Research ArticleENVIRONMENTAL STRESS AND ADAPTATION TO STRESS
Open Access

Galactinol and Raffinose Constitute a Novel Function to Protect Plants from Oxidative Damage

Ayako Nishizawa, Yukinori Yabuta, Shigeru Shigeoka

Published July 2008. DOI: https://doi.org/10.1104/pp.108.122465

Article Figures & Data

Figures

  • Figure 1.
    Figure 1.

    Biosynthetic pathway of galactinol, raffinose, and stachyose in plants.

  • Figure 2.
    Figure 2.

    Expression of the HsfA2, GolS, and RS genes in the leaves of wild-type and Ox-HsfA2 plants. Four-week-old wild-type and Ox-HsfA2-6 plants grown under control growth conditions were used for the analysis. The procedures are described in the “Materials and Methods.” Relative amounts were normalized to Actin2 mRNA (=100%). Mean ± sd values from three experiments are shown. Asterisks indicate that the values are significantly different from those in the wild-type plants (P < 0.05).

  • Figure 3.
    Figure 3.

    Galactinol, raffinose, and stachyose contents in the leaves of wild-type and Ox-HsfA2 plants. Four-week-old wild-type and Ox-HsfA2-6 plants grown under control growth conditions were used for the analysis. The procedures are described in “Materials and Methods.” Mean ± sd values from three experiments are shown. Asterisks indicate that the values are significantly different from those in the wild-type plants (P < 0.05). FW, Fresh weight.

  • Figure 4.
    Figure 4.

    Effects of treatment with MV under control growth conditions on the transcript levels of HsfA2, GolS, and RS genes in the leaves of wild-type plants. Four-week-old wild-type plants grown in soil under control growth conditions were sprayed with MV (50 μm) in 0.1% Tween 20 (5 mL) and then transferred to control growth conditions (100 μE m−2 s−1) for 6 h. The procedures are described in “Materials and Methods.” Relative amounts were normalized to Actin2 mRNA (100%). Mean ± sd values from three experiments are shown. Asterisks indicate that the values are significantly different from those in the wild-type plants (P < 0.05).

  • Figure 5.
    Figure 5.

    Effects of treatment with MV under control growth conditions on total GolS activity and galactinol and raffinose contents in the leaves of wild-type plants. Four-week-old wild-type plants grown in soil under control growth conditions were sprayed with MV (50 μm) in 0.1% Tween 20 (5 mL) and then transferred to control growth conditions (100 μE m−2 s−1) for 6 h. A, Total GolS activities. B, Galactinol and raffinose contents. Mean ± sd values from three experiments are shown. Asterisks indicate that the values are significantly different from those in the wild-type plants (P < 0.05).

  • Figure 6.
    Figure 6.

    Effects of treatment with MV under high-light conditions on total GolS activity and galactinol and raffinose contents in the leaves of wild-type plants. Four-week-old wild-type plants grown in soil under control growth conditions were sprayed with MV (50 μm) in 0.1% Tween 20 (5 mL) and then transferred to high-light conditions (1,600 μE m−2 s−1) for 1 and 3 h. A, Total GolS activities. B, Galactinol and raffinose contents. Mean ± sd values from three experiments are shown. Asterisks indicate that the values are significantly different from those in the wild-type plants (P < 0.05).

  • Figure 7.
    Figure 7.

    The expression levels of the transgene and galactinol and raffinose contents in the leaves of Ox-GolS1 and Ox-GolS2 plants. Four-week-old wild-type, Ox-GolS1-11, Ox-GolS2-8, and Ox-GolS2-29 plants grown under control growth conditions were used for the analysis. The procedures are described in “Materials and Methods.” A, The transcript level of GolS1 or GolS2. Relative amounts were normalized to Actin2 mRNA (100%). B, Total GolS activities. C, Galactinol and raffinose contents. Mean ± sd values from three experiments are shown. Asterisks indicate that the values are significantly different from those in the wild-type plants (P < 0.05).

  • Figure 8.
    Figure 8.

    Effects of MV treatment under control growth conditions on AsA and GSH contents in the leaves of wild-type, Ox-GolS1, and Ox-GolS2 plants. Four-week-old wild-type, Ox-GolS1-11, Ox-GolS2-8, and Ox-GolS2-29 plants grown in soil under control growth conditions were sprayed with MV (50 μm) in 0.1% Tween 20 (5 mL) and then transferred to control growth conditions (100 μE m−2 s−1) for 6 h. The procedures are described in “Materials and Methods.” Mean ± sd values from three experiments are shown. Different letters indicate significant differences (P < 0.05).

  • Figure 9.
    Figure 9.

