Application of Priming Strategy for Enhanced Paclitaxel Biosynthesis in × Hairy Root Cultures.

Despite huge progress in biotechnological approaches to paclitaxel production, spp. in vitro culture productivity still remains a challenge. This could be solved by developing a new strategy engaging mechanisms of the primed defence response joined with subsequent elicitation treatment to circumvent limitations in paclitaxel biosynthesis. The hairy roots were primed by preincubation with β-aminobutyric acid (BABA) for 24 h or 1 week, and then elicited with methyl jasmonate (MeJA) or a mixture of MeJA, sodium nitroprusside and L-phenylalanine (MIX). The effect of priming was evaluated on a molecular level by examination of the expression profiles of the four genes involved in paclitaxel biosynthesis, i.e., (taxadiene synthase), (baccatin III: 3-amino, 3-phenylpropanoyltransferase), (3'--debenzoyl-2-deoxytaxol--benzoyltransferase) and (phenylalanine aminomutase), as well as (cytokinin-β-glucosidase), originated from the T-DNA of . The maximum paclitaxel yield was achieved in cultures primed with BABA for 1 week and elicited with MIX (3179.9 ± 212 µg/g dry weight), which corresponded to the highest expression levels of and genes. Although BABA itself induced the investigated gene expression over control level, it was not translated into paclitaxel production. Nevertheless, preincubation with BABA essentially affected paclitaxel yield, and the duration of BABA pretreatment seemed to have the most pronounced impact on its productivity.