Influence of minerals on valerenic acid accumulation in hairy root cultures of Valeriana officinalis L

The roots and rhizomes of Valeriana (Valerianaofficinalis L.) are rich with valuable metabolites such as valerenic acid and valepotriates are used as mild sedatives. The aim of the present study was to investigatethe effect of four levels of calcium and potassium compounds (half, full, 2 and 4-fold) of normal Murashige and Skoog (MS) media including KI and CaCl2on ValerianaofficinalisL. hairy roots for scaling-up producing valerenic acid. Various explants of 42-day-old sterile seedlings derived from V. officinaliswere used for a genetic transformation viaAgrobacterium rhizogenesA13strain.Polymerase chain reaction (PCR) analysis and genes primers ofrolB and virDwere conducted to confirm the transgenic nature of the roots and that the roots were bacteria-free. Then,the hairy root cultures of V. officinaliswere maintained in the media for investigations of valerenic acid production ability. After 35 days the valerenic acid content in hairy roots was measured using high-performance liquid chromatography (HPLC) to determine the best yielding conditions.The highest valerenic acid (0.69±0.03 mg/g DW) accumulation was obtained from hairy roots culturedin2-fold of calcium media, which was1.92 times higher than normal culture (0.36± 0.01 mg/g DW). The results of this experiment also showed that application of double (880 mg/l) calcium in mediahad a positive effect on growth of transformed hairy roots.The results revealed that calcium concentration in the MS medium may be used for the intensification of the valerenic acid productionin Valerianaofficinalis hairy roots cultures.