Testo completoAbstract (sommario):
AbstractIn nature, plants interact with multiple insect herbivores that may arrive simultaneously or sequentially. There is extensive knowledge on how plants defend themselves against single or dual attack. However, we lack information on how plants defend against the attack of multiple herbivores that arrive sequentially. In this study, we investigated whether Brassica nigra L. plants are able to defend themselves against caterpillars of the late-arriving herbivore Plutella xylostella L., when plants had been previously exposed to sequential attack by four other herbivores (P. xylostella, Athalia rosae, Myzus persicae and Brevicoryne brassicae). We manipulated the order of arrival and the history of attack by four herbivores to investigate which patterns in sequential herbivory determine resistance against the fifth attacker. We recorded that history of sequential herbivore attack differentially affected the capability of B. nigra plants to defend themselves against caterpillars of P. xylostella. Caterpillars gained less weight on plants attacked by a sequence of four episodes of attack by P. xylostella compared to performance on plants that were not previously damaged by herbivores. The number of times the plant was attacked by herbivores of the same feeding guild, the identity of the first attacker, the identity and the guild of the last attacker as well as the order of attackers within the sequence of multiple herbivores influenced the growth of the subsequent herbivory. In conclusion, this study shows that history of sequential attack is an important factor determining plant resistance to herbivores.
2
SCHMIDT, GEROLD, e GERHARD ZOTZ. "Herbivory in the epiphyte, Vriesea sanguinolenta Cogn. & Marchal (Bromeliaceae)". Journal of Tropical Ecology 16, n. 6 (novembre 2000): 829–39. http://dx.doi.org/10.1017/s0266467400001747.
Testo completoAbstract (sommario):
Although herbivory in ground-rooted flora is well documented, current knowledge of the herbivore pressure on vascular epiphytes remains mostly anecdotal. Here, we present the results of a 3-year study on the herbivory in a population of the epiphytic bromeliad Vriesea sanguinolenta. In different years, 26–61% of all epiphytes showed traces of herbivore attack, while up to 4.4% of the entire leaf area of the epiphyte population was consumed annually. The recorded levels of damage to photosynthetic tissue, mostly caused by the larvae of Napaea eucharilla (Riodinidae, Lepidoptera), indicate that vascular epiphytes may be regularly and sometimes even lethally attacked by insect herbivores. The level of damage is comparable to ground-rooted tropical flora, which certainly does not support the prevalent notion of low and negligible levels of herbivory in vascular epiphytes.
3
Bont, Zoe, Marc Pfander, Christelle A. M. Robert, Meret Huber, Erik H. Poelman, Ciska E. Raaijmakers e Matthias Erb. "Adapted dandelions trade dispersal for germination upon root herbivore attack". Proceedings of the Royal Society B: Biological Sciences 287, n. 1921 (26 febbraio 2020): 20192930. http://dx.doi.org/10.1098/rspb.2019.2930.
Testo completoAbstract (sommario):
A plant's offspring may escape unfavourable local conditions through seed dispersal. Whether plants use this strategy to escape insect herbivores is not well understood. Here, we explore how different dandelion ( Taraxacum officinale agg.) populations, including diploid outcrossers and triploid apomicts, modify seed dispersal in response to root herbivore attack by their main root-feeding natural enemy, the larvae of the common cockchafer Melolontha melolontha. In a manipulative field experiment, root herbivore attack increased seed dispersal potential through a reduction in seed weight in populations that evolved under high root herbivore pressure, but not in populations that evolved under low pressure. This increase in dispersal potential was independent of plant cytotype, but associated with a reduction in germination rate, suggesting that adapted dandelions trade dispersal for establishment upon attack by root herbivores. Analysis of vegetative growth parameters suggested that the increased dispersal capacity was not the result of stress flowering. In summary, these results suggest that root herbivory selects for an induced increase in dispersal ability in response to herbivore attack. Induced seed dispersal may be a strategy that allows adapted plants to escape from herbivores.
4
Kliebenstein, Daniel, Deana Pedersen, Bridget Barker e Thomas Mitchell-Olds. "Comparative Analysis of Quantitative Trait Loci Controlling Glucosinolates, Myrosinase and Insect Resistance in Arabidopsis thaliana". Genetics 161, n. 1 (1 maggio 2002): 325–32. http://dx.doi.org/10.1093/genetics/161.1.325.
Testo completoAbstract (sommario):
Abstract Evolutionary interactions among insect herbivores and plant chemical defenses have generated systems where plant compounds have opposing fitness consequences for host plants, depending on attack by various insect herbivores. This interplay complicates understanding of fitness costs and benefits of plant chemical defenses. We are studying the role of the glucosinolate-myrosinase chemical defense system in protecting Arabidopsis thaliana from specialist and generalist insect herbivory. We used two Arabidopsis recombinant inbred populations in which we had previously mapped QTL controlling variation in the glucosinolate-myrosinase system. In this study we mapped QTL controlling resistance to specialist (Plutella xylostella) and generalist (Trichoplusia ni) herbivores. We identified a number of QTL that are specific to one herbivore or the other, as well as a single QTL that controls resistance to both insects. Comparison of QTL for herbivory, glucosinolates, and myrosinase showed that T. ni herbivory is strongly deterred by higher glucosinolate levels, faster breakdown rates, and specific chemical structures. In contrast, P. xylostella herbivory is uncorrelated with variation in the glucosinolate-myrosinase system. This agrees with evolutionary theory stating that specialist insects may overcome host plant chemical defenses, whereas generalists will be sensitive to these same defenses.
5
Campos, Wellington G., Ana P. Faria, Maria Goreti A. Oliveira e Hérica L. Santos. "Induced response against herbivory by chemical information transfer between plants". Brazilian Journal of Plant Physiology 20, n. 4 (dicembre 2008): 257–66. http://dx.doi.org/10.1590/s1677-04202008000400001.
Testo completoAbstract (sommario):
Plants respond to herbivores and pathogens attack with increased emission of volatile organic compounds. These molecules act as indirect defences when attracting natural enemies of herbivores and thus benefit the plant. It remains controversial whether undamaged plants capture chemicals released by damaged neighbouring plants and respond to them by increasing their defensive barriers against an imminent attack. In spite of public appeal and of this being the 25th year of the Talking Trees Hypothesis, only recently have the most sceptical scientists been convinced. The induced response to herbivory by interplant information transfer has been found in two plant-herbivore systems. However, the universality of the phenomenon and its ecological and evolutionary relevance remain unclear. The integration of Molecular Biology, Biochemistry, Physiology, and Ecology begin to shed light on the mechanisms of the signal transfer. This integrative approach has developed new and more sensitive tools for identification of complex volatile mixtures and for understanding the process of biosynthesis, emission, transportation and reception of signals.
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Bebber, Dan, Nick Brown e Martin Speight. "Drought and root herbivory in understorey Parashorea Kurz (Dipterocarpaceae) seedlings in Borneo". Journal of Tropical Ecology 18, n. 5 (21 agosto 2002): 795–804. http://dx.doi.org/10.1017/s0266467402002511.
Testo completoAbstract (sommario):
The influence of herbivory on dipterocarp seedling growth and survival in Bornean primary lowland forest understorey during and after the 1997–8 El Niño-Southern Oscillation was investigated. During the drought, a coleopteran (Scolytidae) root borer attacked dipterocarp seedlings, primarily of the genus Parashorea. Infestation was spatially heterogeneous on a large (c. 100 m) scale. Attack rate decreased with plant vigour within infested areas. Experiments showed that root damage was fatal under drought conditions, but not after rain. Defoliation and apical meristem removal did not increase mortality. The spatio-temporal heterogeneity of herbivore outbreaks and difficulties involved in experimenting with root herbivores limit the power of such short-term investigations. However, the study shows that herbivores can cause differential mortality between species, and can therefore influence dipterocarp regeneration dynamics. The effect of herbivory depends on the plant organ attacked and interactions with other stresses such as drought. El Niño-related droughts are increasing in frequency in South-East Asian rain forests, which may lead to increased numbers of herbivore outbreaks and greater seedling mortality due to these factors.
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Rusman, Quint, Peter N. Karssemeijer, Dani Lucas-Barbosa e Erik H. Poelman. "Settling on leaves or flowers: herbivore feeding site determines the outcome of indirect interactions between herbivores and pollinators". Oecologia 191, n. 4 (4 novembre 2019): 887–96. http://dx.doi.org/10.1007/s00442-019-04539-1.
