Genome-wide identification of carboxyesterase family members reveals the function of GeCXE9 in the catabolism of parishin A in Gastrodia elata.

Key message: GeCXE9 can catalyze the hydrolysis of parishin A via two pathways during the medicinal processing of Gastrodia elata. Gastrodia elata Bl. is used in traditional Chinese medicine for its bioactive compounds, particularly phenols. The molecular mechanisms of phenols formation and regulation remain to be fully explored. Here, we identified 13 GeCXE genes in G. elata. These members were mapped to eight chromosomes and possessed motifs necessary for catalysis. Phylogenetic analyses grouped them into four categories, supported by gene structure and motif composition. The cis-acting elements analysis indicated most GeCXEs contained elements associated with plant hormones or stress response. In vitro expression experiments revealed that GeCXE9 can catalyze the hydrolysis of parishin A via two pathways, producing parishin B and parishin C, respectively. Whereas in the absence of GeCXE9, parishin A is hydrolyzed solely to parishin B. In conclusion, GeCXE9 plays a crucial role in determining the metabolic pathways of phenols in G. elata, and its discovery provides a viable approach for the artificial regulation of phenols in this species.