Jean-Pierre Metraux

Jean-Pierre Metraux
Université de Fribourg · Department Biology

PhD

About

195
Publications
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Publications

Publications (195)
Article
Full-text available
We isolated previously several Arabidopsis thaliana mutants with constitutive expression of the early MAMP-induced gene ATL2, named eca (expresión constitutiva de ATL2). Here we further explored the interaction of eca mutants with pest and pathogens. Of all eca mutants, eca2 was more resistant to a fungal (Botrytis cinerea) and a bacterial (Pseudom...
Article
Full-text available
Plants interpret their immediate environment through perception of small molecules. Microbe-associated molecular patterns (MAMPs) such as flagellin and chitin are likely to be more abundant in the rhizosphere than plant-derived damage-associated molecular patterns (DAMPs). We investigated how the Arabidopsis thaliana root interprets MAMPs and DAMPs...
Data
Quantification of promoter::YFPN constructs at the infection site of roots invaded by F. oxysporum. (a) Quantification of microscopic analysis of F. oxysporum—infected roots expressing promoter::YFPN constructs in independent transformation lines when compared to Fig 6. Bars represent the mean of ≥ 6 images ± SE. (b) Quantification of microscopic a...
Data
Induction of promoter::YFPN constructs adjacent to invading hyphae of GFP-labelled F. oxysporum. Microscopic analysis of the responses of 12-day old roots in the mature part 2 days after inoculation with spores from F. oxysporum. Fluorescence derived from promoter::YFPN constructs is localized in the root nuclei while fungal hyphae are green filame...
Data
Time dependency of elicitor effects on promoter::YFPN expression in the root. Roots were analysed following treatment with 100 nM flg22, chi7, AtPep1 or 0.5x MS as control. Scale bar 200 μm. (PDF)
Data
Expression of MAMP/DAMP receptor genes in roots. (PDF)
Data
AtPEPR2 determines root growth inhibition by AtPep1. Allele distribution of pepr1 and pepr2 in a segregating F2 population of a pepr1 pepr2 cross with promoter::YFPN lines selected for loss of root inhibition on 0.5x MS containing 100 nM AtPep1. Numbers represent individual plants genotyped for the respective pepr allele. (PDF)
Data
Quantification of elicitor-triggered responses of defence-associated promoters in the root. Quantification of microscopic analysis of promoter::YFPN constructs in two independent lines of 7-days old seedlings following treatment with 100 nM flg22, chi7, AtPep1 or 0.5x MS as control. Images were analysed using Fiji. Bars represent the mean of ≥ 3 im...
Data
Summary of elicitor-triggered responses and amplification settings used for microscopic analysis. (a) Overview of inductive and suppressive responses of promoter::YFPN constructs expressed in 7-days old seedlings following treatment with 100 nM flg22, chi7, AtPep1 or 0.5x MS as control. Numbers represent the factors calculated as fold-change for 2...
Data
Expression of promoter::YFPN constructs in the mature part of roots infected with F. oxysporum. (a) Microscopic analysis of the responses of 12-day old roots in the mature part 2 days after inoculation with spores from F. oxysporum. Fluorescence derived from promoter::YFPN constructs is localized in the root nuclei and shown in green, while propidi...
Article
Full-text available
In the last decades, the plant innate immune responses against pathogens have been extensively studied while biocontrol interactions between soilborne fungal pathogens and their hosts have received much less attention. Treatment of Arabidopsis thaliana with the non-pathogenic bacterium Paenibacillus alvei K165 was shown previously to protect agains...
Article
We have explored the importance of the phyllosphere microbiome in plant resistance in the cuticle mutants bdg (BODYGUARD) or lacs2.3 (LONG CHAIN FATTY ACID SYNTHASE 2) that are strongly resistant to the fungal pathogen Botrytis cinerea. The study includes infection of plants under sterile conditions, 16S ribosomal DNA sequencing of the phyllosphere...
Article
Full-text available
AsES (Acremonium strictum Elicitor and Subtilisin) is a novel extracellular elicitor protein produced by the avirulent isolate SS71 of the opportunist strawberry fungal pathogen Acremonium strictum. Here we describe the activity of AsES in the plant-pathogen system Arabidopsis thaliana-Botrytis cinerea. We show that AsES renders Arabidopsis thalian...
