Oligosaccharide-triggered plant immunity and plant protection

National audience

β-Aminobutyric Acid Primes an NADPH Oxidase–Dependent Reactive Oxygen Species Production During Grapevine-Triggered Immunity

International audience; The molecular mechanisms underlying the process of priming are poorly understood. In the present study, we investigated the early signaling events triggered by β-aminobutyric acid (BABA), a well-known priming-mediated plant resistance inducer. Our results indicate that, in contrast to oligogalacturonides (OG), BABA does not elicit typical defense-related early signaling events nor defense-gene expression in grapevine. However, in OG-elicited cells pretreated with BABA, production of reactive oxygen species (ROS) and expression of the respiratory-burst oxidase homolog RbohD gene were primed. In response to the causal agent of downy mildew Plasmopara viticola, a strong…

Identification and characterization of the grapevine flagellin receptor vvfls2

International audience

Influence of leaf age on induced resistance in grapevine against Plasmopara viticola

International audience; Sulfated laminarin (PS3) has previously been shown to induce resistance of grapevine leaves against the oomycete Plasmopara viticola, the causal agent of grape downy mildew. Here, we observed that the level of PS3-induced resistance (PS3-IR) was higher in the adult leaf (in position P3) than in the younger, not fully expanded leaf (in position P1, located above P3). By investigating grapevine defense reactions upon PS3 treatment and inoculation, we found that the production of H2O2, of phytoalexins, and the deposition of phenolics were more abundant in P3 than in P1 leaves. In addition, PS3 significantly reduced stomatal colonization by zoospores only in P3 leaves. T…

Perception of pathogenic or beneficial bacteria and their evasion of host immunity: pattern recognition receptors in the frontline

International audience; Plants are continuously monitoring the presence of microorganisms to establish an adapted response. Plants commonly use pattern recognition receptors (PRRs) to perceive microbe- or pathogen-associated molecular patterns (MAMPs/PAMPs) which are microorganism molecular signatures. Located at the plant plasma membrane, the PRRs are generally receptor-like kinases (RLKs) or receptor-like proteins (RLPs). MAMP detection will lead to the establishment of a plant defense program called MAMP-triggered immunity (MTI). In this review, we overview the RLKs and RLPs that assure early recognition and control of pathogenic or beneficial bacteria. We also highlight the crucial func…

Carbohydrates in plant immunity and plant protection: roles and potential application as foliar sprays.

International audience; Increasing interest is devoted to carbohydrates for their roles in plant immunity. Some of them are elicitors of plant defenses whereas other ones act as signaling molecules in a manner similar to phytohormones. This review first describes the main classes of carbohydrates associated to plant immunity, their role and mode of action. More precisely, the state of the art about perception of "PAMP, MAMP, and DAMP (Pathogen-, Microbe-, Damage-Associated Molecular Patterns) type" oligosaccharides is presented and examples of induced defense events are provided. A particular attention is paid to the structure/activity relationships of these compounds. The role of sugars as…

Glutathione deficiency of the Arabidopsis mutant pad2-1 affects oxidative stress-related events, defense gene expression and hypersensitive response

L'article original est publié par The American Society of Plant Biologists; International audience; The Arabidopsis (Arabidopsis thaliana) phytoalexin-deficient mutant pad2-1 displays enhanced susceptibility to a broad range of pathogens and herbivorous insects that correlates with deficiencies in the production of camalexin, indole glucosinolates, and salicylic acid (SA). The pad2-1 mutation is localized in the GLUTAMATE-CYSTEINE LIGASE (GCL) gene encoding the first enzyme of glutathione biosynthesis. While pad2-1 glutathione deficiency is not caused by a decrease in GCL transcripts, analysis of GCL protein level revealed that pad2-1 plants contained only 48% of the wild-type protein amoun…

Characterization of the role of flagellin in the innate immunity triggered by the endophytic pgpr burkholderia phytofirmans in arabidopsis and grapevine

International audience

Knowledge-based strategy to trigger grapevine immunity

Identification of the VvFLS2 grapevine flagellin receptor by a functional genomics strategy

