Bacillus thuringiensis isolates from Great Nicobar Islands.

Area of Science:

• Microbiology
• Entomology
• Biodiversity Studies

Background:

• Great Nicobar Islands are a biodiversity hotspot with unexplored microbial resources.
• Bacillus thuringiensis (Bt) is a bacterium known for its insecticidal properties, crucial for biological pest control.

Purpose of the Study:

• To isolate and characterize novel Bacillus thuringiensis strains from the Great Nicobar Islands.
• To assess the insecticidal potential of these new isolates against key agricultural pests.

Main Methods:

• Soil samples were screened for Bt isolation.
• Isolates were characterized using microscopy, SDS-PAGE for cry gene profiling, and toxicity assays.
• PCR was used to identify specific cry genes (cry1B and cry8b).

Main Results:

• 36 new Bt isolates were obtained, exhibiting diverse crystal protein profiles (66-35 kDa, >130 kDa, 130 kDa, 73 kDa, 18 kDa).
• Significant insecticidal activity was observed: 50% against Ash weevils, 16% against cotton bollworm, and 38% against both.
• PCR analysis confirmed the presence of cry1B- and cry8b-like genes in many isolates.

Conclusions:

• This study represents the first isolation and characterization of local Bt strains in the Great Nicobar Islands.
• Several isolates demonstrate potent insecticidal activity, making them promising candidates for biological control strategies.
• These findings support the use of novel Bt strains in integrated pest management for sustainable agriculture in the region.