Relaxation of an induced defense after exclusion of herbivores: spines on Acacia drepanolobium

Oecologia ◽  
1998 ◽  
Vol 115 (4) ◽  
pp. 508-513 ◽  
Author(s):  
Truman P. Young ◽  
Bell D. Okello
Keyword(s):  
Induced Defense ◽  
Acacia Drepanolobium

scholarly journals Ecophysiological Aspects and sxt Genes Expression Underlying Induced Chemical Defense in STX-Producing Raphidiopsis raciborskii (Cyanobacteria) against the Zooplankter Daphnia gessneri

Toxins ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 406
Author(s):  
Mauro C. P. Vilar ◽  
Thiago F. C. P. Rodrigues ◽  
Luan O. Silva ◽  
Ana Beatriz F. Pacheco ◽  
Aloysio S. Ferrão-Filho ◽  
...  
Keyword(s):  
Induced Defense ◽  
Toxin Production ◽  
Grazing Pressure ◽  
Chemical Defenses ◽  
Widespread Occurrence ◽  
Genes Expression ◽  
Freshwater Bodies ◽  
Predator Response ◽  
Aquatic Food ◽  
Shed Light

Cyanobacteria stand out among phytoplankton when they form massive blooms and produce toxins. Because cyanotoxin genes date to the origin of metazoans, the hypothesis that cyanotoxins function as a defense against herbivory is still debated. Although their primary cellular function might vary, these metabolites could have evolved as an anti-predator response. Here we evaluated the physiological and molecular responses of a saxitoxin-producing Raphidiopsis raciborskii to infochemicals released by the grazer Daphnia gessneri. Induced chemical defenses were evidenced in R. raciborskii as a significant increase in the transcription level of sxt genes, followed by an increase in saxitoxin content when exposed to predator cues. Moreover, cyanobacterial growth decreased, and no significant effects on photosynthesis or morphology were observed. Overall, the induced defense response was accompanied by a trade-off between toxin production and growth. These results shed light on the mechanisms underlying zooplankton–cyanobacteria interactions in aquatic food webs. The widespread occurrence of the cyanobacterium R. raciborskii in freshwater bodies has been attributed to its phenotypic plasticity. Assessing the potential of this species to thrive over interaction filters such as zooplankton grazing pressure can enhance our understanding of its adaptive success.

scholarly journals Induction of cell wall phenolic monomers as part of direct defense response in maize to pink stem borer (Sesamia inferens Walker) and non-insect interactions

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
P. Lakshmi Soujanya ◽  
J. C. Sekhar ◽  
C. V. Ratnavathi ◽  
Chikkappa G. Karjagi ◽  
E. Shobha ◽  
...  
Keyword(s):  
Induced Defense ◽  
Stem Borer ◽  
Defense Responses ◽  
Short Term ◽  
Mechanical Wounding ◽  
Leaf Tissues ◽  
Short And Long Term ◽  
Insect Interactions ◽  
Induced Defense Responses

AbstractPink stem borer (PSB) causes considerable yield losses to maize. Plant–insect interactions have significant implications for sustainable pest management. The present study demonstrated that PSB feeding, mechanical wounding, a combination of mechanical wounding and PSB regurgitation and exogenous application of methyl jasmonate have induced phenolic compound mediated defense responses both at short term (within 2 days of treatment) and long term (in 15 days of treatment) in leaf and stalk tissues of maize. The quantification of two major defense related phenolic compounds namely p-Coumaric acid (p-CA) and ferulic acid (FA) was carried out through ultra-fast liquid chromatography (UFLC) at 2 and 15 days after imposing the above treatments. The p-CA content induced in leaf tissues of maize genotypes were intrinsically higher when challenged by PSB attack at V3 and V6 stages in short- and long-term responses. Higher p-CA content was observed in stalk tissues upon wounding and regurgitation in short- and long-term responses at V3 and V6 stages. Significant accumulation of FA content was also observed in leaf tissues in response to PSB feeding at V3 stage in long-term response while at V6 stage it was observed both in short- and long-term responses. In stalk tissues, methyl jasmonate induced higher FA content in short-term response at V3 stage. However, at V6 stage PSB feeding induced FA accumulation in the short-term while, wounding and regurgitation treatment-induced defense responses in the long-term. In general, the resistant (DMRE 63, CM 500) and moderately resistant genotypes (WNZ ExoticPool) accumulated significantly higher contents of p-CA and FA content than susceptible ones (CM 202, BML 6) in most of the cases. The study indicates that phenolic mediated defense responses in maize are induced by PSB attack followed by wounding and regurgitation compared to the other induced treatments. Furthermore, the study confirmed that induced defense responses vary with plant genotype, stage of crop growth, plant tissue and short and long-term responses. The results of the study suggested that the Phenolic acids i.e. p-CA and FA may contribute to maize resistance mechanisms in the maize-PSB interaction system.