Testo completoAbstract (sommario):
Abstract Herbivore attack can alter plant interactions with pollinators, ranging from reduced to enhanced pollinator visitation. The direction and strength of effects of herbivory on pollinator visitation could be contingent on the type of plant tissue or organ attacked by herbivores, but this has seldom been tested experimentally. We investigated the effect of variation in feeding site of herbivorous insects on the visitation by insect pollinators on flowering Brassica nigra plants. We placed herbivores on either leaves or flowers, and recorded the responses of two pollinator species when visiting flowers. Our results show that variation in herbivore feeding site has profound impact on the outcome of herbivore–pollinator interactions. Herbivores feeding on flowers had consistent positive effects on pollinator visitation, whereas herbivores feeding on leaves did not. Herbivores themselves preferred to feed on flowers, and mostly performed best on flowers. We conclude that herbivore feeding site choice can profoundly affect herbivore–pollinator interactions and feeding site thereby makes for an important herbivore trait that can determine the linkage between antagonistic and mutualistic networks.
8
Castro, Jorge. "Postfire Burnt-Wood Management Affects Plant Damage by Ungulate Herbivores". International Journal of Forestry Research 2013 (2013): 1–6. http://dx.doi.org/10.1155/2013/965461.
Testo completoAbstract (sommario):
I analyze the effect of post-fire burnt wood management on herbivore attack on a woody plant species (Ulex parviflorus). Two experimental plots of ca. 20 hectares were established at two elevations in a burnt area in a Mediterranean mountain (Sierra Nevada, Spain). Three replicates of three treatments differing in post-fire burnt wood management were established per plot: “no intervention” (NI, all trees remained standing), “partial cut plus lopping” (PCL, felling the trees, cutting the main branches, and leaving all the biomassin situ), and “salvage logging” (SL; removal of logs and elimination of woody debris). Risk of herbivory and damage intensity were monitored for two years. The pattern of attack by ungulate herbivores varied among treatments and years. In any case, there was an overall reduction in the risk of herbivory in the PCL treatment, presumably because the highest habitat complexity in this treatment hampered ungulate movement and foraging. As a result, the burnt logs and branches spread over the ground acted as a physical barrier that protected seedlings from herbivores. This protection may be used for the regeneration of shrubs and trees, and it is of interest for the regeneration of burnt sites either naturally or by reforestation.
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García-Guzmán, Graciela, e Julieta Benítez-Malvido. "Effect of litter on the incidence of leaf-fungal pathogens and herbivory in seedlings of the tropical tree Nectandra ambigens". Journal of Tropical Ecology 19, n. 2 (6 febbraio 2003): 171–77. http://dx.doi.org/10.1017/s0266467403003195.
Testo completoAbstract (sommario):
Effects of litter cover on insect herbivory, leaf-fungal damage, and seedling performance (survival, growth in height and leaf number), were assessed on established Nectandra ambigens seedlings in three sites of a Mexican tropical rain forest. Naturally occurring seedlings were measured for height, leaf number and standing levels of leaf damage by herbivores and pathogens. Thereafter, seedlings were exposed for 1 y to three litter treatments: (1) litter addition, (2) control and (3) continuous litter removal. There was a significant effect of site on the proportion of surviving seedlings and on the relative growth rates in terms of leaf number. Overall, seedlings with higher initial leaf number showed higher survival and produced more leaves after 12 mo than seedlings with lower initial leaf number. Litter addition resulted in seedlings with lower relative growth rates in height and higher levels of damage by herbivores and pathogens. On average, leaf area damaged by pathogens was < 6% and herbivory was < 27%. Seedlings with higher levels of herbivory showed higher levels of pathogen attack. Herbivory and pathogen attack had no effect on seedling performance. This study reveals the importance of litter-cover on the interactions between seedlings, herbivores and pathogens, as well as on the performance of tropical seedlings.
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Lawrence, Susan D., Nicole G. Novak, Chelsea J. T. Ju e Janice E. K. Cooke. "Examining the molecular interaction between potato (Solanum tuberosum) and Colorado potato beetle Leptinotarsa decemlineata". Botany 86, n. 9 (settembre 2008): 1080–91. http://dx.doi.org/10.1139/b08-074.
Testo completoAbstract (sommario):
Colorado potato beetle (CPB) is a devastating herbivorous pest of solanaceous plants. Despite the economic impact, little is known about the molecular interaction of CPB with these plants. Using an 11 421 expressed sequence tag (EST) potato microarray, we identified 320 genes differentially expressed in potato leaves in response to CPB herbivory. Amongst these were genes putatively encoding proteinase inhibitors along with enzymes of terpenoid, alkaloid, and phenylpropanoid biosynthetic pathways, suggesting the defensive chemistries that constitute potato’s defense against CPB herbivory. Several genes, such as those encoding proteinase inhibitors, represent mechanisms implicated in other plant–herbivory interactions, and could correspond with general defensive chemistry strategies. In other cases, products of the differentially expressed genes may represent taxa-specific defensive chemistry. For example, the presumed alkaloid products of a putative tropinone reductase I are specific to a subset of the Solanaceae. Two herbivory-induced genes, not specific to potato, are implicated in the synthesis of volatiles known to attract CPB predators. Comparison of continuous herbivore attack versus recovery from CPB attack indicates that fewer genes involved in defensive chemistry are induced after continuous feeding than after feeding and recovery, suggesting the plant’s ability to mount a full defense response is enhanced under light versus heavy attack.
11
Cooper-Driver, Gillian. "Anti-predation strategies in pteridophytes—a biochemical approach". Proceedings of the Royal Society of Edinburgh. Section B. Biological Sciences 86 (1985): 397–402. http://dx.doi.org/10.1017/s0269727000008381.
Testo completoAbstract (sommario):
SynopsisSince they first evolved, pteridophytes have been subjected to attack by micro-organisms and arthropods. Present-day ferns are associated with a complex array of, not only phytophagous, scavenging, predatory and parasitic arthropod species but also fungi, bacteria, viruses and herbivorous mammals.Recent research has tended to stress the importance of secondary plant chemistry in deterring feeding by herbivores and attack by pathogens. Although ferns have a more limited chemical repertoire than the angiosperms, many of the classes of secondary compounds isolated from ferns have been shown to have anti-microbial and anti-herbivore activity under both laboratory and field conditions. Quantitative and qualitative levels are not constant and show great seasonal variation. This chemical variation is important in determining the seasonal patterning of insects and fungi on ferns. New chemical techniques are increasing our knowledge of the biosynthesis and chemical structures of these ecologically important compounds.Flowering plants show both constitutive and induced resistance as a consequence of herbivore attack. A search for short-term induced chemical responses in ferns have so far yielded negative results in terms of phytoalexin synthesis or direct chemical response to herbivory.
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Malé, Pierre-Jean G., Kyle M. Turner, Manjima Doha, Ina Anreiter, Aaron M. Allen, Marla B. Sokolowski e Megan E. Frederickson. "An ant–plant mutualism through the lens of cGMP-dependent kinase genes". Proceedings of the Royal Society B: Biological Sciences 284, n. 1862 (13 settembre 2017): 20170896. http://dx.doi.org/10.1098/rspb.2017.0896.
Testo completoAbstract (sommario):
In plant–animal mutualisms, how an animal forages often determines how much benefit its plant partner receives. In many animals, foraging behaviour changes in response to foraging gene expression or activation of the cGMP-dependent protein kinase (PKG) that foraging encodes. Here, we show that this highly conserved molecular mechanism affects the outcome of a plant–animal mutualism. We studied the two PKG genes of Allomerus octoarticulatus, an Amazonian ant that defends the ant–plant Cordia nodosa against herbivores. Some ant colonies are better ‘bodyguards’ than others. Working in the field in Peru, we found that colonies fed with a PKG activator recruited more workers to attack herbivores than control colonies. This resulted in less herbivore damage. PKG gene expression in ant workers correlated with whether an ant colony discovered an herbivore and how much damage herbivores inflicted on leaves in a complex way; natural variation in expression levels of the two genes had significant interaction effects on ant behaviour and herbivory. Our results suggest a molecular basis for ant protection of plants in this mutualism.
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Faraone, Nicoletta, e N. Kirk Hillier. "Preliminary Evaluation of a Granite Rock Dust Product for Pest Herbivore Management in Field Conditions". Insects 11, n. 12 (11 dicembre 2020): 877. http://dx.doi.org/10.3390/insects11120877.
Testo completoAbstract (sommario):
The effects of granite rock dust in dry and aqueous formulations were evaluated under field conditions for control of insect pests in different crop systems and ornamental plants. We tested efficacy of crop protection following foliar applications on lily, squash, and cabbage plants by evaluating subsequent pest damage, overall plant health, and quantity of crops produced over one season. Lily plants treated with dry and aqueous formulations of rock dust were subject to lower herbivore damage (>1% and 11% herbivory damage, respectively) when compared to the controls (30% herbivory damage). Treatment on cabbage was less effective to protect plants against herbivory damage, and no statistically significant differences were reported within treatments. The foliar applications (dry and aqueous formulations) had positive impacts on growth of squash fruit resulting in a 2.5-fold increase in size relative to the control squash fruit. These results support the potential field application of granite dust to protect ornamental plants against herbivory attack, and reveal an alternative positive effect of the silica-based product on plant growth and development.
