Expression and insecticidal activity of insect-specific neurotoxin BjαIT

According to the codon bias of Pichia pastoris,the insect-specific neurotoxin gene BjαIT was synthesized based on its amino acid sequence and was cloned to vectors of PET-30a (+) and pPIC9K respectively. The fusion protein of BjαIT expressed in Escherichia coli was induced with IPTG and was purified with Ni-NTA His Bind Column. The purified fusion protein was used to prepare antiserum and conduct bioactivity test. Dot blotting was used to screen the high-level expressed transformants of P. pastoris. The results showed that the highest expression of recombinant BjαIT in P. pastoris was about 20 mg/L in baffled flasks,and the BjαIT fusion protein expressed in E. coli was not toxic to locust Locusta migratoria manilensis and cockroach Blattela germanica,but that expressed in P. pastoris had insecticidal activity against locust and cockroach through injection.