Limits...
Characterisation of Lipid Changes in Ethylene-Promoted Senescence and Its Retardation by Suppression of Phospholipase Dδ in Arabidopsis Leaves.

Jia Y, Li W - Front Plant Sci (2015)

Bottom Line: Lipid profiling revealed that ethylene caused a decrease in all lipids levels, except phosphatidic acid (PA), caused increases in the ratios of digalactosyl diglyceride/monogalactosyl diglyceride (MGDG) and phosphatidylcholine (PC)/phosphatidylethanolamine (PE), and caused degradation of plastidic lipids before that of extraplastidic lipids in wild-type plants.The accelerated degradation of plastidic lipids during ethylene-promoted senescence in wild-type plants was attenuated in PLDδ-KO plants.The integrity of the cell membrane in PLDδ-KO plants facilitated maintenance of the membrane function and of the proteins associated with the membrane.

View Article: PubMed Central - PubMed

Affiliation: Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences Kunming, China.

ABSTRACT
Ethylene and abscisic acid (ABA) both accelerate senescence of detached Arabidopsis leaves. We previously showed that suppression of Phospholipase Dδ (PLDδ) retarded ABA-promoted senescence. Here, we report that ethylene-promoted senescence is retarded in detached leaves lacking PLDδ. We further used lipidomics to comparatively profile the molecular species of membrane lipids between wild-type and PLDδ-knockout (PLDδ-KO) Arabidopsis during ethylene-promoted senescence. Lipid profiling revealed that ethylene caused a decrease in all lipids levels, except phosphatidic acid (PA), caused increases in the ratios of digalactosyl diglyceride/monogalactosyl diglyceride (MGDG) and phosphatidylcholine (PC)/phosphatidylethanolamine (PE), and caused degradation of plastidic lipids before that of extraplastidic lipids in wild-type plants. The accelerated degradation of plastidic lipids during ethylene-promoted senescence in wild-type plants was attenuated in PLDδ-KO plants. No obvious differences in substrate and product of PLDδ-catalyzed phospholipid hydrolysis were detected between wild-type and PLDδ-KO plants, which indicated that the retardation of ethylene-promoted senescence by suppressing PLDδ might not be related to the role of PLDδ in catalyzing phospholipid degradation. In contrast, higher plastidic lipid content, especially of MGDG, in PLDδ-KO plants was crucial for maintaining photosynthetic activity. The lower relative content of PA and higher PC/PE ratio in PLDδ-KO plants might contribute to maintaining cell membrane integrity. The integrity of the cell membrane in PLDδ-KO plants facilitated maintenance of the membrane function and of the proteins associated with the membrane. Taking these findings together, higher plastidic lipid content and the integrity of the cell membrane in PLDδ-KO plants might contribute to the retardation of ethylene-promoted senescence by the suppression of PLDδ.

No MeSH data available.


Related in: MedlinePlus

Retardation of abscisic acid (ABA)-promoted senescence was compared between wassilewskija (WS) and PLDδ-KO detached leaves. Leaves detached from WS and PLDδ-KO plants were treated with sterile 50 μM ethephon for 5 days. (A) Yellow coloration (left) or low Fv/Fm values for variable fluorescence (right) indicated senescence. The color bar on the bottom indicates Fv/Fm values. (B) Chlorophyll content (top) and cell death rate (bottom) of leaves from WS and PLDδ-KO plants. FW, fresh weight. Values are means ± SD (n = 5). Values with different letters are significantly different (p < 0.05). Annotation: data of “#” column is from Jia et al. (2013).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4663248&req=5

Figure 1: Retardation of abscisic acid (ABA)-promoted senescence was compared between wassilewskija (WS) and PLDδ-KO detached leaves. Leaves detached from WS and PLDδ-KO plants were treated with sterile 50 μM ethephon for 5 days. (A) Yellow coloration (left) or low Fv/Fm values for variable fluorescence (right) indicated senescence. The color bar on the bottom indicates Fv/Fm values. (B) Chlorophyll content (top) and cell death rate (bottom) of leaves from WS and PLDδ-KO plants. FW, fresh weight. Values are means ± SD (n = 5). Values with different letters are significantly different (p < 0.05). Annotation: data of “#” column is from Jia et al. (2013).

Mentions: Leaves detached from WS plants started yellowing 1 day after treatment and turned almost completely yellow 5 days after incubation in 50 μM ethephon under light. In contrast, most parts of the PLDδ-KO leaves were still green after the 5-day ethylene treatment, which indicated a much slower senescence process in the PLDδ-deficient leaves (Figure 1A, top). Consistent with the visible yellowing, the photochemical quantum efficiency of the photosystem II (PS II) reaction center (Fv/Fm) in ethylene-treated leaves was much lower in WS plants than in PLDδ-KO mutants (Figure 1A, bottom). Measurements of chlorophyll content showed that chlorophyll was lost more quickly from WS leaves, diminishing by 37% after 5 days, whereas PLDδ-KO mutant leaves lost just 20% of their chlorophyll content upon treatment with ethylene (Figure 1B, top). Data on cell viability showed that the rate of cell death was significantly higher in the WS leaves during the ethylene-promoted senescence process, as measured by Evans blue staining (Figure 1B, bottom). These results indicate that the suppression of PLDδ retarded, to some extent, ethylene-promoted senescence.


