Glucosamine causes overproduction of reactive oxygen species, leading to repression of hypocotyl elongation through a hexokinase-mediated mechanism in Arabidopsis

Hyun Woo Ju, Eun Ji Koh, Sun Hee Kim, Kang Il Kim, Hojoung Lee, Suk Whan Hong

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    23 Citations (Scopus)

    Abstract

    Glucosamine (GlcN) is a naturally occurring amino-sugar that is synthesized by amidation of fructose-6-phosphate. Although a number of reports have examined the biological effects of GlcN on insulin resistance in mammalian systems, little is known about its effects on plant growth. In this study, we have shown that exogenous GlcN inhibits hypocotyl elongation in Arabidopsis, whereas glucose and its analogs alleviate this inhibitory effect. The hexokinase (HXK)-specific inhibitor mannoheptulose also restored hypocotyl elongation. The gin2-1 mutants with an alteration in AtHXK1 exhibited higher tolerance to GlcN. We also found that GlcN induces a significant increase in the production of reactive oxygen species (ROS). In addition, the GlcN-mediated inhibition of hypocotyl elongation was relieved by reducing agents such as ascorbic acid and glutathione. GlcN treatment resulted in significant induction of expression of GST1, GST2 and GST6, which are marker genes for ROS production. The gin2 mutation also represses the ROS production and the GST2 induction by GlcN treatment. Taken together, these results provide evidence that GlcN induces HXK-mediated induction of oxidative stress, leading to growth repression in Arabidopsis thaliana.

    Original languageEnglish
    Pages (from-to)203-212
    Number of pages10
    JournalJournal of Plant Physiology
    Volume166
    Issue number2
    DOIs
    Publication statusPublished - 2009 Jan 30

    Bibliographical note

    Funding Information:
    This research was supported by a grant to S.W.H. from the Korea Science and Engineering Foundation (APSRC, R11-2001-092-01008-0), the Agricultural R&D Promotion Center (106074-03-2) and the Korea Research Foundation (C00545). H.W.J. is supported by a fellowship from the Korea Research Foundation (S2-2006-000-00460-1).

    Keywords

    • Glucosamine
    • Glutathione-S-transferase
    • Hexokinase
    • Reactive oxygen species
    • gin2-1

    ASJC Scopus subject areas

    • Physiology
    • Agronomy and Crop Science
    • Plant Science

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