THE EFFECTS OF ETHYLENE ON THE COORDINATED SYNTHESIS OF MULTIPLE PROTEINS - ACCUMULATION OF AN ACIDIC CHITINASE AND A BASIC GLYCOPROTEIN INDUCED BY ETHYLENE IN LEAVES OF AZUKI-BEAN, VIGNA-ANGULARIS

The ethylene-induced synthesis and accumulation of proteins were studied in the primary leaves of azuki bean (Vigna angularis). Seven different proteins, designated AZ17, 23, 27, 32, 35, 36, 42 according to their molecular masses, were synthesized and accumulated in response to ethylene. AZ27 and AZ42 were purified to homogeneity and characterized. AZ27 was identified as an acidic chitinase and accumulated in the extracellular space. The sequence of the 40 N-terminal amino acids of AZ27 showed no similarity to that of a basic chitinase from bean and tobacco, but it was highly homologous to that of a chitinase from virus-infected cucumber leaves. AZ42 was identified as a glycoprotein that accumulated intracellularly. A search for proteins with sequences homologous to an internal sequence of 18 amino acids in AZ42 was unsuccessful. Immunochemical examination revealed that auxin and abscisic acid enhanced the ethylene-induced accumulation of AZ27 but not of AZ42. In contrast, levels of AZ42 were not affected by auxin or abscisic acid, but cytokinin suppressed the accumulation of one of the doublet bands of AZ42. Translatable mRNAs coding for AZ27 and AZ42 were not present in leaves that had not been treated with ethylene, but levels of these mRNAs increased after such treatment.