Photosynthesis and oxidative stress tolerance of tobacco transgenic plants overexpressing ferredoxin-NADP(H) reductase.

RAMIRO ESTEBAN RODRIGUEZ VIRASORO; ANABELLA LODEYRO; HUGO POLI; VANESA TOGNETTI; JAVIER PALATNIK; ESTELA VALLE; NESTOR CARRILLO

Iguazú, Argentina

Congreso; XXXX Reunión Anual Nacional de la Sociedad Argentina de Investigaciones en Bioquímica y Biología Molecular (SAIB); 2004

Ferredoxin-NADP(H) reductases (FNR) catalyse the reversible electron transfer between two molecules of obligatory one-electron carriers as ferredoxin and flavodoxin (Fd) and a single molecule of NADP(H). Antisense tobacco plants with reduced amounts of this enzime display diminished photosynthetic activity (Hajirezaei et. al. Plant J. (2002) 29:281) and enhanced photo-oxidative damage (Palatnik et. al. Plant J. (2003) 35:332). In this work we describe the preparation of transgenic tobacco plants overexpressing pea FNR and the evaluation of their photosynthetic activity and oxidative stress tolerance. Altough FNR levels raised up to 500% in these transgenic lines, only a moderate increase in CO2 asimilation was observed (30%) under saturating light and CO2. These plants were subjected to oxidative stress conditions by exposure to the superoxide radical propagator metyl viologen or combinations of high irradiance and low temperature. Measurements of chlorophyll degradation, membrane damage and chlorophyll‑a fluorescence shows that the overexpressing transgenic plants are more tolerant to the oxidative stress conditions assayed.