scholarly journals Induced Resistance by Ascorbate Oxidation Involves Potentiating of the Phenylpropanoid Pathway and Improved Rice Tolerance to Parasitic Nematodes

2021 ◽  
Vol 12 ◽  
Author(s):  
Richard Raj Singh ◽  
Jessil Ann Pajar ◽  
Kris Audenaert ◽  
Tina Kyndt
Keyword(s):  
Plant Defense ◽  
Induced Resistance ◽  
Phenylpropanoid Pathway ◽  
Nematode Infection ◽  
Systemic Resistance ◽  
Ascorbate Oxidase ◽  
Parasitic Nematodes ◽  
Reflection Index ◽  
Pal Activity ◽  
Activity Measurements

Anticipating an increased ecological awareness, scientists have been exploring new strategies to reduce the use of chemical pesticides to control pests and diseases. Triggering the intrinsic plant defense system is one of the promising strategies to reduce yield loss by pathogenic organisms, such as nematodes. Ascorbate oxidase (AO) enzyme plays an important role in plant defense by regulating the apoplastic ascorbate/dehydroascorbate (DHA) ratio via the ascorbate oxidation process. Ascorbate oxidation is known to induce systemic resistance in rice against parasitic root-knot nematodes (RKN). Here, we sought to evaluate if AO- or DHA-induced resistance (IR) against RKN M. graminicola involves activation of the phenylpropanoid pathway and whether this IR phenotype has potential effects on growth of rice seedlings under stressed and unstressed conditions. Our results show that AO/DHA-IR against these parasitic nematodes is dependent on activation of phenylalanine ammonia lyase (PAL). However, application of reduced ascorbic acid (AA) did not induce this response. Gene expression analysis via qRT-PCR showed that OsPAL2 and OsPAL4 are highly expressed in AO/DHA-sprayed nematode-infected roots and PAL-activity measurements confirmed that AO/DHA spraying triggers the plants for primed activation of this enzyme upon nematode infection. AO/DHA-IR is not effective in plants sprayed with a chemical PAL inhibitor confirming that AO/DHA-induced resistance is dependent on PAL activity. Improved plant growth and low nematode infection in AO/DHA-sprayed plants was found to be correlated with an increase in shoot chlorophyll fluorescence (Fv/Fm), chlorophyll index (ChlIdx), and modified anthocyanin reflection index which were proven to be good above-ground parameters for nematode infestation. A detailed growth analysis confirmed the improved growth of AO/DHA-treated plants under nematode-infected conditions. Taken together, our results indicate that ascorbate oxidation enhances the phenylpropanoid-based response to nematode infection and leads to a tolerance phenotype in treated rice plants.

scholarly journals dl-β-Aminobutyric Acid–Induced Resistance of Potato Against Phytophthora infestans Requires Salicylic Acid but Not Oxylipins

2010 ◽  
Vol 23 (5) ◽  
pp. 585-592 ◽  
Author(s):  
Lennart Eschen-Lippold ◽  
Simone Altmann ◽  
Sabine Rosahl
Keyword(s):  
Salicylic Acid ◽  
Phytophthora Infestans ◽  
Induced Resistance ◽  
Crop Plants ◽  
Aminobutyric Acid ◽  
Systemic Resistance ◽  
Lipoxygenase Pathway ◽  
Promising Alternative ◽  
Functional Analyses ◽  
Late Blight Pathogen

Inducing systemic resistance responses in crop plants is a promising alternative way of disease management. To understand the underlying signaling events leading to induced resistance, functional analyses of plants defective in defined signaling pathway steps are required. We used potato, one of the economically most-important crop plants worldwide, to examine systemic resistance against the devastating late blight pathogen Phytophthora infestans, induced by treatment with dl-β-aminobutyric acid (BABA). Transgenic plants impaired in either the 9-lipoxygenase pathway, which produces defense-related compounds, or the 13-lipoxygenase pathway, which generates jasmonic acid–derived signals, expressed wild-type levels of BABA-induced resistance. Plants incapable of accumulating salicylic acid (SA), on the other hand, failed to mount this type of induced resistance. Consistently, treatment of these plants with the SA analog 2,6-dichloroisonicotinic acid restored BABA-induced resistance. Together, these results demonstrate the indispensability of a functional SA pathway for systemic resistance in potato induced by BABA.

