Cloning, expression, and bioinformatics analysis of the chitinase gene PlCHI in Picea likiangensis var. balfouriana

The full-length cDNA of the chitinase gene PlCHI was cloned from Picea likiangensis var. balfouriana (Rehd. et Wils.) Hillier ex Slsvin by RT-PCR, with sequence characteristics and gene expression levels then analyzed. Results showed that the open reading frame of PlCHI was 1017 bp in length and encoded a protein with 338 amino acids. Protein sequence domain analysis indicated that PlCHI was a class Ⅰ chitinase that belonged to the 19 family and exhibited lysozyme activity. The sequence of PlCHI had high similarity to the protein sequences of other plant chitinases. Phylogenetic analysis showed that the PlCHI sequence was closely related to Pinaceae plants such as Picea sitchensis (Bong.) Corr. and Pinus thunbergii Parl. In this study, we further transferred the PlCHI recombinant plasmid into E. coli BL21 (DE3) to express a protein of about 45 kD, which was mainly in the form of an inclusion body. The optimal expression conditions of the gene were 0.2 mmol/L IPTG at 25℃ for 4 h induction.