Root rot of pea: characterization and biocontrol of the soil-borne disease complex including Aphanomyces euteiches

Pea root rot is an increasing constraint in most of intensive pea cropping areas across the globe. The pathogenic complex responsible for the disease is composed of soil-borne fungal and oomycete pathogens such as Fusarium solani, F.oxysporum, F. avenaceum, F. culmorum, Rhizoctonia solani, Thielaviopsis basicola, Ascochyta pinodella, Pythium spp., Aphanomyces euteiches and probably others not yet identified. The diversity of their ecological and pathogenic properties can explain the worldwide dispersion of the disease and the absence of chemical, agricultural or genetic control tools. My research program aims at characterizing the parasitic consortium occurring in the North of France and at…

Mechanisms involved in spatial and temporal mobility of disease patches caused by Rhizoctonia solani in sugar beet field : Induction of antagonists within disease patch

National audience; Rhizoctonia solani AG 2-2 causes damping-off and root rot on sugar beet in patches that are highly mobile both on spatial and temporal scales. They never occur in the same place where they were in the previous season. The aim of the present study was to uncover the mechanisms underlying the dynamics of disease patches. It was observed that soil inoculum potential was higher within diseased patch than in healthy area. However, the dormant pathogen in healthy area was stimulated by addition of buckwheat meal more than that in diseased patch. In addition soil from diseased area was more suppressive towards the disease. We did not observe significant differences in bacterial …

Nomenclature of potato blemishes needs rationalisation

International audience

The control of soil borne vascular diseases: Limits of genetic resistance of cultivars and rootstocks for controlling Fusarium oxysporum f. sp. melonis (melon) and Verticillium sp. (eggplant)

After using resistant cultivars or resistant rootstocks for many years to control soil-borne pathogenic fungi causing wilt disease, growers observe more and more frequently wilt like symptoms in their melon and eggplant cultures. Ctifl, in close collaboration with INRA, regional extension services, and seed companies, set up a study designed to investigate the causative pathological agents. The results show the prevalence of Fusarium oxysporum f. sp. melonis race 1-2 yellowing on melon and of Verticillium dahlia on eggplant. Both pathogens are often found together with other pathogenic soil fungi, which act as aggravating factors. The isolates of F. oxysporum f. sp. melonis collected from i…

Fusariose du cyclamen : travaux sur la lutte biologique. Phytoma-La défense des végétaux

SPEIPM; Fusariose du cyclamen : travaux sur la lutte biologique. Phytoma-La défense des végétaux

Identification of potential mycoherbicides using a metabarcoding approach

National audience

Identification of the pathogens responsible for the surface deteriorations on the potato tubers

Nouveaux concepts de gestion des bioagresseurs du sol par approche conservatoire de leur biodiversité

Fusariose du cyclamen : vers un outil de détection précoce

SPEIPM; Fusariose du cyclamen : vers un outil de détection précoce

Functionnal aspects of biodiversity in relation to plant health

 Texte intégral; The most visible impact of human activities on biodiversity concerns species which are part of our cultural heritage but a huge part of the diversity is still hidden, mainly in the ocean, in extreme environments and of course in the soil. Although some estimations can be proposed, they are all considered as under-evaluations of the putative number of taxa that could be present on (in?) the planet Earth. Despite it is not yet known, this biodiversity contributes to different services through the functioning of ecosystems, and thus influences the sustainability of these ecosystems. This was the case for instance when the unsuspected major roles of the archeabacteria in the bi…

Hydro-contamination fongique par Fusarium spp. en milieu hospitalier pendant une période de construction

Détermination des causes de l'apparition des altérations superficielles du tubercule de pomme de terre

Épidémiologie de populations de Fusarium oxysporum et F. dimerum en milieu hospitaliers à Dijon et Nancy

Fusarium oxysporum et F. dimerum sont des champignons d'origine tellurique présents dans de nombreux écosystèmes terrestres mais ils ont été récemment détectés dans les systèmes de distribution d'eau de bâtiments hospitaliers1. Une enquête épidémiologique incluant divers bâtiments hospitaliers sur différents sites, des complexes non-hospitaliers et des maisons individuelles a été menée pendant deux ans dans deux villes françaises, Dijon et Nancy. Les champignons ont été détectés seulement dans les canalisations de bâtiments hospitaliers et n'ont pas été détectés dans celles des autres immeubles ni dans l'eau du réseau urbain. Cette distribution surprenante s'explique par une combinaison de …

Are soils suppressive to fungal diseases the sources of biocontrol agents ?

