A root-specific cDNA clone, PVR3 was isolated from a bean (Phaseolus vulgaris L.) root cDNA library by a differential screening procedure. The nucleotide sequence of PVR3 includes an open reading frame coding for an 11.14 kDa polypeptide of 102 amino acid residues : the first 25 amino acids correspond to the sequence characteristic. of a signal peptide. Comparison of the deduced PVR3 polypeptide sequence with the polypeptide sequences of previously cloned genes indicates that PVR3 may encode an ns-LTP-like protein. Molecular modeling of the PVR3 protein predicts that it has a three-dimensional structure that is similar to the three-dimensional model determined from the maize ns-LTP. The PVR3 mRNA accumulated mainly in the seedling root. It can be detected at low levels in flowers, but it is not detected in other organs. PVR3 mRNA accumulation is developmentally regulated within the root, with higher levels in the apical region and low levels in the mature region of the root. In situ hybridization shows that PVR3 mRNA specifically accumulates in the cortical cellular layer of apical region. Genomic Southern blot analysis indicates that the genomic DNA corresponding to PVR3 cDNA is encoded by a single gene in the bean genome.