A cDNA for a novel phytocyanin homolog was cloned from apical buds of morning glory (Pharbitis nil). The predicted protein was most similar to a family of early nodulins, which are expressed during the formation of symbiotic root nodules of legume plants, and less similar to typical phytocyanins such as lacquer tree stellacyanin and cucumber basic protein. The amino acid sequence predicted that it is a secreted protein associated with other components of the extracellular matrix. Hybridization analyses showed that the transcript was expressed specifically in meristems and procambia of apical buds and root tips. The transcript level in the apical buds decreased significantly on flower-inducing treatment. Involvement of this phytocyanin-related protein in plant organ differentiation is discussed.