Pleiotropic Effects of the Wheat Dehydrin DHN-5 on Stress Responses in Arabidopsis

We have previously reported that transgenic Arabidopsisplants overexpressing the wheat dehydrin DHN-5 showenhanced tolerance to osmotic stresses. In order to under-stand the mechanisms through which DHN-5 exerts thiseffect, we performed transcriptome profiling using theAffymetrix ATH1 microarray. Our data show an altered ex-pression of 77 genes involved mainly in transcriptional regu-lation, cellular metabolism, stress tolerance and signaling.Among the up-regulated genes, we identified those whichare known to be stress-related genes. Several late embryo-genesis abundant (LEA) genes, ABA/stress-related genes(such as RD29B) and those involved in pathogen responses(PR genes) are among the most up-regulated genes. In add-ition,theMDHARgeneinvolvedintheascorbatebiosynthet-ic pathway was also up-regulated. This up-regulation wascorrelated with higher ascorbate content in two dehydrintransgenic lines. In agreement with this result and as ascor-bate is known to be an antioxidant, we found that bothtransgenic lines show enhanced tolerance to oxidativestress caused by H