A new biotechnological source of rosmarinic acid and surface flavonoids: Hairy root cultures of Dracocephalum kotschyi Boiss

Abstract

Hairy root induction in Dracocephalum kotschyi Boiss was investigated as a method of producing rosmarinic acid and surface flavonoids, plant secondary metabolites well-known for their antioxidant and anticancer activities. The transformation of D. kotschyi hairy root lines induced by infection with Agrobacterium rhizogenes LBA 9402 was confirmed by PCR detection of rolC and aux1 genes, and their capacity to grow and biosynthesize rosmarinic acid and surface flavonoids was studied. Two types of morphology, typical hairy root and callus-like were observed in the induced root lines. The rolC and aux1 genes were detected in the genome of both morphological types of root lines, although aux1 was more frequently observed in callus-like roots. Our results showed the capacity of the obtained hairy root lines to produce rosmarinic acid and methoxylated flavonoids. Rosmarinic acid content in hairy root lines ranged from 10 to 1500μg/g DW, which at its peak was 15 times higher than in the intact control roots. Surface flavonoids were identified in most hairy root lines, some of which showed a surface flavonoid content higher than the roots of the whole plant but generally lower than the plant leaves.