National audience; Grapevine (Vitis vinifera) is a crop of high agronomic interest subject to many destructive diseases. Pattern recognition receptors (PRRs) mediate detection of potential pathogens via the perception of pathogen associated molecular patterns (PAMPs), which is important for plant disease resistance. A well studied PRR is the Arabidopsis leucine-rich repeat receptor kinase FLS2 that recognizes bacterial flagellin (or its minimal motif flg22). Flagellin perception plays an important role in restricting bacterial invasion into plant leaves. Until now, functional FLS2 orthologues have been characterized in Nicotiana benthamiana, rice and tomato. Despite its economical importanc…

The grapevine LysM receptor-like kinase VvLYK5-1 mediates chitin-triggered immunity

The establishment of defense reactions to protect plants against invading pathogens first requiresthe recognition of Microbe-Associated Molecular Patterns (MAMPs), detected by plasmamembrane-bound Pattern Recognition Receptors (PRRs). These MAMPs, also termed elicitors, areused in several biocontrol products that are gradually developing to reduce the use of chemicalpesticides in agriculture. Chitin, the main component of fungal cell walls, as well as its deacetylatedderivative, chitosan, are two chitooligosaccharides (COS) that can be found in some of theseproducts. Unfortunately, the mechanism allowing the perception of these molecules is still poorlyunderstood in Vitis vinifera, sometime…

Etude des éliciteurs, du laboratoire au vignoble

IPMSPEUB; Etude des éliciteurs, du laboratoire au vignoble. Journée Recherches Vigne et Vin en Bourgogne

Membre du comité d'organisation de 1st « Cellular Signaling » Winter School of the FORTHEM Universities Alliance. Valencia, 18-19th November 2021

Does leaf position influence induced resistance to grape downy mildew?

National audience; We observed that protection against grape downy mildew achieved by resistance inducers was higher in the adult leaf than in the younger, not fully expanded leaf. Using sulfated laminarin as inducer, this difference of efficacy could be correlated to stronger defense reactions (i. e. H2O2, defense gene expression) in adult leaf as compared to the younger one. These findings should be taken into account in disease control strategies involving induced resistance.

Stimuler l’immunité de la vigne : un levier pour réduire les traitements fongicides ?

Les stimulateurs de défense des plantes (SDP ou éliciteurs) font partie des méthodes visant à réduire les doses de produits phytosanitaires, donc l’Indicateur de Fréquence de Traitements (IFT), et à ce titre ils font l’objet d’une forte attente de la part des viticulteurs. Plusieurs produits sont homologués en viticulture depuis quelques années. Hormis les phosphonates (à la fois SDP et fongicides) dont l’efficacité est reproductible, celle des autres SDP s’avère encore assez variable. Ainsi leur intégration dans les programmes de protection du vignoble pose encore de nombreuses questions. Des recherches se poursuivent pour mieux caractériser les réponses de défense de la vigne au champ et …

Activation of Grapevine Defense Mechanisms: Theoretical and Applied Approaches

part 4.; International audience; Grapevine, as other plants, possesses an innate immune system that usually prevents infection by pathogens. General elicitors are compounds of different biochemical families capable of inducing plant defense reactions. In grapevine, the cascade of defense events induced by elicitors has been studied among others in cell suspensions. The perception of the elicitor triggers signaling events that allow the activation of defense genes encoding PR proteins and other proteins involved in phytoalexin production and cell wall reinforcement. The grapevine phytoalexins resveratrol and derivated compounds have been largely studied. In addition to their antimicrobial ac…

Role of Lys-M Receptor Kinases in the perception of chitooligosaccharides to trigger signaling events and immune responses in grapevine (Vitis vinifera)

Role of glutathione in plant signaling under biotic stress

International audience; Glutathione (GSH) is a non-protein thiol compound which has been repeatedly reported to play an important role in plant responses during biotic stresses. However, our knowledge of glutathione-related molecular mechanisms underlying plant defense responses still remains limited. We first discovered that the Arabidopsis thaliana phytoalexin deficient 2-1 (pad2-1) mutant was linked to glutathione deficiency since the mutation was identified in the GSH1 gene encoding the first enzyme of glutathione biosynthesis: Glutamate Cysteine Ligase (GCL). Interestingly, this glutathione-deficient mutant pad2-1 also displays a high susceptibility to a wide range of invaders. We rece…

Genomics of the grapevine - pathogen interactions Botrytis cinerea virulence factors and molecular mechanisms of induced resistance

International audience

Lutter contre les infections bactériennes : le système immunitaire des plantes est aussi très efficace !

