Light
quality is one of the key elicitors that directly affect
plant cell growth and biosynthesis of secondary metabolites. In this
study, the red callus of spine grape was cultured under nine light
qualities (namely, dark, white, red, yellow, blue, green, purple,
warm-yellow, and warm-white light). The effects of different light
qualities were studied on callus growth, accumulation of phenolic
compounds, and total antioxidant capacity of the red callus of spine
grape. The results showed that blue and purple light induced increased
red coloration in the callus, whereas yellow light induced the greatest
callus proliferation. Among all of the light quality treatments, darkness
treatment downregulated the contents of phenolic compounds, whereas
blue light was the treatment most conducive to the accumulation of
total phenolics. White, blue, and purple light induced increased anthocyanin
accumulation. Mixed-wavelength light was beneficial to the accumulation
of flavonoids. Blue and purple light were conducive to the accumulation
of proanthocyanidins. A further study showed that cyanidin 3-glucoside
(Cy3G) and peonidin 3-glucoside (P3G) were the main anthocyanin components
in the callus, and blue, purple, and white light treatments promoted
their accumulation, whereas flavan-3-ols and flavonols were the main
components of non-anthocyanin phenolics, and their accumulation changed
in response to not only light quality but also culture duration. The
total antioxidant capacity of the callus cultures changed significantly
in response to different light qualities. These results will provide
evidence for an abiotic elicitor strategy to stimulate callus growth
and enhance the accumulation of the main phenolic compounds in the
red callus of spine grape.