A petunia (Petunia hybrida) eDNA was isolated from the cDNA library produced from mRNA extracted from the cultured petal protoplasts of petunia. This clone contains 741 by open reading frame encoding for a 26kD polypeptide of 246 amino acid residues: the first 21 amino acids correspond to the sequence characteristic of a signal peptide. The predicted amino acid sequence shows homology with osmotin (82%) and osmotin-like protein (OLP; 89%) from tobacco. Thus, we designated this cDNA clone as PhOSM (Petunia hybrida osmotin). The accumulation of PhOSM mRNA was high in the root. The low levels of PhOSM mRNA was detected in the flower and leaf. Especially in the pistil, accumulation of PhOSM mRNA was increased after anthesis. Accumulation of PhOSM was also induced by abiotic stimuli, such as NaCl, abscisic acid (ABA), and low temperature in young seedlings. These results suggest that osmotin-like proteins may play important roles in normal development and plant defense against environmental stresses.