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Norghauer, Julian M., Jay R. Malcolm e Barbara L. Zimmerman. "Juvenile mortality and attacks by a specialist herbivore increase with conspecific adult basal area of Amazonian Swietenia macrophylla (Meliaceae)". Journal of Tropical Ecology 22, n. 4 (luglio 2006): 451–60. http://dx.doi.org/10.1017/s0266467406003257.
Testo completoAbstract (sommario):
According to the Janzen–Connell model, host-specific natural enemies can promote species coexistence of canopy trees in tropical forests by attacking progeny where they are most concentrated. However, empirical evidence relating negative density-dependent mortality to herbivory and, in particular, attack by specialist herbivores, remains rare. We investigated density dependence in a natural population of Swietenia macrophylla in a south-eastern Amazon forest of Brazil. Across 24 adult trees, we found that initial juvenile densities were positively correlated with basal area of adult conspecifics whereas subsequent survivorship over 1 y for these juveniles declined strongly with increasing basal area of adult conspecifics. For 18 trees with > 5 juveniles surviving for 1 y, further evidence supporting the Janzen–Connell mechanism was obtained in that leaf herbivory and attack by a specialist microlepidopteran moth (Steniscadia poliophaea) increased, and overall foliar condition decreased, with conspecific basal area. Moreover, when differences in mean juvenile size (number of extant leaves) were accounted for, juvenile survival over 1 y decreased with increased specialist leaf herbivory. Collectively, these results indicate that herbivores, in particular S. poliophaea, may contribute to density dependence among S. macrophylla juveniles. We conclude that the survival of juveniles and their probability of recruitment into the canopy is decreased where conspecific adults are largest and/or most numerous and find support for the importance of host-specific pests in driving density dependence among tropical trees.
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Dávila-Lara, Alberto, Asifur Rahman-Soad, Michael Reichelt e Axel Mithöfer. "Carnivorous Nepenthes x ventrata plants use a naphthoquinone as phytoanticipin against herbivory". PLOS ONE 16, n. 10 (22 ottobre 2021): e0258235. http://dx.doi.org/10.1371/journal.pone.0258235.
Testo completoAbstract (sommario):
Carnivorous plants feed on animal prey, mainly insects, to get additional nutrients. This carnivorous syndrome is widely investigated and reported. In contrast, reports on herbivores feeding on carnivorous plants and related defenses of the plants under attack are rare. Here, we studied the interaction of a pitcher plant, Nepenthes x ventrata, with a generalist lepidopteran herbivore, Spodoptera littoralis, using a combination of LC/MS-based chemical analytics, choice and feeding assays. Chemical defenses in N. x ventrata leaves were analyzed upon S. littoralis feeding. A naphthoquinone, plumbagin, was identified in Nepenthes defense against herbivores and as the compound mainly responsible for the finding that S. littoralis larvae gained almost no weight when feeding on Nepenthes leaves. Plumbagin is constitutively present but further 3-fold increased upon long-term (> 1 day) feeding. Moreover, in parallel de novo induced trypsin protease inhibitor (TI) activity was identified. In contrast to TI activity, enhanced plumbagin levels were not phytohormone inducible, not even by defense-related jasmonates although upon herbivory their level increased more than 50-fold in the case of the bioactive jasmonic acid-isoleucine. We conclude that Nepenthes is efficiently protected against insect herbivores by naphthoquinones acting as phytoanticipins, which is supported by additional inducible defenses. The regulation of these defenses remains to be investigated.
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Lee Díaz, Ana Shein, Muhammad Syamsu Rizaludin, Hans Zweers, Jos M. Raaijmakers e Paolina Garbeva. "Exploring the Volatiles Released from Roots of Wild and Domesticated Tomato Plants under Insect Attack". Molecules 27, n. 5 (28 febbraio 2022): 1612. http://dx.doi.org/10.3390/molecules27051612.
Testo completoAbstract (sommario):
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.
17
Silva, Nathália Thaís Cavalcante da, Maria Aline Soares da Silva, Alissandra Trajano Nunes e Hiram Marinho Falcão. "Effect of herbivory by goats on primary and secondary metabolism of Cocos nucifera L. (Arecaceae) in a semi-arid environment in Brazilian Northeast". Journal of Environmental Analysis and Progress 5, n. 3 (9 settembre 2020): 337–45. http://dx.doi.org/10.24221/jeap.5.3.2020.3446.337-345.
Testo completoAbstract (sommario):
The relationship between herbivores and plants has important ecological implications for both organisms and directly affects the plant’s physiological responses, which need to invest in structures and secondary metabolites to overcome the damages. This study aimed to evaluate functional attributes related to the primary and secondary metabolism of Cocos nucifera L. (Arecaceae) submitted to herbivory by goats. Five individuals of C. nucifera were selected in two areas, one with and one without goats. The carbohydrate content, specific leaf mass, and phytochemical screening were obtained, evaluating the presence or absence of saponins, tannins, flavonoids, steroids, alkaloids, and glycosides. The results show that plants under herbivory showed 50% more sugars and a higher specific leaf mass than no-herbivory plants. Also, plants under herbivory showed a higher amount of saponins, steroids, and alkaloids. The production of defense metabolites, which are energetically costly, require the energy supply provided by the carbohydrates produced in photosynthesis; thus, higher levels of sugars were observed in attacked plants. Even under attack, C. nucifera plants allocate resources for biomass production, to increase leaf sclerophylly and hinder herbivory. The investment in saponins, steroids, and alkaloids is related to herbivory, as demonstrated by the analysis of principal components analysis. We conclude that herbivory by goats activates defense responses in C. nucifera plants, making them allocate sugars to produce secondary metabolites.
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Witwicka, Alicja, Danuta Frydryszak, Andrzej Antoł e Marcin Czarnoleski. "Effects of habitat, leaf damage and leaf rolling on the predation risk of caterpillars in the tropical rain forest of Borneo". Journal of Tropical Ecology 35, n. 5 (11 luglio 2019): 251–53. http://dx.doi.org/10.1017/s0266467419000191.
Testo completoAbstract (sommario):
AbstractAddressing what affects predation among caterpillars, we conducted an experiment in a Bornean rain forest on 212 clay models of Tortricidae caterpillars (the herbivore) and 53 trees of Kopsia pauciflora (the host), located either in the open or under closed canopies. We predicted that the frequency of predatory attacks towards caterpillars increases (1) in canopy gaps and (2) on leaves damaged by herbivory, but (3) decreases among caterpillars that wrap their body in leaves. Each plant with caterpillar models was consecutively allocated to one of four treatments: caterpillars artificially rolled in leaves vs caterpillars on unrolled leaves, and caterpillars on artificially damaged vs undamaged leaves. Each time, caterpillar models were placed on the plants for 48 h, and then replaced with new models that were subjected to a new treatment. On average, our caterpillar models had a 21% chance of being attacked per 24 h. More attacks were performed by insects (81.6%) than birds. The attack frequency did not depend on the canopy cover or on leaf damage, but decreased among models rolled in leaves. This pattern was mainly attributable to insect attacks, which were also more frequent than bird attacks. Overall, the Tortricidae caterpillars seem to suffer comparable predation rates in the open and under closed canopies irrespective of the herbivory damage of leaves, but their leaf-rolling behaviour might reduce predation.
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Farnsworth, Elizabeth J., e Aaron M. Ellison. "Dynamics of herbivory in Belizean mangal". Journal of Tropical Ecology 9, n. 4 (novembre 1993): 435–53. http://dx.doi.org/10.1017/s0266467400007501.
Testo completoAbstract (sommario):
ABSTRACTWe report long-term observations on leaf herbivory in the mangroves Rhizophora mangle and Avicennia germinans, on the Placencia Peninsula of Belize. We labelled and traced leaves and recorded the amount of damage appearing over a period of 310 days. Herbivores had damaged 1–4% of total mean leaf area within the first 10 days, but damage rates levelled off thereafter, to a final total of 4–10% damage. Herbivores did not concentrate on leaves of younger age classes. Rhizophora mangle growing in the high tidal zone (HHW) exhibited the highest initial and total attack rates at all but the final sampling dates. We also documented the dynamics of injury expansion and necrosis following artificial injury to seedling and tree leaves. Artificial holes in leaves were associated with higher subsequent rates of herbivory that varied among leaf age classes, and particular damage types were more prevalent in previously injured leaves. Artificial holes expanded significantly more in young leaves of both species. Holes in young leaves of both species expanded by up to 45.1% in area over 50 days, consistent with a similar study in Australia. Substantial necrotic areas developed around the injury site; a secondary effect of damage not often considered in herbivory studies. We discuss the implications of hole expansion and necrosis in estimating error in herbivory measurements. Temporally dynamic studies of herbivory are especially needed in tropical systems that show non-deciduous phenologies and long-lived leaves.
