title: Silicon enhances suberization and lignification in roots of rice (Oryza sativa).
abstract: The beneficial element silicon (Si) may affect radial oxygen loss (ROL) of rice roots depending on suberization of the exodermis and lignification of sclerenchyma. Thus, the effect of Si nutrition on the oxidation power of rice roots, suberization and lignification was examined. In addition, Si-induced alterations of the transcript levels of 265 genes related to suberin and lignin synthesis were studied by custom-made microarray and quantitative Real Time-PCR. Without Si supply, the oxidation zone of 12 cm long adventitious roots extended along the entire root length but with Si supply the oxidation zone was restricted to 5 cm behind the root tip. This pattern coincided with enhanced suberization of the exodermis and lignification of sclerenchyma by Si supply. Suberization of the exodermis started, with and without Si supply, at 4-5 cm and 8-9 cm distance from the root tip (drt), respectively. Si significantly increased transcript abundance of 12 genes, while two genes had a reduced transcript level. A gene coding for a leucine-rich repeat protein exhibited a 25-fold higher transcript level with Si nutrition. Physiological, histochemical, and molecular-biological data showing that Si has an active impact on rice root anatomy and gene transcription is presented here.
authors.affiliation: Institute of Plant Nutrition, Faculty of Natural Sciences, Leibniz University Hannover, Herrenhäuser Str. 2, D-30419 Hannover, Germany. fleck@pflern.uni-hannover.de
authors.forename: Alexander T
authors.initials: AT
authors.lastname: Fleck
authors.forename: Thandar
authors.initials: T
authors.lastname: Nye
authors.forename: Cornelia
authors.initials: C
authors.lastname: Repenning
authors.forename: Frank
authors.initials: F
authors.lastname: Stahl
authors.forename: Marc
authors.initials: M
authors.lastname: Zahn
authors.forename: Manfred K
authors.initials: MK
authors.lastname: Schenk
mesh_terms: D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D008031:Lignin / Q000378:metabolism*; D008055:Lipids / Q000502:physiology*; D012275:Oryza / Q000254:growth & development / Q000378:metabolism*; D010084:Oxidation-Reduction; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism*; D012824:Silicic Acid / Q000378:metabolism*; D012825:Silicon / Q000378:metabolism
chemical_list: D008055:Lipids; D012824:Silicic Acid; C065875:suberin; D008031:Lignin; D012825:Silicon