SPE IPM UB CNRS Agrosup

Peut-on éliciter l'immunité de la vigne pour améliorer sa résistance aux maladies?

SPEIPMUB; Peut-on éliciter l'immunité de la vigne pour améliorer sa résistance aux maladies?. Séminaire de Recherche du Plan National Dépérissement du Vignoble

Induced resistance in grapevine : from concept to vineyard application

International audience

Induced resistance as a strategy for vineyard protection

National audience; As most grown grapevine Vitis vinifera varieties are susceptible to diseases such as downy and powdery mildews, numerous treatments are required to ensure a satisfactory yield and harvest quality. However, the use of phytochemical fungicides has serious drawbacks: some of them are potentially harmful for the environment and human health and contribute to the selection of resistant pathogen strains. Nowadays, in an objective of sustainable viticulture, there is increasing societal request, political incitation and winegrower’s awareness to reduce the use of pesticides. For these reasons, alternative strategies of protection are under research. In our laboratory, we are stu…

Priming: getting ready for battle

International audience; Infection of plants by necrotizing pathogens or colonization of plant roots with certain beneficial microbes causes the induction of a unique physiological state called “priming.” The primed state can also be induced by treatment of plants with various natural and synthetic compounds. Primed plants display either faster, stronger, or both activation of the various cellular defense responses that are induced following attack by either pathogens or insects or in response to abiotic stress. Although the phenomenon has been known for decades, most progress in our understanding of priming has been made over the past few years. Here, we summarize the current knowledge of p…

Are the xyloglucans new elicitors of plant immunity ?

Damaged-Associated Molecular Patterns (DAMPs) are endogenous molecules released from the plant cell wall after wounding by pathogens. DAMPs are recognized by Pattern- Recognition Receptors (PRRs) that play a key role in plant immunity by mediating defense responses. The plant cell wall-derived oligogalacturonides (OG) are well characterized DAMPs that elicit plant immune responses such as MAPK activation, [Ca2+]cyt variations, H2O2 production, defense-related gene expression and enhanced resistance against Botrytis cinerea. Our study focused on a new polysaccharide component of the plant cell wall called xyloglucans (Xh) and compared the immune events triggered by OG and Xh in Arabidopsis t…

Récepteurs de l'immunité chez les plantes

ß-1,4 cellodextrins, ß-1,3 glucans and a-1,4 oligogalacturonides are potent elicitors of various defense-related responses in grapevine

International audience; Plant cell-wall degradation products can be considered as ‘microbe-induced molecular patterns’ (MIMPs) recognized through plant receptors as ‘pathogen-induced modified self’. So cell-wall oligosaccharides originating from plants can play an important role in the perception of the invading pathogen by the plant. Cellodextrins (CD) are the end-products from cellulose degradation in plant cell walls, consisting og a linear ß-(1,4) linked glucose backbone. The role of these oligosaccharides in triggering plant defense reactions has not yet been established. Here, we investigated the elicitor activity of CD oligomers in grapevine cells. We show that CD triggered induction…

The grapevine flagellin receptor VvFLS2 differentially recognizes flagellin-derived epitopes from the endophytic growth-promoting bacterium Burkholderia phytofirmans and plant pathogenic bacteria.

International audience; The role of flagellin perception in the context of plant beneficial bacteria still remains unclear. Here, we characterized the flagellin sensing system flg22-FLAGELLIN SENSING 2 (FLS2) in grapevine, and analyzed the flagellin perception in the interaction with the endophytic plant growth-promoting rhizobacterium (PGPR) Burkholderia phytofirmans. The functionality of the grapevine FLS2 receptor, VvFLS2, was demonstrated by complementation assays in the Arabidopsis thaliana fls2 mutant, which restored flg22-induced H2O2 production and growth inhibition. Using synthetic flg22 peptides from different bacterial origins, we compared recognition specificities between VvFLS2…