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Blatt, S. E., R. C. Smallegange, L. Hess, J. A. Harvey, M. Dicke e J. J. A. van Loon. "Tolerance of Brassica nigra to Pieris brassicae herbivory". Botany 86, n. 6 (giugno 2008): 641–48. http://dx.doi.org/10.1139/b08-040.
Testo completoAbstract (sommario):
Black mustard, Brassica nigra (L.) Koch, is a wild annual species found throughout Europe and fed on by larvae of the large cabbage-white butterfly, Pieris brassicae L. We examined the impact of herbivory from P. brassicae, a gregarious herbivore, on B. nigra grown from wild seed collected locally. In greenhouse studies, the response of B. nigra to four herbivore densities in two developmental stages of the plant was quantified by measuring leaf damage, plant height, days to flowering, silique number, and seed production. Pieris brassicae readily attacked B. nigra leaves, although the timing of the attack did not affect seed production; attacked plants produced as many seeds as as nonattacked plants. Plant height was affected when plants were attacked early, but not later, in development, suggesting a connection between their belowground zone of influence and ability to regain biomass. These results demonstrate that at the herbivore densities and timing of damage studied, B. nigra tolerates folivory from Pieris brassicae through compensation.
21
Bacht, Michael, Mika T. Tarkka, Iván Fernández López, Markus Bönn, Roland Brandl, François Buscot, Lasse Feldhahn, Thorsten E. E. Grams, Sylvie Herrmann e Martin Schädler. "Tree Response to Herbivory Is Affected by Endogenous Rhythmic Growth and Attenuated by Cotreatment With a Mycorrhizal Fungus". Molecular Plant-Microbe Interactions® 32, n. 6 (giugno 2019): 770–81. http://dx.doi.org/10.1094/mpmi-10-18-0290-r.
Testo completoAbstract (sommario):
Herbivores and mycorrhizal fungi interactively influence growth, resource utilization, and plant defense responses. We studied these interactions in a tritrophic system comprising Quercus robur, the herbivore Lymantria dispar, and the ectomycorrhizal fungus Piloderma croceum under controlled laboratory conditions at the levels of gene expression and carbon and nitrogen (C/N) allocation. Taking advantage of the endogenous rhythmic growth displayed by oak, we thereby compared gene transcript abundances and resource shifts during shoot growth with those during the alternating root growth flushes. During root flush, herbivore feeding on oak leaves led to an increased expression of genes related to plant growth and enriched gene ontology terms related to cell wall, DNA replication, and defense. C/N-allocation analyses indicated an increased export of resources from aboveground plant parts to belowground. Accordingly, the expression of genes related to the transport of carbohydrates increased upon herbivore attack in leaves during the root flush stage. Inoculation with an ectomycorrhizal fungus attenuated these effects but, instead, caused an increased expression of genes related to the production of volatile organic compounds. We conclude that oak defense response against herbivory is strong in root flush at the transcriptomic level but this response is strongly inhibited by inoculation with ectomycorrhizal fungi and it is extremely weak at shoot flush.
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Murata, Mika, Kotaro Konno, Naoya Wasano, Atsushi Mochizuki e Ichiro Mitsuhara. "Expression of a gene for an MLX56 defense protein derived from mulberry latex confers strong resistance against a broad range of insect pests on transgenic tomato lines". PLOS ONE 16, n. 1 (11 gennaio 2021): e0239958. http://dx.doi.org/10.1371/journal.pone.0239958.
Testo completoAbstract (sommario):
Insect pests cause serious damage in crop production, and various attempts have been made to produce insect-resistant crops, including the expression of genes for proteins with anti-herbivory activity, such as Bt (Bacillus thuringiensis) toxins. However, the number of available genes with sufficient anti-herbivory activity is limited. MLX56 is an anti-herbivory protein isolated from the latex of mulberry plants, and has been shown to have strong growth-suppressing activity against the larvae of a variety of lepidopteran species. As a model of herbivore-resistant plants, we produced transgenic tomato lines expressing the gene for MLX56. The transgenic tomato lines showed strong anti-herbivory activities against the larvae of the common cutworm, Spodoptera litura. Surprisingly, the transgenic tomato lines also exhibited strong activity against the attack of western flower thrips, Frankliniera occidentalis. Further, growth of the hadda beetle, Henosepilachna vigintioctopunctata, fed on leaves of transgenic tomato was significantly retarded. The levels of damage caused by both western flower thrips and hadda beetles were negligible in the high-MLX56-expressing tomato line. These results indicate that introduction of the gene for MLX56 into crops can enhance crop resistance against a wide range of pest insects, and that MLX56 can be utilized in developing genetically modified (GM) pest-resistant crops.
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Engelberth, Jurgen, e Marie Engelberth. "The Costs of Green Leaf Volatile-Induced Defense Priming: Temporal Diversity in Growth Responses to Mechanical Wounding and Insect Herbivory". Plants 8, n. 1 (18 gennaio 2019): 23. http://dx.doi.org/10.3390/plants8010023.
Testo completoAbstract (sommario):
Green leaf volatiles (GLVs) have long been associated with plant defense responses against insect herbivory. Although some of their biological activities appear to directly affect the attacking herbivore, one of the major functions of GLVs seems to be the priming of these defense responses. This priming is generally considered to impose low costs on the plant should no direct attack happen. Here, we demonstrate that priming of maize seedlings with GLVs is costly for the plants as it results in significantly reduced growth. We further demonstrate that priming very selectively affects growth responses after insect elicitor treatment and mechanical wounding depending on the age and/or the developmental stage of the treated plant. The differential growth response of maize seedlings to treatment with GLVs and subsequent herbivory-related damage sheds new light on the biological activity of these important plant volatile compounds and indicates consequences that go beyond defense.
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Costa, Fernanda Vieira da, Antônio César Medeiros de Queiroz, Maria Luiza Bicalho Maia, Ronaldo Reis Júnior e Marcílio Fagundes. "Resource allocation in Copaifera langsdorffii (Fabaceae): how a supra-annual fruiting affects plant traits and herbivory?" Revista de Biología Tropical 64, n. 2 (13 maggio 2016): 507. http://dx.doi.org/10.15517/rbt.v64i2.18586.
Testo completoAbstract (sommario):
<p>Plants have limited resources to invest in reproduction, vegetative growth and defence against herbivorous. Trade-off in resources allocation promotes changes in plant traits that may affect higher trophic levels. The trade-off between vegetative growth and defence, and their indirect effects on herbivory in <em>Copaifera langsdorffii </em>was evaluated during two consecutive years of high and low reproductive investment of host plant. We asked: (i) does the resource investment on reproduction causes a depletion in vegetative growth as predicted by CNBH, resulting in more availability of resources to be allocated for defence? (ii) does the variation in resource allocation for growth and defence between years of high and low fruiting leads to indirect changes in herbivory? Thirty-five trees located in a cerrado area were monitored during 2008 (high fruiting) and 2009 (no fruiting) years to evaluate the differential investment in vegetative traits (biomass, growth and number of ramifications), plant defence (tannin concentration and plant hypersensitivity) and herbivory. During fruiting year, woody biomass negatively affected tannin concentration, indicating that fruit production restricted the resources which could be invested both in growth and defence. In addition, plant resistance and galling attack were positively influenced by tannin concentration and leaf biomass, suggesting that plants’ resistance to herbivory is a good proxy of plant defence and an effective defence strategy for <em>C. langsdorffii</em>. In summary, the supra-annual fruiting pattern promoted several effects on plant development, demonstrating the importance of evaluating different plants traits when characterizing the vegetative investment of a species. As expected, the trade-off promoted changes in defence compounds production and patterns of herbivory. The understanding of this important element of insect-plant interactions will be fundamental to decipher coevolutionary life histories and interactions between plants reproduction and herbivores attack. These direct and indirect trajectories of animal-plant interactions are important keys for the development of appropriate strategies for diversity conservation in tropical areas.</p>
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Li, Ao-Mei, Miao Wang, Zhong-Liang Chen, Cui-Xian Qin, Fen Liao, Zhen Wu, Wei-Zhong He, Prakash Lakshmanan, You-Qiang Pan e Dong-Liang Huang. "Integrated Transcriptome and Metabolome Analysis to Identify Sugarcane Gene Defense against Fall Armyworm (Spodoptera frugiperda) Herbivory". International Journal of Molecular Sciences 23, n. 22 (8 novembre 2022): 13712. http://dx.doi.org/10.3390/ijms232213712.
