Metabolomic and Transcriptomic Analysis Reveal the Role of Metabolites and Genes in Modulating Flower Color of .

Food-deceptive flowers primarily use visual signals (such as color) to mimic model plants and deceive insects into achieving pollination. is a food-deceptive orchid that has a pink labellum and two purple petals with a yellow base and has been proven to be pollinated by bumblebees. However, the chemical and molecular bases of the floral color are not well understood. We conducted targeted metabolite profiling and transcriptomic analysis to determine the color signal and its genetic basis in . We found that both anthocyanins and carotenoids contribute significantly to the formation of floral color that determines the color signal. Higher concentrations of anthocyanins (cyanidin and peonidin) and carotenoids (primarily lutein and zeaxanthin) were detected in the petal compared to the labellum. The upregulation of structural genes of , ', and on the anthocyanin biosynthesis pathway in petals was identified, as well as three genes of , , and on the carotenoid biosynthesis pathway. Furthermore, we discovered that three and one transcription factors were co-expressed with the expression of different genes. These genes and transcription factors may be responsible for the spatial color difference of . Our study emphasizes that the color of this food-deceptive orchids is achieved through specific genes and transcription factors associated with the pigment biosynthesis pathway.