Genome-Wide Identification and Expression Analysis of the Chalcone Synthase (CHS) Gene Family in Dendrobium catenatum

Flavonoids are considered to be critical metabolites in regulating plant responses to abiotic stress. Chalcone synthase (CHS) catalyzes the first key step in the flavonoid biosynthesis pathway. However, there is no in-depth information on the sequence and functional analysis of CHS genes in Dendrobium catenatum. In this study, a total of 14 DcCHS genes were identified, encoding proteins of 349–504 amino acids in length, a protein molecular weight ranging between 39.08 and 56.56 kDa, and isoelectric points from 5.64 to 9.63. The DcCHS proteins were then divided into three groups according to their phylogenetic relationships. The members of each group had similar conserved motifs and gene structures. Quantitative real-time RT-PCR (RT-qPCR) analysis revealed that the DcCHS genes exhibited variable expression patterns in the different plant tissues evaluated. Furthermore, six genes were differentially expressed following exposure to abiotic stresses: DcCHS-6, DcCHS-5/-6, DcCHS-13/-14, and DcCHS-6/-8/-9/-13, which were specifically expressed in response to drought, heat, cold, and salt stress, respectively. This is the first genome-wide analysis of the CHS genes in D. catenatum, and our findings can provide essential information for a better understanding of the function of DcCHS genes, thus facilitating further research on D. catenatum stress tolerance.