Testo completoAbstract (sommario):
Sugarcane is the most important sugar crop, contributing ≥80% to total sugar production around the world. Spodoptera frugiperda is one of the main pests of sugarcane, potentially causing severe yield and sugar loss. The identification of key defense factors against S. frugiperda herbivory can provide targets for improving sugarcane resistance to insect pests by molecular breeding. In this work, we used one of the main sugarcane pests, S. frugiperda, as the tested insect to attack sugarcane. Integrated transcriptome and metabolomic analyses were performed to explore the changes in gene expression and metabolic processes that occurred in sugarcane leaf after continuous herbivory by S. frugiperda larvae for 72 h. The transcriptome analysis demonstrated that sugarcane pest herbivory enhanced several herbivory-induced responses, including carbohydrate metabolism, secondary metabolites and amino acid metabolism, plant hormone signaling transduction, pathogen responses, and transcription factors. Further metabolome analysis verified the inducement of specific metabolites of amino acids and secondary metabolites by insect herbivory. Finally, association analysis of the transcriptome and metabolome by the Pearson correlation coefficient method brought into focus the target defense genes against insect herbivory in sugarcane. These genes include amidase and lipoxygenase in amino acid metabolism, peroxidase in phenylpropanoid biosynthesis, and pathogenesis-related protein 1 in plant hormone signal transduction. A putative regulatory model was proposed to illustrate the sugarcane defense mechanism against insect attack. This work will accelerate the dissection of the mechanism underlying insect herbivory in sugarcane and provide targets for improving sugarcane variety resistance to insect herbivory by molecular breeding.
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Becerra, Judith X. "On the factors that promote the diversity of herbivorous insects and plants in tropical forests". Proceedings of the National Academy of Sciences 112, n. 19 (20 aprile 2015): 6098–103. http://dx.doi.org/10.1073/pnas.1418643112.
Testo completoAbstract (sommario):
Some of the most fascinating and challenging questions in ecology are why biodiversity is highest in tropical forests and whether the factors involved are unique to these habitats. I did a worldwide test of the hypotheses that plant community divergence in antiherbivore traits results in higher insect herbivore diversity, and that predominant attack by specialized herbivores promotes plant richness. I found strong correlative support for both ideas. Butterfly diversity was greatest in regions where the community average species-pairwise dissimilarity in antiherbivore traits among plant species was highest. There was also a strong positive relationship between specialized (insect) vs. generalized (mammal) herbivores and plant richness. Regions where herbivory impact by mammals was higher than that of insects tended to have lower plant diversities. In contrast, regions in which insects are the main consumers, particularly in the Central and South American tropics, had the highest plant richness. Latitude did not explain any residual variance in insect or plant richness. The strong connections found between insect specialization, plant defense divergence, and plant and insect diversities suggest that increasing our understanding of the ecology of biological communities can aid in considerations of how to preserve biodiversity in the future.
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Radny, Janina, e Katrin M. Meyer. "The role of biotic factors during plant establishment in novel communities assessed with an agent-based simulation model". PeerJ 6 (8 agosto 2018): e5342. http://dx.doi.org/10.7717/peerj.5342.
Testo completoAbstract (sommario):
Background Establishment success of non-native species is not only influenced by environmental conditions, but also by interactions with local competitors and enemies. The magnitude of these biotic interactions is mediated by species traits that reflect competitive strength or defence mechanisms. Our aim was to investigate the importance of species traits for successful establishment of non-native species in a native community exhibiting biotic resistance in the form of competition and herbivory. Methods We developed a trait-based, individual-based simulation model tracking the survival of non-native plants in a native community. In the model, non-native plants are characterized by high or low values of competition and defence traits. Model scenarios included variation of initial number of non-natives, intensity of competitive interaction, density of herbivores and density as well as mixture of the native community. Results Traits related to competition had a much greater impact on survival of non-native species than traits related to defence. Survival rates of strong competitors never fell below 50% while survival of weak competitors averaged at about 10%. Weak competitors were also much more susceptible to competitive pressures such as community density, composition and competition intensity. Strong competitors responded negatively to changes in competition intensity, but hardly to composition or density of the native community. High initial numbers of non-native individuals decreased survival rate of strong competitors, but increased the survival rate of weak competitors. Survival under herbivore attack was only slightly higher for plants with high defensive ability than for those with low defensive ability. Surprisingly, though, herbivory increased survival of species classified as weak competitors. Discussion High survival rates of strong non-native competitors relate to a higher probability of successful establishment than for weak competitors. However, the reduced survival of strong competitors at high initial numbers indicates a self-thinning effect, probably mediated by a strongly competitive milieu. For weak competitors, our model emphasizes positive effects of high propagule pressure known from field studies. General effects of herbivory or defence abilities on survival were not supported by our model. However, the positive effect of herbivory on survival of weak competitors indicated side effects of herbivory, such as weakening resident competitors. This might play an important role for establishment of non-natives in a new community.
28
Dobesberger, Erhard John. "Stochastic simulation of growth loss in thinned balsam fir stands defoliated by the spruce budworm in Newfoundland". Canadian Journal of Forest Research 28, n. 5 (1 maggio 1998): 703–10. http://dx.doi.org/10.1139/x98-042.
Testo completoAbstract (sommario):
A stochastic simulation model was developed to derive a damage function for the spruce budworm, Choristoneura fumiferana Clem. (Lepidoptera: Tortricidae), and balsam fir, Abies balsamea (L.) Mill., herbivore interaction at the stand level for open-grown trees. Both aggregated and uniform models of attack pattern by late-instar larvae based on k of the negative binomial were evaluated to determine the impact of larval density and attack pattern on the loss in stemwood volume increment of young, thinned balsam fir stands in Newfoundland. Percentage loss in stemwood increment was a nonlinear, negative exponential function of initial larval density. Implementation of control measures to prevent 50% defoliation that is caused by about 14 larvae/branch tip would result in saving 24% of the annual stemwood increment after 1 year of defoliation and about 32% after 2 years of cumulative defoliation. Aggregation of spruce budworm larvae among trees within a forest stand results in less growth loss compared with a uniform pattern of attack. The nonlinear damage function may suggest tolerance and possibly compensatory growth after herbivory by low population levels of the spruce budworm.
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Palacios-Mosquera, Y., D. Mondragón e A. Santos-Moreno. "Vertebrate florivory of vascular epiphytes: the case of a bromeliad". Brazilian Journal of Biology 79, n. 2 (aprile 2019): 201–7. http://dx.doi.org/10.1590/1519-6984.176023.
Testo completoAbstract (sommario):
Abstract The avoidance of vertebrate herbivory is thought to be one of the possible drivers for the evolution of epiphytism. Scarce literature suggests that epiphyte herbivory is mainly related to insect attack on reproductive structures. In a pine-oak forest we observed almost all inflorescences of an epiphytic bromeliad (Tillandsia carlos-hankii) with signs of florivory; the degree of damage suggested that vertebrate herbivores could be involved. To assess the intensity of vertebrate florivory damage we recorded the percentage of damaged individuals in a 500 m2 plots during two flowering seasons. To identify possible vertebrate herbivores, we installed 20 mixed capture stations, 10 photo-traps focused on bromeliads and analyzed stomach contents of captured vertebrates. Florivory was observed on 62% of individuals during the first flowering season and 77% on the second; and average one individual lost 41% of reproductive structures. Vertebrates associated with florivory were a bird, Icterus bullockii (Aves, Passeriformes, Icteridae), a squirrel Sciurus aureogaster (Mammalia, Rodentia, Sciuridae), and mice, Peromyscus gratus, P. levipes and P. aztecus (Mammalia, Rodentia, Cricetidae). Our results suggest that vascular epiphytes are used as opportunistic resources for small vertebrates during seasons when preferred resources are scarce.
30
Pan, Yu, Shi-wen Zhao, Xin-long Tang, Shang Wang, Xiao Wang, Xin-xin Zhang, Jing-Jiang Zhou e Jing-hui Xi. "Transcriptome analysis of maize reveals potential key genes involved in the response to belowground herbivore Holotrichia parallela larvae feeding". Genome 63, n. 1 (gennaio 2020): 1–12. http://dx.doi.org/10.1139/gen-2019-0043.
Testo completoAbstract (sommario):
The larvae of Holotrichia parallela, a destructive belowground herbivore, causes tremendous damages to maize plants. However, little is known if there are any defense mechanisms in maize roots to defend themselves against this herbivore. In the current research, we carried out RNA-sequencing to investigate the changes in gene transcription level in maize roots after H. parallela larvae infestation. A total of 644 up-regulated genes and 474 down-regulated genes was found. In addition, Gene ontology (GO) annotation analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were performed. Weighted gene co-expression network analysis (WGCNA) indicated that peroxidase genes may be the hub genes that regulate maize defenses to H. parallela larvae attack. We also found 105 transcription factors, 44 hormone-related genes, and 62 secondary metabolism-related genes within differentially expressed genes (DEGs). Furthermore, the expression profiles of 12 DEGs from the transcriptome analysis were confirmed by quantitative real-time PCR experiments. This transcriptome analysis provides insights into the molecular mechanisms of the underground defense in maize roots to H. parallela larvae attack and will help to select target genes of maize for defense against belowground herbivory.
