Induced Resistance (induced + resistance)

Distribution by Scientific Domains
Distribution within Life Sciences


Selected Abstracts


Induced Resistance by , -Aminobutyric Acid in Artichoke against White Mould Caused by Sclerotinia sclerotiorum

JOURNAL OF PHYTOPATHOLOGY, Issue 10 2010
Emanuela Marcucci
Abstract ,-aminobutyric acid (BABA) was assessed for the ability to protect two artichoke cultivars, C3 and Exploter, against white mould caused by Sclerotinia sclerotiorum, which represents a major problem in the cultivation of this crop in many growing areas of Central Italy. Changes in the activity and isoenzymatic profiles of the pathogenesis-related (PR) proteins ,-1,3-glucanase, chitinase and peroxidase in plantlets upon BABA treatment and following inoculation of the pathogen in plantlets and leaves detached from adult plants were also investigated as molecular markers of induced resistance and priming. BABA treatments by soil drenching induced a high level of resistance against S. sclerotiorum in artichoke plantlets of both cultivars C3 and Exploter with a similar level of protection and determined a consistent increase in peroxidase activity paralleled with the differential induction of alkaline isoenzyme with a pI 8.6. A consistent change was found in Exploter in the peroxidase activity following BABA treatments and pathogen inoculation and was paralleled with the expression of an anionic band in plantlets and both anionic and cationic bands in leaves. Our results showed a correlation between BABA-induced resistance (BABA-IR) and a augmented capacity to express basal defence responses, more pronounced in cultivar C3 and associated ,-1,3-glucanase accumulation in both plantlets and leaves inoculated with the pathogen, whereas chitinase resulted affected only at plantlet stage. The present results represent the first one showing the effect of BABA in inducing resistance in artichoke and associated accumulation of selected PRs. If confirmed in field tests, the use of BABA at early plant stages may represent a promising approach to the control soilborne pathogens, such as the early infection of S. sclerotiorum. [source]


Induced Resistance in Yali Pear (Pyrus bretschneideri Rehd.) Fruit against Infection by Penicillium expansum by Postharvest Infiltration of Acibenzolar-S-methyl

JOURNAL OF PHYTOPATHOLOGY, Issue 11-12 2005
J. Cao
Abstract The objective of the present study was to evaluate how disease resistance in Yali pear fruit (Pyrus bretschneideri Rehd.) was affected by the infiltration of acibenzolar-S-methyl (ASM) after harvest. The disease incidence and lesion area in/on the fruit inoculated with Penicillium expansum significantly (P < 0.05) decreased by the infiltration with 0.5 mm ASM, and the duration of protection conferred by ASM lasted over 15 days. ASM did not directly inhibit the mycelial growth of P. expansum in vitro. However, ASM treatment significantly enhanced activities of the main defence enzymes including peroxidase, phenylalanine ammonia-lyase and chitinase, and activities of antioxidant enzymes including superoxide dismutase and catalase in the fruit during the infection. Two kinds of second metabolites, total phenolic compounds and flavonoids, and two productions of lipid peroxidation, H2O2 and malondialdehyde, were also involved in the resistance and significantly accumulated in ASM-treated fruit in the infection. The inhibitory effect of ASM on the disease may be related to its ability to enhance defence responses in the fruit. The application of ASM in inducing resistance in fruit possesses promising in control of postharvest diseases alternative to fungicides. [source]


Induced resistance of Norway spruce, variation of phenolic compounds and their effects on fungal pathogens

FOREST PATHOLOGY, Issue 2 2000
P. C. Evensen
Summary Three clones of Norway spruce (Picea abies) were studied for their response to mass-inoculation with the blue-stain fungus Ceratocystis polonica. The effect of different pretreatments (fungal inoculation and wounding) before mass-inoculation was investigated for their possible role in an acquired resistance reaction. Pretreated trees showed enhanced resistance to the subsequent mass-inoculation relative to control trees that received no pretreatment. Furthermore, the fungal colonization of inoculated trees was less than that of wounded trees. The phenolic content of the bark, analysed by RP-HPLC, was compared in trees receiving different treatments. Trees inoculated with C. polonica had higher average concentration of (+)-catechin, taxifolin and trans-resveratrol than wounded trees. Both inoculated and wounded trees had higher average concentrations of these compounds than control trees. The effect of the phenolic extract of Norway spruce bark on the growth of the root rot fungus Heterobasidion annosum and the blue-stain fungi C. polonica and Ophiostoma penicillatum were investigated in vitro. Heterobasidion annosum was not negatively affected, and the extracts had fungistatic effects on the blue-stain fungi. The growth of O. penicillatum was more inhibited than the growth of the more aggressive C. polonica. [source]


