Periodic Reporting for period 4 - WallWatchers (Plant cell wall communication and remodelling: the wall watchers.) Periodo di rendicontazione: 2022-01-01 al 2023-06-30 Sintesi del contesto e degli obiettivi generali del progetto One of the biggest challenges nowadays is to achieve sufficient, sustainable and environmentally friendly crop production. The cell wall system in plants plays a key role in coordinating plant growth, plant reproduction and development, and it also serves as a link with the outside world. This ability of plants to sense changes in the composition and mechanical properties of the cell wall can only be explained by the existence of sensing and signaling systems that communicate the outside with the inside of the cell. Excellent candidates for sensing and integrating changes in the cell wall are cell-wall anchored and receptor proteins at the cell surface. These receptors work as modulators being able to read and shape the chemical and mechanical properties of the cell wall. However, despite the key role of the cell wall in plant growth, development, pathogen protection and other interactions with the environment, very little is known about how the cell wall properties are read and modified to meet the wall architecture and chemical composition required to support and sustain cell function. The aim of my laboratory in the course of this Action has been to uncover novel molecular mechanisms integrating the role of protein-ligand interactions in the context of cell wall signalling and patterning to better understand how plants drive growth, reproduction, defense, development and interactions with the environment. To do that we have used an integrated approach, using detailed atomic models with quantitative biochemistry, precise plant phenotypes and super resolution microscopy. My team and I proposed a project on deciphering the molecular insights of cell-wall signalling and patterning which offers the opportunity to study a fundamental biological process with many open questions, multiple challenges and potential applications in crop science. Lavoro eseguito dall’inizio del progetto fino alla fine del periodo coperto dalla relazione e principali risultati finora ottenuti During the Action my laboratory has dissected the 3D structure of two cell-wall sensors that are key components in controlling pollen tube cell expansion and plant reproduction. We have also dissected the molecular mechanisms in vitro and in planta on how these cell-wall sensors perceive the chemical ligand to coordinate the patterning of cell-wall polymers to allow for cell expansion and plant reproduction. Our structural, biochemical and physiological work uncovers the unique dual signaling and structural role of the a family of small proteins to shape the cell wall assembly during cell expansion and morphogenesis and may provide inspiration for novel mechanisms of protein-polysaccharide interactions to define tissue architecture and properties. Progressi oltre lo stato dell’arte e potenziale impatto previsto (incluso l’impatto socioeconomico e le implicazioni sociali più ampie del progetto fino ad ora) This Project has set important technological milestones and made several breakthrough discoveries in the field of plant biology and cell wall sensing and integrity. For the scientific community we have set a new expression and purification protocol to produce folded small cys-rich proteins. Similarly, we have also established solid methods to measure binding with carbohydrates using different methods as well as measuring different rheology properties of artificial cell walls. We have also uncovered the recognition mechanisms of a family of peptides by two distinct families (Moussu et al., PNAS, 2020), we have also uncovered how plant cells molecularly pattern their cell wall to sustain cell expansion (Moussu et al., Acta D, 2018; Moussu, Lee et al., Science, 2023; Schoenaers, Lee et al.,, Nat Plants, in press) and we have discovered new cell wall receptors that are involved in enhancing plant immunity against several pathogens. In addition, we have dissected molecularly distinct receptor-peptide recognition mechanisms that ensure signal specificity in cells (Roman, Jímenez-Sandoval et al., Nat Commns, 2021) and we have contributed to shed light in multiple cell wall and cell signaling pathways through different collaborations, promoting a synergistic scientific network. 3D structure of the plant LRX-RALF4 cell-wall sensor complex
