Abstract: The full length cry8Ea gene was amplified by PCR using a pair of special primers,JJX5 and JJX3,de-signed according to cry8-type genes sequences,and inserted into E. coli expression vector pET-21b to obtain the recom 2 binant plasmid.Nucleic acid sequence analysis showed that this gene was 3 495 base pairs encoding 1 164 amino acids, which were homologof 99.31 % compared with Cry8Ea1,the molecular weight of the protein was 131.8 kDa with isoelec-tric point pH4.71. This gene sequence had been registered in GenBank(accession number was EU047597),and named cry8Ea-as a novel gene by Bacillus thuringiensis Delta Endotoxin Nomenclature Committee. The result of SDS-PAGE in- dicated that cry8Ea-gene could be expressed as a 130 kDa protein in E. coli BL21 (DE3) strain induced by IPTG.Bioassay of the expression product from the cry8Ea-gene showed evident toxic to the larvae of Popillia flavosella-ta, Holotrichia parallela and Plagiodera versicolora,with the corrected mortality of 46.67 %,55 1 56 % and 33.33 %,re-spectively.

Key words: Bacillus thuringiensis, cry8Ea2 gene, Cloning, Protein expression, Insecticidal activity

CLC Number: 

• Q785