Expression of antioxidant genes in relation to water deficit in cambium and leaves of poplar

The expression of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX) in water deficit conditions was investigated in poplar cambium and leaf to study the regulation of the different members of these multigene families during water stress. The daily stem radial growth was used to evaluate plant water status at the whole-tree level and after 22 days of reduced irrigation regime, a decline of radial growth of 37% was observed. The expression patterns of the genes were analysed by means of relative quantitative RT-PCR. Water deficiency affected significantly the expression of the peroxisomal APX and mitochondrial MnSODs genes in the cambium, evidencing the crucial role of these subcellular compartments for the redox homeostasis in this tissue. To our knowledge, this is the first report of a transcriptional analysis of multiple SOD, CAT and APX genes in poplar cambium in response to water deficit.