Using nutritional indices to study LOX3-dependent insect resistance

PLANT CELL & ENVIRONMENT, Issue 8 2006
CBGOWDA RAYAPURAM
ABSTRACT Induced resistance to biotic attackers is thought to be mediated by responses elicited by jasmonic acid (JA), a subset of which are lipoxygenase 3 (LOX3) dependent. To understand the importance of LOX3-mediated insect resistance, we analysed the performance of Manduca sexta larvae on wild-type (WT) and on isogenic Nicotiana attenuata plants silenced in NaLOX3 expression and JA signalling, and we used Waldbauer nutritional indices to measure the pre- and post-ingestive effects. LOX3-mediated defenses reduced larval growth, consumption and frass production. These defenses reduced how efficiently late-instar larvae converted digested food to body mass (ECD). In contrast, LOX3-mediated defenses decreased approximate digestibility (AD) in early instar larvae without affecting the ECD and total food consumption. Larvae of all instars feeding on defended WT plants behaviourally compensate for their reduced body mass by consuming more food per unit of body mass gain. We suggest that larvae feeding on plants silenced in NaLOX3 expression (as-lox) initially increase their AD, which in turn enables them to consume more food in the later stages and consequently, to increase their ECD and efficiency of conversion of ingested food (ECI). We conclude that N. attenuata's oxylipin-mediated defenses are important for resisting attack from M. sexta larvae, and that Waldbauer nutritional assays reveal behavioural and physiological counter responses of insects to these plant defenses. [source]


Systemic induced resistance in Monterey pine

FOREST PATHOLOGY, Issue 2 2001
Bonello
The pathogenic fungus Fusarium circinatum causes pitch canker of pines. This study shows that Monterey pine (Pinus radiata), one of the most economically important pine species in the world and the main host in California, responds to infection by Fusarium circinatum in a manner consistent with systemic induced resistance. Repeated mechanical inoculations of the same trees in the field produced progressively smaller lesions over a period of 2 years, with mean lesion length decreasing significantly from 2.89 ± 0.42 cm to 1.04 ± 0.17 cm. In the greenhouse, predisposing inoculations with the pathogen induced a significant lesion length reduction, from 5.5 ± 0.21 cm in control trees to 4.46 ± 0.36 cm in predisposed trees over a period of 6 weeks. Under constant environmental conditions in a growth chamber, predisposing inoculations also induced a significant reduction in lesion size, from 3.01 ± 0.15 cm to 2.55 ± 0.18 cm over a period of 4 weeks. This is the first unequivocal report of systemic induced resistance in a conifer. Résistance systémique induite chez le Pinus radiata Fusarium circinatum est l'agent causal du ,pitch canker' des pins. Le Pinus radiata est l'un des pins les plus importants économiquement dans le monde, et le principal hôte de la maladie en Californie. Cette étude montre que P. radiata réagit régulièrement à l'infection de Fusarium circinatum d'une façon qui peut être de la résistance systémique induite. Des inoculations mécaniques répétées sur de mêmes arbres en nature ont produit progressivement des lésions dont la taille diminuait au cours d'une période de deux ans; la longueur des lésions diminuait significativement de 2.89 ± 0.42 cm à 1.04 ± 0.17 cm. En serre, des inoculations de pré-conditionnement avec le parasite ont entraîné une réduction significative de la longueur des lésions, de 5.5 ± 0.21 cm chez les témoins à 4.46 ± 0.36 cm chez les arbres pré-conditionnés, au cours d'une période de six semaines. En conditions environnementales constantes en chambre climatique, les inoculations de pré-conditionnement ont aussi induit une réduction significative de la taille des lésions, de 3.01 ± 0.15 cm à 2.55 ± 0.18 cm, en une période de 4 semaines. Ceci est la première mention non équivoque d'une résistance systémique induite chez un conifère. Induzierte systemische Resistenz in Monterey-Kiefer Der pathogene Pilz Fusarium circinatum verursacht einen Krebs an Kiefern (pitch canker). Die vorliegende Untersuchung zeigt, dass die Monterey-Kiefer (Pinus radiata), eine der ökonomisch wichtigsten Kiefernarten der Welt und Hauptwirt in Kalifornien, auf Infektionen durch Fusarium circinatum mit induzierter systemischer Resistenz reagiert. Wiederholte mechanische Inokulationen der gleichen Bäume im Feld führten zu zunehmend kleineren Läsionen über einen Beobachtungszeitraum von zwei Jahren. Die Länge der Läsionen nahm von 2.89 ± 0.42 cm auf 1.04 ± 0.17 cm signifikant ab. Im Gewächshaus bewirkten prädisponierende Inokulationen mit dem Pathogen eine signifikante Reduktion der Läsionslänge von 5.5 ± 0.21 cm in den Kontrollen auf 4.46 ± 0.36 cm in den prädisponierten Pflanzen über einen Beobachtungszeitraum von sechs Wochen. Prädisponierende Inokulationen bewirkten auch unter konstanten Umweltbedingungen in einer Klimakammer eine signifikante Abnahme der Läsionsgrösse von 3.01 ± 0.15 cm auf 2.55 ± 0.18 über eine Periode von vier Wochen. Es handelt sich hier um den ersten eindeutigen Nachweis von induzierter systemischer Resistenz bei einer Konifere. [source]


