Overproduction of Ascorbate Peroxidase in the Tobacco Chloroplast Does Not Provide Protection against Ozone

Torsethaugen, Gro; Pitcher, Lynne H.; Zilinskas, Barbara A.; Pell, Eva J.

doi:10.1104/pp.114.2.529

Cited by 90 publications

(43 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This result agrees with the experimentally observed increased tolerance to methyl viologen damage reported in tobacco (Nicotiana tabacum) plants overexpressing cytosolic APX (Pitcher et al, 1994), although it is in apparent contradiction with data obtained by the same authors (Torsethaugen et al, 1997), indicating that overproduction of APX in tobacco chloroplasts does not provide protection against O 3 -induced stress. This may be due to the above-mentioned fact that V APX remained nearly constant above a certain value (about 10 mM under the conditions used here) even when the [APX] was increased.…”

Section: Effects On the System Of Varying Antioxidant Enzyme Concentrsupporting

confidence: 89%

Computer Simulation of the Dynamic Behavior of the Glutathione-Ascorbate Redox Cycle in Chloroplasts

et al. 2009

View full text Add to dashboard Cite

The glutathione-ascorbate redox pathway in chloroplasts is a complex network of spontaneous, photochemical, and enzymatic reactions for detoxifying hydrogen peroxide. This article presents a comprehensive sensitivity analysis of the system. A model has been constructed to simulate oxidative stress conditions, enabling steady-state concentrations of the metabolites involved in the pathway and photochemical and enzymatic fluxes to be calculated. The model includes an electron source whose flux is distributed among three competitive routes (photogeneration of O 2 2 , photoreduction of NADP 1 to NADPH, and photoreduction of monodehydroascorbate to ascorbate) and that allows the simulation of variations in NADPH concentration with time. Each enzyme considered is introduced in the model, taking into account its particular catalytic mechanism, including the inactivation of ascorbate peroxidase in the presence of low-ascorbate concentrations. Computer simulations pointed to the great sensitivity of the system to the ratio among fluxes corresponding to ascorbate and NADPH photoproduction and NADPH consumption by the Calvin cycle. Under oxidative stress conditions, the model shows a sequential depletion of antioxidant power in chloroplasts in the order NADPH, glutathione, ascorbate and their recovery in the reverse order. Decreasing levels of glutathione reductase, ascorbate peroxidase, and superoxide dismutase led to the irreversible photoinactivation of ascorbate peroxidase and the subsequent increase in hydrogen peroxide concentration, preceded by a maximum in dehydroascorbate reductase activity.

show abstract

Section: Effects On the System Of Varying Antioxidant Enzyme Concentrsupporting

confidence: 89%

Computer Simulation of the Dynamic Behavior of the Glutathione-Ascorbate Redox Cycle in Chloroplasts

et al. 2009

View full text Add to dashboard Cite

show abstract

“…These O3 exposure studies, in conjunction with findings fiom sir-nilar chr-onic O3 exposure studies performed on Be]-W3 tobacco (Torsethaugen et al 1997), indicate that the Petit Havana and Bel-W3 cultivars do not express 03-induced accelerated foliar senescence. The absence of accelerated foliar senescence in tobacco might be explained by the presence of a cell plasma men-rbrane which is particularly vulnerable to oxidation (Keitel & Amdt 1983), Vulnerability to oxidation could be a refiection of the structure and/or particular composition of the membrane.…”

Section: Discussionsupporting

confidence: 59%

Influence of ozone on transgenic tobacco plants expressing reduced quantities of Rubisco

Wiese

Pell

1997

Plant Cell & Environment

Self Cite

View full text Add to dashboard Cite

ABSTRACT/ZAcS-antisense transformed tobacco plants (Nicotiana tabacutn cv. Petit Havana) expressing reduced quantities of Rubisco protein were used to examine the role of Rubisco quantity in determining ozone (O3) sensitivity. Transformed and wild-type plants were exposed to O3 in the greenhouse and in the field. Stomatal conductance, net photosynthesis and Rubisco protein quantity were measured at various times. Antisense-transformed genotypes responded to O3 hy exhihiting rapid, severe foliar necrosis. The wild-type plants responded more slowly, exhibiting limited injury. Decreases in stomatal conductance, net photosynthesis or Ruhisco quantity in plants exposed to O3 were not observed in asymptomatic leaves. Total biomass was lower for the transformed genotypes and decreased in both genotypes after exposure to O3. Shoot-root ratio and specific leaf area were higher in the transformed genotypes and increased in both genotypes with exposure to O3. Measurements of intercellular airspace demonstrated the presence of larger intercellular spaces in the transformed plants. The indirect effects of the rbcS antisense transformation, including morphological changes in the leaf, probably rendered the transformed plants more sensitive to the oxidant. The decreased quantity of Rubisco is not thought to be directly related to increased O3 sensitivity in the transformed plants.

show abstract

“…For each line, chlorophyll content (lg chlorophyll/g fresh weight) after Pq treatment is given as % value with respect to its value in the mock-treated sample. Results represent the mean of two independent experiments; bars correspond to the standard deviation protection against noxious effects of ROS has been established through transgenic modification of the expression of various APX isoenzymes in different plant systems (Allen et al 1997;Torsethaugen et al 1997;Wang et al 1999;Shi et al 2001;Payton et al 2001;Rizhsky et al 2002;Yabuta et al 2002;Murgia et al 2004a). …”

Section: Discussionmentioning

confidence: 99%

Antisense reduction of thylakoidal ascorbate peroxidase in Arabidopsis enhances Paraquat-induced photooxidative stress and Nitric Oxide-induced cell death

Tarantino

Vannini

Bracale

et al. 2005

Planta

View full text Add to dashboard Cite

The production and characterization of Arabidopsis plants containing a transgene in which the Arabidopsis tAPX is inserted in antisense orientation, is described. tAPX activity in these transgenic tAPX plants is around 50% of control level. The tAPX antisense plants are phenotypically indistinguishable from control plants under normal growth conditions; they show, however, enhanced sensitivity to the O2- -generating herbicide, Paraquat. Interestingly, the tAPX antisense plants show enhanced symptoms of damage when cell death is triggered through treatment with the nitric oxide-donor, SNP. These results are in accordance with the ones recently obtained with transgenic plants overexpressing tAPX; altogether, they suggest that tAPX, besides the known ROS scavenging role, is also involved in the fine changes of H2O2 concentration during signaling events.

show abstract

Overproduction of Ascorbate Peroxidase in the Tobacco Chloroplast Does Not Provide Protection against Ozone

Cited by 90 publications

References 34 publications

Computer Simulation of the Dynamic Behavior of the Glutathione-Ascorbate Redox Cycle in Chloroplasts

Computer Simulation of the Dynamic Behavior of the Glutathione-Ascorbate Redox Cycle in Chloroplasts

Influence of ozone on transgenic tobacco plants expressing reduced quantities of Rubisco

Antisense reduction of thylakoidal ascorbate peroxidase in Arabidopsis enhances Paraquat-induced photooxidative stress and Nitric Oxide-induced cell death

Contact Info

Product

Resources

About