Abstract：Bacillus thuringiensis (Bt) is an insect pathogenic bacteria that has been widely used in biological control of agricultural insect pests. In this study, one Bt strain was isolated from 159 samples collected from coalfields in Tianhu Mountain, Yongchun County, Fujian Province. Bipyramidal parasporal crystal of isolated Bt strain was observed under microscope. PCR results showed that isolated Bt strain carried cry1 type gene using general primers of cry1/7/9, cry2, cry3, cry4/10, cry5, cry6, cry8, cry11 and cry1I genes, then cry1 gene was cloned and sequenced. Homology analysis of nucleotide sequence of cry1 showed that it was of high similarity with the reported cry1Ac genes. Results of SDS-PAGE and 2-dimensional electrophoresis/mass spectrometry (2-DE/MS) showed that isolated Bt strain encoded approximately 130 kD crystal protein, which was then identified as insecticidal protein Cry1Ac by mass spectrometry (MALDI-TOF/TOF-MS). Molecular chaperone GroEL, ATP F0F1 synthase subunit beta, elongation factor Tu and pyruvate dehydrogenase were identified by MALDI-TOF/TOF-MS, respectively. Further understanding of protein functions were conducted through bioinformatics analysis, leading to correct folding of nascent peptides, energy production and conversion, as well as improving the ability of cells to withstand adverse external stimuli. This work provides basic data for discovering new Bt resources, new insecticidal protein and using microbial to control heavy metal pollution.
