title: A mechanism for localized lignin deposition in the endodermis.
abstract: The precise localization of extracellular matrix and cell wall components is of critical importance for multicellular organisms. Lignin is a major cell wall modification that often forms intricate subcellular patterns that are central to cellular function. Yet the mechanisms of lignin polymerization and the subcellular precision of its formation remain enigmatic. Here, we show that the Casparian strip, a lignin-based, paracellular diffusion barrier in plants, forms as a precise, median ring by the concerted action of a specific, localized NADPH oxidase, brought into proximity of localized peroxidases through the action of Casparian strip domain proteins (CASPs). Our findings in Arabidopsis provide a simple mechanistic model of how plant cells regulate lignin formation with subcellular precision. We speculate that scaffolding of NADPH oxidases to the downstream targets of the reactive oxygen species (ROS) that they produce might be a widespread mechanism to ensure specificity and subcellular precision of ROS action within the extracellular matrix.
authors.affiliation: Department of Plant Molecular Biology, University of Lausanne, UNIL-Sorge, Biophore Building, 1015 Lausanne, Switzerland.
authors.forename: Yuree
authors.initials: Y
authors.lastname: Lee
authors.forename: Maria C
authors.initials: MC
authors.lastname: Rubio
authors.forename: Julien
authors.initials: J
authors.lastname: Alassimone
authors.forename: Niko
authors.initials: N
authors.lastname: Geldner
mesh_terms: D017360:Arabidopsis / Q000737:chemistry / Q000166:cytology* / Q000201:enzymology* / Q000378:metabolism; D001692:Biological Transport; D002473:Cell Wall / Q000378:metabolism; D004058:Diffusion; D006861:Hydrogen Peroxide / Q000378:metabolism; D008031:Lignin / Q000378:metabolism*; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D058105:Polymerization; D013481:Superoxides / Q000378:metabolism
chemical_list: D010940:Plant Proteins; D013481:Superoxides; D008031:Lignin; D006861:Hydrogen Peroxide; D019255:NADPH Oxidases