Plant Cell Wall Differentiation (terrestrial plants, algae)

Cellulose, Lignin (click chemistry)

Developmental and ectopic lignin

Raman microspectroscopy and Raman Imaging

(a)biotic stress and impacts on cell wall

Plant Fibers (flax, hemp)

Plant Histology and Cytology

In situ hybridization (genes involved in Lignin pathway)

Plant Development, Anatomy and Embryology

My research career was built in two stages. The first covers the period 1996-2008 and focused on the study of early phenomena linked to the dedifferentiation of somatic cells then to their reprogramming into totipotent cells via descriptive approaches of parietal modifications (somatic embryogenesis of chicory). This took place in a team associated with INRAE at UdL. In this case, osmotic stress induced this dedifferentiation. Much of my work has focused on the identification, characterization and localization of Arabino-Galactan Proteins (AGP, matrix cell wall glycoproteins). Following my HDR, I was able to be an expert member for the evaluation of UMR 1098 BDPCP (May 2002, Montpellier, France). I was in charge of the evaluation of the PHIV platform (plant histology/histochemistry).

The second part of my work started in 2008 and continues today. It was during this period that I moved to Hors Classe Lecturer grade (Sept. 2010). I joined a new team (Plant Cell Wall Physiology) in January 2008, directed by Pr Simon Hawkins. I was able to prepare for this retraining thanks to a specific research period (without teaching) obtained in 2010 over a period of 2 years full-time 2011-2013. My research naturally refocused on the plant cell wall of fiber plants, especially with the integration of my new team now called Plant Fibers in the UMR CNRS Structural and Functional Glycobiology Unit of the University of Lille, in June 2015. Now, my research focuses on the dynamics of cell walls, namely their biosynthesis, their differentiation and their lignification (hypolignification of fibers, hyperlignification of wood). I chose to broaden my microscopy approaches by initiating a collaboration with the UMR CNRS LASIRE 8516 of the UdL in order to optimize and develop RAMAN or FT-IR vibrational microscopy techniques on plant histological sections (and not on shredded material, as is often the case in the literature). These spectroscopic tools were implemented for the first time in the UMR UGSF on plant study models. It seems important to me to build interdisciplinary bridges, and atomistic and spectral chemistry is one of them. I was able to acquire a bank of spectral profiles characteristic of the different types of walls according to their state of differentiation (primary or secondary, cellulosic or lignified), during the growth of flax (by estimating the part of the chronological aspects and the ontogenic aspects), under optimal culture conditions or under the effect of stress (gravitropic, injury). We wish to “image” these walls undergoing differentiation or remodeling, at the histological threshold. A standard 3-step study protocol (acquisition of spectra, multivariate analyses, chemical imaging) of all plant organs and tissues is therefore available in the laboratory (a publication is in progress on this subject). We are currently developing another spectral data processing pipeline that will allow us to build imagery this time, by principal components, which allows us to isolate the pure contributions. This year, the combined techniques of click chemistry (integration of molecules modified during the biosynthesis of parietal polymers in situ, then imaging using reporters) and RAMAN (spectral analysis of said polymer or neighboring walls) are in progress. Now, I am working on terrestrial fiber plants (flax, hemp) but also on aquatic micro-algae. These vibrational microscopy approaches will also be transmitted in teaching in an M2 course of the Master’s degree in Chemistry and Life Sciences (opening of M2 in September 2022).