Role de la Recherche et l’Innovation dans le développement économique d’un pays

National audience

The endopolygalacturonase 1 from botrytis cinerea activates grapevine defense reactions unrelated to its enzyumatic activity

A purified glycoprotein from Botrytis cinerea(strain T4), identified as endopolygalacturonase 1 (T4BcPG1) by mass spectrometry analysis, has been shown to activate defense reactions in grapevine (Vitis vinifera cv. Gamay). These reactions include calcium influx, production of active oxygen species, activation of two mitogen-activated protein kinases, defense gene transcript accumulation, and phytoalexin production. Most of these defense reactions were also activated in grapevine in response to purified oligogalacturonides (OGA) with a degree of polymerization of 9 to 20. In vivo, these active OGA might be a part of the released products resulting from endopolygalacturonase activity on plan…

Induced resistance in grapevine: from concept to vineyard application

SPE IPM Chapitre 11; International audience

Chitoprotect: development of a chitosan-based biocontrol product against plant diseases (powdery & downy mildews)

Botrytis cinerea strains infecting grapevine and tomato display contrasted repertoires of accessory chromosomes, transposons and small RNAs

Botrytis cinerea stands out for having a wide host range and is qualified as generalist.Nevertheless, recent studies suggest that it actually corresponds to co-existing populationsthat show a certain level of host specialization, as described for the French populations T andG1, specialized on tomato and grapevine, respectively (Mercier et al., 2019, Env. Microbiol.21, 4808–21; Mercier et al., 2021 Phytopathology, 111,2355-66).What are the molecular determinants responsible for such host-specialization? PreviousIllumina sequencing data revealed genes under positive selection encoding cellulases,pectinases and enzymes involved in the oxidative stress response suggesting that theseactivities m…

Les stimulateurs de défense des plantes (SDP) en viticulture - Un tour d’horizon sur les principes, les applications et les perspectives

IPMSPEINRAUBCNRS; Les stimulateurs de défense des plantes (SDP) en viticulture - Un tour d’horizon sur les principes, les applications et les perspectives

Le génome de Botrytis décrypté

 ; absent

Dual mode of action of grape cane extracts against Botrytis cinerea

International audience; Crude extracts of Vitis vinifera canes represent a natural source of stilbene compounds with well characterized antifungals properties. In our trials, exogenous application of a stilbene extract (SE) obtained from grape canes on grapevine leaves reduces the necrotic lesions caused by Botrytis cinerea. The SE showed to possess a direct antifungal activity by inhibiting the mycelium growth. The activation of some grapevine defense mechanism was also investigated. H2O2 production and activation of mitogen-activated protein kinase (MAPK) phosphorylation cascades as well as accumulation of stilbenoid phytoalexins were explored on grapevine cell suspension. Moreover, the t…

Role of Lys-M Receptor Kinases in the perception of chitooligosaccharides to trigger signaling events and immune responses in grapevine (Vitis vinifera)

The establishment of defense reactions to protectplants against invading pathogens first requires therecognition of Microbe-Associated MolecularPatterns (MAMPs), detected by plasma membrane-bound Pattern Recognition Receptors (PRRs). TheseMAMPs, also termed elicitors, are used in severalbiocontrol products that are gradually developing toreduce the use of chemical pesticides inagriculture. Chitin, the main component of fungalcell walls, as well as its deacetylated derivative,chitosan, are two chitooligosaccharides (COS) thatcan be found in some of these products.Unfortunately, the mechanism allowing theperception of these molecules is still poorlyunderstood in Vitis vinifera, sometimes hamp…

Involvement of the glutamate receptor AtGLR3.3 in plant defense signaling and resistance toHyaloperonospora arabidopsidis

Like their animal counterparts, plant glutamate receptor-like (GLR) homologs are intimately associated with Ca(2+) influx through plasma membrane and participate in various physiological processes. In pathogen-associated molecular patterns (PAMP)-/elicitor-mediated resistance, Ca(2+) fluxes are necessary for activating downstream signaling events related to plant defense. In this study, oligogalacturonides (OGs), which are endogenous elicitors derived from cell wall degradation, were used to investigate the role of Arabidopsis GLRs in defense signaling. Pharmacological investigations indicated that GLRs are partly involved in free cytosolic [Ca(2+)] ([Ca(2+)]cyt) variations, nitric oxide (N…