Soils suppressive to soil-borne diseases are defined by a low disease incidence in spite of the presence of a virulent pathogen and a susceptible plant. In many cases, the inhibition of the disease development relies on the activity of the resident soil microbiome. Suppressiveness can be transmitted to conducive soil by mixing a small amount of suppressive soil into the conducive one. To identify microbial taxons linked to the suppressive phenotype of soils, culture independent-based methods have been employed to analyze and compare microbial diversities in two different soils suppressive (respectively conducive) to either Fusarium wilt of flax or Rhizoctonia diseases of sugar beet. Metagen…

Adaptation inattendue de populations de Fusarium oxysporum et F. Dimerum au milieu aquatique urbain des conduites d'eau de bâtiments hospitaliers à Dijon et Nancyξ

National audience; Fusarium oxysporum et F. dimerum sont des champignons d'origine tellurique présents dans de nombreux écosystèmes terrestres mais ils ont été récemment détectés dans les systèmes de distribution d'eau de bâtiments hospitaliers. Une enquête épidémiologique incluant divers bâtiments hospitaliers sur différents sites, des complexes non-hospitaliers et des maisons individuelles a été menée pendant 2 ans dans deux villes françaises Dijon et Nancy. Les champignons ont été détectés seulement dans les canalisations de bâtiments hospitaliers et n'ont pas été détectés dans celles des autres immeubles ni dans l'eau du réseau urbain. Cette distribution surprenante s'explique par une c…

RésiLens: A research project aiming at identifying bruchid and root rot resistance sources in lentil (Lens culinaris)

National audience; Introducing legumes in modern cropping systems increases crop diversity and reduces the use of external inputs. It thus contributes to achieving sustainable food and feed production. Lentil (Lens culinaris Medik.) is an environmentally friendly, nutritious, protein-rich legume food crop. It is grown in a wide range of climatic conditions and fixes atmospheric nitrogen through bacterial symbiosis. In France, lentil cultivated areas are continuously increasing but are still largely inferior to the areas cultivated with cereals or other legumes such as pea and faba bean. One of the most serious problems for lentil cultivation is due to the insect pests known as seed beetles …

Microbial metacommunity: a METABAR coding approach

Microbial metacommunity: a METABAR coding approach. 2017 Scientific MEM days: Journées scientifiques MEM (Métaomiques et écosystèmes microbiens)

Involvement of various anastomosis groups of Rhizoctonia solani in the superficial blemishes on potato tubers

Ecological role of mycotoxins in wheat crop residues and consequences on the multitrophic interactions in the soil and further development of Fusarium graminearum

Format du poster : 21 X 29,7; absent

Utilisation et comparaison de méthodes de caractérisation moléculaire appliquées au genre Fusarium dans le cadre de la gestion de la collection de Microorganismes d’Intérêt Agro-Environnemental (MIAE)

Affiche; Les champignons microscopiques du genre Fusarium (phylum des Ascomycètes) sontresponsables de nombreuses maladies sur plantes (blé, tomate, palmier …) engendrant de fortespertes de rendement. Ils sont par ailleurs responsables de la production de mycotoxines quipeuvent avoir un impact non négligeable en santé animale et humaine.

