Silicon enhances suberization and lignification in roots of rice (Oryza sativa)

• Published in: Journal of experimental botany Vol. 62; no. 6; pp. 2001 - 2011
• Main Authors: Fleck, Alexander T., Nye, Thandar, Repenning, Cornelia, Stahl, Frank, Zahn, Marc, Schenk, Manfred K.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.03.2011
• Subjects: Biological and medical sciences; Cell walls; Fundamental and applied biological sciences. Psychology; Gene Expression Profiling; Gene Expression Regulation, Plant; Genes; Lignification; Lignin; Lignin - metabolism; Lipids - physiology; Nutrient solutions; Oryza - growth & development; Oryza - metabolism; Oxidation-Reduction; Plant roots; Plant Roots - growth & development; Plant Roots - metabolism; Plants; RESEARCH PAPER; Research Papers; Rice; Silicic Acid - metabolism; Silicon; Silicon - metabolism; Suberization; Lignin; Monocotyledones; Oxygen; Root; Silicic acid; Oryza sativa (rice); radial oxygen loss (ROL); Leucine; exodermis; Cereal crop; Protein; Oryza sativa; Suberin; Lignification; Gramineae; Angiospermae; Botany; Spermatophyta; Silicon; Suberization; leucine-rich repeat protein (LRR); Conductive tissue
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/erq392

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.