Isolation and characterization of a strain of Bacillus thuringiensis subsp. morrisoni PG-14 encoding delta-endotoxin...

Area of Science:

• Microbiology
• Entomology
• Biotechnology

Background:

• Mushroom flies (Lycoriella mali and Coboldia fuscipes) are significant pests in mushroom cultivation.
• Bacillus thuringiensis (B.t.) is a soil bacterium known for its insecticidal properties.

Purpose of the Study:

• To characterize a novel B.t. strain (656-3) isolated from mushroom farm soil.
• To evaluate its insecticidal efficacy against key mushroom fly pests.
• To identify the specific insecticidal genes present in the strain.

Main Methods:

• Isolation and identification of B.t. 656-3 from soil samples.
• Bioassays to determine toxicity against Lycoriella mali and Coboldia fuscipes.
• Analysis of B.t. 656-3 inclusions and serological typing.
• Plasmid and protein profiling for comparison with reference strains.
• Polymerase Chain Reaction (PCR) using cry gene primers.

Main Results:

• B.t. 656-3 exhibited high toxicity against both Lycoriella mali and Coboldia fuscipes.
• The strain produced bipyramidal inclusions and serologically matched B. thuringiensis subsp. morrisoni (H8a8b).
• PCR analysis revealed the presence of cry4A, cry4B, cry10A, cry11A, and cry1Ac genes, distinguishing it from its reference strain.

Conclusions:

• B.t. 656-3 represents a unique strain with a distinct cry gene profile.
• Its high efficacy against mushroom flies suggests potential as a targeted biological control agent in mushroom farming.
• Further research into the specific Cry proteins and their mode of action is warranted.