Article
Plants have evolved efficient defence systems against pathogens that often rely on specific transcriptional responses. Priming is part of the defence syndrome, by establishing a hypersensitive state of defence genes such as after a first encounter with a pathogen. Because activation of defence responses has a fitness cost, priming must be tightly c...
Article
Full-text available
Background An important signal transduction pathway in plant defence depends on the accumulation of salicylic acid (SA). SA is produced in chloroplasts and the multidrug and toxin extrusion transporter ENHANCED DISEASE SUSCEPTIBILITY5 (EDS5; At4g39030) is necessary for the accumulation of SA after pathogen and abiotic stress. EDS5 is localized at t...
Article
Full-text available
The cuticle provides a physical barrier against water loss and protects against irradiation, xenobiotics, and pathogens. Components of the cuticle are perceived by invading fungi and activate developmental processes during pathogenesis. In addition, cuticle alterations of various types induce a syndrome of reactions that often results in resistance...
Article
Full-text available
Plant defences comprise both pre-existing barriers as well as defences induced upon perception of pathogen-associated molecular patterns (PAMPs) or microbe-associated molecular patterns (MAMPs) or molecules produced from damage as a result of infection (damage-associated molecular patterns (DAMPs)). This chapter focuses on the induced mechanisms of...
Article
Full-text available
Wounded leaves of Arabidopsis thaliana produce reactive oxygen species (ROS) within minutes after wounding and become resistant to the pathogenic fungus Botrytis cinerea at a local level. This fast response of the plants to the wound is called wound-induced resistance (WIR). However the molecular mechanisms of this response and the signal cascade b...
Article
Full-text available
In a previous study we have shown that wounding of Arabidopsis thaliana leaves induces a strong and transient immunity to Botrytis cinerea, the causal agent of grey mould. Reactive oxygen species (ROS) are formed within minutes after wounding and are required for wound--induced resistance to B. cinerea. In this study, we have further explored ROS a...
Article
Full-text available
Pathogen and Circadian Controlled 1 (PCC1) was previously characterized as a regulator of defence against pathogens and stress-activated transition to flowering. Plants expressing an RNA interference construct for the PCC1 gene (iPCC1 plants) showed a pleiotropic phenotype. They were hypersensitive to abscisic acid (ABA) as shown by reduced germina...
Article
Full-text available
Salicylic acid (SA) is central for the defense of plants to pathogens and abiotic stress. SA is synthesized in chloroplasts from chorismic acid by an isochorismate synthase (ICS1); SA biosynthesis is negatively regulated by auto-inhibitory feedback at ICS1. Genetic studies indicated that the MATE (Multidrug And Toxin Extrusion) transporter EDS5, is...
Chapter
Plants can express multilayered defenses against invading organisms. This article will present a general framework of the current concept on the immune reaction in plants. It highlights how systemically induced resistance mechanisms are generated from localized infections and the current state of knowledge on the transmission of a signal and its ac...
Article
Botrytis cinerea is a major pre‐ and post‐harvest necrotrophic pathogen with a broad host range that causes substantial crop losses. The plant hormone jasmonic acid (JA) is involved in the basal resistance against this fungus. Despite basal resistance, virulent strains of B. cinerea can cause disease on Arabidopsis thaliana and virulent pathogens c...
Data
ROS production in NADPH oxidase mutants. ROS (measured as DCF-DA fluorescence) and WIR to B. cinerea were still detected after wounding in atrboh D and atrboh F as well as in the double mutant atrboh D/F. After wounding, all plants were kept under humid conditions. W: wounded; Ctrl: unwounded control plants. The experiment was carried out twice wit...
Data
Direct and indirect effects of H2O2 against B. cinerea. (A) Leaves were treated with H2O2 or water (Ctrl) (during 1 d in high humidity) then rinsed with water and subsequently inoculated with B. cinerea (n = 15; ±SD). Different letters above each bar represent statistically significant differences (Dunn's test; P<0.05). (B) Effect of H2O2 or water...
