Profiling of Bacillus thuringiensis Biopesticides: A High-Resolution LC-MS/MS Approach for Subspecies Identification...

Area of Science:

• Agricultural Science
• Analytical Chemistry
• Environmental Science

Background:

• Bacillus thuringiensis (Bt)-based biopesticides are widely used in organic farming.
• Limited data exists on insecticidal protein concentrations in treated samples and the environment post-application.
• Accurate quantification is needed for quality control and environmental risk assessment.

Purpose of the Study:

• To develop and validate a sensitive analytical method for identifying and quantifying Bt crystal proteins.
• To differentiate between Bt subspecies (kurstaki, aizawai, israelensis).
• To provide reliable data for Bt biopesticide application monitoring.

Main Methods:

• Development of an LC-HR-MS/MS-PRM method.
• Selection and validation of marker peptides for subspecies differentiation and quantification.
• Utilized stable-isotope-labeled (SIL) standards for accurate quantification.
• Analysis of various sample matrices, including treated basil plants.

Main Results:

• The developed method exhibits high sensitivity (ng/g range), precision, and selectivity.
• Accurate identification of Bt subspecies and quantification of crystal proteins were achieved in treated basil samples.
• The method successfully differentiated between the analyzed Bt subspecies.

Conclusions:

• The LC-HR-MS/MS-PRM method provides a robust analytical tool for Bt biopesticide assessment.
• This approach supports product quality control and enhances environmental safety evaluations.
• It addresses critical limitations in current methods for monitoring Bt toxins.