TOBACCO PLANTS EXPRESSING A CYANOBACTERIAL FERREDOXIN DISPLAY INCREASED OXIDATIVE STRESS TOLERANCE

CECCOLI, ROMINA D.; BLANCO, NICOLÁS E.; CARRILLO, NÉSTOR

Mar del Plata, Argentina

Congreso; XLIII Reunión Anual de la Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2007

SAIB

Ferredoxins (Fd) are iron-sulfur proteins involved in many different one-electron transfer pathways in plants, animals and microorganisms. In chloroplasts and cyanobacteria, Fd distributes the reducing equivalents generated in the photosynthetic electron transport chain to various essential oxidoreductive pathways. Fd levels decrease under adverse environmental conditions, affecting severely plant physiology. Moreover, antisense Fd plants display drastic alterations in growth and development. The aim of this study is to evaluate the effect of the expression of a bacterial version of this protein which is free from endogenous regulation on the tolerance to oxidative stress conditions. We generated transgenic tobacco plants expressing Anabaena PCC7120 Fd in plastids under the control of the cauliflower mosaic virus 35S promoter by Agrobacterium tumefaciens-mediated leaf disc transformation. Inmunoblots were used to confirm the expression of the alien Fd. No phenotypic differences were observed between wild-type and transgenic plants cultured in a growth chamber. We evaluated oxidative stress tolerance using the redox-cycling herbicide methyl-viologen (MV) that propagates reactive oxygen species. The transgenic plants exhibit enhanced tolerance to oxidative damage. This suggests that expression of the cyanobacterial Fd might contribute to improve stress tolerance.