Using RT-PCR combined with RACE techniques,we cloned the chitinases gene PhCHT (GenBank accession number:KT992851) from Phalaenopsis.The full length cDNA was 1 210 bp,containing a 5′-UTR of 37 bp,a 3′-UTR of 240 bp,and an opening reading frame of 933 bp encoding 310 amino acids;The deduced protein belonged to glycoside hydrolase family 19 and may have lysozyme activity.The bioinformatics analysis indicated that this protein was predicted to be an extracellular secreted protein with a N-terminal signal peptide and a transmembrane structure;It was highly identified with the chitinase-like protein of Phoenix dactylifera,Elaeis guineensis,Setaria italica,and Arabidopsis thaliana.Phylogenetic analysis showed that PhCHT belongs to a clade with other class Ⅶ chtinase genes from Gossypium hirsutum and Saccharum spp.The PhCHT gene was expressed in vegetative and reproductive organs with a higher expression level in root than others.The expression of PhCHT was decreased by a low temperature of 13 ℃/8 ℃ for 3,6,9 and 15 d,and increased by 4 ℃ treatment for 1,2 and 4 h.Our results suggest that the PhCHT plays a crucial role in responding to the short-term cold stress.These results could provide the foundation for further study the phyletic evolution of chitinase genes and the stress resistance breeding of Phalaenopsis.