Induced Resistance by , -Aminobutyric Acid in Artichoke against White Mould Caused by Sclerotinia sclerotiorum

JOURNAL OF PHYTOPATHOLOGY, Issue 10 2010
Emanuela Marcucci
Abstract ,-aminobutyric acid (BABA) was assessed for the ability to protect two artichoke cultivars, C3 and Exploter, against white mould caused by Sclerotinia sclerotiorum, which represents a major problem in the cultivation of this crop in many growing areas of Central Italy. Changes in the activity and isoenzymatic profiles of the pathogenesis-related (PR) proteins ,-1,3-glucanase, chitinase and peroxidase in plantlets upon BABA treatment and following inoculation of the pathogen in plantlets and leaves detached from adult plants were also investigated as molecular markers of induced resistance and priming. BABA treatments by soil drenching induced a high level of resistance against S. sclerotiorum in artichoke plantlets of both cultivars C3 and Exploter with a similar level of protection and determined a consistent increase in peroxidase activity paralleled with the differential induction of alkaline isoenzyme with a pI 8.6. A consistent change was found in Exploter in the peroxidase activity following BABA treatments and pathogen inoculation and was paralleled with the expression of an anionic band in plantlets and both anionic and cationic bands in leaves. Our results showed a correlation between BABA-induced resistance (BABA-IR) and a augmented capacity to express basal defence responses, more pronounced in cultivar C3 and associated ,-1,3-glucanase accumulation in both plantlets and leaves inoculated with the pathogen, whereas chitinase resulted affected only at plantlet stage. The present results represent the first one showing the effect of BABA in inducing resistance in artichoke and associated accumulation of selected PRs. If confirmed in field tests, the use of BABA at early plant stages may represent a promising approach to the control soilborne pathogens, such as the early infection of S. sclerotiorum. [source]


Soil properties, but not plant nutrients (N, P, K) interact with chemically induced resistance against powdery mildew in barley

JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 3 2003
Joachim Wiese
Abstract Chemically induced resistance is a promising method of plant protection against diseases, which can be triggered by systemically acting chemical inducers such as BTH (benzo(1, 2, 3)thiadiazole-carbothioic-acid-S-methylester). BTH is commercially distributed as a 50,% formulation, called Bion®. The uncertain success of Bion® application in controlling infection by powdery mildew is a major obstacle in using induced resistance for plant protection in agriculture. This study aimed to investigate the effect of soil properties, selected macronutrients (N, P, and K), and addition of organic matter on induced resistance and to identify possible factors responsible for the high variability of BTH effect under field conditions. A pot experiment under open-air conditions was set up using the pathosystem Hordeum vulgare cv. Ingrid / Blumeria graminis f. sp. hordei race A6. The different soils strongly affected the resistance of barley plants against powdery mildew after BTH treatment. The infection of barley by powdery mildew was lower than on all other soils when grown on an acid forest soil which was limed up to pH 4.9, even after BTH treatment. A reproducible induction of pathogen resistance by BTH was shown only on a mineral soil (Kleinlinden) with a negligible C content. Application of N, P, and K did not consistently affect the induction of resistance by BTH. The addition of green manure and compost led to an enhanced variability of resistance induction on the soil "Kleinlinden". Possible effects of soil microflora on resistance induction are discussed. Bodeneigenschaften, aber nicht Pflanzennährstoffe (N, P, K) interagieren mit der chemisch induzierten Resistenz gegen Gerstenmehltau in Gerste Chemisch induzierte Resistenz ist eine viel versprechende Methode im Pflanzenschutz, welche durch systemisch wirkende Substanzen wie BTH (Benzo(1, 2, 3)-thiadiazolcarbothion-Säure- S -Methylester) induziert werden kann. BTH ist die wirksame Komponente des kommerziell erhältlichen Produkts Bion®. Allerdings ist die Wirksicherheit von Bion® im Feld gering, wodurch die Anwendung des Produkts im Pflanzenschutz eingeschränkt ist. Das Ziel der vorliegenden Arbeit war es, den Einfluss verschiedener Böden, ausgewählter Makronährstoffe (N, P und K) und des Zusatzes von organischem Material zum Boden auf die induzierte Resistenz zu untersuchen und Faktoren zu identifizieren, die für die unsichere BTH-Wirkung im Feld verantwortlich sind. Dafür wurden Gefäßexperimente unter freilandähnlichen Bedingungen durchgeführt. In diesen wurde das Pathosystem Hordeum vulgare cv. Ingrid / Blumeria graminis f. sp. hordei Stamm A6 verwendet. Es wurde ein starker Einfluss des Bodens auf die Resistenz der Gerste gegen Gerstenmehltau nach BTH-Behandlung ermittelt. Die Mehltauinfektion von Gerste, welche auf einem sauren Waldboden kultiviert wurde, der auf einen pH-Wert von 4, 9 aufgekalkt worden war, war niedriger als auf allen anderen Böden, selbst nach BTH-Behandlung. Eine reproduzierbare Induktion der Pathogenresistenz durch BTH konnte nur auf einem Mineralboden mit vernachlässigbarem C-Gehalt gezeigt werden. Die Ernährung mit N, P und K hatte keinen konsistenten Einfluss auf die Resistenzinduktion mittels BTH. Der Zusatz von Kompost und Gründünger zum Boden ,Kleinlinden" erhöhte die Variabilität der Resistenzinduktion. Der mögliche Einfluss der Bodenmikroflora auf die Resistenzinduktion wird diskutiert. [source]


Priming of plant innate immunity by rhizobacteria and ,-aminobutyric acid: differences and similarities in regulation

NEW PHYTOLOGIST, Issue 2 2009
Sjoerd Van der Ent
Summary ,,Pseudomonas fluorescens WCS417r bacteria and ,-aminobutyric acid can induce disease resistance in Arabidopsis, which is based on priming of defence. ,,In this study, we examined the differences and similarities of WCS417r- and ,-aminobutyric acid-induced priming. ,,Both WCS417r and ,-aminobutyric acid prime for enhanced deposition of callose-rich papillae after infection by the oomycete Hyaloperonospora arabidopsis. This priming is regulated by convergent pathways, which depend on phosphoinositide- and ABA-dependent signalling components. Conversely, induced resistance by WCS417r and ,-aminobutyric acid against the bacterial pathogen Pseudomonas syringae are controlled by distinct NPR1-dependent signalling pathways. As WCS417r and ,-aminobutyric acid prime jasmonate- and salicylate-inducible genes, respectively, we subsequently investigated the role of transcription factors. A quantitative PCR-based genome-wide screen for putative WCS417r- and ,-aminobutyric acid-responsive transcription factor genes revealed distinct sets of priming-responsive genes. Transcriptional analysis of a selection of these genes showed that they can serve as specific markers for priming. Promoter analysis of WRKY genes identified a putative cis -element that is strongly over-represented in promoters of 21 NPR1-dependent, ,-aminobutyric acid-inducible WRKY genes. ,,Our study shows that priming of defence is regulated by different pathways, depending on the inducing agent and the challenging pathogen. Furthermore, we demon-strated that priming is associated with the enhanced expression of transcription factors. [source]


