Ferroptosis is an oxidative iron-dependent form of cell death recently described in eukaryotic or... more Ferroptosis is an oxidative iron-dependent form of cell death recently described in eukaryotic organisms like animals, plants and parasites. Here we report that a similar process takes place in the cyanobacterium Synechocystis sp. PCC 6803 in response to heat stress. After a heat shock, Synechocystis cells undergo a cell death pathway that can be suppressed by canonical ferroptosis inhibitors or by external addition of calcium, glutathione or ascorbic acid. Moreover, as described for eukaryotic cells ferroptosis, this pathway is characterized by an early depletion of antioxidants, and by lipid peroxidation. As in general prokaryotes membranes contain poorly oxidizable saturated or monounsaturated lipid molecules, it was thought that they were not susceptible to ferroptosis. Interestingly, cyanobacteria contain thylakoid membranes that are enriched in polyunsaturated-fatty-acid-containing phospholipids, which might explain their sensitivity to ferroptosis. These results indicate that...
Light is one of the most important factors modulating processes and sequences in plants life, lik... more Light is one of the most important factors modulating processes and sequences in plants life, like fruit ripening and the concentrations of water and lipid soluble antioxidants. The aim of this work was to evaluate the most effective frequency of low irradiance light pulses (LP) during the night and to analyze its effect on plant and fruit growth, as well as on modifications of concentrations of soluble sugar, amino acids, antioxidants and organic acids. LP of 15 min each were applied over the plants in a temperature controlled greenhouse after fruit set till they turned to mature red, with a frequency of 2 and 4 h. LP induced no changes in the typical maturation indexes such as soluble solid, total acidity, pH or firmness; meanwhile there was an 18% increase in fruit yield when plants were exposed to 15 min LP every 2 h during the night. Furthermore, by analyzing the tomato cluster receiving this LP treatment separately, the biomass of the fruit was found to have increased by 28% compared with the same cluster in control plants. In coincidence with this, fruit treated with a frequency of 2 and 4 h LP showed an increase in lycopene concentration, concomitantly with a rise in the proportion of red mature fruit harvested from the whole plant. On the other hand, there was a drop in the concentration of soluble sugars and free amino acids, possibly conducing to a decrease in water soluble antioxidants (ascorbic acid and glutathione) and citric and malic acids concentration. Overall, these results showed that nocturnal LP treatments improved fruit yield in tomato plants with higher amounts of lycopene, which indicate earlier fruit ripening.
Blueberries are a perishable fruit that loses its firmness and weight rapidly after harvest. High... more Blueberries are a perishable fruit that loses its firmness and weight rapidly after harvest. High concentrations of ascorbic acid (AA) and phenolic compounds such as anthocyanins are important attributes contributing to the quality of the fruit. The aim of this work is to extend the postharvest life of three blueberries cultivars; 'Mistý and 'Blue Cuinex, firm and soft cultivars respectively and 'Blue Chiṕ with intermediate firmness. The fruit was treated separately or in combination with a nitric oxide donor, S-nitrosoglutathione (GSNO) and 1-methylcyclopropene (1-MCP) and stored at 4°C for 14 d. The best treatment for 'Blue Cuinex́was the combination of 1-MCP and GSNO, while 'Mistý softened slower when treated with 1-MCP, and 'Blue Chiṕ was not affected by treatment. The 1-MCP + GSNO treatment maintained higher concentrations of AA and GSH in 'Blue Cuinex. AA concentrations declined in 'Mistý but did not respond to GSNO. The combination of 1-MCP and GSNO extended the postharvest life of 'Blue Cuinex́by improving the concentrations of AA and glutathione in the berries but not for 'Mistý. These results demonstrate that blueberry cultivars respond differentially to 1-MCP and nitric oxide, and that the sequence of application could be used to slow fruit softening and maintain antioxidant properties.
Ascorbic acid (AA) is synthesized in plant mitochondria through the oxidation of L-galactono-1,4-... more Ascorbic acid (AA) is synthesized in plant mitochondria through the oxidation of L-galactono-1,4-lactone (L-GalL) and then distributed to different cell compartments. AA-deficient Arabidopsis thaliana mutants (vtc2) and exogenous applications of L-GalL were used to generate plants with different AA content in their leaves. This experimental approach allows determining specific AA-dependent effects on carbon metabolism. No differences in O 2 uptake, malic and citric acid and NADH content suggest that AA synthesis or accumulation did not affect mitochondrial activity; however, L-GalL treatment increased CO 2 assimilation and photosynthetic electron transport rate in vtc2 (but not wt) leaves demonstrating a stimulation of photosynthesis after L-GalL treatment. Increased CO 2 assimilation correlated with increased leaf stomatal conductance observed in L-GalL-treated vtc2 plants.
