Phenylalanine and LED lights enhance phenolic compound production in Tartary buckwheat sprouts

The present study aimed to investigate the effects of different l-phenylalanine (l-Phe) concentrations and various light-emitting diodes (LEDs) on the accumulation of phenolic compounds (chlorogenic acid, vitexin, rutin, quercetin, cyanidin 3-O-glucoside, and cyanidin 3-O-rutinoside) in Tartary buckwheat sprouts. We found that 5 mM was the optimum l-Phe concentration for the synthesis of total and individual phenolic compounds. The highest rutin (53.09 mg/g DW) and chlorogenic acid (5.62 mg/g DW) content was observed with Red + Blue and white lights. Comprehensive differences in total and individual anthocyanin content were observed between different lights; however, the total anthocyanin content (9.12 mg/g DW) was 1.5-fold higher in blue light. The expression levels of regulatory genes, such as FtDFR and FtANS, were 7.1-fold higher with l-Phe treatment. Gene expression results showed that the phenolic compounds in Tartary buckwheat sprouts increased with the use of l-Phe and LED lights.