Red and blue light have different effects on flavonols and proanthocyanidins accumulation in the cell culture of tartary buckwheat

Tartary buckwheat Fagopyrum tataricum (L.) Gaertn. is a pharmaceutically important plant, which contains a plenty of phenolic compounds, of which one of the most abundant is rutin having antihyperglycemic, antihypertensive and antioxidative properties. Rutin is UV-B absorbing flavonoid synthesized in higher plants to protect them from the harmful effects of UV-B irradiation. This study was aimed at developing the approaches for increasing the synthesis of rutin and other phenolic compounds (PCs) in buckwheat suspension culture with blue and red light treatment. It was found that the exposure to specific light spectrum promoted the synthesis of certain classes of PCs in F. tataricum suspension culture: blue light enhanced the accumulation of proanthocyanidins (PAs) (both soluble and insoluble), but decreased by almost 4 times the content of flavonols (quercetin and its glycosides - rutin and quercitrin); red light, on the contrary, suppressed the synthesis of insoluble PAs and did not affect the content of soluble PAs, but increased the content of rutin by 1.6 times compared to darkness conditions. Morphogenic suspension culture of F. tataricum can be a convenient model system for studying the functions of PCs and regulating their biosynthesis, as well as an alternative source for the biotechnological production of rutin and other physiologically active PCs.