Defense-related signaling by interaction of arabinogalactan proteins and β-glucosyl Yariv reagent inhibits gibberellin signaling in barley aleurone cells

Kiyoshi Mashiguchi, Eriko Urakami, Morifumi Hasegawa, Kazutsuka Sanmiya, Ichiro Matsumoto, Isomaro Yamaguchi, Tadao Asami, Yoshihito Suzuki

    Research output: Contribution to journalArticlepeer-review

    32 Citations (Scopus)

    Abstract

    Arabinogalactan proteins (AGPs) are hydroxyproline-rich glycoproteins present at the plasma membrane and in extracellular spaces. A synthetic chemical, β-glucosyl Yariv reagent (β-GlcY), binds specifically to AGPs. We previously reported that gibberellin signaling is specifically inhibited by β-GlcY treatment in barley aleurone protoplasts. In the present study, we found that β-GlcY also inhibited gibberellin-induced programmed cell death (PCD) in aleurone cells. We examined the universality and specificity of the inhibitory effect of β-GlcY on gibberellin signaling using microarray analysis and found that β-GlcY was largely effective in repressing gibberellin-induced gene expression. In addition, >100 genes were up-regulated by β-GlcY in a gibberellin-independent manner, and many of these were categorized as defense-related genes. Defense signaling triggered by several defense system inducers such as jasmonic acid and a chitin elicitor could inhibit gibberellin-inducible events such as α-amylase secretion, PCD and expression of some gibberellin-inducible genes in aleurone cells. Furthermore, β-GlcY repressed the gibberellin-inducible Ca 2+-ATPase gene which is important for gibberellin-dependent gene expression, and induced known repressors of gibberellin signaling, two WRKY genes and a NAK kinase gene. These effects of β-GlcY were also phenocopied by the chitin elicitor and/or jasmonic acid. These results indicate that gibberellin signaling is under the regulation of defense-related signaling in aleurone cells. It is also probable that AGPs are involved in the perception of stimuli causing defense responses.

    Original languageEnglish
    Pages (from-to)178-190
    Number of pages13
    JournalPlant and Cell Physiology
    Volume49
    Issue number2
    DOIs
    Publication statusPublished - 2008 Feb

    Keywords

    • Aleurone layer
    • Arabinogalactan protein
    • Barley
    • Defense response
    • Gibberellin
    • Protoplast

    ASJC Scopus subject areas

    • Physiology
    • Plant Science
    • Cell Biology

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