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Tocopherol deficiency reduces sucrose export from salt-stressed potato leaves independently of oxidative stress and symplastic obstruction by callose.

Asensi-Fabado MA, Ammon A, Sonnewald U, Munné-Bosch S, Voll LM - J. Exp. Bot. (2014)

Bottom Line: Based on comprehensive gene expression analyses, we propose that enhanced responsiveness of SnRK1 target genes in mesophyll cells and altered redox regulation of phloem loading by SUT1 contribute to the attenuation of sucrose export from salt-stressed SXD:RNAi source leaves.In leaves of the SXD1:RNAi plants, sodium accumulation was diminished, while proline accumulation and pools of soluble antioxidants were increased.As supported by phytohormone contents, these differences seem to increase longevity and prevent senescence of SXD:RNAi leaves under salt stress.

View Article: PubMed Central - PubMed

Affiliation: University of Barcelona, Faculty of Biology, Department of Plant Biology, Diagonal Avenue 643, E-08028 Barcelona, Spain.

No MeSH data available.


Related in: MedlinePlus

Effects of salt treatment on the pool size of foliar soluble antioxidants in source leaves of StSXD1-silenced potato plants. Total glutathione (top panels) and total ascorbate content (bottom panels) are depicted. Left panels represent middle leaves (leaf 8); right panels represent bottom leaves (leaf 11). Samples were collected 19 days after the onset of treatments (salt stress, black bars; control, white bars) and data represent the mean ± SE of four individual plants. Data were analysed by t-test; significant differences between the transgenic lines and the wild type (WT) within a treatment are indicated by a black asterisk (control treatment) or a white asterisk (stress treatment), while diamonds indicate significant differences between control and salt stress within a genotype (P < 0.05).
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Figure 7: Effects of salt treatment on the pool size of foliar soluble antioxidants in source leaves of StSXD1-silenced potato plants. Total glutathione (top panels) and total ascorbate content (bottom panels) are depicted. Left panels represent middle leaves (leaf 8); right panels represent bottom leaves (leaf 11). Samples were collected 19 days after the onset of treatments (salt stress, black bars; control, white bars) and data represent the mean ± SE of four individual plants. Data were analysed by t-test; significant differences between the transgenic lines and the wild type (WT) within a treatment are indicated by a black asterisk (control treatment) or a white asterisk (stress treatment), while diamonds indicate significant differences between control and salt stress within a genotype (P < 0.05).

Mentions: The pool sizes of the major water-soluble antioxidants, ascorbate and glutathione, were elevated in middle and bottom source leaves of the transgenic plants compared to the wild type, in control conditions already (Fig. 7). Salt stress caused a decrease in total glutathione and, to a greater extent, total ascorbate content of middle wild-type leaves, while total glutathione and ascorbate contents were comparable in stressed and non-stressed bottom wild-type leaves. Ascorbate and glutathione pool sizes were also diminished in tocopherol-deficient plants upon salt treatment, but commonly both pools remained larger compared to wild-type controls (Fig. 7). The redox state of the ascorbate and glutathione pools were very similar across genotypes and treatments, with glutathione showing values higher than 90%, while ascorbate redox state ranged around 80% (Supplementary Figure S4). MDA levels were not significantly different between the genotypes irrespective of treatment and, in addition, MDA levels were not increased upon salt stress in the transgenic plants, indicating the absence of excessive lipid peroxidation in salt-stress conditions (Supplementary Figure S4).


Tocopherol deficiency reduces sucrose export from salt-stressed potato leaves independently of oxidative stress and symplastic obstruction by callose.

Asensi-Fabado MA, Ammon A, Sonnewald U, Munné-Bosch S, Voll LM - J. Exp. Bot. (2014)

Effects of salt treatment on the pool size of foliar soluble antioxidants in source leaves of StSXD1-silenced potato plants. Total glutathione (top panels) and total ascorbate content (bottom panels) are depicted. Left panels represent middle leaves (leaf 8); right panels represent bottom leaves (leaf 11). Samples were collected 19 days after the onset of treatments (salt stress, black bars; control, white bars) and data represent the mean ± SE of four individual plants. Data were analysed by t-test; significant differences between the transgenic lines and the wild type (WT) within a treatment are indicated by a black asterisk (control treatment) or a white asterisk (stress treatment), while diamonds indicate significant differences between control and salt stress within a genotype (P < 0.05).
© Copyright Policy - creative-commons
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4321552&req=5

Figure 7: Effects of salt treatment on the pool size of foliar soluble antioxidants in source leaves of StSXD1-silenced potato plants. Total glutathione (top panels) and total ascorbate content (bottom panels) are depicted. Left panels represent middle leaves (leaf 8); right panels represent bottom leaves (leaf 11). Samples were collected 19 days after the onset of treatments (salt stress, black bars; control, white bars) and data represent the mean ± SE of four individual plants. Data were analysed by t-test; significant differences between the transgenic lines and the wild type (WT) within a treatment are indicated by a black asterisk (control treatment) or a white asterisk (stress treatment), while diamonds indicate significant differences between control and salt stress within a genotype (P < 0.05).
Mentions: The pool sizes of the major water-soluble antioxidants, ascorbate and glutathione, were elevated in middle and bottom source leaves of the transgenic plants compared to the wild type, in control conditions already (Fig. 7). Salt stress caused a decrease in total glutathione and, to a greater extent, total ascorbate content of middle wild-type leaves, while total glutathione and ascorbate contents were comparable in stressed and non-stressed bottom wild-type leaves. Ascorbate and glutathione pool sizes were also diminished in tocopherol-deficient plants upon salt treatment, but commonly both pools remained larger compared to wild-type controls (Fig. 7). The redox state of the ascorbate and glutathione pools were very similar across genotypes and treatments, with glutathione showing values higher than 90%, while ascorbate redox state ranged around 80% (Supplementary Figure S4). MDA levels were not significantly different between the genotypes irrespective of treatment and, in addition, MDA levels were not increased upon salt stress in the transgenic plants, indicating the absence of excessive lipid peroxidation in salt-stress conditions (Supplementary Figure S4).

Bottom Line: Based on comprehensive gene expression analyses, we propose that enhanced responsiveness of SnRK1 target genes in mesophyll cells and altered redox regulation of phloem loading by SUT1 contribute to the attenuation of sucrose export from salt-stressed SXD:RNAi source leaves.In leaves of the SXD1:RNAi plants, sodium accumulation was diminished, while proline accumulation and pools of soluble antioxidants were increased.As supported by phytohormone contents, these differences seem to increase longevity and prevent senescence of SXD:RNAi leaves under salt stress.

View Article: PubMed Central - PubMed

Affiliation: University of Barcelona, Faculty of Biology, Department of Plant Biology, Diagonal Avenue 643, E-08028 Barcelona, Spain.

No MeSH data available.


Related in: MedlinePlus