Transcriptome of the early steps of Botrytis cinerea infection

International audience

Nitric oxide production mediates oligogalacturonide-triggered immunity and resistance to Botrytis cinerea in Arabidopsis thaliana

Nitric oxide (NO) regulates a wide range of plant processes from development to environmental adaptation. In this study, we investigated the production and/or function of NO in Arabidopsis thaliana leaf discs and plants elicited by oligogalacturonides (OGs) and challenged with Botrytis cinerea. We provided evidence that OGs triggered a fast and long lasting NO production which was Ca(2+) dependent and involved nitrate reductase (NR). Accordingly, OGs triggered an increase of both NR activity and transcript accumulation. NO production was also sensitive to the mammalian NO synthase inhibitor L-NAME. Intriguingly, we showed that L-NAME affected NO production by interfering with NR activity, t…

Etudier l’immunité des plantes pour améliorer la résistance induite de la vigne aux agents pathogènes. Recherche de motifs moléculaires associés aux pathogènes (Pathogen Associated Molecular Patterns) et des récepteurs associés (Pattern Recognition Receptors).

Evolution de la résistance basale à Botrytis cinerea au cours de la maturation de la baie

National audience; Mature grapevine berries at the harvesting stage (MB) are very susceptible to the grey mould fungus Botrytis cinerea while veraison berries (VB) are not. We conducted simultaneous microscopic and transcriptomic analyses of the pathogen and the host to investigate the infectious process developed by B. cinerea on MB versus VB, and the plant defence mechanisms deployed to stop the fungus development. On the pathogen side, our genome-wide transcriptomic data revealed that B. cinerea genes up-regulated during infection of MB are enriched in functional categories related to necrotrophy such as degradation of plant cell wall, proteolysis, membrane transport, oxidative stress re…

Recherche de récepteurs de l’immunité des plantes et étude de l’impact de biostimulants sur leur expression et la résistance induite chez des organes sensibles

National audience; La stimulation des défenses immunitaires des plantes représente une stratégie durable deprotection des cultures qui pourrait permettre de réduire l’utilisation de pesticides chimiquesencore trop répandue en viticulture. Son principe réside en l’application, au contact des cellulesvégétales, de molécules élicitrices détectées comme des signaux de danger par la plante. Cessignaux de dangers peuvent être de différente nature et origine comme par exemple la chitine,un chito-oligosaccharide (COS) retrouvé dans les parois fongiques. Leur détection par desrécepteurs de l’immunité entraine une cascade de signalisation complexe, conduisant àl’activation de réactions de défense et …

Integrated signaling network involving calcium, nitric oxide, active oxygen species but not mitogen-activated protein kinases in BcPG1-elicited grapevine defenses.

We have already reported the identification of the endopolygalacturonase 1 (BcPG1) from Botrytis cinerea as a potent elicitor of defense responses in grapevine, independently of its enzymatic activity. The aim of the present study is the analysis of the signaling pathways triggered by BcPG1 in grapevine cells. Our data indicate that BcPG1 induces a Ca2+ entry from the apoplasm, which triggers a phosphorylation-dependent nitric oxide (NO) production via an enzyme probably related to a NO synthase. Then NO is involved in i) cytosolic calcium homeostasis, by activating Ca2+ release from internal stores and regulating Ca2+ fluxes across the plasma membrane, ii) plasma membrane potential variat…

PATRIC : Application of PAMP Triggered Immunity in Crops

Soybean and casein hydrolysates induce grapevine immune responses and resistance against Plasmopara viticola

International audience; Plasmopara viticola, the causal agent of grapevine downy mildew, is one of the most devastating grape pathogen in Europe and North America. Although phytochemicals are used to control pathogen infections, the appearance of resistant strains and the concern for possible adverse effects on environment and human health are increasing the search for alternative strategies. In the present investigation, we successfully tested two protein hydrolysates from soybean (soy) and casein (cas) to trigger grapevine resistance against P. viticola. On Vitis vinifera cv. Marselan plants, the application of soy and cas reduced the infected leaf surface by 76 and 63%, as compared to th…

