Paclitaxel production and PAL activity in hairy root cultures of Taxus x media var. Hicksii carrying a taxadiene synthase transgene elicited with nitric oxide and methyl jasmonate

The role of sodium nitroprusside (SNP, 10 μM), a nitric oxide (NO) donor, and/or methyl jasmonate (MJ, 100 μM) spiked with l-phenylalanine (PHEN, 100 μM) and additional sucrose (S; 30 g l−1), in taxane production and phenyl ammonia lyase (PAL) activity in cultures of two Taxus media x var. Hicksii transgenic root lines (ATMA and ATM) carrying the taxadiene synthase transgene was investigated. SNP addition, when applied together with MJ and/or PHEN, resulted in paclitaxel production only in ATMA cultures. The application of the NO donor gave the highest paclitaxel content (7.56 mg l−1) in the combination of SNP+S+MJ+PHEN, after 2 weeks of treatment in the ATMA root line. In ATM cultures, taxane production was not affected by SNP. In both ATMA and ATM lines the highest total (intra+extracellular) paclitaxel yield was determined when elicited with MJ+PHEN, and amounted to 10.78 mg l−1 at 1 week and 1.63 mg l−1 at 2 weeks of treatment, in cultures of ATMA and ATM lines, respectively. The excretion of paclitaxel was observed only in ATMA cultures, with the highest level (2.34 mg l−1) obtained after elicitation with S+MJ+PHEN. The comparison of PAL activity in the two root lines revealed that this enzyme was almost 3-times more active in ATM than ATMA roots. An increase in both PAL activity and paclitaxel production was only observed in ATMA cultures growing in medium supplemented with S+MJ+PHEN.