Phenylpropanoid biosynthetic gene expression and nutrient uptake kinetics for enhanced rosmarinic acid production in suspension cultured cells of Halodule pinifolia

Abstract

This study investigated the effect of precursors (phenylalanine and tyrosine) and elicitors (methyl jasmonate and yeast) on enhanced rosmarinic acid (RA) biosynthesis, their transcript levels (HpPAL, HpC4H, Hp4CL, HpTAT and HpHPPR) and nutrient uptake kinetics from cell cultures of Halodule pinifolia (Miki) Hartog under in-vitro conditions. Different concentrations of precursors and elicitors were used, among which methyl jasmonate (20 μM) induced higher accumulation of RA (123.16 ± 3.30 mg g−1 DW) followed by phenylalanine (57.086 ± 1.01 mg g−1 DW), tyrosine (28.723 ± 1.55 mg g−1 DW) and yeast elicitor (1.95 mg g−1 DW). Further, the transcript levels of phenylpropanoid biosynthetic genes HpPAL, HpC4H and Hp4CL from MeJA treated cells were found to increase transiently, while TAT and HPPR did not express. It clearly conveyed that H. pinifola culture has undergone phenylpropanoid pathway for RA biosynthesis as compared to the control. Nutrient uptake kinetics determined the consumption of major nutrients such as phosphate, nitrate, sucrose and variations in pH during RA biosynthesis and the optimum pH was found to be pH -7.4, where the concentration of RA accumulated higher during the aforementioned pH. Therefore, the study concludes that methyl jasmonate acts as a potent elicitor for RA accumulation and the enhanced RA biosynthesis in the treated cells might be due to the activation of phenylproponoid genes HpPAL, HpC4H and Hp4CL. Furthermore, the work should be made to influence and optimize the H. pinifolia culture system for better productivity of rosmarinic acid for the food, cosmetic, pharmacy and neutraceutical applications.