Consequences of sequential attack for resistance to herbivores when plants have specific induced responses

OIKOS, Issue 8 2007
D. V. Viswanathan
Plants in nature are attacked sequentially by herbivores, and theory predicts that herbivore-specific responses allow plants to tailor their defenses. We present a novel field test of this hypothesis, and find that specific responses of Solanum dulcamara lead to season-long consequences for two naturally colonizing herbivores, irrespective of the second herbivore to attack plants. This result indicates that responses induced by the initial herbivore made plants less responsive to subsequent attack. We show that initial herbivory by flea beetles and tortoise beetles induce distinct plant chemical responses. Initial herbivory by flea beetles lowered the occurrence of conspecifics and tortoise beetles relative to controls. Conversely, initial herbivory by tortoise beetles did not influence future herbivory. Remarkably, the experimentally imposed second herbivore to feed on plants did not modify consequences (induced resistance or lack thereof) of the first attacker. Induction of plant chemical responses was consistent with these ecological effects; i.e. the second herbivore did not modify the plant's initial induced response. Thus, canalization of the plant resistance phenotype may constrain defensive responses in a rapidly changing environment. [source]


Damage-induced changes in woody plants and their effects on insect herbivore performance: a meta-analysis

OIKOS, Issue 2 2004
Heli Nykänen
We conducted a meta-analysis of 68 studies published between 1982 and 2000 in which the responses of woody plants to natural or simulated herbivore damage and/or insect herbivore performance on control and damaged plants were measured. Cumulative meta-analyses revealed dramatic temporal changes in the magnitude and direction of the plant and herbivore responses reported during the last two decades. Studies conducted in the 1980s reported increase in phenolic concentrations, reduction in nutrient concentrations and negative effect on herbivore performance, consistently with the idea of induced resistance. In contrast, in the early 1990s when the idea that some types of plant damage may result in induced susceptibility was generally accepted, studies reported non-significant results or induced susceptibility, and smaller effects on herbivores. The above changes may reflect paradigm shifts in the theory of induced defenses and/or the differences between study systems used in the early and the more recent studies. Overall, plant growth and carbohydrate concentrations were reduced in damaged plants despite enhanced photosynthetic rates. Damage increased the concentrations of carbon and phenolics, while terpene concentrations tended to decrease after damage; changes in nutrient concentrations after damage varied according to nutrient mobility, inherent plant growth rate, ontogenetic stage and plant type (deciduous/evergreen). Early season damage caused more pronounced changes in plants than late season damage, which is in accordance with the assumption that vigorously growing foliage has a greater capacity to respond to damage. Insect growth rate and female pupal weight decreased on previously damaged plants, while herbivore survival, consumption and male pupal weight were not significantly affected. The magnitude and direction of herbivore responses depended on the type of plant, the type of damage, the time interval between the damage and insect feeding (rapid/delayed induced resistance), and the timing of the damage. [source]


Local early induced resistance of plants as the first line of defence against bacteria,

