Metabolomic Analysis of the Anthocyanins Associated with Different Colors of <i>Cymbidium goeringii</i> in Guizhou, China

Cymbidium goeringii is an economically important ornamental plant, and flower color is one of the main features of C. goeringii that contributes to its high economic value. To clarify the molecular mechanisms underlying the role of anthocyanins in mediating differences in color among varieties, liquid chromatography–tandem mass spectrometry was used to perform anthocyanin-targeted metabolomics of seven C. goeringii varieties, including 'Jin Qian Yuan' (JQY), 'Jin Xiu Qian Yuan' (JXQY), 'Miao Jiang Su Die' (MJSD), 'Qian Ming Su' (QMS), 'Shi Chan' (SC), and 'Yang Ming Su' (YMS), as well as the C. goeringii. We detected 64 anthocyanins, including cyanidins, delphinidins, malvidins, pelargonidins, peonidins, petunidins, procyanidins, and flavonoids. We identified six shared differentially accumulated metabolites (DAMs), including cyanidin-3-O-rutinoside, delphinidin-3-O-sophoroside, pelargonidin-3-O-rutinoside, peonidin-3-O-(6-O-malonyl-beta-D-glucoside), peonidin-3-O-sophoroside, and chalcone. Most DAMs were enriched in the anthocyanin biosynthesis pathway. Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that the differentially expressed metabolites were significantly enriched in the anthocyanin biosynthesis pathway. Analysis of the content of differentially expressed metabolites indicated that peonidin-3-O-(6-O-malonyl-beta-D-glucoside) was the key metabolite underlying color differences among C. goeringii varieties. Procyanidin B2, pelargonidin-3-O-galactoside, and naringenin might also affect the color formation of JQY and QMS, SC, and MJSD, respectively. The results of this study shed light on the metabolic mechanism underlying flower color differences in C. goeringii at the molecular level. Our findings will aid future studies of the mechanism of flower color regulation in C. goeringii and have implications for the breeding of new varieties.