Les missions du poste
- Cell wall will be characterized using enzymatic fingerprinting approaches (LC-MS).
- Oligosaccharide profiling will be performed to assess cell wall remodeling .
- Monosaccharide analysis.
- Cloning of proWAKL7-WAKL7-GFP (underway in the lab) using biology molecular kits or using pUBIQUITIN promoter or other candidates
- GFP-Pull down will be realized as described in Desprez et al.,2007 and MS sequencing will be realized at the proteomic platformPAPPSO (Le Moulon).
- crispR-cas9 mutants
Le profil recherché
On recherche un étudiant motivé, curieux et passionné par la biologie avec des connaissances en biologie cellulaire, physiologie et génétique
Bienvenue chez Doctorat.Gouv.Fr
Établissement : Université Paris-Saclay GS Biosphera - Biologie, Société, Ecologie & Environnement, Ressources, Agriculture & Alimentation École doctorale : Sciences du Végétal : du gène à l'écosystème Laboratoire de recherche : IJPB - Institut Jean-Pierre Bourgin-Sciences du Végétal Direction de la thèse : Samantha VERNHETTES ORCID 0000000290948924 Début de la thèse : 2026-10-01 Date limite de candidature : 2026-05-06T23:59:59 La paroi cellulaire entoure chaque cellule végétale et est composée de cellulose, d'hémicelluloses et de pectines. Elle constitue également un réservoir de molécules de signalisation issues de la dégradation des polysaccharides tels que les pectines. Ce sujet dethèse, qui combine biologie moléculaire, physiologie cellulaire, génétique, glycochimie et imagerie de cellules vivantes, vise à étudier le rôle des récepteurs de type Wall-Associated Kinase Like (WAKL) dans la perception des xylo- et homogalacturonanes, deux composés pectiques. La nature de ces composés est contrôlée par l'activité de diverses pectine-méthylestérases (PMEs), capables de déméthylestérifier les xylo- et/ou homogalacturonanes, ce qui rend ces polysaccharides sensibles à l'activité des polygalacturonases.Ces dernières générent des petits fragments de la paroi cellulaire, appelés oligogalacturonides (OG). Ces OGs et les pectines dont ils sont issus peuvent être perçus par des récepteurs impliqués dans la régulation de l'intégrité de la paroi cellulaire.
L'objectif de ce projet sera d'identifier le rôle des différents membres de la famille WAKL et la nature précise de leurs substrats, une approche distincte de la plupart des équipes qui se concentrent principalement sur les voies de signalisation. De plus, il/elle caractérisera les complexes membranaires contenant des WAKL récepteurs, dont la fonction dépend probablement de l'écotype et joue un rôle clé dans le développement et l'immunité des plantes. Ces recherches approfondies permettront d'identifier de nouveaux bioproduits, notamment des molécules associées à la paroi cellulaire, et de développer de nouvelles stratégies de biocontrôle pour améliorer l'adaptation des plantes aux stress abiotiques et biotiques. Plant cell walls, which encase each cell, are composed of cellulose microfibrils that interact with matrix polysaccharides such ashemicelluloses and pectins. These cell walls are highly dynamic structures that are continuously and actively remodeled throughout allstages of plant development and in response to abiotic and biotic stresses. Plants can sense modifications to their cell walls caused byenvironmental changes or pathogen attacks (Baez et al., 2022). This monitoring of cell wall integrity is mediated by kinase receptors located in the plasma membrane, such as Wall-Associated Kinases (WAKs) and their close homologs, WAK-like proteins (WAKLs)(Verica and He, 2002; Kohorn and Kohorn, 2012; Huerta et al., 2023). In our laboratory, we are studying the pectin methylesterase 17(PME17) capable of demethylesterifying pectins (Sénéchal et al., 2014). PME17 belongs to a multigenic family of 68 members andshows the highest expression when the plant is attacked by Botrytis cinerea, a necrotrophic fungus, and upon ageing. Our preliminary results suggest that PME17 activity is detected by the WAKL7 receptor, which works with coreceptors to translate this signal into the cell.Our results also suggest that the WAKL7 protein in Col-0 is non-functional, while the Ws-WAKL7 variant may be involved in sensing changes in cell wall integrity and regulating plant development and defense.