scholarly journals Systemic Acquired Resistance in Canola Is Linked with Pathogenesis-Related Gene Expression and Requires Salicylic Acid

2007 ◽  
Vol 97 (7) ◽  
pp. 794-802 ◽  
Author(s):  
Shobha D. Potlakayala ◽  
Darwin W. Reed ◽  
Patrick S. Covello ◽  
Pierre R. Fobert
Keyword(s):  
Salicylic Acid ◽  
Pseudomonas Syringae ◽  
Systemic Acquired Resistance ◽  
Induced Defense ◽  
Acquired Resistance ◽  
Microbial Pathogens ◽  
Broad Host Range ◽  
Avirulent Strain ◽  
Enhanced Resistance ◽  
Pathogenesis Related

Systemic acquired resistance (SAR) is an induced defense response that confers long-lasting protection against a broad range of microbial pathogens. Here we show that treatment of Brassica napus plants with the SAR-inducing chemical benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH) significantly enhanced resistance against virulent strains of the bacterial pathogen Pseudomonas syringae pv. maculicola and the fungal pathogen Leptosphaeria maculans. Localized preinoculation of plants with an avirulent strain of P. syringae pv. maculicola also enhanced resistance to these pathogens but was not as effective as BTH treatment. Single applications of either SAR-inducing pretreatment were effective against P. syringae pv. maculicola, even when given more than 3 weeks prior to the secondary challenge. The pretreatments also led to the accumulation of pathogenesis-related (PR) genes, including BnPR-1 and BnPR-2, with higher levels of transcripts observed in the BTH-treatment material. B. napus plants expressing a bacterial salicylate hydroxylase transgene (NahG) that metabolizes salicylic acid to catechol were substantially compromised in SAR and accumulated reduced levels of PR gene transcripts when compared with untransformed controls. Thus, SAR in B. napus displays many of the hallmarks of classical SAR including long lasting and broad host range resistance, association with PR gene activation, and a requirement for salicylic acid.

Inter-tree variability in the induced defense reaction of Scots pine to single inoculations by Ophiostoma brunneo-ciliatum, a bark-beetle-associated fungus

1993 ◽  
Vol 59 (3-4) ◽  
pp. 257-270 ◽  
Author(s):  
François Lieutier ◽  
Jacques Garcia ◽  
Paul Romary ◽  
Annie Yart ◽  
Hervé Jactel ◽  
...  
Keyword(s):  
Scots Pine ◽  
Bark Beetle ◽  
Induced Defense ◽  
Defense Reaction ◽  
Ophiostoma Brunneo Ciliatum

scholarly journals Caterpillar salivary enzymes: "eliciting" a response

2004 ◽  
Vol 85 (1) ◽  
pp. 33-37 ◽  
Author(s):  
Magali Merkx-Jacques ◽  
Jacqueline C. Bede
Keyword(s):  
Artificial Diet ◽  
Spodoptera Exigua ◽  
Induced Defense ◽  
Defense Responses ◽  
Beet Armyworm ◽  
Herbivorous Insect ◽  
Plant Responses ◽  
Plant Defense Responses ◽  
Induced Defense Responses ◽  
Bertha Armyworm