    Effects of MV treatment under control growth conditions on phenotype, PSII activity, CO2 fixation, and lipid hydroperoxide levels in the leaves of wild-type, Ox-GolS1, and Ox-GolS2 plants. Four-week-old wild-type, Ox-GolS1-11, Ox-GolS2-8, and Ox-GolS2-29 plants grown in soil under control growth conditions were sprayed with MV (50 μm) in 0.1% Tween 20 (5 mL) and then transferred to control growth conditions (100 μE m−2 s−1) for 6 h. A, Phenotypes of plants exposed to oxidative stress. B, Effects of the stress on PSII activity in wild-type, Ox-GolS1-11, Ox-GolS2-8, and Ox-GolS2-29 plants. The PSII activity (Fv/Fm) in the rosette leaves of Arabidopsis plants was determined at 25°C after adaptation to the dark for 30 min. C, CO2 fixation in wild-type, Ox-GolS1-11, Ox-GolS2-8, and Ox-GolS2-29 plants. D, Lipid peroxidation expressed as MDA content in wild-type, Ox-GolS1-11, Ox-GolS2-8, and Ox-GolS2-29 plants. Mean ± sd values from three experiments are shown. Asterisks indicate that the values are significantly different from those in the wild-type plants (P < 0.05).

  • Figure 10.
    Figure 10.

    Effects of MV treatment under high light on phenotype, PSII activity, and lipid hydroperoxide levels in wild-type, Ox-GolS1, and Ox-GolS2 plants. Four-week-old wild-type, Ox-GolS1-11, Ox-GolS2-8, and Ox-GolS2-29 plants grown in soil under control growth conditions were sprayed with MV (50 μm) in 0.1% Tween 20 (5 mL) and then transferred to high light (1,600 μE m−2 s−1) for 3 h. A, Phenotypes of plants exposed to oxidative stress. B, Effects of the stress on PSII activity in wild-type, Ox-GolS1-11, Ox-GolS2-8, and Ox-GolS2-29 plants. The PSII activity (Fv/Fm) in the rosette leaves of Arabidopsis plants was determined at 25°C after adaptation to the dark for 30 min. C, Lipid peroxidation expressed as MDA content in wild-type, Ox-GolS1-11, Ox-GolS2-8, and Ox-GolS2-29 plants. Mean ± sd values from three experiments are shown. Asterisks indicate that the values are significantly different from those in the wild-type plants (P < 0.05).

  • Figure 11.
    Figure 11.

    Effects of salinity on phenotype, PSII activity, and lipid hydroperoxide levels in wild-type, Ox-GolS1, and Ox-GolS2 plants. Four-week-old wild-type, Ox-GolS1-11, Ox-GolS2-8, and Ox-GolS2-29 plants grown in soil under control growth conditions were irrigated with NaCl solutions (100 mm) every 2 d for up to 14 d. A, Phenotypes of plants exposed to salinity. B, Effects of the stress on PSII activity in wild-type, Ox-GolS1-11, Ox-GolS2-8, and Ox-GolS2-29 plants. The PSII activity (Fv/Fm) in the rosette leaves of Arabidopsis plants was determined at 25°C after adaptation to the dark for 30 min. C, Lipid peroxidation expressed as MDA content in wild-type, Ox-GolS1-11, Ox-GolS2-8, and Ox-GolS2-29 plants. Mean ± sd values from three experiments are shown. Asterisks indicate that the values are significantly different from those in the wild-type plants (P < 0.05).

  • Figure 12.
    Figure 12.

    Hydroxyl radical-scavenging activities of galactinol and raffinose. The competitive inhibition of radical-induced formation of 2,3-dihydroxy-benzoic acid (DHBA) by adding increasingly higher concentrations of galactinol (circles) and raffinose (squares) was analyzed. The procedures are described in “Materials and Methods.” The values are means ± sd (n = 10).

Tables

  • Table I.

    Second-order rate constants for reactions between hydroxyl radicals and various compounds

    Data represent means ± sd (n = 10). ID50, 50% inhibitory dose.

    CompoundID50Rate Constant
    mmm−1 s−1
    Galactinol3.1 ± 0.37.8 ± 0.81 × 109
    Raffinose2.9 ± 0.28.4 ± 0.46 × 109
    Glc6.0 ± 0.44.0 ± 0.28 × 109
    Fru6.2 ± 0.43.8 ± 0.23 × 109
    Suc2.7 ± 0.28.9 ± 0.68 × 109
    Mannitol4.8 ± 0.25.0 ± 0.22 × 109
    Pro15.0 ± 0.91.6 ± 0.09 × 109
    AsA16.4 ± 1.31.5 ± 0.11 × 109
    GSH3.0 ± 0.28.1 ± 0.58 × 109

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Galactinol and Raffinose Constitute a Novel Function to Protect Plants from Oxidative Damage
Ayako Nishizawa, Yukinori Yabuta, Shigeru Shigeoka
Plant Physiology Jul 2008, 147 (3) 1251-1263; DOI: 10.1104/pp.108.122465
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