31
Paulo, P. D., C. G. Lima, A. B. Dominiquini, M. A. M. Fadini, S. M. Mendes e C. G. S. Marinho. "Maize plants produce direct resistance elicited by Tetranychus urticae Koch (Acari: Tetranychidae)". Brazilian Journal of Biology 78, n. 1 (26 giugno 2017): 13–17. http://dx.doi.org/10.1590/1519-6984.19915.
Testo completoAbstract (sommario):
Abstract Plants can be attacked by a wide variety of herbivores. Thus, developing protective mechanisms for resistance against these agents is an advantage for survival and reproduction. Over the course of evolution, many resistance mechanisms against herbivory have been developed by the plants. Induced direct and indirect resistance mechanisms can manifest in plants after herbivore attack. The two-spotted spider mite Tetranychus urticae is not a pest of maize crops (Zea mays), despite being reported infesting plants that may have resistances against this herbivore. We tested the hypothesis that maize plants would be able to induce direct resistance against T. urticae after, evaluating the effect of T. urticae infestation in maize plants on the development and reproduction of conspecifics. We tested induced direct resistance performing infestation and measuring biological parameters upon a second infestation. Maize plants, 40 days after sowing, were divided into two groups: 30 not infested by T. urticae (clean plants clean) and, 30 infested by the spider mite. Infestation of maize plants by T. urticae reduced the conspecific female adult survival. However, no change in the survival of immature or reproduction was observed. These results suggest the induction of induced direct resistances in maize by T. urticae. This is first report of direct resistance induction in Z. mays by the two-spotted spider mite T. urticae.
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Moreira, Xoaquín, Luis Abdala-Roberts, Hans Henrik Bruun, Felisa Covelo, Pieter De Frenne, Andrea Galmán, Álvaro Gaytán et al. "Latitudinal variation in seed predation correlates with latitudinal variation in seed defensive and nutritional traits in a widespread oak species". Annals of Botany 125, n. 6 (20 dicembre 2019): 881–90. http://dx.doi.org/10.1093/aob/mcz207.
Testo completoAbstract (sommario):
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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MARQUIS, ROBERT J., IVONE R. DINIZ e HELENA C. MORAIS. "Patterns and correlates of interspecific variation in foliar insect herbivory and pathogen attack in Brazilian cerrado". Journal of Tropical Ecology 17, n. 1 (gennaio 2001): 127–48. http://dx.doi.org/10.1017/s0266467401001080.
Testo completoAbstract (sommario):
Patterns of insect herbivore and leaf pathogen attack are described for 25 plant species (10 trees, 10 shrubs and five herbs) at a Brazilian savanna (cerrado) site. Plant and leaf traits were correlated with interspecific variation in attack by herbivores and pathogens in order to account for differences among plant species. Across all species, pathogen damage was 1.5 times higher than insect damage (17.3% vs. 6.8%, respectively). Most insect damage occurred to young leaves while they were expanding (end of the dry season). In contrast, pathogen attack was low on young expanding leaves at the end of the dry season, increased as those leaves matured in the wet season, but continued to increase through the next dry season. Protein-binding capacity was negatively associated with interspecific differences in insect damage to mature leaves. Protein availability and plant height were positive predictors of pathogen attack among plant species, while leaf expansion rate was a significant negative predictor. Interspecific differences in leaf phenology had little effect on the amount of damage caused by either insects or pathogens. However, new leaves produced during the wet season suffered less insect damage than leaves produced during the dry season, the time of greatest leaf production. Timing of young leaf production affected pathogen attack but the season of escape depended on plant species. In contrast, there was no evidence for escape in space as common species were less likely to suffer high pathogen attack than rare species. New and mature leaf toughness, and time for a leaf to reach full expansion all increased from herbs to shrub to trees, while mature leaf nitrogen decreased in that order.
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Singh, Archana, Amit Kumar, Susan Hartley e Indrakant Kumar Singh. "Silicon: its ameliorative effect on plant defense against herbivory". Journal of Experimental Botany 71, n. 21 (27 giugno 2020): 6730–43. http://dx.doi.org/10.1093/jxb/eraa300.
Testo completoAbstract (sommario):
Abstract Plants protect themselves against pest attack utilizing both direct and indirect modes of defense. The direct mode of defense includes morphological, biochemical, and molecular barriers that affect feeding, growth, and survival of herbivores whereas the indirect mode of defense includes release of a blend of volatiles that attract natural enemies of the pests. Both of these strategies adopted by plants are reinforced if the plants are supplied with one of the most abundant metalloids, silicon (Si). Plants absorb Si as silicic acid (Si(OH)4) and accumulate it as phytoliths, which strengthens their physical defense. This deposition of Si in plant tissue is up-regulated upon pest attack. Further, Si deposited in the apoplast, suppresses pest effector molecules. Additionally, Si up-regulates the expression of defense-related genes and proteins and their activity and enhances the accumulation of secondary metabolites, boosting induced molecular and biochemical defenses. Moreover, Si plays a crucial role in phytohormone-mediated direct and indirect defense mechanisms. It is also involved in the reduction of harmful effects of oxidative stress resulting from herbivory by accelerating the scavenging process. Despite increasing evidence of its multiple roles in defense against pests, the practical implications of Si for crop protection have received less attention. Here, we highlight recent developments in Si-mediated improved plant resistance against pests and its significance for future use in crop improvement.
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Johnson, Scott N., Olivia L. Reynolds, Geoff M. Gurr, Jessica L. Esveld, Ben D. Moore, Gavin J. Tory e Andrew N. Gherlenda. "When resistance is futile, tolerate instead: silicon promotes plant compensatory growth when attacked by above- and belowground herbivores". Biology Letters 15, n. 7 (luglio 2019): 20190361. http://dx.doi.org/10.1098/rsbl.2019.0361.
Testo completoAbstract (sommario):
Plants have evolved numerous herbivore defences that are resistance- or tolerance-based. Resistance involves physical and chemical traits that deter and/or harm herbivores whereas tolerance minimizes fitness costs of herbivory, often via compensatory growth. The Poaceae frequently accumulate large amounts of silicon (Si), which can be used for herbivore resistance, including biomechanical and (indirectly) biochemical defences. To date, it is unclear whether Si improves tolerance of herbivory. Here we report how Si enabled a cereal ( Triticum aestivum ) to tolerate damage inflicted by above- and belowground herbivores. Leaf herbivory increased Si concentrations in the leaves by greater than 50% relative to herbivore-free plants, indicating it was an inducible defensive response. In plants without Si supplementation, leaf herbivory reduced shoot biomass by 52% and root herbivory reduced root biomass by 68%. Si supplementation, however, facilitated compensatory growth such that shoot losses were more than compensated for (+14% greater than herbivore-free plants) and root losses were minimized to −16%. Si supplementation did not improve plant resistance since Si did not enhance biomechanical resistance (i.e. force of fracture) or reduce leaf consumption and herbivore relative growth rates. We propose that Si-based defence operates in wheat via tolerance either in addition or as an alternative to resistance-based defence.
36
Iason, Glenn R., Julianne M. O'Reilly-Wapstra, Mark J. Brewer, Ron W. Summers e Ben D. Moore. "Do multiple herbivores maintain chemical diversity of Scots pine monoterpenes?" Philosophical Transactions of the Royal Society B: Biological Sciences 366, n. 1569 (12 maggio 2011): 1337–45. http://dx.doi.org/10.1098/rstb.2010.0236.
Testo completoAbstract (sommario):
A central issue in our understanding of the evolution of the diversity of plant secondary metabolites (PSMs) is whether or not compounds are functional, conferring an advantage to the plant, or non-functional. We examine the hypothesis that the diversity of monoterpene PSMs within a plant species (Scots pine Pinus sylvestris ) may be explained by different compounds acting as defences against high-impact herbivores operating at different life stages. We also hypothesize that pairwise coevolution, with uncorrelated interactions, is more likely to result in greater PSM diversity, than diffuse coevolution. We tested whether up to 13 different monoterpenes in Scots pine were inhibitory to herbivory by slugs ( Arion ater ), bank voles ( Clethrionomys glareolus ), red deer ( Cervus elaphus ) and capercaillie ( Tetrao urogallus) , each of which attack trees at a different life stage. Plants containing more α-pinene were avoided by both slugs and capercaillie, which may act as reinforcing selective agents for this dominant defensive compound. Herbivory by red deer and capercaillie were, respectively, weakly negatively associated with δ 3 -carene, and strongly negatively correlated with the minor compound β-ocimene. Three of the four herbivores are probably contributory selective agents on some of the terpenes, and thus maintain some, but by no means all, of the phytochemical diversity in the species. The correlated defensive function of α-pinene against slugs and capercaillie is consistent with diffuse coevolutionary processes.