scholarly journals Induced Systemic Resistance in Arabidopsis thaliana Against Pseudomonas syringae pv. tomato by 2,4-Diacetylphloroglucinol-Producing Pseudomonas fluorescens

2012 ◽  
Vol 102 (4) ◽  
pp. 403-412 ◽  
Author(s):  
David M. Weller ◽  
Dmitri V. Mavrodi ◽  
Johan A. van Pelt ◽  
Corné M. J. Pieterse ◽  
Leendert C. van Loon ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Pseudomonas Fluorescens ◽  
Induced Resistance ◽  
Pseudomonas Syringae ◽  
Induced Systemic Resistance ◽  
Signal Transduction Pathway ◽  
Systemic Resistance ◽  
Wild Type ◽  
Challenge Inoculation ◽  
Dependent Signal

Pseudomonas fluorescens strains that produce the polyketide antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) are among the most effective rhizobacteria that suppress root and crown rots, wilts, and damping-off diseases of a variety of crops, and they play a key role in the natural suppressiveness of some soils to certain soilborne pathogens. Root colonization by 2,4-DAPG-producing P. fluorescens strains Pf-5 (genotype A), Q2-87 (genotype B), Q8r1-96 (genotype D), and HT5-1 (genotype N) produced induced systemic resistance (ISR) in Arabidopsis thaliana accession Col-0 against bacterial speck caused by P. syringae pv. tomato. The ISR-eliciting activity of the four bacterial genotypes was similar, and all genotypes were equivalent in activity to the well-characterized strain P. fluorescens WCS417r. The 2,4-DAPG biosynthetic locus consists of the genes phlHGF and phlACBDE. phlD or phlBC mutants of Q2-87 (2,4-DAPG minus) were significantly reduced in ISR activity, and genetic complementation of the mutants restored ISR activity back to wild-type levels. A phlF regulatory mutant (overproducer of 2,4-DAPG) had ISR activity equivalent to the wild-type Q2-87. Introduction of DAPG into soil at concentrations of 10 to 250 μM 4 days before challenge inoculation induced resistance equivalent to or better than the bacteria. Strain Q2-87 induced resistance on transgenic NahG plants but not on npr1-1, jar1, and etr1 Arabidopsis mutants. These results indicate that the antibiotic 2,4-DAPG is a major determinant of ISR in 2,4-DAPG-producing P. fluorescens, that the genotype of the strain does not affect its ISR activity, and that the activity induced by these bacteria operates through the ethylene- and jasmonic acid-dependent signal transduction pathway.

scholarly journals Induced resistance for plant defense

2015 ◽  
Vol 6 ◽  
Author(s):  
Andrés A. Borges ◽  
Luisa M. Sandalio
Keyword(s):  
Plant Defense ◽  
Induced Resistance

scholarly journals Monitoring of the PAL Enzymatic Activity and Polyphenolic Compounds in Leaves and Fruits of Two Myrtle Cultivars during Maturation

Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 389
Author(s):  
Silvia Medda ◽  
Leonarda Dessena ◽  
Maurizio Mulas
Keyword(s):  
Phenolic Compounds ◽  
Phenylalanine Ammonia Lyase ◽  
Raw Materials ◽  
Phenylpropanoid Pathway ◽  
Polyphenolic Compounds ◽  
Antioxidant Compounds ◽  
Total Polyphenols ◽  
Spectrophotometric Methods ◽  
Pal Activity ◽  
Potential Use

The leaves and berries of myrtle (Myrtus communis L.) are rich in phenolic compounds, such as phenolic acids, flavonoids, and flavanols. The richness of these antioxidant compounds allows the potential use of myrtle biomasses as raw materials for medicinal and functional food products. Most of the phenolic compounds originate from the phenylpropanoid pathway, where phenylalanine ammonia lyase (PAL) enzyme activates the first step. The objective of this research is to study the activity of PAL as related to accumulation in the myrtle fruits and leaves of some phenolic compounds in the period between blossom and full berry ripening. With this aim, we compared two model genotypes with different fruit coloration. In leaves and berries of two cultivars, ‘Giovanna’ with pigmented berries and ‘Grazia’ with white berries, the PAL activity and content of polyphenols, anthocyanins, flavonoids, and tannins were determined with spectrophotometric methods. PAL activity was quite constant in leaves and variable in berries: Greater in berries of ‘Giovanna’ than in those of ‘Grazia’ cultivar, and increasing from berry color-break to full ripening. In berries, a positive correlation between PAL and flavonoids (r = 0.44), and between PAL and anthocyanins (r = 0.69), as well as a negative correlation between PAL and total polyphenols (r = −0.471), were found.

