New Bacillus thuringiensis strain isolated from the gut of Malabari goat is effective against Tetranychus macfarlanei

作者：Neethu K B; Priji P; Unni K N; Sajith S; Sreedevi S; Ramani N; Anitha K; Rosana B; Girish M B; Benjamin S^*

来源：JOURNAL OF APPLIED ENTOMOLOGY, 2016, 140(3): 187-198.

DOI：10.1111/jen.12235

• Bt strain BPU5
• Malabari goat
• mite
• rumen
• Tetranychus macfarlanei
• -endotoxin

This study illustrates a novel strain (designated as BPU5) of Bacillus thuringiensis (Bt) isolated from the rumen of Malabari goat, capable of producing polymorphic -endotoxin crystals concomitantly with sporulation in Luria-Bertani medium (LB), and the -endotoxin was efficient to combat Tetranychus macfarlanei, a devastating mite. Polymorphic -endotoxin crystals produced were assessed by scanning electron microscopy and monitored its production concomitantly with sporulation in LB with or without sugar supplements. Toxicity of the -endotoxin was assessed on T.macfarlanei using leaf disc bioassay method. Mortality rate was determined by comparing the survival of mites on the diet (prepared in 10% sucrose and powdered rice husk) containing different concentrations (1-10mg/ml) of 72-h-old crude pellet (dried mixture of -endotoxin (17mg/g pellet), endospores and a few vegetative cells) or control diet with autoclaved pellet. The maximum production (1.39mg/ml) of -endotoxin was observed at 72h in LB. Among the sugars (glucose, sucrose, maltose or lactose) tested as additional carbon source, glucose (8g/l) enhanced (1.82mg/ml) the production of -endotoxin by 30%. The lethal concentration (LC50) required to kill 50% mites was estimated as 8.024mg/ml. The -endotoxin produced by B.thuringiensis BPU5 is shown to efficiently combat T.macfarlanei, a devastating mite infesting agricultural fields.

• 出版日期2016-4