Data
Time-course of ROS after wounding. To follow the rapid formation of ROS (measured as DCF-DA fluorescence), WT leaves were infiltrated with DCF-DA and then wounded. The first fluorescent signal was detected 2 min after wounding. The experiment was repeated twice with similar results. (TIF)
Data
Composition of aliphatic monomers of A. thaliana and ABA mutants leaf cuticle. Wild type (WT) leaves were wounded and maintained for 1.5 h under high humidity in tightly covered well-watered trays (humid) or in uncovered trays at room conditions (dry) prior to fatty acid analysis. The fatty acid composition was determined for 15 to 20 leaves of wou...
Data
Cuticle permeability is impaired in WT, ABA mutants and cuticle mutants after ABA treatment. Chlorophyll leaching decreased upon ABA treatment (+ABA) in WT, aba2, aba3, lacs2.3 and bdg mutants compared to untreated plants (-ABA) (measured at 40 and 60 min after immersion in ethanol 80%). Plants were treated with ABA 100 mM for 24 h under humid cond...
Data
Expression of ABA-dependent genes RAB18, RD298 and NCED23. Leaves were wounded and maintained for 1.5 h under high humidity in tightly covered well-watered trays (humid) or in uncovered trays at room conditions (dry) prior to expression of ABA-dependent genes. Gene expression was determined 0, 15 or 30 min after wounding in plants incubated under h...
Data
Number of stomata in lacs2.3, bdg, aba2 and aba3 mutants compared to WT plants (n = 10; ±SD). Different letters above each bar represent statistically significant differences (Dunn's test; P<0.05). The experiment was carried out twice with similar results. (TIF)
Article
Botrytis cinerea is a major pre- and post-harvest necrotrophic pathogen with a broad host range that causes substantial crop losses. The plant hormone jasmonic acid (JA) is involved in the basal resistance against this fungus. Despite basal resistance, virulent strains of B. cinerea can cause disease on Arabidopsis thaliana and virulent pathogens c...
Article
Full-text available
Wounded leaves of Arabidopsis thaliana show transient immunity to Botrytis cinerea, the causal agent of grey mould. Using a fluorescent probe, histological staining and a luminol assay, we now show that reactive oxygen species (ROS), including H2O2 and O2−, are produced within minutes after wounding. ROS are formed in the absence of the enzymes Atr...
Article
Full-text available
Salicylic acid (SA) is an important signal involved in the activation of plant defence responses against abiotic and biotic stress. SA may derive from the phenylpropanoid pathway or via isochorismate synthase as demonstrated in Nicotiana benthamiana, tomato and Arabidopsis thaliana. The phenylpropanoid pathway as well as isochorismate synthase are...
Article
Full-text available
Although the multilayered structure of the plant cuticle was discovered many years ago, the molecular basis of its formation and the functional relevance of the layers are not understood. Here, we present the permeable cuticle1 (pec1) mutant of Arabidopsis thaliana, which displays features associated with a highly permeable cuticle in several organ...
Article
Full-text available
Rhizoctonia solani Kühn is a soil-borne fungal pathogen that causes disease in a wide range of plants worldwide. Strains of the fungus are traditionally grouped into genetically isolated anastomosis groups (AGs) based on hyphal anastomosis reactions. This article summarizes aspects related to the infection process, colonization of the host and mole...
Article
Full-text available
Ionic aluminum (mainly Al3+) is rhizotoxic and can be present in acid soils at concentrations high enough to inhibit root growth. Many forest tree species grow naturally in acid soils and often tolerate high concentrations of Al. Previously, we have shown that aspen (Populus tremula) releases citrate and oxalate from roots in response to Al exposur...
Data
Primers used to perform real-time reverse transcription PCR in aspen.
Data
List of Al-responsive genes in root tips of aspen.
Data
Lists of MIPS categories whose genes were significantly enriched (p < 0.05; FDR < 0.05).
Data
Sequences of single-stranded sense oligonucleotides specifying amplicons of ACT9, ALS3, and MATE of aspen.
Article
Plants activate direct and indirect defences in response to insect egg deposition. However, whether eggs can manipulate plant defence is unknown. In Arabidopsis thaliana, oviposition by the butterfly Pieris brassicae triggers cellular and molecular changes that are similar to the changes caused by biotrophic pathogens. In the present study, we foun...