Using CrispR-Cas9 approach, cloning technique and microscopy, the PhD student will be in charge in producing genetic resources to compare the functional role of WAKL7 in Ws-4 and Col-0 Arabidopsis accessions. He/She will also identify the WAKL7 co-receptors aswell as their pectic ligand(s) by using biochemistry and analytical chemistry approaches The goal of this PhD project is to characterize the ecotype dependent role of WAKL7-centered receptor network and the initial signalthat triggers the adaptation of the plants.
The PhD objectives are to
1. Characterize the WAKL7 co-receptors and their pectic ligand(s)
2. Advance our understanding of the dynamics of the WAKL7-centered receptor network in the plasma membrane as well as theassociated signaling pathway
- Laser scanning confocal microscopy and spinning disk - ImageJ software to analyze pictures.
L'objectif de ce projet sera d'identifier le rôle des différents membres de la famille WAKL et la nature précise de leurs substrats, une approche distincte de la plupart des équipes qui se concentrent principalement sur les voies de signalisation. De plus, il/elle caractérisera les complexes membranaires contenant des WAKL récepteurs, dont la fonction dépend probablement de l'écotype et joue un rôle clé dans le développement et l'immunité des plantes. Ces recherches approfondies permettront d'identifier de nouveaux bioproduits, notamment des molécules associées à la paroi cellulaire, et de développer de nouvelles stratégies de biocontrôle pour améliorer l'adaptation des plantes aux stress abiotiques et biotiques. Plant cell walls, which encase each cell, are composed of cellulose microfibrils that interact with matrix polysaccharides such ashemicelluloses and pectins. These cell walls are highly dynamic structures that are continuously and actively remodeled throughout allstages of plant development and in response to abiotic and biotic stresses. Plants can sense modifications to their cell walls caused byenvironmental changes or pathogen attacks (Baez et al., 2022). This monitoring of cell wall integrity is mediated by kinase receptors located in the plasma membrane, such as Wall-Associated Kinases (WAKs) and their close homologs, WAK-like proteins (WAKLs)(Verica and He, 2002; Kohorn and Kohorn, 2012; Huerta et al., 2023). In our laboratory, we are studying the pectin methylesterase 17(PME17) capable of demethylesterifying pectins (Sénéchal et al., 2014). PME17 belongs to a multigenic family of 68 members andshows the highest expression when the plant is attacked by Botrytis cinerea, a necrotrophic fungus, and upon ageing. Our preliminary results suggest that PME17 activity is detected by the WAKL7 receptor, which works with coreceptors to translate this signal into the cell.Our results also suggest that the WAKL7 protein in Col-0 is non-functional, while the Ws-WAKL7 variant may be involved in sensing changes in cell wall integrity and regulating plant development and defense.
Using CrispR-Cas9 approach, cloning technique and microscopy, the PhD student will be in charge in producing genetic resources to compare the functional role of WAKL7 in Ws-4 and Col-0 Arabidopsis accessions. He/She will also identify the WAKL7 co-receptors aswell as their pectic ligand(s) by using biochemistry and analytical chemistry approaches The goal of this PhD project is to characterize the ecotype dependent role of WAKL7-centered receptor network and the initial signalthat triggers the adaptation of the plants.
The PhD objectives are to
1. Characterize the WAKL7 co-receptors and their pectic ligand(s)
2. Advance our understanding of the dynamics of the WAKL7-centered receptor network in the plasma membrane as well as theassociated signaling pathway
- Laser scanning confocal microscopy and spinning disk - ImageJ software to analyze pictures.
Publiée le 15/04/2026 - Réf : 42122f9169cfa372b4d68c6e17e478e7
