Role of ferredoxin on the mechanism of antioxidant defence using transgenic plants

BLANCO, N.E.; POLI, H.O.; VALLE, E.M.; CARRILLO N.

Iguazú, Misiones, Argentina

Congreso; - SAIB -XL Annual Meeting - ARGENTINE SOCIETY FOR BIOCHEMISTRY AND MOLECULAR BIOLOGYBlanco NE, Poli HO, Valle EM, Carrillo N.; 2004

Sociedad Argentina de Investigación en Bioquímica y Biología Molecular (S.A.I.B.)

Ferredoxins (Fd) are a group of low molecular-weight proteins which have Fe-S centres. Their major function is electronic transfer. The Fds of the 2Fe-2S class act as a soluble electronic transporters between Photosystem I and ferredoxin-NADPH reductase (FNR) during the light phase of photosynthesis, to generate NADPH needed for CO2 fixation. A novel cDNA encoding tobacco ferredoxin (Nicotiana tabacum cv Petit Havana) was isolated by PCR (fdn-1, accesion number: AY552781). When compared to another sequence of plant ferredoxin, fdn-1 was identified as the leaf-specific ferredoxin isoform I. This sequence was cloned in antisense orientation into a pCAMBIA vector under the control of the constitutive promotor CAMV 35S, in order to generate transgenic tobacco plants with decreased Fd levels. These plants showed variegated levels of chlorophyll in the same leaf, that resemble photoinhibition characteristics observed in FNR antisense plant. As compared to the wild-type siblings, sense and antisense plants show similar growth rates. In addition, transgenic plants overexpressing pea Fd display higher sensitivity to the redoxcycling herbicide methyl viologen.