Ferroptosis is an oxidative iron-dependent form of cell death recently described in eukaryotic or... more Ferroptosis is an oxidative iron-dependent form of cell death recently described in eukaryotic organisms like animals, plants and parasites. Here we report that a similar process takes place in the cyanobacterium Synechocystis sp. PCC 6803 in response to heat stress. After a heat shock, Synechocystis cells undergo a cell death pathway that can be suppressed by canonical ferroptosis inhibitors or by external addition of calcium, glutathione or ascorbic acid. Moreover, as described for eukaryotic cells ferroptosis, this pathway is characterized by an early depletion of antioxidants, and by lipid peroxidation. As in general prokaryotes membranes contain poorly oxidizable saturated or monounsaturated lipid molecules, it was thought that they were not susceptible to ferroptosis. Interestingly, cyanobacteria contain thylakoid membranes that are enriched in polyunsaturated-fatty-acid-containing phospholipids, which might explain their sensitivity to ferroptosis. These results indicate that...
Light is one of the most important factors modulating processes and sequences in plants life, lik... more Light is one of the most important factors modulating processes and sequences in plants life, like fruit ripening and the concentrations of water and lipid soluble antioxidants. The aim of this work was to evaluate the most effective frequency of low irradiance light pulses (LP) during the night and to analyze its effect on plant and fruit growth, as well as on modifications of concentrations of soluble sugar, amino acids, antioxidants and organic acids. LP of 15 min each were applied over the plants in a temperature controlled greenhouse after fruit set till they turned to mature red, with a frequency of 2 and 4 h. LP induced no changes in the typical maturation indexes such as soluble solid, total acidity, pH or firmness; meanwhile there was an 18% increase in fruit yield when plants were exposed to 15 min LP every 2 h during the night. Furthermore, by analyzing the tomato cluster receiving this LP treatment separately, the biomass of the fruit was found to have increased by 28% compared with the same cluster in control plants. In coincidence with this, fruit treated with a frequency of 2 and 4 h LP showed an increase in lycopene concentration, concomitantly with a rise in the proportion of red mature fruit harvested from the whole plant. On the other hand, there was a drop in the concentration of soluble sugars and free amino acids, possibly conducing to a decrease in water soluble antioxidants (ascorbic acid and glutathione) and citric and malic acids concentration. Overall, these results showed that nocturnal LP treatments improved fruit yield in tomato plants with higher amounts of lycopene, which indicate earlier fruit ripening.
Blueberries are a perishable fruit that loses its firmness and weight rapidly after harvest. High... more Blueberries are a perishable fruit that loses its firmness and weight rapidly after harvest. High concentrations of ascorbic acid (AA) and phenolic compounds such as anthocyanins are important attributes contributing to the quality of the fruit. The aim of this work is to extend the postharvest life of three blueberries cultivars; 'Mistý and 'Blue Cuinex, firm and soft cultivars respectively and 'Blue Chiṕ with intermediate firmness. The fruit was treated separately or in combination with a nitric oxide donor, S-nitrosoglutathione (GSNO) and 1-methylcyclopropene (1-MCP) and stored at 4°C for 14 d. The best treatment for 'Blue Cuinex́was the combination of 1-MCP and GSNO, while 'Mistý softened slower when treated with 1-MCP, and 'Blue Chiṕ was not affected by treatment. The 1-MCP + GSNO treatment maintained higher concentrations of AA and GSH in 'Blue Cuinex. AA concentrations declined in 'Mistý but did not respond to GSNO. The combination of 1-MCP and GSNO extended the postharvest life of 'Blue Cuinex́by improving the concentrations of AA and glutathione in the berries but not for 'Mistý. These results demonstrate that blueberry cultivars respond differentially to 1-MCP and nitric oxide, and that the sequence of application could be used to slow fruit softening and maintain antioxidant properties.
Ascorbic acid (AA) is synthesized in plant mitochondria through the oxidation of L-galactono-1,4-... more Ascorbic acid (AA) is synthesized in plant mitochondria through the oxidation of L-galactono-1,4-lactone (L-GalL) and then distributed to different cell compartments. AA-deficient Arabidopsis thaliana mutants (vtc2) and exogenous applications of L-GalL were used to generate plants with different AA content in their leaves. This experimental approach allows determining specific AA-dependent effects on carbon metabolism. No differences in O 2 uptake, malic and citric acid and NADH content suggest that AA synthesis or accumulation did not affect mitochondrial activity; however, L-GalL treatment increased CO 2 assimilation and photosynthetic electron transport rate in vtc2 (but not wt) leaves demonstrating a stimulation of photosynthesis after L-GalL treatment. Increased CO 2 assimilation correlated with increased leaf stomatal conductance observed in L-GalL-treated vtc2 plants.
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