Photoinhibition of photosystem II in tobacco plants overexpressing glutathione reductase and poplars overexpressing superoxide dismutase

A - Papers appearing in refereed journals

Tyystjarvi, E., Riikonen, M., Arisi, A-C. M., Kettunen, R., Jouanin, L. and Foyer, C. H. 1999. Photoinhibition of photosystem II in tobacco plants overexpressing glutathione reductase and poplars overexpressing superoxide dismutase. Physiologia Plantarum. 105 (3), pp. 409-416.

AuthorsTyystjarvi, E., Riikonen, M., Arisi, A-C. M., Kettunen, R., Jouanin, L. and Foyer, C. H.
Abstract

We studied photoinhibition in two cultivars of tobacco (Nicotiana tabacum L,) expressing the bacterial gor gene In the cytosol and in four lines of poplar (Populus tremula x P, alba) expressing the FeSOD gene of Arabidopsis thaliana in the chloroplast, The respective total activities of glutathione reductase (EC 1.6.4.2) in leaves of gor tobaccos and superoxide dismutase (EC 1.15.1.1) in the FeSOD poplars were 5-8 times higher than in the respective untransformed control plants. Leaves of control and transformed plants were subjected to high-light stress at 20 degrees C, and photoinhibition of photosystem Il (PSII) was measured by oxygen evolution and chlorophyll fluorescence, The leaves were illuminated both in the presence and absence of lincomycin, which inhibits chloroplast protein synthesis. In both cases, the time course of loss of PSII activity was identical in plants overproducing superoxide dismutase (SOD) and in the untransformed controls, suggesting that the ability to convert superoxide to hydrogen peroxide is not a limiting factor in protection against photoinhibition, or in the repair of photoinhibitory damage or that the site of O-2(-) production is not accessible to the transgene product. The rate constant of photoinhibition, measured in lincomycin-treated leaves, was smaller in glutathione reductase (GR) overproducing tobacco cv, Samsun than in the respective wild-type, but this difference was not seen in cv, Eel W3, The steady-state level of PSII activity measured when the PSII repair cycle was allowed to equilibrate with photoinhibitory damage under high light was not higher in the GR overproducing cv, Samsun, suggesting that the repair of photoinhibitory damage was not enhanced in plants overproducing GR in the cytosol.

KeywordsPlant Sciences
Year of Publication1999
JournalPhysiologia Plantarum
Journal citation105 (3), pp. 409-416
Digital Object Identifier (DOI)doi:10.1034/j.1399-3054.1999.150304.x
Open accessPublished as non-open access
Funder project or code314
413
Project: 014149
ISSN00319317
PublisherWiley

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