Transcriptomes of compatible and non-compatible gray mold/grapevine interactions compared in search of resistance factors

National audience; Gray mold (Botrytis cinerea) causes significant annual yield and quality losses to viticulture. Comparison of transcriptomes of compatible and non-compatible interaction with Vitis vinifera cv Marselan – on harvesting stage berries or véraison stage berries, respectively – suggest the jasmonic acid pathway is activated in the former, while the salicylic acid pathway is more pronounced in the latter. In addition, in the non-compatible case, reactive oxygen species accumulation seems to be both early and strong, and some genes involved in cell-wall reinforcement are up-regulated.

Early signaling events induced by elicitors of plant defenses

International audience; Plant pathogen attacks are perceived through pathogenissued compounds or plant-derived molecules that elicit defense reactions. Despite the large variety of elicitors, general schemes for cellular elicitor signaling leading to plant resistance can be drawn. In this article, we review early signaling events that happen after elicitor perception, including reversible protein phosphorylations, changes in the activities of plasma membrane proteins, variations in free calcium concentrations in cytosol and nucleus, and production of nitric oxide and active oxygen species. These events occur within the first minutes to a few hours after elicitor perception. One specific eli…

"Omics-" for a mapping of grapevine response to elicitors and identification of induced resistance markers

SPEIPMINRAUBCNRS; "Omics-" for a mapping of grapevine response to elicitors and identification of induced resistance markers . 12. European Fondation for Plant Pathology (EFPP) & 10. French Society for Plant Pathology Conference ‘Deepen Knwoledge in Plant Pathology for Innovative Agro-Ecology’

Elicitor and resistance-inducing activities of -1,4 cellodextrins in grapevine, comparison with -1,3 glucans and -1,4 oligogalacturonides

Cellodextrins (CD), water-soluble derivatives of cellulose composed of beta-1,4 glucoside residues, have been shown to induce a variety of defence responses in grapevine (Vitis vinifera L.) cells. The larger oligomers of CD rapidly induced transient generation of H2O2 and elevation in free cytosolic calcium, followed by a differential expression of genes encoding key enzymes of the phenylpropanoid pathway and pathogenesis-related (PR) proteins as well as stimulation of chitinase and beta-1,3 glucanase activities. Most of these defence reactions were also induced by linear beta-1,3 glucans (betaGlu) and alpha-1,4 oligogalacturonides (OGA) of different degree of polymerization (DP), but the i…

Characterization of a new, nonpathogenic mutant of Botrytis cinerea with impaired plant colonization capacity.

International audience; Botrytis cinerea is a necrotrophic pathogen that attacks more than 200 plant species.Here, the nonpathogenic mutant A336, obtained via insertional mutagenesis, was characterized.Mutant A336 was nonpathogenic on leaves and fruits, on intact and wounded tissue, while still able to penetrate the host plant. It grew normally in vitro on rich media but its conidiation pattern was altered. The mutant did not produce oxalic acid and exhibited a modified regulation of the production of some secreted proteins (acid protease 1 and endopolygalacturonase 1). Culture filtrates of the mutant triggered an important oxidative burst in grapevine ( Vitis vinifera ) suspension cells, a…

Comment stimuler l’immunité de la vigne avec des éliciteurs

Induced resistance as a strategy for vineyard protection

National audience

Analysis of the Molecular Dialogue Between Gray Mold (Botrytis cinerea) and Grapevine (Vitis vinifera) Reveals a Clear Shift in Defense Mechanisms During Berry Ripening

Mature grapevine berries at the harvesting stage (MB) are very susceptible to the gray mold fungus Botrytis cinerea, while veraison berries (VB) are not. We conducted simultaneous microscopic and transcriptomic analyses of the pathogen and the host to investigate the infection process developed by B. cinerea on MB versus VB, and the plant defense mechanisms deployed to stop the fungus spreading. On the pathogen side, our genome-wide transcriptomic data revealed that B. cinerea genes upregulated during infection of MB are enriched in functional categories related to necrotrophy, such as degradation of the plant cell wall, proteolysis, membrane transport, reactive oxygen species (ROS) genera…