Photosynthetic function, lipid peroxidation, and α-tocopherol content in spinach leaves during exposure to UV-B radiation

DeLong, John M.; Steffen, Kenneth L.

doi:10.4141/p96-162

Cited by 40 publications

(23 citation statements)

References 24 publications

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“…Obviously, conditions under which the formation of PUFA radicals and especially ROS are favoured lead to much higher c-tocopherol concentrations than treatment with octadecanoids where hydroperoxy molecules are formed. Enhanced tocopherol formation has been shown for different forms of stress, such as drought, high light and UV exposure (DeLong and Steffen 1997;Munne´-Bosch et al 1999;Trebst et al 2002). Also, aging of plants leads to considerable induction of TAT and massive increases in a-and c-tocopherol levels (data not shown).…”

Section: Discussionmentioning

confidence: 91%

Jasmonate is involved in the induction of tyrosine aminotransferase and tocopherol biosynthesis in Arabidopsis thaliana

Sandorf

Holländer-Czytko

2002

Planta

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Coronatine-inducible tyrosine aminotransferase (TAT), which catalyses the transamination from tyrosine to p-hydroxyphenylpyruvate, is the first enzyme of a pathway leading via homogentisic acid to plastoquinone and tocopherols, the latter of which are known to be radical scavengers in plants. TAT can be also induced by the octadecanoids methyl jasmonate (MeJA) and methyl-12-oxophytodienoic acid (MeOPDA), as well as by wounding, high light, UV light and the herbicide oxyfluorfen. In order to elucidate the role of octadecanoids in the process of TAT induction in Arabidopsis thaliana (L.) Heynh., the jasmonate-deficient mutant delayed dehiscence (dde1) was used, in which the gene for 12-oxophytodienoic acid reductase 3 is disrupted. The amount of immunodetectable TAT was low. The enzyme was still fully induced by coronatine as well as by MeJA although induction by the latter was to a lesser extent and later than in the wild type. Treatment with MeOPDA, wounding and UV light, however, had hardly any effects. Tocopherol levels that showed considerable increases in the wild type after some treatments were much less affected in the mutant. However, starting levels of tocopherol were higher in non-induced dde1 than in the wild type. We conclude that jasmonate plays an important role in the signal transduction pathway regulating TAT activity and the biosynthesis of its product tocopherol.

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Section: Discussionmentioning

confidence: 91%

Jasmonate is involved in the induction of tyrosine aminotransferase and tocopherol biosynthesis in Arabidopsis thaliana

Sandorf

Holländer-Czytko

2002

Planta

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“…Although tocopherols may be similarly important in plant tissues, their antioxidant activity in plant cells is much less well documented. The involvement of thylakoid tocopherols in the photoprotection of plants is supported by the strong augmentation of the tocopherol content in plants exposed to adverse environmental conditions that induce oxidative stress (e.g., Delong and Steffen, 1997;Havaux et al, 2000;Munné -Bosch and Alegre, 2000;Fryer et al, 2002;Mü llerMoulé et al, 2004). However, up to now, there is no clear demonstration that tocopherol does function as an efficient inhibitor of lipid peroxidation in plants exposed to high light stress.…”

Section: Introductionmentioning

confidence: 99%

Vitamin E Protects against Photoinhibition and Photooxidative Stress in Arabidopsis thaliana

et al. 2005

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Vitamin E is considered a major antioxidant in biomembranes, but little evidence exists for this function in plants under photooxidative stress. Leaf discs of two vitamin E mutants, a tocopherol cyclase mutant (vte1) and a homogentisate phytyl transferase mutant (vte2), were exposed to high light stress at low temperature, which resulted in bleaching and lipid photodestruction. However, this was not observed in whole plants exposed to long-term high light stress, unless the stress conditions were extreme (very low temperature and very high light), suggesting compensatory mechanisms for vitamin E deficiency under physiological conditions. We identified two such mechanisms: nonphotochemical energy dissipation (NPQ) in photosystem II (PSII) and synthesis of zeaxanthin. Inhibition of NPQ in the double mutant vte1 npq4 led to a marked photoinhibition of PSII, suggesting protection of PSII by tocopherols. vte1 plants accumulated more zeaxanthin in high light than the wild type, and inhibiting zeaxanthin synthesis in the vte1 npq1 double mutant resulted in PSII photoinhibition accompanied by extensive oxidation of lipids and pigments. The single mutants npq1, npq4, vte2, and vte1 showed little sensitivity to the stress treatments. We conclude that, in cooperation with the xanthophyll cycle, vitamin E fulfills at least two different functions in chloroplasts at the two major sites of singlet oxygen production: preserving PSII from photoinactivation and protecting membrane lipids from photooxidation.

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“…Increased F 0 levels after UV-B or UV-A irradiation have been detected for different photosynthetic organisms (van Hasselt et al 1996;DeLong and Steffen 1997;Sharma et al 1998;Tevini et al 1988;Vass et al 1999;Xiong et al 1999;Heraud and Beardall 2000;Pfündel 2003) and in vitro preparations like thylakoids or PSII particles Nayak et al 2003). However, decreases in F 0 after UV irradiation have also been described (Tevini and Iwanzik 1983;Panagopoulos et al 1990).…”

Section: Comparison Of Chlorophyll Fluorescence and Thermoluminescencementioning

confidence: 89%

Effects of UV irradiation on barley and tomato leaves: thermoluminescence as a method to screen the impact of UV radiation on crop plants

Gilbert

Skotnica

Weingart

et al. 2004

Functional Plant Biol.

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The effect of different UV intensities and irradiation times on barley and tomato leaves was investigated by analysis of thermoluminescence (TL) and chlorophyll (chl) fluorescence measurements. Epifluorescence microscopy was used to estimate the epidermal UV transmittance of leaves. In barley a strong supression of TL emission from the S 2 Q B − (B-band) and the S 2 Q A − (Q-band) charge recombination was observed, increasing with prolonged UV exposure. Primary barley leaves were more sensitive to UV than secondary leaves. In tomato plants a decrease in the B-band only takes place at very high UV intensities and after prolonged exposure times (4 h). The impact of UV in cotyledons was more pronounced than in pinnate leaves of tomato plants. The strong differences in sensitivity to UV in the investigated barley and tomato variety may be due to different concentrations of UV screening pigments in the epidermal layer as demonstrated by epifluorescence measurements. The results show that TL has the same potential to analyse the sensitivity or tolerance of crop plants to UV irradiation as routine fluorescence techniques. Furthermore, TL is directly monitoring the radical pair states of PSII and can distinguish between UV-induced donor and acceptor site-related damage.

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Photosynthetic function, lipid peroxidation, and α-tocopherol content in spinach leaves during exposure to UV-B radiation

Cited by 40 publications

References 24 publications

Jasmonate is involved in the induction of tyrosine aminotransferase and tocopherol biosynthesis in Arabidopsis thaliana

Jasmonate is involved in the induction of tyrosine aminotransferase and tocopherol biosynthesis in Arabidopsis thaliana

Vitamin E Protects against Photoinhibition and Photooxidative Stress in Arabidopsis thaliana

Effects of UV irradiation on barley and tomato leaves: thermoluminescence as a method to screen the impact of UV radiation on crop plants

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