Time dependent response of Rhizoctonia solani to mustard incorporation

SPE;EA communication orale, résumé; International audience

Identification des agents pathogènes du sol associés aux altérations superficielles du tubercule de pomme de terre

Biocontrol against the root parasitic plant species Phelipanche ramosa, branched broomrape of tobacco

The branched orobanche, Phelipanche ramosa L., is an obligate parasitic weed that has become, in France, a major agronomic problem in tobacco crops; yield and quality losses can be total and cause growers to reduce the producing area due to lack of available healthy plots or to abandon the crop. Because chemical management is not effective, biocontrol is certainly the alternative to propose but there is currently no biological control agent on the market to meet the expectations of producers and control this parasitic plant. Only a few microorganisms or molecules, are presented as potential and promising candidates in conclusion of scientific articles but the finalization is absent. A colle…

Interest of cultural practices to manage soilborne diseases

Identification des agents pathogènes du sol associés responsables des altérations superficielles du tubercule de pomme de terre

Pathogenic variability and genetic characterization of Rhizoctonia solani AG-2-2 causing crown and root rot on sugar beet in France

Root rot of pea : characterization and biocontrol of the soil-borne disease complex including Aphanomyces euteiches

Pea root rot is an increasing constraint in most of intensive pea cropping areas across the globe. The pathogenic complex responsible for the disease is composed of soil-borne fungal and oomycete pathogens such as Fusarium solani, F.oxysporum, F. avenaceum, F. culmorum, Rhizoctonia solani, Thielaviopsis basicola, Ascochyta pinodella, Pythium spp., Aphanomyces euteiches and probably others not yet identified. The diversity of their ecological and pathogenic properties can explain the worldwide dispersion of the disease and the absence of chemical, agricultural or genetic control tools. My research program aims at characterizing the parasitic consortium occurring in the North of France and at…

Impact de pratiques culturales sur les caractéristiques du sol

National audience; Plusieurs caractéristiques d'un sol ont été évaluées dans une parcelle expérimentale du Ctifl, suite à l'apport d'amendements organiques ou une biodésinfection (culture de radis fourrager, broyage et enfouissement, roulage, bâchage avec film plastique puis semis de carottes). Les résultats de la première année montrent que la biodésinfection a un impact marqué sur les communautés de microbes et de nématodes des sols, et que cette pratique réduit significativement la sensibilité des sols à la fonte de semis due à R. solani.

Characterization of field isolates of Trichoderma antagonistic towards Rhizoctonia solani

Rhizoctonia solani AG 2-2 is a phytopathogenic fungus causing damping off and root rot in sugar beet. The disease occurs in the form of patches. In monoculture, these patches are highly mobile and never occur at the same place where they were observed the previous year. The soil from within patches was found more suppressive towards the disease than soil from healthy area. Comparison of the microbial genetic structures between the different soil samples suggested that Trichoderma spp. were involved in the increased suppressiveness. Trichoderma spp. are well known for their antagonistic activities. The aim of the present study was to characterize sixteen Trichoderma isolates isolated from wi…

Impact d'amendements organiques sur la structure des communautés microbienne des sols : Choix des méthodes, validation et résultats

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…

Diversité des populations pathogènes de Fusarium oxysporum associés à la tomate en Algérie et sur le pourtour Méditerranéen

Fusarium oxysporum f. sp. cyclaminis: Identification of specific molecular markers for improved disease prevention

Fusarium oxysporum is a well-known soil-borne and ubiquitous fungus. The species includes a high diversity of saprophytic and pathogenic populations. The phytopathogenic ones are subdivided into formae speciales according to their host specificity. The forma specialis cyclaminis (FoCy) is causing Fusarium wilt only on cyclamen. It causes damages during the entire production line and can raise more than 50 % losses. FoCy is considered as the more destructive pathogen on cyclamen. To achieve a better understanding of the disease and a more efficient and eco-friendly way of control, we aim at finding a specific molecular marker allowing for early detection and quantification of the pathogen an…

Functionnal aspects of biodiversity towards biocontrol in agricultural soils

Fusarium oxysporum f. sp. melonis chez le melon, enseignements issus du projet VASCUlég

