Expression of chitinase B and C genes of Serratia marcescens and determining their insecticidal activities against Galleria mellonella

There are significant amount of chitin in the structure of peritrophic membrane which surround cuticle and gut in insects. Degradation of the chitin, found in the structure of cuticle and peritrophic membrane by the chitinase enzymes, decreases the feeding and the defence of the insect and thus makes the insect weak. Therefore chitinases are important enzymes which have potential as being use biological control agent against harmful insects.In this study, the genes encoding chitinase B (chiB) and chitinase C (chiC) from Serratiamarcescensthat isolated fromXyleborusdispar, amplified with dejenerate primers by PCR.For identifying the nucleotide sequence of the amplified genes, PCR products were sequenced. Nucleotide sequences of chiB and chiC genes were determined and compared with other chiB and chiC genes.Analysis results showed that chiB and chiC genes belong to S. marcescens have96% homology with S.marcescens(BJL200) chiB gene for chitinaseB and 96% homology with S. marcescenschiC (AJ630582.1) for chitinaseC. Chitinase genes from S. marcescenswere cloned into the pHY300PLK shuttle vector and these recombinant plasmids were introduced into E. coli DH10ß and various strains of Bt by electroporation.Plasmid stability test was performed to the B. thuringiensisstrains and E. coli DH10ß cells including recombinant strains. According to the test results it is determined that host cells could not save the recombinant plasmids.Insecticidal activity of B. thuringiensisstrains containing recombinant plasmids were tested on G. mellonellalarvae. As a result Bt strains harboring recombinant plasmids showed higher insecticidal activity than parental Bt strains and S. marcescens.KeyWords:Bacillusthuringiensis,Chitinase, Serratiamarcescens,İnsecticida lactivity