Month Flat Week Day
Tuesday, September 19, 2023 16:30 - 17:30
1 Hour
UPSC Seminar

Edouard Pesquet
Associate Professor at Stockholm University, Stockholm, Sweden

Title: Unravelling the functions behind differences in lignin chemistry between cell types for plant development and environmental resiliance

Host: Stéphane Verger

The biopolymer lignin, deposited in the cell walls of vascular cells, is essential for plant long-distance water conduction, structural support and resistance to biotic and abiotic constraints. Independently of the plant species, the cell wall layers of each vascular cell type contain specific lignin chemistries differing in aromatic substitutions and aliphatic functions. Yet, both the spatial control and the biological function of this conserved and specific lignin chemistry for the cell wall layers of each vascular cell type remain unclear. This lack of clarity is due to our current methodologies for analyzing lignin mainly restricted to ground or ball-milled samples that averages out the spatial and developmental differences between each cell type. We thus optimized in situ quantitative chemical imaging methods to determine changes in lignin structure, concentration and/or composition at subcellular levels in whole plant biopsies using direct methods such as Raman spectroscopy, UV fluorescence and histochemistry [1-4]. We combined functional genetics, using a collection of mutants in Arabidopsis and poplar, with in situ quantitative chemical imaging to unravel the molecular mechanisms controlling the spatial accumulation of specific lignin chemistries in distinct cell types and its impact on each cellular function. We found that specific lignin chemistries accumulated dynamically and differently during the maturation of each cell type and morphotype, changing the concentration and composition of their lignin [5]. We found that lignin spatial accumulation in each cell type and cell wall layer depended on different paralog combination of phenol oxidizing enzymes exhibiting substrate specificities [6-7]. We lastly showed using multivariate analyses that modifying this specific lignin chemistry impaired the cell wall biomechanics of each cell type and morphotype, and consequently plant growth and its response to abiotic constraints [5-6]. Altogether, we show that lignin chemistry is differently controlled for each cell type and morphotype during their maturation to dynamically adjust their function in response to developmental and environmental constraints.

[1] Decou R, Serk H, Ménard D, Pesquet E. Methods Mol. Biol. 1544, 233-247, 2017.
[2] Blaschek L, Champagne A, Dimotakis C, Nuoendagula, Decou R, Hishiyama S, Kratzer S, Kajita S, Pesquet E. Front Plant Sci. 11, 109, 2020.
[3] Blaschek L, Nuoendagula, Bacsik Z, Kajita S, Pesquet E. ACS Sustainable Chem. Eng. 8, 4900–4909, 2020.
[4] Yamamoto M, Blaschek L, Subbotina E, Kajita S, Pesquet E. ChemSusChem. 13, 4400-4408, 2020.
[5] Ménard D, Blaschek L, Kriechbaum K, Lee CC, Serk H, Lyubartsev A, Bacsik Z, Bergström L, Mathew A, Kajita S, Pesquet E. The Plant Cell 34, 4877-96, 2022.
[6] Blaschek L, Murozuka E, Ménard D, Pesquet E. The Plant Cell 35, 889-909, 2023.
[7] Blaschek L, Pesquet E. Front Plant Sci. 12,754601, 2021.