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Mundim, Fabiane M., Emilio M. Bruna, Ernane H. M. Vieira-Neto e Heraldo L. Vasconcelos. "Attack frequency and the tolerance to herbivory of Neotropical savanna trees". Oecologia 168, n. 2 (2 agosto 2011): 405–14. http://dx.doi.org/10.1007/s00442-011-2088-8.
Testo completo
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Svensson, Brita M., Bengt Å. Carlsson e Jerry M. Melillo. "Changes in species abundance after seven years of elevated atmospheric CO2 and warming in a Subarctic birch forest understorey, as modified by rodent and moth outbreaks". PeerJ 6 (29 maggio 2018): e4843. http://dx.doi.org/10.7717/peerj.4843.
Testo completoAbstract (sommario):
A seven-year long, two-factorial experiment using elevated temperatures (5 °C) and CO2 (concentration doubled compared to ambient conditions) designed to test the effects of global climate change on plant community composition was set up in a Subarctic ecosystem in northernmost Sweden. Using point-frequency analyses in permanent plots, an increased abundance of the deciduous Vaccinium myrtillus, the evergreens V. vitis-idaea and Empetrum nigrum ssp. hermaphroditum and the grass Avenella flexuosa was found in plots with elevated temperatures. We also observed a possibly transient community shift in the warmed plots, from the vegetation being dominated by the deciduous V. myrtillus to the evergreen V. vitis-idaea. This happened as a combined effect of V. myrtillus being heavily grazed during two events of herbivore attack—one vole outbreak (Clethrionomys rufocanus) followed by a more severe moth (Epirrita autumnata) outbreak that lasted for two growing seasons—producing a window of opportunity for V. vitis-idaea to utilize the extra light available as the abundance of V. myrtillus decreased, while at the same time benefitting from the increased growth in the warmed plots. Even though the effect of the herbivore attacks did not differ between treatments they may have obscured any additional treatment effects. This long-term study highlights that also the effects of stochastic herbivory events need to be accounted for when predicting future plant community changes.
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Denham, Sander O., David R. Coyle, A. Christopher Oishi, Bronson P. Bullock, Kari Heliövaara e Kimberly A. Novick. "Tree resin flow dynamics during an experimentally induced attack by Ips avulsus, I. calligraphus, and I. grandicollis". Canadian Journal of Forest Research 49, n. 1 (gennaio 2019): 53–63. http://dx.doi.org/10.1139/cjfr-2018-0024.
Testo completoAbstract (sommario):
The success of tree colonization by bark beetles depends on their ability to overcome host tree defenses, including resin exudation and toxic chemicals, which deter bark beetle colonization. Resin defenses during insect outbreaks are challenging to study in situ, as outbreaks are stochastic events that progress quickly and thus preclude the establishment of baseline observations of non-infested controls. We use synthetic aggregation pheromones to demonstrate that confined Ips bark beetle herbivory can be successfully initiated to provide opportunities for studying interactions between bark beetles and their hosts, including the dynamics of constitutive and induced resin exudation. In Pinus taeda L. plantations between 12 and 19 years old in North and South Carolina, U.S., trees were affixed with pheromone lures, monitored for evidence of bark beetle attacks, and resin samples were collected throughout the growing season. Baiting increased beetle herbivory to an extent sufficient to produce an induced resin response. Attacked trees exuded about three times more resin at some time than control trees. This supports previous work that demonstrated that information on constitutive resin dynamics alone provides an incomplete view of a host tree’s resistance to bark beetle attack.
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Pena, João Carlos De Castro, Pedro Luna, Felipe Aoki-Gonçalves, María Fernanda Chávez Jacobo, TAMARA MARTÍNEZ PATIÑO, KASSANDRA SÁNCHEZ MORALES, MIGUELINA VIVER VÁZQUEZ, JUAN HECTOR GARCÍA-CHÁVEZ e WESLEY DÁTTILO. "I Can See You: Temporal Variation in Ant Aggressiveness Towards Herbivores under Continuous Provision of High- or Low-quality Food Sources". Sociobiology 67, n. 1 (18 aprile 2020): 26. http://dx.doi.org/10.13102/sociobiology.v67i1.4727.
Testo completoAbstract (sommario):
To reduce herbivory, plants bearing extrafloral nectaries interact with ants and attract them by providing food. As plant bodyguards, ants respond to the resource provision and, using their antennae, detect chemical messages from the host plants that help them to locate herbivores. Ants can also use their vision to explore the environment; however, information is lacking on how interactions between visual signs and the availability of extrafloral nectar affect ant aggressiveness near resources. We addressed the following question in this study: does the ants’ ability to visualize potential herbivores enhance their aggression under a constant provision of a high-quality food source? Using an experimental approach within the semiarid intertropical region of Tehuacan-Cuicatlán (Mexico), we manipulated the availability of food sources by constantly offering artificial nectaries on the shrub Prosopis laevigata (Fabaceae). Over two time periods (day and night), we tested how the presence of a high-quality food source affected ant aggressiveness to herbivores. Therefore, we offered dummy caterpillars and counted the number of marks left by enemy attacks. Overall the attack rate was extremely high: 84.25% of the dummy caterpillars were injured. Ants were responsible for 86.22% of the marks left by enemies, and their aggression increased during the day, especially towards caterpillars in trees with high-quality food sources. During the night, ants probably rely mostly on their antennae to detect potential herbivores; therefore, their ability to detect dummy caterpillars was greater during the day. We show that, besides nectar quality and availability, visualizing herbivores may enhance ant aggressiveness.
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Havko, Nathan E., Michael R. Das, Alan M. McClain, George Kapali, Thomas D. Sharkey e Gregg A. Howe. "Insect herbivory antagonizes leaf cooling responses to elevated temperature in tomato". Proceedings of the National Academy of Sciences 117, n. 4 (21 gennaio 2020): 2211–17. http://dx.doi.org/10.1073/pnas.1913885117.
Testo completoAbstract (sommario):
As global climate change brings elevated average temperatures and more frequent and extreme weather events, pressure from biotic stresses will become increasingly compounded by harsh abiotic stress conditions. The plant hormone jasmonate (JA) promotes resilience to many environmental stresses, including attack by arthropod herbivores whose feeding activity is often stimulated by rising temperatures. How wound-induced JA signaling affects plant adaptive responses to elevated temperature (ET), however, remains largely unknown. In this study, we used the commercially important crop plant Solanum lycopersicum (cultivated tomato) to investigate the interaction between simulated heat waves and wound-inducible JA responses. We provide evidence that the heat shock protein HSP90 enhances wound responses at ET by increasing the accumulation of the JA receptor, COI1. Wound-induced JA responses directly interfered with short-term adaptation to ET by blocking leaf hyponasty and evaporative cooling. Specifically, leaf damage inflicted by insect herbivory or mechanical wounding at ET resulted in COI1-dependent stomatal closure, leading to increased leaf temperature, lower photosynthetic carbon assimilation rate, and growth inhibition. Pharmacological inhibition of HSP90 reversed these effects to recapitulate the phenotype of a JA-insensitive mutant lacking the COI1 receptor. As climate change is predicted to compound biotic stress with larger and more voracious arthropod pest populations, our results suggest that antagonistic responses resulting from a combination of insect herbivory and moderate heat stress may exacerbate crop losses.
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Johnson, Scott N., Matthias Erb e Susan E. Hartley. "Roots under attack: contrasting plant responses to below- and aboveground insect herbivory". New Phytologist 210, n. 2 (19 gennaio 2016): 413–18. http://dx.doi.org/10.1111/nph.13807.
Testo completo
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Barboza, Deise Mari, Márcia Cristina Mendes Marques, José Henrique Pedrosa-Macedo e Terence Olckers. "Plant population structure and insect herbivory on Solanum mauritianum Scopoli (Solanaceae) in southern Brazil: a support to biological control". Brazilian Archives of Biology and Technology 52, n. 2 (aprile 2009): 413–20. http://dx.doi.org/10.1590/s1516-89132009000200019.
Testo completoAbstract (sommario):
Solanum mauritianum Scopoli (Solanaceae), a native Brazilian shrub, has become naturalized and invasive in several countries. In South Africa, where invasions are severe, herbivorous insects that attack S. mauritianum in its native area have been considered for introduction as biological control agents. To assess the action of such herbivores on the plant, studies were carried out on a population of S. mauritianum in an area undergoing regeneration in southern Brazil. An analysis of the structure of that population was performed, as well as of herbivory by insects, in particular of Anthonomus (Curculionidae). The population structure showed an "inverted J" pattern in diameter classes, but not in height classes. Individual plants showed an aggregate distribution. The damage caused by Anthonomus did not amount to the loss of a large leaf area, but since it was inflicted on young leaves and in a large proportion, could lead to the survival decrease.
