Know more

About cookies

What is a "cookie"?

A "cookie" is a piece of information, usually small and identified by a name, which may be sent to your browser by a website you are visiting. Your web browser will store it for a period of time, and send it back to the web server each time you log on again.

Different types of cookies are placed on the sites:

  • Cookies strictly necessary for the proper functioning of the site
  • Cookies deposited by third party sites to improve the interactivity of the site, to collect statistics

Learn more about cookies and how they work

The different types of cookies used on this site

Cookies strictly necessary for the site to function

These cookies allow the main services of the site to function optimally. You can technically block them using your browser settings but your experience on the site may be degraded.

Furthermore, you have the possibility of opposing the use of audience measurement tracers strictly necessary for the functioning and current administration of the website in the cookie management window accessible via the link located in the footer of the site.

Technical cookies

Name of the cookie

Purpose

Shelf life

CAS and PHP session cookies

Login credentials, session security

Session

Tarteaucitron

Saving your cookie consent choices

12 months

Audience measurement cookies (AT Internet)

Name of the cookie

Purpose

Shelf life

atid

Trace the visitor's route in order to establish visit statistics.

13 months

atuserid

Store the anonymous ID of the visitor who starts the first time he visits the site

13 months

atidvisitor

Identify the numbers (unique identifiers of a site) seen by the visitor and store the visitor's identifiers.

13 months

About the AT Internet audience measurement tool :

AT Internet's audience measurement tool Analytics is deployed on this site in order to obtain information on visitors' navigation and to improve its use.

The French data protection authority (CNIL) has granted an exemption to AT Internet's Web Analytics cookie. This tool is thus exempt from the collection of the Internet user's consent with regard to the deposit of analytics cookies. However, you can refuse the deposit of these cookies via the cookie management panel.

Good to know:

  • The data collected are not cross-checked with other processing operations
  • The deposited cookie is only used to produce anonymous statistics
  • The cookie does not allow the user's navigation on other sites to be tracked.

Third party cookies to improve the interactivity of the site

This site relies on certain services provided by third parties which allow :

  • to offer interactive content;
  • improve usability and facilitate the sharing of content on social networks;
  • view videos and animated presentations directly on our website;
  • protect form entries from robots;
  • monitor the performance of the site.

These third parties will collect and use your browsing data for their own purposes.

How to accept or reject cookies

When you start browsing an eZpublish site, the appearance of the "cookies" banner allows you to accept or refuse all the cookies we use. This banner will be displayed as long as you have not made a choice, even if you are browsing on another page of the site.

You can change your choices at any time by clicking on the "Cookie Management" link.

You can manage these cookies in your browser. Here are the procedures to follow: Firefox; Chrome; Explorer; Safari; Opera

For more information about the cookies we use, you can contact INRAE's Data Protection Officer by email at cil-dpo@inrae.fr or by post at :

INRAE

24, chemin de Borde Rouge -Auzeville - CS52627 31326 Castanet Tolosan cedex - France

Last update: May 2021

Menu Logo Principal UB AgroSup CNRS

Home

Dïnia Cartry

Analysis of the taxonomic and functional diversity of fungi associated with branched broomrape, Phelipanche ramosa (L.) Pomel, parasitic plant of winter oilseed rape, Brassica napus (L.)

Defence on the 23 february at 14H in the conférence Room INRAE BFC

Composition of the jury

Mme Prigent-Combaret, Claire          Directrice de recherche, CNRS Lyon                Rapporteuse

Mme Le Corff, Josiane                      Professeur, Agrocampus Ouest-INHP, Angers Rapporteuse

Mme Poulin, Lucie                             Maître de conférences, Université de Nantes       Examinatrice

Mr Wipf, Daniel                                  Professeur, Université de Bourgogne                  Examinateur

Mme Gibot-Leclerc, Stéphanie          Maître de conférences, Institut Agro, Dijon                Codirectrice de thèse

Mr Steinberg, Christian                      Directeur de recherche, INRAE, Dijon               Directeur de thèse

Abstract

Phelipanche ramosa (L.) Pomel, the winter rapeseed broomrape Brassica napus L., is a parasitic weed that needs the host plant to grow. The parasitic lifestyle requires a close relationship with the host plant from the earliest stages of development. This weed has caused significant yield losses in oilseed rape crops in France for around thirty years. Conventional methods are not very effective against this parasitic plant. In this context, the objectives of my thesis were to acquire new knowledge relating to the development of P. ramosa interacting with B. napus and the associated microbiomes to identify regulatory mechanisms that could be implemented later for biocontrol compatible with the agro-ecological transition in which our agricultural production system must fit.

A bibliographic review first identified the main known regulatory factors and highlighted the need to focus on the microbiome associated with P. ramosa. The first stages of underground development of this parasitic plant are not only those on which microorganisms have a major role but they are also those that biocontrol must target. This is why a molecular analysis of the fungal diversity of this microbiome was carried out. Concretely, this analysis concerned three fundamentally interconnected microbiomes: that of P. ramosa, that of B. napus and that of the rhizospheric soil, the seat of interactions between all the partners of the pathosystem considered as a holobiont. The fungal microbiomes of P. ramosa and B. napus are built independently from that of the rhizospheric soil, have very different specific richness and are specific to the plant that hosts them. A focus on the genus Fusarium revealed a great specific diversity (21 species and species complexes) associated with P. ramosa, which augurs well for a particular relationship between this fungal genus and this plant species although we didn’t identify the mechanisms. This result nevertheless suggested that the genus Fusarium could harbor species or strains with pathogenic activity against P. ramosa. A Pasteurian analysis confirmed this hypothesis since more than 90% of the isolates obtained (125) from symptomatic P. ramosa are Fusarium belonging to 11 different species. The characterization of the pathogenicity of the isolates revealed that this function is distributed independently of the species within the genus Fusarium but that none of the 99 isolates tested can be considered as the specific pathogen of P. ramosa. The Fusarium community combines different modes of action of varying intensity depending on the strains. The ability to colonize seeds and tissues of P. ramosa, demonstrated by microscopic analysis, is one of the modes of action, in the same way as the inhibition of seed germination or the lethal necrotic activities on tubers and the buds of P. ramosa.

In conclusion, we propose to decipher the mechanisms of the particular interaction between the genus Fusarium and P. ramosa, to develop a bioassay allowing i) to characterize the infectious potential of plots to diagnose the risk of growing a host plant in a given plot and ii) to evaluate the performance of candidate strains for biocontrol. Insofar as the regulation of the development of P. ramosa cannot be ensured by a single strain but could be by a community, we propose to explore the strategy of conservation biocontrol. We also propose to exploit the potential of secondary metabolites produced by Fusarium to identify molecules that can participate in the biological control of conservation.