Screening of wood/forest and vine by-products as sources of new drugs for sustainable strategies to control fusarium graminearum and the production of mycotoxins

Fusarium graminearum is a fungal pathogen that can colonize small-grain cereals and maize and secrete type B trichothecene (TCTB) mycotoxins. The development of environmental-friendly strategies guaranteeing the safety of food and feed is a key challenge facing agriculture today. One of these strategies lies on the promising capacity of products issued from natural sources to counteract crop pests. In this work, the in vitro efficiency of sixteen extracts obtained from eight natural sources using subcritical water extraction at two temperatures was assessed against fungal growth and TCTB production by F. graminearum. Maritime pine sawdust extract was shown to be extremely efficient, leading to a significant inhibition of up to 89% of the fungal growth and up to 65% reduction of the mycotoxin production by F. graminearum. Liquid chromatography/mass spectrometry analysis of this active extract revealed the presence of three families of phenolics with a predominance of methylated compounds and suggested that the abundance of methylated structures, and therefore of hydrophobic compounds, could be a primary factor underpinning the activity of the maritime pine sawdust extract. Altogether, our data support that wood/forest by-products could be promising sources of bioactive compounds for controlling F. graminearum and its production of mycotoxins.Développement d'une infrastructure française distribuée pour la métabolomique dédiée à l'innovatio

Computational Strategy for Minimizing Mycotoxins in Cereal Crops: Assessment of the Biological Activity of Compounds Resulting from Virtual Screening

Cereal crops are frequently affected by toxigenic Fusarium species, among which the most common and worrying in Europe are Fusarium graminearum and Fusarium culmorum. These species are the causal agents of grain contamination with type B trichothecene (TCTB) mycotoxins. To help reduce the use of synthetic fungicides while guaranteeing low mycotoxin levels, there is an urgent need to develop new, efficient and environmentally-friendly plant protection solutions. Previously, F. graminearum proteins that could serve as putative targets to block the fungal spread and toxin production were identified and a virtual screening undertaken. Here, two selected compounds, M1 and M2, predicted, respectively, as the top compounds acting on the trichodiene synthase, a key enzyme of TCTB biosynthesis, and the 24-sterol-C-methyltransferase, a protein involved in ergosterol biosynthesis, were submitted for biological tests. Corroborating in silico predictions, M1 was shown to significantly inhibit TCTB yield by a panel of strains. Results were less obvious with M2 that induced only a slight reduction in fungal biomass. To go further, seven M1 analogs were assessed, which allowed evidencing of the physicochemical properties crucial for the anti-mycotoxin activity. Altogether, our results provide the first evidence of the promising potential of computational approaches to discover new anti-mycotoxin solution

Réactions des composés phénoliques dans les vins rouges induites par la technique de micro-oxygénation (caractérisation de nouveaux produits de condensation des anthocyanes avec l'acétaldéhyde)

MONTPELLIER-SupAgro La Gaillarde (341722306) / SudocSudocFranceF

Stilbenoids as promising natural product-based solutions in a race against mycotoxigenic fungi : a comprehensive review

Exposure to mycotoxins can pose a variety of adverse health effects to mammals. Despite dozens of mycotoxin decontamination strategies applied from pre-to postharvest stages, it is always challenging to guarantee a safe level of these natural toxic compounds in food and feedstuffs. In the context of the increased occurrence of drug-resistance strains of mycotoxin-producing fungi driven by the overuse of fungicides, the search for new natural-product-based solutions is a top priority. This review aims to shed a light on the promising potential of stilbenoids extracted from renewable agricultural wastes (e.g., grape canes and forestry byproducts) as antimycotoxin agents. Deeper insights into the mode of actions underlying the bioactivity of stilbenoid molecules against fungal pathogens, together with their roles in plant defense responses, are provided. Safety aspects of these natural compounds on humans and ecology are discussed. Perspectives on the development of stilbenoid-based formulations using encapsulation technology, which allows the bypassing of the limitations related to stilbenoids, particularly low aqueous solubility, are addressed. Optimistically, the knowledge gathered in the present review supports the use of currently underrated agricultural byproducts to produce stilbenoid-abundant extracts with a high efficiency in the mitigation of mycotoxins in food and feedstuffs

Effect of linoleic-derived hydroperoxides on fumonisins and trichothecenes production by Fusarium spp. verticillioides and graminearum

International audienc

Metabolomics to decipher the chemical defense of cereals against Fusarium graminearum and deoxynivalenol accumulation

International audienceFusarium graminearum is the causal agent of Fusarium head blight (FHB) and Gibberella ear rot (GER), two devastating diseases of wheat, barley, and maize. Furthermore, F. graminearum species can produce type B trichothecene mycotoxins that accumulate in grains. Use of FHB and GER resistant cultivars is one of the most promising strategies to reduce damage induced by F. graminearum. Combined with genetic approaches, metabolomic ones can provide powerful opportunities for plant breeding through the identification of resistant biomarker metabolites which have the advantage of integrating the genetic background and the influence of the environment. In the past decade, several metabolomics attempts have been made to decipher the chemical defense that cereals employ to counteract F. graminearum. By covering the major classes of metabolites that have been highlighted and addressing their potential role, this review demonstrates the complex and integrated network of events that cereals can orchestrate to resist to F. graminearum

