Damage to functional components and partial degradation of Photosystem II reaction center proteins upon chloroplast exposure to ultraviolet-B radiation

Melis, Anastasios; Nemson, Jeff A.; Harrison, Michael A.

doi:10.1016/0167-4838(92)90487-x

Cited by 187 publications

(114 citation statements)

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“…3a, insert) is consistent with the hypothesis that under UVBR stress conditions, there is an active down regulation of photosynthesis in the cells for achieving protection (Malanga et al, 1997). PSII is one of the main targets likely to be affected by UVR (Melis et al, 1992), and several sites might be susceptible to damage (Bumann & Oesterhelt, 1995) in association to the D1 protein, which connects the primary electron donors with the active PSII receptors. Leu et al (2006) reported a decrease in optimum quantum yield of PSII between day 6 and 15 in the Arctic diatom Thalassiosira antarctica var.…”

Section: Discussionsupporting

confidence: 69%

Non enzymatic antioxidant photoprotection against potential UVBR induced damage in an Antarctic diatom (Thalassiosira sp.)

Hernando

Malanga

Puntarulo

et al. 2011

lajar

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ABSTRACT. In January 1999, unialgal cultures of the diatom Thalassiosira sp., solate from natural phytoplankton assemblages from Potter Cove, Antarctica, were exposed to solar ultraviolet radiation (UVR, 280-400 nm) in order to study the long-term acclimation of this species. Ultraviolet radiation B (UVBR, 280-315 nm) inhibited the growth rate during the first and second days of exposure. No UVBR inhibition was observed on the third day. The initial content of α-tocopherol (13 pmol (10 4 cell)) showed a marked decrease during the exponential growth phase (4 pmol (10 4 cell -1 ) by day 3). The initial content of β-carotene (3 pmol (10 4 cell) -1 ) did not show significant differences over time in cells exposed to UVBR. Two mycosporine-like amino acids (MAAs) were identified: porphyra-334 and shinorine. Cellular concentrations of MAAs increased significantly on days 2 and 3, and exposure of the algae to UVBR significantly enhanced this value. The relative importance of MAAs concentration was significant (P < 0.05) in relation to the α-tocopherol content. A positive correlation was shown between cellular MAAs concentration and growth rate. Our results suggest that photoprotection against UV-induced damage is characterized by short-term consumption of α-tocopherol and longer-term synthesis of MAAs. The UVBR damage/repair ratio during long-term exposure involves the combined action of several endogenous factors within the cell, with MAAs synthesis being the most effective factor related to photoprotection. Keywords: β-carotene, α-tocopherol, growth rate, diatoms, MAAs, photoprotection, Antarctica.Fotoprotección antioxidante no-enzimática contra el potencial daño inducido por UVBR en una diatomea antártica (Thalassiosira sp.) RESUMEN. Durante enero 1999, cultivos unialgales de una diatomea Thalassiosira sp., aislada de poblaciones fitoplanctónicas naturales de Caleta Carlos Potter, Antártida, fueron expuestos a radiación solar ultravioleta (UVR, 280-400 nm) con el objetivo de estudiar su aclimatación a largo plazo. La radiación ultravioleta B (UVBR, 280-315 nm) inhibió la tasa de crecimiento durante el primer y segundo día de exposición. No se observó inhibición por UVBR durante el tercer día. El contenido inicial de α-tocopherol (13 pmol (10 4 cel) -1 ) mostró una marcada disminución durante la fase de crecimiento exponencial (4 pmol (10 4 cel) -1 al día 3). El contenido inicial de β-caroteno (3 pmol (10 4 cel)) no mostró diferencias significativas entre días en células expuestas a UVBR. Se identificaron dos aminoácidos parecidos a micosporina (MAAs), porfira-334 y shinorina. Las concentraciones celulares de MAAs mostraron aumentos significativos en los días 2 y 3, que resultaron mayores cuando las algas fueron expuestas a UVBR. La importancia relativa de la concentración de MAAs fue significativa (P < 0.05) en relación al contenido de α-tocopherol. Se encontró una relación positiva entre la concentración celular de MAAs y la tasa de crecimiento. Estos resultados sugieren que la fotoprotección contra el daño inducido...

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Section: Discussionsupporting

confidence: 69%

Non enzymatic antioxidant photoprotection against potential UVBR induced damage in an Antarctic diatom (Thalassiosira sp.)

Hernando

Malanga

Puntarulo

et al. 2011

lajar

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“…Several indoor studies have concluded that PSII is a sensitive target of UV-B [46,47]; however most outdoor studies under realistic spectral regimes have not detected significant reductions in F v /F m [9,19]. Near-ambient UV-B initially reduced F v /F m by 17% on the first sampling date and the effect decreased as leaves aged (Figure 2c), suggesting that PSII may be more susceptible to UV-B damage in developing foliage when concentrations of UV-B-absorbing phenolics are presumably lower [48,49].…”

Section: Discussionmentioning

confidence: 99%

Solar Ultraviolet-B Radiation Increases Phenolic Content and Ferric Reducing Antioxidant Power in Avena sativa

et al. 2007

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Abstract:We examined the influence of solar ultraviolet-B radiation (UV-B; 280-320 nm) on the maximum photochemical efficiency of photosystem II (F v /F m ), bulk-soluble phenolic concentrations, ferric-reducing antioxidant power (FRAP) and growth of Avena sativa. Treatments involved placing filters on frames over potted plants that reduced levels of biologically effective UV-B by either 71% (reduced UV-B) or by 19% (near-ambient UV-B) over the 52 day experiment (04 July -25 August 2002). Plants growing under nearambient UV-B had 38% less total biomass than those under reduced UV-B. The reduction in biomass was mainly the result of a 24% lower leaf elongation rate, resulting in shorter leaves and less total leaf area than plants under reduced UV-B. In addition, plants growing under near-ambient UV-B had up to 17% lower F v /F m values early in the experiment, and this effect declined with plant age. Concentrations of bulk-soluble phenolics and FRAP values were 17 and 24% higher under near-ambient UV-B than under reduced UV-B, respectively. There was a positive relationship between bulk-soluble phenolic concentrations and FRAP values. There were no UV-B effects on concentrations of carotenoids (carotenes + xanthophylls).