Fusarium wilt of melon, caused by Fusariumoxysporum f.sp. melonis (F.o.melonis),is still a major problem for growers. Aresearch programme was therefore developpedincluding 23 partners (VASCUlég).Analysing the situation revealed that thebioagressors are adapting, particularlyF.o.melonis race 1.2 whether it be on its ownor associated with other pathogens. Molecularcharacterisation of the F.o.melonisstrains shows strong genetic diversity.However, new sources of resistance to therace 1.2 of F.o.melonis were identified. Thisresult must be used in combination with acertain number of other complementarytechniques tested within the framework ofthe project, such as the cropping system,biofumigation,…

La santé des plantes passe par la santé des sols

Diversité génétique au sein de la forme spéciale cyclaminis de Fusarium oxysporum et recherche d’un marqueur spécifique

Le cyclamen est la 3e plante fleurie la plus vendue en France. Une des maladies dommageables de cette culture est la fusariose, causée par Fusarium oxysporum f. sp. cyclaminis (FoCy). Cette forme spéciale, inféodée au cyclamen n’est pas différenciable des autres formes spéciales et souches saprophytes. En se développant dans le xylème, FoCy entraîne la mort de la plante. Quand les symptômes externes apparaissent, la plante est condamnée. La lutte chimique est inefficace, la lutte variétale est inexistante, et les mesures prophylactiques sont difficilement applicables. Pour détecter le pathogène précocement et améliorer la lutte, nous nous sommes intéressés à sa diversité génétique. Pour cel…

Verticillium chez l'aubergine à travers le projet Vasculeg. Bioagresseurs présents et caractérisation (1ère partie)

Vascular wilt diseases of vegetable crops remain a major problem for eggplant growers in particular. After having used genetic resistance to Verticillium for several years, they are again confronted with the same problems. The VASCUleg project has led to a precise evaluation of the current situation on farms. Apart from the fungus that causes vascular disease, other pathogens are also present creating a whole range of bioagressors in different zones of production. The characterisation of isolated strains is quite complicated due to the complexity of Verticllium: new classification of Verticillium species, difficult identification of races and low aggressiveness of strains. V. dahliae is onl…

Orobanche rameuse du tabac (Phelipanche ramosa L.) : Identifier de nouvelles solutions conventionnelles et de biocontrôle

The branching broomrape, Phelipanche ramosa L. is an obligate parasitic plant, which in a few years became a major agronomic problem for tobacco crops in France. Two approaches, aiming at controlling broomrape were tested within the framework of the ELIOT project grouping Arvalis, the CT2F cooperative and the INRA center of Dijon. The first relates to sulfonylurea herbicides, including rimsulfuron and sulfosulfuron and a systemic herbicide of the cyclohexanediones family, clethodim. The results, although instructive, do not reflect an effective control of broomrape. The second approach deals with the search for soil-borne fungi that are pathogenic to broomrape. A large number of fungal stra…

Can Rhizoctonia solani disease be naturally controlled in a sugar beet field ?

International audience

Recherche de bioindicateurs d'impact du recyclage de produits résiduaires organiques en sols cultivés : lien avec la disponibilité de micropolluants organiques et métalliques

Impact of deoxynivalenol on soil microflora and fauna

F. graminearum is an important pathogen that causes head blight of cereal crops as wheat and maize. It also produces the mycotoxins (as Deoxynivalenol=DON) which are toxic to the human and animals. During the off season the pathogen survives in the soil, on weeds and in crop residues. A 24 weeks study was conducted in controlled conditions (microcosms of natural soil, 17 °C, 80% WHC) to test whether the presence of DON in the wheat crop residues gives competitive advantage to F. graminearum over the other soil microflora and fauna to survive and develop a primary inoculum during the decomposition process. This study was carried out in the presence of the whole soil biota (i.e. fungi, bacter…

Évaluation de bioindicateurs d'impact du recyclage de produits résiduaires organiques en sols cultivés: lien avec les modifications des caractéristiques physico-chimiques du sol

Communication orale, résumé étendu; absent