Identification of an Antifungal Chitinase from a Potential Biocontrol Agent, Streptomyces plicatus Strain 101, and its New Antagonistic Spectrum of Activity

Abstract

Streptomyces spp. are beneficial soil bacteria which are potential candidates as biological control agents against soil-borne plant pathogens. The Iranian Streptomyces plicatus strain 101 showed chitinolytic activity on minimal chitin agar medium (MCA) and antifungal inhibitory effects on mycelial growth of Rhizoctonia solani, Sclerotinia sclerotiorum, Fusarium graminearum, F. solani, Rosellinia necatrix and Pythium aphanidermatum mainly by extracellular chitinase production. A chitinase gene (400 bp) was partially isolated from this strain and its deduced amino acids sequence showed high similarity with other chitinase amino acid sequences of Streptomycetes. Partial chitinase amino acid sequence alignment of S. plicatus strain 101 has 92.1% identity with S. plicatus type strain. Key Words: antifungal chitinase, phytopathogen, Streptomyces plicatus