MOLECULAR CHARACTERIZATION, ORGAN DISTRIBUTION AND STRESS-MEDIATED INDUCTION OF 2 GLUTATHIONE PEROXIDASE-ENCODING MESSENGER-RNAS IN SUNFLOWER (HELIANTHUS-ANNUUS)

Using a reverse transcription PCR (RT-PCR) amplification strategy, wit h degenerate primers localized in highly conserved domains of known gl utathione peroxidase (GPX) proteins, GPX-encoding cDNA fragments were generated from sunflower (Helianthus annuus L.) hypocotyl RNA. Along w ith the sequences of two distinct GPX-encoding cDNAs (GPXha-1 and GPXh a-2) and the alignment of their conceptually translated products with to date cloned plant GPXs, we report here that the two corresponding m RNAs are qualitatively and quantitatively differentially expressed in various organs of H. annuus. Using northern blotting we have shown tha t more sunflower GPX-like transcripts accumulate in plants which have been subjected to either wounding or infection by a biotrophic pathoge n (Plasmopara halstedii) suggesting that the corresponding genes are i nducible under various stress conditions.