Figure 4
Carotenoid biosynthesis pathway in Oncidium orchid and analysis of the expression level of OgPSY in transgenic Oncidium . (A) The scheme of carotenoid biosynthesis pathway in Oncidium orchid. *Indicates the target gene of PSY for RNA interference-based gene silencing. (B) Relative transcript level of OgPSY gene in wild type and OgPSY RNAi transgenic Oncidium orchid. GGDS: GGPP synthase; PSY: phytoene synthase; PDS: phytoene desaturase; ZDS: zeaxanthin desaturase; LCY: lycopene cyclase. ZEP: zeaxanthin epoxidase. Gene transcript levels were measured by RT-qPCR. Transcript levels were calculated and normalized with respect to ubiquitin mRNA. The experiment was repeated three times.