Know more

Our use of cookies

Cookies are a set of data stored on a user’s device when the user browses a web site. The data is in a file containing an ID number, the name of the server which deposited it and, in some cases, an expiry date. We use cookies to record information about your visit, language of preference, and other parameters on the site in order to optimise your next visit and make the site even more useful to you.

To improve your experience, we use cookies to store certain browsing information and provide secure navigation, and to collect statistics with a view to improve the site’s features. For a complete list of the cookies we use, download “Ghostery”, a free plug-in for browsers which can detect, and, in some cases, block cookies.

Ghostery is available here for free: https://www.ghostery.com/fr/products/

You can also visit the CNIL web site for instructions on how to configure your browser to manage cookie storage on your device.

In the case of third-party advertising cookies, you can also visit the following site: http://www.youronlinechoices.com/fr/controler-ses-cookies/, offered by digital advertising professionals within the European Digital Advertising Alliance (EDAA). From the site, you can deny or accept the cookies used by advertising professionals who are members.

It is also possible to block certain third-party cookies directly via publishers:

Cookie type

Means of blocking

Analytical and performance cookies

Realytics
Google Analytics
Spoteffects
Optimizely

Targeted advertising cookies

DoubleClick
Mediarithmics

The following types of cookies may be used on our websites:

Mandatory cookies

Functional cookies

Social media and advertising cookies

These cookies are needed to ensure the proper functioning of the site and cannot be disabled. They help ensure a secure connection and the basic availability of our website.

These cookies allow us to analyse site use in order to measure and optimise performance. They allow us to store your sign-in information and display the different components of our website in a more coherent way.

These cookies are used by advertising agencies such as Google and by social media sites such as LinkedIn and Facebook. Among other things, they allow pages to be shared on social media, the posting of comments, and the publication (on our site or elsewhere) of ads that reflect your centres of interest.

Our EZPublish content management system (CMS) uses CAS and PHP session cookies and the New Relic cookie for monitoring purposes (IP, response times).

These cookies are deleted at the end of the browsing session (when you log off or close your browser window)

Our EZPublish content management system (CMS) uses the XiTi cookie to measure traffic. Our service provider is AT Internet. This company stores data (IPs, date and time of access, length of the visit and pages viewed) for six months.

Our EZPublish content management system (CMS) does not use this type of cookie.

For more information about the cookies we use, contact INRA’s Data Protection Officer by email at cil-dpo@inra.fr or by post at:

INRA
24, chemin de Borde Rouge –Auzeville – CS52627
31326 Castanet Tolosan CEDEX - France

Dernière mise à jour : Mai 2018

Menu Institut Sophia Agrobiotech Logo Marque Etat - République Française Logo_INRAE_noir Logo Université Côte d'Azur CNRS

Home page

Institut Sophia Agrobiotech

UMR INRA - Univ. Nice Sophia Antipolis - Cnrs

http://www.paca.inra.fr/institut-sophia-agrobiotech_eng/

Thesis defense - Dries AMEZIAN

Jeudi 20 Janvier - 9:00 - Visioconférence par ZOOM

Thesis defense
Dries AMEZIAN : "Use of the cell model of the fall armyworm, Spodoptera frugiperda, Sf9 cells to study the role of transcription factors on the expression of detoxification genes in response to xenobiotics."

En présentiel (limité) ou via Zoom :  https://inrae-fr.zoom.us/j/2943306815

ID de réunion : 294 330 6815

Président/te du jury :

  • Dr. Christine COUSTAU, DR CNRS, Sophia Antipolis

Rapporteurs/trices :

  • Pr. Emeritus Philip BATTERHAM, University of Melbourne, Australia
  • Dr. Jean-Philippe DAVID, CR CNRS, LECA, Grenoble

Examinateurs/trices :

  • Pr. Thomas VAN LEEUWEN, University of Ghent, Belgium

Directeur/trice de Thèse :

  • Dr. Ralf NAUEN, Dinstinguished Science Fellow, Bayer AG, Monheim, Germany
  • Dr. Gaëlle LE GOFF, CR INRAE, ISA, Sophia Antipolis

Abstract :

The fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera: Noctuidae) is a polyphagous pest feeding on numerous host-plants including important crops such as maize, rice and sorghum. It is one of the world’s most destructive pests which only recently invaded the eastern hemisphere incl. Asia. It provides exceptional economic damage in many crops across continents each year. Controlling this insect pest largely relies on the application of insecticides resulting in the development of resistance to many classes of synthetic insecticides. FAW has developed sophisticated adaptative mechanisms to eliminate xenobiotics (plant secondary metabolites and insecticides), among them, upregulation and duplication of genes expressing detoxification enzymes. They are often expressed at low basal level and induced when the insect is exposed to xenobiotics. While the role of these enzymes is well characterized in several pest insects, the transcription factors controlling their expression remain largely unexplored. The aim of my thesis was to determine the role of Cap'n'collar isoform C (CncC) and musculoaponeurotic fibrosarcoma (Maf) in S. frugiperda adaptation to xenobiotics employing an Sf9 cell model.

I used the cell model of S. frugiperda, the Sf9 cells and showed that CncC, Maf and several detoxification enzymes are induced after exposure to indole 3-carbinol (I3C), a glucosinolate found in Brassicaceae such as cabbage and broccoli, and methoprene (Mtp), a juvenile hormone (JH) mimic insecticide. I showed that transient overexpression of CncC and Maf in Sf9 cells was followed by overexpression of several detoxification genes. In order to characterize the role of these transcription factors in response to xenobiotics two types of stably transformed cell lines were established. The first cell lines overexpress CncC, Maf or both genes while the second were mutated for CncC (Knock-Out, KO) using the CRISPR/Cas9 technique. I performed cell viability assays (MTT) and used molecular probes in High Content Screening (HCS) to test whether the modification of the CncC:Maf pathway affected the ability of Sf9 cells to cope with toxic stress. The OE cell lines were more tolerant to I3C and Mtp than the control (wildtype Sf9 cell line), whereas the KO cell lines were more sensitive to these xenobiotics. The activities of some detoxification enzymes, carboxylesterases (CEs) and glutathione S-transferases (GSTs) toward model substrates were also increased in OE cell lines, whereas they were decreased in KO cell lines. Recent studies have suggested that activation of the CncC:Maf pathway is mediated by the production of reactive oxygen species (ROS) upon toxic stress. I therefore measured ROS production in Sf9 cells treated with I3C and Mtp. Both xenobiotics triggered in-cell ROS pulses although at limited levels in OE lines, unlike to KO lines for which ROS levels were more prominent. The use of an antioxidant suppressed the ROS pulses and restored tolerance of KO cells to I3C and Mtp. Finally, I compared the differentially expressed genes in the OE and KO cell lines in a transcriptomic analysis using RNA-seq. This allowed me to identify genes potentially controlled by CncC and Maf, most of them being detoxification genes with a role in insecticide resistance and metabolism of plant compounds as demonstrated in several studies. In conclusion, I present here new data in designed model Sf9 cell lines suggesting that the CncC:Maf signaling pathway plays a central role in FAW adaptation to toxic environmental compounds and insecticides. This knowledge helps to better understand pathways in detoxification gene expression and can be helpful to design next generation insect control measures by interfering with these pathways and detoxification gene expression.

Keywords:

Cap’n’collar isoform C (CncC), detoxification, resistance, plant adaptation, gene regulation