Dehydrin induction during drought and osmotic stress in Populus

A cDNA encoding a dehydrin prepared from poplar (Populus euramericana cv Dorskamp clone) leaf mRNA was characterized. The cDNA, designated peudhn1, is 1046 nucleotides long and has a 675 bp open reading frame with a 225 residues deduced amino acid sequence. The Peudhn1 sequence contains two conserved repeats of the characteristic lysine-rich-K-segment (EKKGIMDKIKEKLPG) preceded by an 8-serine residue stretch, but the Y-segment (DEYGNP) conserved motif, common to many dehydrins, is absent. The sequence of the predicted Peudhn1 protein shows structural domains similar to Arabidopsis thaliana ERD14, COR47 and LTI29 dehydrins. In unstressed poplar cuttings, a low level of peudhn1 transcripts was clearly detected in leaf and root tissues. Peudhn1 was induced by withholding water, salt stress, cold and osmotic stress generated by addition of PEG 6000. A precocious induction of peudhn1 transcript in leaves was observed within 5 min of PEG 6000 treatment in hydroponic condition.