scholarly journals Bacillus amyloliquefaciens MBI600 differentially induces tomato defense signaling pathways depending on plant part and dose of application

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Anastasia Dimopoulou ◽  
Ioannis Theologidis ◽  
Burghard Liebmann ◽  
Kriton Kalantidis ◽  
Nikon Vassilakos ◽  
...  
Keyword(s):  
Plant Defense ◽  
Stress Responses ◽  
Bacillus Amyloliquefaciens ◽  
Plant Pathogens ◽  
Biological Control Agent ◽  
Induced Defense ◽  
Systemic Resistance ◽  
Marker Genes ◽  
Dependent Manner ◽  
Plant Host

AbstractThe success of Bacillus amyloliquefaciens as a biological control agent relies on its ability to outgrow plant pathogens. It is also thought to interact with its plant host by inducing systemic resistance. In this study, the ability of B. amyloliquefaciens MBI600 to elicit defense (or other) responses in tomato seedlings and plants was assessed upon the expression of marker genes and transcriptomic analysis. Spray application of Serifel, a commercial formulation of MBI600, induced responses in a dose-dependent manner. Low dosage primed plant defense by activation of SA-responsive genes. Suggested dosage induced defense by mediating synergistic cross-talk between JA/ET and SA-signaling. Saturation of tomato roots or leaves with MBI600 elicitors activated JA/ET signaling at the expense of SA-mediated responses. The complex signaling network that is implicated in MBI600-tomato seedling interactions was mapped. MBI600 and flg22 (a bacterial flagellin peptide) elicitors induced, in a similar manner, biotic and abiotic stress responses by the coordinated activation of genes involved in JA/ET biosynthesis as well as hormone and redox signaling. This is the first study to suggest the activation of plant defense following the application of a commercial microbial formulation under conditions of greenhouse crop production.

scholarly journals Phenylpropanoid Pathway Engineering: An Emerging Approach towards Plant Defense

Pathogens ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 312 ◽  
Author(s):  
Vivek Yadav ◽  
Zhongyuan Wang ◽  
Chunhua Wei ◽  
Aduragbemi Amo ◽  
Bilal Ahmed ◽  
...  
Keyword(s):  
Cell Wall ◽  
Plant Defense ◽  
Plant Cell Wall ◽  
Shikimate Pathway ◽  
Gene Families ◽  
Phenylpropanoid Pathway ◽  
Pathway Engineering ◽  
Multiple Gene ◽  
Regulator Genes ◽  
Microbial Attack

Pathogens hitting the plant cell wall is the first impetus that triggers the phenylpropanoid pathway for plant defense. The phenylpropanoid pathway bifurcates into the production of an enormous array of compounds based on the few intermediates of the shikimate pathway in response to cell wall breaches by pathogens. The whole metabolomic pathway is a complex network regulated by multiple gene families and it exhibits refined regulatory mechanisms at the transcriptional, post-transcriptional, and post-translational levels. The pathway genes are involved in the production of anti-microbial compounds as well as signaling molecules. The engineering in the metabolic pathway has led to a new plant defense system of which various mechanisms have been proposed including salicylic acid and antimicrobial mediated compounds. In recent years, some key players like phenylalanine ammonia lyases (PALs) from the phenylpropanoid pathway are proposed to have broad spectrum disease resistance (BSR) without yield penalties. Now we have more evidence than ever, yet little understanding about the pathway-based genes that orchestrate rapid, coordinated induction of phenylpropanoid defenses in response to microbial attack. It is not astonishing that mutants of pathway regulator genes can show conflicting results. Therefore, precise engineering of the pathway is an interesting strategy to aim at profitably tailored plants. Here, this review portrays the current progress and challenges for phenylpropanoid pathway-based resistance from the current prospective to provide a deeper understanding.