Structure of a new dimeric acetaldehyde malvidin 3-glucoside condensation product

11 ref.International audienc

Uso de macromicetos para prevenir y reducir las micotoxinas en productos de cereales

International audienceBackground: Biological control for cereal diseases caused by mycotoxigenic fungi is part of the alternative methods to be developed to secure food and feed production, recognizing the negative effects these fungi have on crop yield and their potential production of mycotoxins. Objective: Update recent knowledge about the potential of mushroom-forming fungi as biological control agents of mycotoxigenic fungi species, acting as antagonists on crop debris, as source of active extracts with antifungal and/or antimycotoxin properties and as detoxifying agents in solid-state fermentation processes of contaminated cereals.Methods: A literature review of the published works was carried out, the main topics were analyzed, as well as the species with the greatest potential of biological control agents of mycotoxingenic fungi.Results and conclusions: Mushroom forming fungi could be used as antagonists on crop debris or grains, as sour-ces of active extracts with antifungal and/or antimycotoxin properties, and as detoxifying agents. An integration of these three potentials gives rise to an environment friendly process for production of both safe grains and edible mushrooms.Antecedentes: El control biológico de las enfermedades de los cereales causadas por hongos micotoxigénicos forma parte de los métodos alternativos a desarrollar para asegurar la producción de alimentos y forrajes, debido a los efectos negativos que estos hongos tienen sobre el rendimiento de los cultivos y su producción potencial de micotoxinas.Objetivo: Actualizar el conocimiento sobre el potencial de los hongos formadores de hongos como agentes de control biológico de especies de hongos micotoxigénicos, actuando como: antagonistas en residuos de cultivos, fuente de extractos activos con propiedades antifúngicas y/o antimicotoxinas y como agentes detoxificantes en procesos de fermentación en estado sólido en cereales contaminados.Métodos: Se realizó una revisión bibliográfica de los trabajos publicados, analizando los temas principales, así como las especies con mayor potencial como agentes de control biológico de los hongos micotoxingénicos.Resultados y conclusiones: Los macromicetos se podrían usar como antagonistas en residuos de cultivos o granos, como fuentes de extractos activos con propiedades antifúngicas y/o antimicotoxigénicas y como agentes desin-toxicantes. Una integración de estos tres potenciales da lugar a un proceso amigable con el medio ambiente para la producción de granos seguros y hongos comestibles

Host-pathogen interaction and signaling molecule secretion are modified in the dpp3 knockout mutant of Candida lusitaniae.

International audienceCandida lusitaniae is an emerging opportunistic yeast and an attractive model to discover new virulence factors in Candida species by reverse genetics. Our goal was to create a dpp3Δ knockout mutant and to characterize the effects of this gene inactivation on yeast in vitro and in vivo interaction with the host. The secretion of two signaling molecules in Candida species, phenethyl alcohol (PEA) and tyrosol, but not of farnesol was surprisingly altered in the dpp3Δ knockout mutant. NO and reactive oxygen species (ROS) production as well as tumor necrosis factor alpha (TNF-α) and interleukin 10 (IL-10) secretion were also modified in macrophages infected with this mutant. Interestingly, we found that the wild-type (WT) strain induced an increase in IL-10 secretion by zymosan-activated macrophages without the need for physical contact, whereas the dpp3Δ knockout mutant lost this ability. We further showed a striking role of PEA and tyrosol in this modulation. Last, the DPP3 gene was found to be an essential contributor to virulence in mice models, leading to an increase in TNF-α secretion and brain colonization. Although reinsertion of a WT DPP3 copy in the dpp3Δ knockout mutant was not sufficient to restore the WT phenotypes in vitro, it allowed a restoration of those observed in vivo. These data support the hypothesis that some of the phenotypes observed following DPP3 gene inactivation may be directly dependent on DPP3, while others may be the indirect consequence of another genetic modification that systematically arises when the DPP3 gene is inactivated

Role of Tocochromanols in Tolerance of Cereals to Biotic Stresses: Specific Focus on Pathogenic and Toxigenic Fungal Species

International audienceFungal pathogens capable of producing mycotoxins are one of the main threats to the cultivation of cereals and the safety of the harvested kernels. Improving the resistance of crops to fungal disease and accumulation of mycotoxins is therefore a crucial issue. Achieving this goal requires a deep understanding of plant defense mechanisms, most of them involving specialized metabolites. However, while numerous studies have addressed the contribution of phenylpropanoids and carotenoids to plant chemical defense, very few have dealt with tocochromanols. Tocochromanols, which encompass tocopherols and tocotrienols and constitute the vitamin E family, are widely distributed in cereal kernels; their biosynthetic pathway has been extensively studied with the aim to enrich plant oils and combat vitamin E deficiency in humans. Here we provide strong assumptions arguing in favor of an involvement of tocochromanols in plant–fungal pathogen interactions. These assumptions are based on both direct effects resulting from their capacity to scavenge reactive oxygen species, including lipid peroxyl radicals, on their potential to inhibit fungal growth and mycotoxin yield, and on more indirect effects mainly based on their role in plant protection against abiotic stresses