Article
This chapter reviews our current knowledge about mechanisms of suppression developed by pathogens to avoid host defense responses. In general, plants perceive pathogens by diverse pathogen- or microbe- or even damage-associated molecular patterns (PAMPs, MAMPs, DAMPs) and induce a variety of defense mechanisms referred to as horizontal or basal res...
Article
Full-text available
To identify Nicotiana tabacum genes involved in resistance and susceptibility to Rhizoctonia solani, suppression subtractive hybridization was used to generate a cDNA library from transcripts that are differentially expressed during a compatible and incompatible interaction. This allowed the isolation of a protein kinase cDNA that was down-regulate...
Article
Full-text available
Mitogen-activated protein (MAP) kinase phosphatases are important negative regulators of the levels and kinetics of MAP kinase activation that modulate cellular responses. The dual-specificity phosphatase MAP KINASE PHOSPHATASE1 (MKP1) was previously shown to regulate MAP KINASE6 (MPK6) activation levels and abiotic stress responses in Arabidopsis...
Article
The three closely related Arabidopsis basic leucine zipper (bZIP) transcription factors TGA2, TGA5 and TGA6 are required for the establishment of the salicylic acid (SA)-dependent plant defense response systemic acquired resistance, which is effective against biotrophic pathogens. Here we show that the same transcription factors are essential for t...
Article
Arabidopsis thaliana is known to produce the phytoalexin camalexin in response to abiotic and biotic stress. Here we studied the mechanisms of tolerance to camalexin in the fungus Botrytis cinerea, a necrotrophic pathogen of A. thaliana. Exposure of B. cinerea to camalexin induces expression of BcatrB, an ABC transporter that functions in the efflu...
Article
Full-text available
Salicylic acid (SA) is an important mediator of plant defense response. In Arabidopsis (Arabidopsis thaliana), this compound was proposed to derive mainly from isochorismate, itself produced from chorismate through the activity of ISOCHORISMATE SYNTHASE1 (ICS1). Null ics1 mutants still accumulate some SA, suggesting the existence of an enzymatic ac...
Data
Full-text available
Nuclear localization of AtPP7-GFP and ankyrin-GFP in transgenic lines. (1.57 MB PDF)
Data
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The complete AtPP7 protein (FLAG-tagged) interacts with a complete NDPK2 (6xHis-tagged) protein in vitro. (0.08 MB PDF)
Data
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Anthocyanin content in blue light treated seedlings expressing various level of AtPP7. (0.05 MB PDF)
Data
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Complementation of the cotyledon enlargement phenotype of psi2 mutant by genomic AtPP7. (0.05 MB PDF)
Data
Complementation of the phenotypic hypersensitivity of the cab2::luciferase reporter gene induction by an intact genomic AtPP7. (0.06 MB PDF)
Data
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Complementation of psi2 mutant by WT genomic AtPP7. Adult plants. (0.52 MB PDF)
Data
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Supporting materials and methods. (0.07 MB PDF)
Article
Full-text available
The psi2 mutant of Arabidopsis displays amplification of the responses controlled by the red/far red light photoreceptors phytochrome A (phyA) and phytochrome B (phyB) but no apparent defect in blue light perception. We found that loss-of-function alleles of the protein phosphatase 7 (AtPP7) are responsible for the light hypersensitivity in psi2 de...
Article
Physical injury inflicted on living tissue makes it vulnerable to invasion by pathogens. Wounding of Arabidopsis thaliana leaves, however, does not conform to this concept and leads to immunity to Botrytis cinerea, the causal agent of grey mould. In wounded leaves, hyphal growth was strongly inhibited compared to unwounded controls. Wound-induced r...
Article
The cuticle is a physical barrier that prevents water loss and protects against irradiation, xenobiotics and pathogens. This classic textbook statement has recently been revisited and several observations were made showing that this dogma falls short of being universally true. Both transgenic Arabidopsis thaliana lines expressing cell wall-targeted...
Article
Salicylic acid (SA) is an important signal involved in the activation of defence responses against abiotic and biotic stress. In tobacco, benzoic acid or glucosyl benzoate were proposed to be precursors of SA. This is in sharp contrast with studies in Arabidopsis thaliana, where SA derives from isochorismate. We have determined the importance of is...