scholarly journals Local Responses and Systemic Induced Resistance Mediated by Ectomycorrhizal Fungi

2020 ◽  
Vol 11 ◽  
Author(s):  
Steven Dreischhoff ◽  
Ishani S. Das ◽  
Mareike Jakobi ◽  
Karl Kasper ◽  
Andrea Polle
Keyword(s):  
Induced Resistance ◽  
Ectomycorrhizal Fungi ◽  
Molecular Mechanisms ◽  
Systemic Acquired Resistance ◽  
Induced Systemic Resistance ◽  
Systemic Resistance ◽  
Future Research ◽  
Root Tips ◽  
Long Distance ◽  
Extramatrical Mycelium

Ectomycorrhizal fungi (EMF) grow as saprotrophs in soil and interact with plants, forming mutualistic associations with roots of many economically and ecologically important forest tree genera. EMF ensheath the root tips and produce an extensive extramatrical mycelium for nutrient uptake from the soil. In contrast to other mycorrhizal fungal symbioses, EMF do not invade plant cells but form an interface for nutrient exchange adjacent to the cortex cells. The interaction of roots and EMF affects host stress resistance but uncovering the underlying molecular mechanisms is an emerging topic. Here, we focused on local and systemic effects of EMF modulating defenses against insects or pathogens in aboveground tissues in comparison with arbuscular mycorrhizal induced systemic resistance. Molecular studies indicate a role of chitin in defense activation by EMF in local tissues and an immune response that is induced by yet unknown signals in aboveground tissues. Volatile organic compounds may be involved in long-distance communication between below- and aboveground tissues, in addition to metabolite signals in the xylem or phloem. In leaves of EMF-colonized plants, jasmonate signaling is involved in transcriptional re-wiring, leading to metabolic shifts in the secondary and nitrogen-based defense metabolism but cross talk with salicylate-related signaling is likely. Ectomycorrhizal-induced plant immunity shares commonalities with systemic acquired resistance and induced systemic resistance. We highlight novel developments and provide a guide to future research directions in EMF-induced resistance.

scholarly journals Effects of Jasmonic Acid, Ethylene, and Salicylic Acid Signaling on the Rhizosphere Bacterial Community of Arabidopsis thaliana

2011 ◽  
Vol 24 (4) ◽  
pp. 395-407 ◽  
Author(s):  
Rogier F. Doornbos ◽  
Bart P. J. Geraats ◽  
Eiko E. Kuramae ◽  
L. C. Van Loon ◽  
Peter A. H. M. Bakker
Keyword(s):  
Salicylic Acid ◽  
Bacterial Community ◽  
Induced Resistance ◽  
Plant Pathogens ◽  
Plant Diseases ◽  
Systemic Resistance ◽  
Culturable Bacteria ◽  
Wild Type ◽  
Defense Signaling ◽  
Rhizosphere Bacterial Community

Systemically induced resistance is a promising strategy to control plant diseases, as it affects numerous pathogens. However, since induced resistance reduces one or both growth and activity of plant pathogens, the indigenous microflora may also be affected by an enhanced defensive state of the plant. The aim of this study was to elucidate how much the bacterial rhizosphere microflora of Arabidopsis is affected by induced systemic resistance (ISR) or systemic acquired resistance (SAR). Therefore, the bacterial microflora of wild-type plants and plants affected in their defense signaling was compared. Additionally, ISR was induced by application of methyl jasmonate and SAR by treatment with salicylic acid or benzothiadiazole. As a comparative model, we also used wild type and ethylene-insensitive tobacco. Some of the Arabidopsis genotypes affected in defense signaling showed altered numbers of culturable bacteria in their rhizospheres; however, effects were dependent on soil type. Effects of plant genotype on rhizosphere bacterial community structure could not be related to plant defense because chemical activation of ISR or SAR had no significant effects on density and structure of the rhizosphere bacterial community. These findings support the notion that control of plant diseases by elicitation of systemic resistance will not significantly affect the resident soil bacterial microflora.

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