Molecular characterization, organ distribution and stress-mediated induction of two glutathione peroxidase-encoding mRNAs in sunflower (Helianthus annuus)

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