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Wetterer, James K. "Attack by Paraponera clavata Prevents Herbivory by the Leaf-Cutting Ant, Atta cephalotes". Biotropica 26, n. 4 (dicembre 1994): 462. http://dx.doi.org/10.2307/2389241.
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Ohata, Yuto, Yuuki Tetsumoto, Sayo Morita, Naoki Mori, Yoichi Ishiguri e Naoko Yoshinaga. "Triterpenes induced by young apple fruits in response to herbivore attack". Bioscience, Biotechnology, and Biochemistry 85, n. 7 (4 maggio 2021): 1594–601. http://dx.doi.org/10.1093/bbb/zbab077.
Testo completoAbstract (sommario):
ABSTRACT Apples Malus domestica, known as a rich source of triterpene acids, induced more variety and quantity of triterpene acids in response to herbivory or mechanical damage. There were 3 major induced compounds: pomaceic acid and euscaphic acid, both of which are known apple triterpene acids, and 2α,19α-dihydroxy-3-oxours-12-en-28-oic acid (named eriobotoric acid), which was first identified in apples. In this study, the 3 compounds’ induction curves after damage, varietal differences in induction amounts, and physiological roles against pest insects were further investigated. Eriobotoric acid showed clear antifeedant activity against lepidopteran insect Spodoptera litura but not against apple pests.
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Hettenhausen, Christian, Juan Li, Huifu Zhuang, Huanhuan Sun, Yuxing Xu, Jinfeng Qi, Jingxiong Zhang et al. "Stem parasitic plant Cuscuta australis (dodder) transfers herbivory-induced signals among plants". Proceedings of the National Academy of Sciences 114, n. 32 (24 luglio 2017): E6703—E6709. http://dx.doi.org/10.1073/pnas.1704536114.
Testo completoAbstract (sommario):
Cuscuta spp. (i.e., dodders) are stem parasites that naturally graft to their host plants to extract water and nutrients; multiple adjacent hosts are often parasitized by one or more Cuscuta plants simultaneously, forming connected plant clusters. Metabolites, proteins, and mRNAs are known to be transferred from hosts to Cuscuta, and Cuscuta bridges even facilitate host-to-host virus movement. Whether Cuscuta bridges transmit ecologically meaningful signals remains unknown. Here we show that, when host plants are connected by Cuscuta bridges, systemic herbivory signals are transmitted from attacked plants to unattacked plants, as revealed by the large transcriptomic changes in the attacked local leaves, undamaged systemic leaves of the attacked plants, and leaves of unattacked but connected hosts. The interplant signaling is largely dependent on the jasmonic acid pathway of the damaged local plants, and can be found among conspecific or heterospecific hosts of different families. Importantly, herbivore attack of one host plant elevates defensive metabolites in the other systemic Cuscuta bridge-connected hosts, resulting in enhanced resistance against insects even in several consecutively Cuscuta-connected host plants over long distances (> 100 cm). By facilitating plant-to-plant signaling, Cuscuta provides an information-based means of countering the resource-based fitness costs to their hosts.
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Morrell, Kimberly, e André Kessler. "The scent of danger: Volatile-mediated information transfer and defence priming in plants". Biochemist 36, n. 5 (1 ottobre 2014): 26–31. http://dx.doi.org/10.1042/bio03605026.
Testo completoAbstract (sommario):
Volatile organic compounds (VOCs) are constantly emitted by plants, and play a major role in information transfer between plants and other organisms. One of the consequences of VOC-mediated information transfer is that plants ‘warn’ neighbouring plants when they are attacked, enabling these neighbours to prime defence responses in anticipation of future attack. Priming refers to a memory effect in which previous exposure to a stimulus (i.e. VOCs) enables plants to respond faster and more strongly when presented with a future stimulus (i.e. herbivory, pathogen infection). In recent years, our knowledge of how VOCs are perceived by plants, and the broad-scale phenotypic changes they induce, has grown dramatically. Multiple plant species seem to prime defence responses following exposure to herbivore-induced VOCs. However, the mechanisms underlying priming remain speculative. In the present article we highlight recent advancements in our understanding of stress perception by plants and discuss hypotheses of what might be happening on a molecular level in primed plants. Furthermore, we discuss ecological consequences of priming responses such as consequences for plant competitive interactions, and interactions with mutualistic and antagonistic animals.
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Kadarsah, Anang. "Analysis of Avicennia Sp. Plants Herbivory and Associated Insects in Mangrove Ecosystem Restoration". Journal of Wetlands Environmental Management 9, n. 1 (23 marzo 2021): 59. http://dx.doi.org/10.20527/jwem.v9i1.261.
Testo completoAbstract (sommario):
Herbivory is<strong> </strong>a<strong> </strong>natural mechanisms for adjustment of tree growth, form, survivorship, and reproductive output of forest ecology including in mangrove ecosystem. The purpose of this study was to compare herbivory and insect diversity in various growth stages of <em>Avicennia</em> Sp. related with restoration of mangrove ecosystem. The research was carried out four months (July-October 2020) in Pagatan Besar mangrove ecosystem in Tanah Laut District, South Kalimantan Province. The results showed that marginal pattern is the most leaf attack case, both in every plant growth stages (39-68%) and canopy (53-58%)<strong> </strong>of <em>Avicennia </em>Sp. The highest average of leaf damage was found in lower canopy (3.06%), and the growth stage of seedling (3.62%). Herbivory most often found at lower canopy (3.17%) and seedling life stages (3.76%) of <em>Avicennia </em>Sp. It was found about 13 species of insects in all growth stages of Avicennia Sp. with the highest Biodiversity Index found in seedling (0.753). Insects function on all life stages of <em>Avicennia</em> Sp. was dominated by predator.
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Chitty, Ruth P., e Alan C. Gange. "Reciprocal interactions between aphids and arbuscular mycorrhizal fungi across plant generations". Arthropod-Plant Interactions 16, n. 1 (20 novembre 2021): 33–43. http://dx.doi.org/10.1007/s11829-021-09875-9.
Testo completoAbstract (sommario):
AbstractThe conditions experienced by one plant generation can influence the growth of the offspring generation. These maternal effects can reduce performance of foliar-feeding insects, through accumulation of plant defences. Arbuscular mycorrhizal fungi (AMF) inhabit the roots of plants and are known to influence the performance of foliar-feeding insects. However, all published studies of the interactions between insects and AMF have taken place within one plant generation, but none across generations. Thus, in the present study, Senecio vulgaris plants were grown with or without aphids and AMF (termed ‘induction events’), and seeds from each treatment were used to grow plants experiencing that same treatment over four successive generations, all grown in identical environmental conditions. Naïve aphids were reared on Senecio plants whose parents had experienced 0, 1, 2 or 3 induction events. We found strong negative maternal effects of herbivory on aphid growth, which were not mitigated by the mycorrhiza. However, teneral weight and growth rate showed a gradual recovery; aphids reared on plants whose previous three generations suffered attack were similar in size to those at the beginning of the study. Herbivory had positive or negative effects on the mycorrhiza, dependent upon the number of previous generations suffering attack or having mycorrhizal associations. We conclude that the outcome of many insect plant fungal experiments is likely to have been influenced by and need to account for maternal effects of the parental plant’s growth conditions.
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Bodenhausen, Natacha, e Philippe Reymond. "Signaling Pathways Controlling Induced Resistance to Insect Herbivores in Arabidopsis". Molecular Plant-Microbe Interactions® 20, n. 11 (novembre 2007): 1406–20. http://dx.doi.org/10.1094/mpmi-20-11-1406.
Testo completoAbstract (sommario):
Insect attack triggers changes in transcript level in plants that are mediated predominantly by jasmonic acid (JA). The implication of ethylene (ET), salicylic acid (SA), and other signals in this response is less understood and was monitored with a microarray containing insect- and defense-regulated genes. Arabidopsis thaliana mutants coi1-1, ein2-1, and sid2-1 impaired in JA, ET, and SA signaling pathways were challenged with the specialist small cabbage white (Pieris rapae) and the generalist Egyptian cotton worm (Spodoptera littoralis). JA was shown to be a major signal controlling the upregulation of defense genes in response to either insect but was found to suppress changes in transcript level only in response to P. rapae. Larval growth was affected by the JA-dependent defenses, but S. littoralis gained much more weight on coi1-1 than P. rapae. ET and SA mutants had an altered transcript profile after S. littoralis herbivory but not after P. rapae herbivory. In contrast, both insects yielded similar transcript signatures in the abscisic acid (ABA)-biosynthetic mutants aba2-1 and aba3-1, and ABA controlled transcript levels both negatively and positively in insect-attacked plants. In accordance with the transcript signature, S. littoralis larvae performed better on aba2-1 mutants. This study reveals a new role for ABA in defense against insects in Arabidopsis and identifies some components important for plant resistance to herbivory.