Identification and characterization of a novel chitinase with antifungal activity from ʻBaozhu’ pear (Pyrus ussuriensis Maxim.)

• The chitinase displayed antifungal activity to several pathogenic fungi.
• The chitinase possesses remarkable pH stability (2.5–6.0).
• The chitinase possesses remarkable thermostability (⩽70 °C).

A novel chitinase from the ʻBaozhu’ pear was found, purified, and characterized in this report. This chitinase was a monomer with a molecular mass of 28.9 kDa. Results of the internal peptide sequence analyses classify this chitinase as a class III chitinase. In the enzymatic hydrolytic assay, this chitinase could hydrolyze chitin derivatives into di-N-acetylchitobiose (GlcNAc2) as a major product in the initial phase, as well as hydrolyze GlcNAc2 into N-acetylglucosamine (GlcNAc), which represents both chitobiosidase and β-N-acetylglucosaminase activity. Biological analyses showed that this chitinase exhibits strong antifungal activity toward agricultural pathogenic fungi. In total, chitinase from ʻBaozhu’ pear is a novel bifunctional chitinase that could be a potential fungicide in the biological control of plant diseases.