Identification and Characterization of Chalcone Isomerase Genes Involved in Flavonoid Production in Dracaena cambodiana

Dragon's blood is a traditional medicine in which flavonoids are the main bioactive compounds; however, the underlying formation mechanism of dragon's blood remains largely poorly understood. Chalcone isomerase (CHI) is the key enzyme in the flavonoid biosynthesis pathway. However, family genes are not well understood in Pierre ex Gagnep, an important source plant of dragon's blood. In this study, 11 family genes were identified from , and they were classified into three types. Evolutionary and transcriptional profiling analysis revealed that and might be involved in flavonoid production. Both and displayed low expression levels in stem under normal growth conditions and were induced by methyl jasmonate (MeJA), 6-benzyl aminopurine (6-BA, synthetic cytokinin), ultraviolet-B (UV-B), and wounding. The recombinant proteins DcCHI1 and DcCHI4 were expressed in and purified by His-Bind resin chromatography. Enzyme activity assay indicated that catalyzed the formation of naringenin from naringenin chalcone, while DcCHI4 lacked this catalytic activity. Overexpression of or enhanced the flavonoid production in and tobacco. These findings implied that and play important roles in flavonoid production. Thus, our study will not only contribute to better understand the function and expression regulation of family genes involved in flavonoid production in but also lay the foundation for developing the effective inducer of dragon's blood.