Characterisation of Lipid Changes in Ethylene-Promoted Senescence and Its Retardation by Suppression of Phospholipase Dδ in Arabidopsis Leaves.

Jia Y, Li W - Front Plant Sci (2015)

Retardation of abscisic acid (ABA)-promoted senescence was compared between wassilewskija (WS) and PLDδ-KO detached leaves. Leaves detached from WS and PLDδ-KO plants were treated with sterile 50 μM ethephon for 5 days. (A) Yellow coloration (left) or low Fv/Fm values for variable fluorescence (right) indicated senescence. The color bar on the bottom indicates Fv/Fm values. (B) Chlorophyll content (top) and cell death rate (bottom) of leaves from WS and PLDδ-KO plants. FW, fresh weight. Values are means ± SD (n = 5). Values with different letters are significantly different (p < 0.05). Annotation: data of “#” column is from Jia et al. (2013).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663248&req=5

Figure 1: Retardation of abscisic acid (ABA)-promoted senescence was compared between wassilewskija (WS) and PLDδ-KO detached leaves. Leaves detached from WS and PLDδ-KO plants were treated with sterile 50 μM ethephon for 5 days. (A) Yellow coloration (left) or low Fv/Fm values for variable fluorescence (right) indicated senescence. The color bar on the bottom indicates Fv/Fm values. (B) Chlorophyll content (top) and cell death rate (bottom) of leaves from WS and PLDδ-KO plants. FW, fresh weight. Values are means ± SD (n = 5). Values with different letters are significantly different (p < 0.05). Annotation: data of “#” column is from Jia et al. (2013).
Mentions: Leaves detached from WS plants started yellowing 1 day after treatment and turned almost completely yellow 5 days after incubation in 50 μM ethephon under light. In contrast, most parts of the PLDδ-KO leaves were still green after the 5-day ethylene treatment, which indicated a much slower senescence process in the PLDδ-deficient leaves (Figure 1A, top). Consistent with the visible yellowing, the photochemical quantum efficiency of the photosystem II (PS II) reaction center (Fv/Fm) in ethylene-treated leaves was much lower in WS plants than in PLDδ-KO mutants (Figure 1A, bottom). Measurements of chlorophyll content showed that chlorophyll was lost more quickly from WS leaves, diminishing by 37% after 5 days, whereas PLDδ-KO mutant leaves lost just 20% of their chlorophyll content upon treatment with ethylene (Figure 1B, top). Data on cell viability showed that the rate of cell death was significantly higher in the WS leaves during the ethylene-promoted senescence process, as measured by Evans blue staining (Figure 1B, bottom). These results indicate that the suppression of PLDδ retarded, to some extent, ethylene-promoted senescence.

Bottom Line: Lipid profiling revealed that ethylene caused a decrease in all lipids levels, except phosphatidic acid (PA), caused increases in the ratios of digalactosyl diglyceride/monogalactosyl diglyceride (MGDG) and phosphatidylcholine (PC)/phosphatidylethanolamine (PE), and caused degradation of plastidic lipids before that of extraplastidic lipids in wild-type plants.The accelerated degradation of plastidic lipids during ethylene-promoted senescence in wild-type plants was attenuated in PLDδ-KO plants.The integrity of the cell membrane in PLDδ-KO plants facilitated maintenance of the membrane function and of the proteins associated with the membrane.

View Article: PubMed Central - PubMed

Affiliation: Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences Kunming, China.

ABSTRACT
Ethylene and abscisic acid (ABA) both accelerate senescence of detached Arabidopsis leaves. We previously showed that suppression of Phospholipase Dδ (PLDδ) retarded ABA-promoted senescence. Here, we report that ethylene-promoted senescence is retarded in detached leaves lacking PLDδ. We further used lipidomics to comparatively profile the molecular species of membrane lipids between wild-type and PLDδ-knockout (PLDδ-KO) Arabidopsis during ethylene-promoted senescence. Lipid profiling revealed that ethylene caused a decrease in all lipids levels, except phosphatidic acid (PA), caused increases in the ratios of digalactosyl diglyceride/monogalactosyl diglyceride (MGDG) and phosphatidylcholine (PC)/phosphatidylethanolamine (PE), and caused degradation of plastidic lipids before that of extraplastidic lipids in wild-type plants. The accelerated degradation of plastidic lipids during ethylene-promoted senescence in wild-type plants was attenuated in PLDδ-KO plants. No obvious differences in substrate and product of PLDδ-catalyzed phospholipid hydrolysis were detected between wild-type and PLDδ-KO plants, which indicated that the retardation of ethylene-promoted senescence by suppressing PLDδ might not be related to the role of PLDδ in catalyzing phospholipid degradation. In contrast, higher plastidic lipid content, especially of MGDG, in PLDδ-KO plants was crucial for maintaining photosynthetic activity. The lower relative content of PA and higher PC/PE ratio in PLDδ-KO plants might contribute to maintaining cell membrane integrity. The integrity of the cell membrane in PLDδ-KO plants facilitated maintenance of the membrane function and of the proteins associated with the membrane. Taking these findings together, higher plastidic lipid content and the integrity of the cell membrane in PLDδ-KO plants might contribute to the retardation of ethylene-promoted senescence by the suppression of PLDδ.

No MeSH data available.


Related in: MedlinePlus