Purification and characterization of an ethylene-induced antifungal protein from leaves of guilder rose (Hydrangea macrophylla).

An ethylene-induced, chitin-binding protein (designated as HM30) from leaves of Hydrangea macrophylla was identified and purified to apparent homogeneity by chitin affinity chromatography followed by FPLC on a Superose 12 column. The molecular mass of HM30 was 30,010.0 Da determined by mass spectrometry and its isoelectric point of 8.4 was estimated by isoelectric focusing. The amino acid composition of HM30 was also determined. The initial 15 amino acid residues of the N-terminal were found to be N-S-M-E-R-V-E-E-L-R-K-K-L-Q-D by automatic Edman degradation. This chitin-binding protein showed antifungal activity toward several crop fungal pathogens. Knowledge of properties of HM30 should be useful for its potential application as a plant fungicidal agent.