Expression levels of carotenoid biosynthetic genes and carotenoid production in the callus of scutellaria baicalensis exposed to white, blue, and red light-emitting diodes

In the present study, efforts were made to determine effect of different light wavelengths on carotenoid biosynthesis in Scutellaria baicalensis, a promising traditional herbal medicine used in North America and Asia. The variation in the transcriptional level of carotenoid biosynthesis genes and carotenoid contents in the callus was analyzed after exposure to light from red (wavelength, 660 nm), blue (wavelength, 470 nm), or white (wavelength, 380 nm) light-emitting diodes. The transcription levels of phytoene synthase (SbPSY), ξ-carotene desaturase (SbZDS), β-ring carotene hydroxylase (SbCHXB), and zeaxanthin epoxidase (SbZEP) were upregulated on exposure to all three lights, with the greatest increase in expression observed upon exposure to blue light. In contrast, the transcriptional levels of two carotenoid cleavage dioxygenases (SbCCD1 and SbCCD4) decreased under all three light treatments. Increased production of zeaxanthin, β-carotene, and 9-cis-β-carotene was observed on exposure to all 3 lights. The total carotenoid production rose by 27.35% under blue light treatment, while the white and red lights did not have any considerable effect. Our findings may establish new approaches for increasing carotenoid production in S. baicalensis as well as in other plants.