Some Plant Defense Stimulators can induce IL-1β production in human immune cells in vitro

8 pages; International audience; Among Plant Protection Products (PPP), a new emerging category of pesticides act by stimulating plant defense in order to improve plant resistance against microbial pathogens. Given that these compounds, the so-called Plant Defense Stimulators (PDS) act on innate immunity, we tested, using an in vitro approach on human mononuclear leucocytes (PBMC), the potential toxicity (XTT assay) and inflammatory effects (production of IL-1β) of 4 PPP belonging to different chemical families. We found that two products (LBG-01F34® and Regalis®) did not induce any cytotoxicity or IL-1 β production. The product BION-50 WG®, that contains Acibenzolar-S-methyl (ASM) and sili…

Determinism of the biocontrol capacity of a strain of Fusarium oxysporum: identification of genes expressed during interactions with tomato

New insights about the role of the chaperon-like protein Cdc48, a target for nitric oxide in plant immunity

Expression de quelques PR protéines dans des cultures cellulaires et des plantes de tomate inoculées avec une souche pathogène ou une souche protectrice de Fusarium oxysporum

NO signaling in cryptogein-induced immune responses in tobacco

Protein S-nitrosylation: specificity and identification strategies in plants

SPE Pôle IPM UB; International audience; The role of nitric oxide (NO) as a major regulator of plant physiological functions has become increasingly evident. To further improve our understanding of its role, within the last few years plant biologists have begun to embrace the exciting opportunity of investigating protein S-nitrosylation, a major reversible NO-dependent post-translational modification (PTM) targeting specific Cys residues and widely studied in animals. Thanks to the development of dedicated proteomic approaches, in particular the use of the biotin switch technique (BST) combined with mass spectrometry, hundreds of plant protein candidates for S-nitrosylation have been identi…

Evolutionary diversification of type-2 HDAC structure, function and regulation in Nicotiana tabacum

Ministère de l'Education Nationale et de la Recherche ; Conseil Régional de Bourgogne (PARI AGRALE8) ; Association pour la Recherche sur les Nicotianacées ; Conseil Régional de Bourgogne; International audience; Type-2 HDACs (HD2s) are plant-specific histone deacetylases that play diverse roles during development and in responses to biotic and abiotic stresses. In this study we characterized the six tobacco genes encoding HD2s that mainly differ by the presence or the absence of a typical zinc finger in their C-terminal part. Of particular interest, these HD2 genes exhibit a highly conserved intron/exon structure. We then further investigated the phylogenetic relationships among the HD2 gen…

Impact de la S-nitrosylation sur la structure des calmoduline chez les plantes

Ecological fitness of the biocontrol agent Fusarium oxysporum Fo47 in soil and its impact on the soil microbial communities

Some nonpathogenic strains of Fusarium oxysporum can control Fusarium diseases responsible for severe damages in many crops. Success of biological control provided by protective strains requires their establishment in the soil. The strain Fo47 has proved its efficacy under experimental conditions, but its ecological fitness has not been carefully studied. In a series of microcosm studies, the ability of a benomyl-resistant mutant Fo47b10 to establish in two different soils was demonstrated. One year after its introduction at two concentrations in the disinfected soils, the biocontrol agent (BCA) established at similar high population densities, whereas in the nondisinfected soils it survive…

Silencing of plant defensin type 1 reduces sensitivity to pathogens and zinc toxicity in arabidopsis thaliana

Ectopic expression of defensins in plants correlates with their increased capacity to withstand abiotic and biotic stresses(Carvalho & Gomes, 2011). However, few studies have explored the effects of decreased plant endogenous defensin transcripts on these stress responses.When over-expressed in Arabidopsis thaliana, some of the seven members of thePlant Defensin type 1 family (PDF1) are recognised to improve plant responses tonecrotrophic pathogens(De Conincket al.,2010)and increase seedling tolerance to excess zinc (Zn;Mirouzeet al., 2006). We carried out an extensive physiological and biochemical comparative characterisation of i) novel transgenic amiRNA lines silenced for the five most s…

Molecular tools to monitor a biocontrol agent and to assess its environmental impacts

The use of non pathogenic strains of Fusarium oxysporum has been proposed to control Fusarium diseases responsible for severe damages in many crops of economical importance. In order to monitor the biocontrol strain Fo47 after application in greenhouse and field, we have developed a specific molecular tool based on a sequence characterized amplified region (SCAR). Primers targeting a 210-bp fragment were designed to set up a real time PCR assay allowing the identification of the biocontrol strain and its quantification in environmental samples. The assay enabled specific detection of the strain in soils without cross detection of autochthonous populations of F. oxysporum. After its introduc…

Functional characterization of the chaperon-like protein Cdc48 in cryptogein-induced immune response in tobacco

SPEIPMUBINRASUPDATDOCT; Cdc48, a molecular chaperone conserved in different kingdoms, is a member of the AAA+ family contributing to numerous processes in mammals including proteins quality control and degradation, vesicular trafficking, autophagy and immunity. The functions of Cdc48 plant orthologues are less understood. We previously reported that Cdc48 is regulated by S-nitrosylation in tobacco cells undergoing an immune response triggered by cryptogein, an elicitin produced by the oomycete Phytophthora cryptogea. Here, we inv estigated the function of NtCdc48 in cryptogein signalling and induced hypersensitive-like cell death. NtCdc48 was found to accumulate in elicited cells at both th…

Eradication of Plasmodiophora brassicae during composting of wastes

Survival of infectious inoculum of the clubroot pathogen Plasmodiophora brassicae was assessed following bench-scale flask composting experiments and large-scale composting procedures. Clubroot-affected material was provided by artificial inoculation of Chinese cabbage or naturally infected Brussels sprout and cabbage roots. Both sets of diseased material were used in flask experiments, and the latter in large-scale windrow and aerated tunnel experiments. Municipal green wastes, onion waste and spent mushroom compost were evaluated in flask experiments with varying temperature, aeration and moisture conditions. Green wastes were used in larger-scale composts. Within the limits of a Chinese …

Déterminisme du pouvoir protecteur d’une souche de Fusarium oxysporum : recherches de gènes impliqués lors de l’interaction avec la tomate

Comparative analysis of PR gene expression in tomato inoculated with virulent Fusarium oxysporum f. sp. lycopersici and the biocontrol strain F. oxysporum Fo47

Non-pathogenic strains of Fusarium oxysporum have the capacity to protect plants against wilt induced by pathogenic strains of F. oxysporum. Among the mechanisms involved in this protection, induced systemic resistance has been demonstrated by using a split-root method. The aim of this study was to follow the accumulation kinetics of transcripts encoding 5 PR proteins in roots and leaves of tomato inoculated with a pathogenic or a protective strain in comparison to non-inoculated control. Moreover quantification of transcripts was assessed by real-time RT-PCR in cell cultures inoculated with the pathogenic or the protective strain. Results showed a lower expression of PR encoding genes in t…