*Article* **Comparative Analysis and Expression Patterns of the** *PLP\_deC* **Genes in** *Dendrobium o*ffi*cinale*

**Lei Zhang 1,2 , Chunyan Jiao 1,2, Yunpeng Cao 3,4 , Xi Cheng 1,2, Jian Wang 1,2, Qing Jin 1,2,\* and Yongping Cai 1,2,\***


Received: 15 November 2019; Accepted: 17 December 2019; Published: 20 December 2019 -

**Abstract:** Studies have shown that the type II pyridoxal phosphate-dependent decarboxylase (*PLP\_deC*) genes produce secondary metabolites and flavor volatiles in plants, and TDC (tryptophan decarboxylase), a member of the *PLP\_deC* family, plays an important role in the biosynthesis of terpenoid indole alkaloids (TIAs). In this study, we identified eight *PLP\_deC* genes in *Dendrobium o*ffi*cinale*(*D. o*ffi*cinale*) and six in *Phalaenopsis equestris*(*P. equestris)*, and their structures, physicochemical properties, response elements, evolutionary relationships, and expression patterns were preliminarily predicted and analyzed. The results showed that *PLP\_deC* genes play important roles in *D. o*ffi*cinale* and respond to different exogenous hormone treatments; additionally, the results support the selection of appropriate candidates for further functional characterization of *PLP\_deC* genes in *D. o*ffi*cinale*.

**Keywords:** *Dendrobium o*ffi*cinale*; *PLP\_deC*; bioinformatics; expression pattern analysis; evolution