Abstract Plants exhibit remarkable plasticity in their ability to differentiate between herbivorous insect species and subtly adjust their defense responses to target distinct pests. One key mechanism used by plants to recognize herbivorous caterpillars is elicitors present in their oral secretions; however, these elicitors not only cause the induction of plant defenses but recent evidence suggests that they may also suppress plant responses. The absence of “expected changes” in induced defense responses of insect-infested plants has been attributed to hydrogen peroxide produced by caterpillar salivary glucose oxidase (GOX). Activity of this enzyme is variable among caterpillar species; it was detected in two generalist caterpillars, the beet armyworm (Spodoptera exigua) and the bertha armyworm (Mamestra configurata), but not in other generalist or specialist caterpillar species tested. In the beet armyworm, GOX activity fluctuated over larval development with high activity associated with the salivary glands of fourth instars. Larval salivary GOX activity of the beet armyworm and the bertha armyworm was observed to be significantly higher in caterpillars reared on artificial diet as compared with those reared on Medicago truncatula plants. This implies that a factor in the diet is involved in the regulation of caterpillar salivary enzyme activity. Therefore, plant diet may be regulating caterpillar oral elicitors that are involved in the regulation of plant defense responses: our goal is to understand these two processes.

Talc-based formulation ofPseudomonas fluorescens-induced defense genes against powdery mildew of grapevine

2007 ◽  
Vol 40 (2) ◽  
pp. 81-89 ◽  
Author(s):  
Vaithiyanathan Sendhilvel ◽  
Thambiayya Marimuthu ◽  
Ramasami Samiappan
Keyword(s):  
Powdery Mildew ◽  
Induced Defense ◽  
Defense Genes

scholarly journals Citronella essential oil in the control and activation of coffee plants defense response against rust and brown eye spot

2012 ◽  
Vol 36 (4) ◽  
pp. 383-390 ◽  
Author(s):  
Ricardo Borges Pereira ◽  
Gilvaine Ciavareli Lucas ◽  
Fabiano José Perina ◽  
Pedro Martins Ribeiro Júnior ◽  
Eduardo Alves
Keyword(s):  
Essential Oil ◽  
Induced Defense ◽  
Defense Responses ◽  
Plant Diseases ◽  
Negative Effects ◽  
Significant Control ◽  
Citronella Oil ◽  
Coffee Plants ◽  
Induced Defense Responses ◽  
Brown Eye Spot

The rust and brown eye spot are the main coffee diseases. The losses are due to intense defoliation of plants, which has reduced its production and longevity. The brown eye spot also occurs in fruits, with negative effects on the beverage quality. Some essential oils have presented promising results in the control of plant diseases, as an alternative to the use of fungicides. The objective of this study was to evaluate citronella essential oil in the control of rust and brown eye spot and in the activation of coffee plants defense responses. Twelve-month-old plants were sprayed with citronella oil 1000 µL L-1, acibenzolar-S-methyl 200 mg L-1 and tebuconazole fungicide 200 mg L-1. Plants were inoculated with Hemileia vastatrix and Cercospora coffeicola seven days later. The application was repeated after 30 days. Plants with five months were sprayed with the same treatments to assess the induced defense responses. Citronella oil controlled rust and brown eye spot with efficiencies of 47.2% and 29.7%, respectively, while tebuconazole presented control of 96.5% and 90.5%, respectively. Acibenzolar-S-methyl reduced brown eye spot by 55.9% and showed no significant control of rust. Citronella oil increased peroxidase and chitinase activities in five months coffee plants 336, and 24 and 336 hours after spraying, respectively. Acibenzolar-S-methyl increased peroxidase, chitinase and ββ-1,3-glucanase activities 192, 288 and 336; 24 and; 240 hours after spraying, respectively. The treatments did not increase accumulation of phenols, but a significant increase in lignin was observed in plants sprayed with citronella oil.

scholarly journals The receptor-like cytoplasmic kinase BSR1 mediates chitin-induced defense signaling in rice cells

2017 ◽  
Vol 81 (8) ◽  
pp. 1497-1502 ◽  
Author(s):  
Yasukazu Kanda ◽  
Naoki Yokotani ◽  
Satoru Maeda ◽  
Yoko Nishizawa ◽  
Takashi Kamakura ◽  
...  
Keyword(s):  
Induced Defense ◽  
Defense Signaling
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