PEST MANAGEMENT SCIENCE (FORMERLY: PESTICIDE SCIENCE), Issue 4 2003
Zoltán Klement
Abstract This paper is an overview of a non-specific local early induced resistance (EIR) mechanism, distinct from the incompatible-specific hypersensitive reaction (HR). We have shown that the local induced resistance (LIR) described earlier is not a single and uniform response to pathogen infection, because an early (EIR) and a late form can be distinguished. EIR operates from 3,6,h post-inoculation (hpi) until about 20,hpi, and is inhibited by a short heat-shock or the eukaryotic protein synthesis inhibitor, cycloheximide. In contrast, LIR, which corresponds to the induced resistance forms discovered earlier, requires more time (about 24,h) and intensive illumination to develop, and is effective for a longer period. EIR develops parallel with HR and is sometimes able to prevent it when the induction time of HR is longer than the time required for the development of EIR. It seems that EIR inhibits the metabolism of bacteria and the activity of hrp genes which otherwise are required for the induction of HR. In a compatible host,pathogen relationship the effect of EIR fails to take place. The rapid development of EIR is greatly influenced by temperature and the physiological state of the plant. EIR activates the accumulation of hydrogen peroxide at the bacterial attachment, expressing new peroxidase isoenzymes in the initiated plant tissue. It seems that this is a native general local defence mechanism which can localise foreign organisms even at the penetration site. © 2003 Society of Chemical Industry [source]


Effects of foliar- and root-applied silicon on the enhancement of induced resistance to powdery mildew in Cucumis sativus

PLANT PATHOLOGY, Issue 5 2005
Y. C. Liang
Two cucumber (Cucumis sativus) cultivars differing in their resistance to powdery mildew, Ningfeng No. 3 (susceptible) and Jinchun No. 4 (resistant), were used to study the effects of foliar- and root-applied silicon on resistance to infection by Podosphaera xanthii (syn. Sphaerotheca fuliginea) and the production of pathogenesis-related proteins (PRs). The results indicated that inoculation with P. xanthii significantly suppressed subsequent infection by powdery mildew compared with noninoculation, regardless of Si application. Root-applied Si significantly suppressed powdery mildew, the disease index being lower in Si-supplied than in Si-deprived plants, regardless of inoculation treatment. The resistant cultivar had a more constant lower disease index than the susceptible cultivar, irrespective of inoculation or Si treatment. Moreover, with root-applied Si, activities of PRs (for example peroxidase, polyphenoloxidase and chitinase) were significantly enhanced in inoculated lower leaves or noninoculated upper leaves in inoculated plants of both cultivars. Root-applied Si significantly decreased the activity of phenylalanine ammonia-lyase in inoculated leaves, but increased it in noninoculated upper leaves. However, Si treatment failed to change significantly the activity of PRs in plants without fungal attack. Compared to the control (no Si), foliar-applied Si had no effects either on the suppression of subsequent infection by P. xanthii or on the activity of PRs, irrespective of inoculation. Based on the findings in this study and previous reports, it was concluded that foliar-applied Si can effectively control infections by P. xanthii only via the physical barrier of Si deposited on leaf surfaces, and/or osmotic effect of the silicate applied, but cannot enhance systemic acquired resistance induced by inoculation, while continuously root-applied Si can enhance defence resistance in response to infection by P. xanthii in cucumber. [source]


Mechanisms involved in control of Blumeria graminis f.sp. hordei in barley treated with mycelial extracts from cultured fungi

PLANT PATHOLOGY, Issue 5 2002
H. Haugaard
Treatment with mycelial extracts, prepared from liquid cultures of Bipolaris oryzae, Pythium ultimum and Rhizopus stolonifer, protected barley (Hordeum vulgare) against powdery mildew disease caused by the fungus Blumeria graminis f.sp. hordei. The mechanisms of this protection were studied using histopathological methods and molecular analysis. Germination and appressorial formation of B. graminis were generally reduced after treatment with mycelial extracts. Although this reduction (between 12 and 62% depending on treatment and experiment) was inconsistent and only occasionally significantly different from the water-treated control, it indicated a direct antifungal effect of the extracts. In situations where the fungus succeeded in forming an appressorium, penetration efficiency and haustorium formation from these appressoria was not affected , no enhanced penetration resistance associated with papilla formation was detected. However, a post-penetration effect was observed, as B. graminis colonies on mycelial extract-treated leaves produced 50% fewer hyphae than on controls. Northern blot analyses showed earlier accumulation of defence-related gene transcripts following treatment with B. oryzae and P. ultimum mycelial extracts, and to a lesser extent R. stolonifer mycelial extract, compared with water-treated leaves. It is suggested that the protection mechanism of the mycelial extracts involves direct antifungal effects and possible induced resistance for the B. oryzae and P. ultimum mycelial extracts. [source]