The precursor of barley plastocyanin Sequence of cDNA clones and gene expression in different tissues

Full length cDNA clones encoding the precursor of plastocyanin have been isolated from a leaf cDNA library from barley (a monocotyledon). The deduced amino acid sequence comprises an N‐terminal transit peptide of 58 amino acids and a mature plastocyanin sequence of 97 amino acids (M r, 10 185) which is two amino acids shorter than the sequence of plastocyanin from dicotyledons. Northern hybridization experiments show that the level of plastocyanin messenger increases greatly in older leaf cells and that the level is 8–20‐fold higher in green leaves than in etiolated leaves. Plastocyanin messenger could not be detected in coleoptiles and roots.