Self-fusion of Streptomyces griseus enhances chitinase production and biocontrol activity against Fusarium oxysporum f. sp. lycopersici

摘要

Protoplasts were isolated from Streptomyces griseus (MTCC - *4734) strain using lysing enzymes and self-fusion of Streptomyces griseus protoplasts was carried out using 50% polyethylene glycol (MW 1000, Sigma Chemicals Co., USA) in protoplast buffer.The regenerated 8 self fused Streptomyces griseus were studied detailed for chitinase production and biocontrol activity. Parent strain (PSg) showed protein content of 2.7 mg/ml with chitinase activity of 120 ID/ml. High chitinase activity was measured in the culture filtrates of most of the self-fusants (87%) than the parent. Among the fusants, the strain SFSg 5 produced protein content of 7.8 mg/ml, maximum chitinase activity of 283.3 ID/ml with a two-fold increase as compared to the parent strain. AHthe self-fusants exhibited increased antagonistic activity against F. oxysporum f. sp. lycopersici than the parent. Maximum inhibition (82%, 80%) of mycelial growth of F. oxysporum was recorded with fusant of SFSg 5, SFSg 1 as against 61.1% with PSg. The result implies that, the self-fused Streptomyces griseus resulted in appreciable increase of chitinase production and biocontrol activity also the significance of the protoplast fusion technique, which could successfully be used to develop hybrid strains also for commercial formulation.