Ascorbate, Tocopherol and Carotenoids: Metabolism, Pathway Engineering and Functions

Smirnoff, Nicholas

doi:10.1002/9780470988565.ch3

Cited by 94 publications

(113 citation statements)

References 169 publications

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“…, . OH and regenerating α-tocopherol from tocopheroxyl radical (Smirnoff, 2005). Data presented here showed that the PEG treatments led to increasing the ASA content in the treated seedlings indicating an active stress adaptation (Fig.…”

Section: Drought Causes Oxidative Stress and Affects The Cell Antioxisupporting

confidence: 53%

Study of the Interactive Effects of Calcium and Abscisic Acid on Drought Stressed Triticum aestivum Seedlings

Sewelam

2017

Egypt. J. Bot.

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IN THEIR natural habitats, plants are continuously subjected to many severe environmental challenges including drought. In this study, the effects of drought on Triticum aestivum seedlings were assessed, and the alleviating roles and interactive effects of calcium (Ca 2+ ) and abscisic acid (ABA) to drought stress were studied. The results showed that pretreating wheat seedlings with calcium chloride (CaCl 2 ) or ABA led to alleviating most of the negative effects of 20% polyethylene glycol (PEG, as a drought imposing agent). Ca 2+ improved the growth criteria, photosynthetic activity, but ABA had no significant effects on growth parameters. Ca 2+ or ABA pretreatments have alleviated the toxic effects of the drought-induced oxidative stress which was marked with the reduction of MDA content. Ca 2+ and/or ABA reduced the PEGinduced catalase activity, and ascorbic acid content. The use of lanthanum chloride (LaCl 3 ) as a calcium channel blocker has confirmed the role of Ca 2+ in ameliorating the drought effects on plant. This study revealed that the application of Ca 2+ has increased the endogenous ABA level of the treated seedlings to a high extent exceeding that of PEG treatment itself suggesting that ABA requires Ca 2+ ions for its induction, and ABA is working downstream from Ca 2+ in the relevant signaling pathways activated by drought stress. The alleviating effects of Ca 2+ was prolonged to the yield stage. Overall, our results suggest that Ca 2+ (10 mM), and with a less extend ABA (0.1 mM), represent signaling agents that can partially alleviate drought stress in plants growing in dry environments.

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Section: Drought Causes Oxidative Stress and Affects The Cell Antioxisupporting

confidence: 53%

Study of the Interactive Effects of Calcium and Abscisic Acid on Drought Stressed Triticum aestivum Seedlings

Sewelam

2017

Egypt. J. Bot.

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“…The oxidative stress model for PPD has also been supported by the discovery of highb-carotene varieties of cassava that have a longer shelf life than low b-carotene lines (Sanchez et al, 2005;Morante et al, 2010). b-Carotene is known to have antioxidant properties and is able to quench ROS (Smirnoff, 2005).…”

Section: Discussionmentioning

confidence: 99%

Extending Cassava Root Shelf Life via Reduction of Reactive Oxygen Species Production

Zidenga

Leyva-Guerrero²,

Moon³

et al. 2012

Plant Physiology

138

168

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One of the major constraints facing the large-scale production of cassava (Manihot esculenta) roots is the rapid postharvest physiological deterioration (PPD) that occurs within 72 h following harvest. One of the earliest recognized biochemical events during the initiation of PPD is a rapid burst of reactive oxygen species (ROS) accumulation. We have investigated the source of this oxidative burst to identify possible strategies to limit its extent and to extend cassava root shelf life. We provide evidence for a causal link between cyanogenesis and the onset of the oxidative burst that triggers PPD. By measuring ROS accumulation in transgenic low-cyanogen plants with and without cyanide complementation, we show that PPD is cyanide dependent, presumably resulting from a cyanide-dependent inhibition of respiration. To reduce cyanide-dependent ROS production in cassava root mitochondria, we generated transgenic plants expressing a codon-optimized Arabidopsis (Arabidopsis thaliana) mitochondrial alternative oxidase gene (AOX1A). Unlike cytochrome c oxidase, AOX is cyanide insensitive. Transgenic plants overexpressing AOX exhibited over a 10-fold reduction in ROS accumulation compared with wild-type plants. The reduction in ROS accumulation was associated with a delayed onset of PPD by 14 to 21 d after harvest of greenhouse-grown plants. The delay in PPD in transgenic plants was also observed under field conditions, but with a root biomass yield loss in the highest AOX-expressing lines. These data reveal a mechanism for PPD in cassava based on cyanideinduced oxidative stress as well as PPD control strategies involving inhibition of ROS production or its sequestration.

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“…Ascorbate is a vital water-soluble antioxidant that reacts with different ROS including H 2 O 2, O 2 •− , and 1 O 2 . It can also scavenge OH • at diffusion-controlled rates (Smirnoff, 2005). Changes in AsA, DHA, and the AsA/DHA ratio are part of the antioxidant defense mechanism of plants ( Alam et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

Relative tolerance of different species of Brassica to cadmium toxicity: Coordinated role of antioxidant defense and glyoxalase systems

Mahmud¹,

Hasanuzzaman²,

Rahman³

et al. 2017

Plant Omics

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The present study was carried out to examine the metal accumulation and tolerance abilities of three Brassica species (B. napus, B. campestris, and B. juncea) seedlings exposed to two levels of cadmium (Cd) stress (0.25 and 0.5 mM CdCl 2 for three days). Of the Brassica species studied, B. juncea accumulated the highest amount of Cd in a dose-dependent manner, and in every case, the Cd content was higher in the roots than the shoots. Cadmium stress reduced seedlings biomass, leaf relative water content (RWC), and chlorophyll (chl) content, whereas proline (Pro), MDA, and H 2 O 2 content and lipoxygenase (LOX) activity increased in all species. Under Cd stress, ascorbate (AsA) content reduction was lower and glutathione (GSH) content increase was higher in B. juncea compared with other species. Monodehydroascorbate reductase (MDHAR), glutathione reductase (GR), and superoxide dismutase (SOD) activities increased significantly in B. juncea under Cd stress compared with the other species. Catalase (CAT) activity did not decrease in B. juncea due to Cd stress, compared with the other species. Dehydroascorbate reductase (DHAR) activity decreased with both levels of Cd stress in all species except for B. juncea under 0.25 mM CdCl 2 stress. Glyoxalase system components performed better in B. juncea than the other species under Cd stress. Methylglyoxal (MG) increased substantially under both levels of Cd stress, but MG content was lower in B. juncea compared with the others. Considering the antioxidant defense and glyoxalase systems performance B. juncea is relatively tolerant species to Cd toxicity though it accumulated highest Cd.

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Ascorbate, Tocopherol and Carotenoids: Metabolism, Pathway Engineering and Functions

Cited by 94 publications

References 169 publications

Study of the Interactive Effects of Calcium and Abscisic Acid on Drought Stressed Triticum aestivum Seedlings

Study of the Interactive Effects of Calcium and Abscisic Acid on Drought Stressed Triticum aestivum Seedlings

Extending Cassava Root Shelf Life via Reduction of Reactive Oxygen Species Production

Relative tolerance of different species of Brassica to cadmium toxicity: Coordinated role of antioxidant defense and glyoxalase systems

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