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“…Numerous investigations have demonstrated that photosystem II (PSII) is the most sensitive component of the thylakoid membrane photosynthetic apparatus to increased exposure to UV-B (Noorudeen & Kulandaivelu 1982;Iwanzik et al 1983;Renger et al 1989;Kulandaivelu, Nedunchezhian & Annamalainathan 1991;Melis, Nemson & Harrison 1992). Consequently, PSII damage has often been implicated as the major potential limitation to photosynthesis in UV-B-treated leaves (Bomman 1989;Caldwell, Teramura & Tevini 1989;Stapleton 1992;Teramura & Sullivan 1994;Fiscus & Booker 1995), as is the case in the photoinhibition of photosynthesis by excess photosynthetically active radiation (380-700 nm) (Baker & Bowyer 1994), although it has been suggested that the mechanism of UV-B-induced damage may be different (Friso et al 1994;Jansen et al 1996).…”

Section: Introductionmentioning

confidence: 99%

Analysis of limitations to CO₂ assimilation on exposure of leaves of two Brassica napus cultivars to UV‐B

Allen

Mckee

Farage

et al. 1997

Plant Cell & Environment

157

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Apex and Bristol cultivars of oilseed rape {Brassica napus) were irradiated with 0-63 W m~^ of UV-B over 5 d. Analyses of the response of net leaf carbon assimilation to intercellular CO2 concentration were used to examine the potential limitations imposed by stomata, carboxylation velocity and capacity for regeneration of ribulose 1,5-bisphosphate on leaf photosynthesis. Simultaneous measurements of chlorophyll fluorescence were used to estimate the maximum quantum efficiency of photosystem II (PSII) photochemistry, the quantum efficiency of linear electron transport at steady-state photosynthesis, and the light and CO2-saturated rate of linear electron transport. Ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) content and activities were assayed in vitro. In both cultivars the UV-B treatment resulted in decreases in the light-saturated rate of CO2 assimilation, which were accompanied by decreases in carboxylation velocity and Rubisco content and activity. No major effects of UV-B were observed on end-product inhibition and stomatal limitation of photosynthesis or the rate of photorespiration relative to CO2 assimilation. In the Bristol cultivar, photoinhibition of PSII and loss of linear electron transport activity were observed when CO2 assimilation was severely inhibited. However, the Apex cultivar exhibited no major inhibition of PSII photochemistry or linear electron transport as the rate of CO2 assimilation decreased. It is concluded that loss of Rubisco is a primary factor in UV-B inhibition of CO2 assimilation.Key-words: Brassica napus; electron transport; fluorescence; leaf gas exchange; photosynthesis; photosystem II; Rubisco; ultraviolet-B radiation.Abbreviations: A, net CO2 assimilation rate; A^.^^, light-saturated net CO2 assimilation rate; Cj, intercellular CO2 concentration; Fo, F^, E^, minimal, maximal and variable fluorescence yields; F,^', EJ, E^, maximal, variable and steady-state fluorescence yields in a light-adapted state; ^max.RuBP' maximum potential rate of electron transport contributing to RuBP regeneration; imax.psii' rate of PSII electron transport at saturating light and CO2; PPFD, photosynthetically active photon flux density; RuBP, ribulose 1,5-bisphosphate; Rubisco, ribulose 1,5-bisphosphate carboxylase/oxygenase; V^..^^^, maximum carboxylation velocity of Rubisco; ^psn, relative quantum efficiency of PSII photochemistry.

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Damage to functional components and partial degradation of Photosystem II reaction center proteins upon chloroplast exposure to ultraviolet-B radiation

Cited by 187 publications

References 40 publications

Non enzymatic antioxidant photoprotection against potential UVBR induced damage in an Antarctic diatom (Thalassiosira sp.)

Non enzymatic antioxidant photoprotection against potential UVBR induced damage in an Antarctic diatom (Thalassiosira sp.)

Solar Ultraviolet-B Radiation Increases Phenolic Content and Ferric Reducing Antioxidant Power in Avena sativa

Analysis of limitations to CO₂ assimilation on exposure of leaves of two Brassica napus cultivars to UV‐B

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Damage to functional components and partial degradation of Photosystem II reaction center proteins upon chloroplast exposure to ultraviolet-B radiation

Cited by 187 publications

References 40 publications

Non enzymatic antioxidant photoprotection against potential UVBR induced damage in an Antarctic diatom (Thalassiosira sp.)

Non enzymatic antioxidant photoprotection against potential UVBR induced damage in an Antarctic diatom (Thalassiosira sp.)

Solar Ultraviolet-B Radiation Increases Phenolic Content and Ferric Reducing Antioxidant Power in Avena sativa

Analysis of limitations to CO2 assimilation on exposure of leaves of two Brassica napus cultivars to UV‐B

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Analysis of limitations to CO₂ assimilation on exposure of leaves of two Brassica napus cultivars to UV‐B