Improvement of biosynthesis and accumulation of bioactive compounds by elicitation in adventitious root cultures of Polygonum multiflorum

Abstract

We examined the effects of abiotic (methyl jasmonate [MeJA] and salicylic acid [SA]) and biotic (yeast extract and chitosan) elicitors for improvement of bioactive compounds production on adventitious root cultures in Polygonum multiflorum. The application of yeast extract resulted in significantly (p ≤ 0.05) higher dry root biomass (9.98 g/L) and relative growth rate versus the control. Cultures treated with abiotic elicitors showed higher percentage of dry weight than the other samples. Low concentrations of all elicitors (50 μM MeJA and SA, and 50 mg/L yeast extract) improved secondary metabolite production except for chitosan, whose performance was worse than that of the control. HPLC analysis of various bioactive compounds revealed significantly higher elicitation efficiency for MeJA than for the other treatments, with an approximately 2-fold increase in root dry weight (22.08 mg/g DW) under 50 μM MeJA treatment versus the control (10.35 mg/g DW). We also investigated the feasibility of scaling up the production process by comparing shake flask cultures with 3- and 5-L balloon type bubble bioreactors (BTBB) using 50 μM MeJA as an elicitor. Growth and metabolite accumulation increased in BTBB compared with shake flask cultures. We detected a non-significant difference in biomass productivity between 3 and 5-L BTBB, but the efficiency of bioactive compound accumulation decreased with increasing volume. These findings will be useful for developing a pilot-scale P. multiflorum adventitious root cultivation process for high biomass and bioactive compound production to meet the demands for natural ingredients by the pharmaceutical and cosmetic industries without affecting the natural habitat of this plant.

Methyl Jasmonate Induced Oxidative Stress and Accumulation of Secondary Metabolites in Plant Cell and Organ Cultures

“…In addition, increasing of withanolide derivatives accumulation (14-fold) was achieved in 40-day-old hairy roots elicited with 15 µM MJ for 4 h exposure time [70]. In the previous studies on P. multiflorum, the phenolic compound in adventitious root culture reached to 2-fold higher than the control after 7-days treatment with 50 µM MJ, whereas 3.4-fold higher was observed in hairy roots after 5-day of exposure time [34,62]. Besides, an increase in 4.5-fold of triterpenoid in hairy root cultures of Centella asiatica was reported [71].…”

“…The metabolic profiling of a plant is influenced by various micro-environmental and macroenvironmental conditions. The plant responds to its surrounding environmental factors (as biotic and abiotic stress) through the stimulation of secondary metabolism to produce the desired compounds needed for its survival, the process is known as elicitation [58][59][60][61][62]. In recent days, MJ has been used extensively for elicitation studies involving in vitro culture systems such as cell suspension, adventitious root, hairy root and multiple shoot culture system (Table 1).…”

“…It also plays a role in the signal transduction, which speeds up enzyme catalysis, thereby leading to the formation of specific compounds such as polyphenol, terpenoids, flavonoids, and alkaloids [4,30]. Ho et al [62] reported that phenolic levels increased approximately 2-fold in adventitious root samples treated with 50 µM MJ (22.08 mg•g −1 DW) versus the control (10.08 mg•g −1 DW) in Polygonum multiflorum. In addition, hairy root cultures of P. multiflorum, the highest total phenolic content (52.87 mg•g −1 DW) was 3.4-fold higher than the control, especially, MJ treatment led to significantly higher levels of almost all individual phenolics, such as 1.13-fold increase of physcion, 3.83-fold of quercetin, 1.58-fold of kaempferol, 5.48-fold of p-hydroxybenzoic acid, and 4.3-fold of salicylic acid [62].…”

“…Ho et al [62] reported that phenolic levels increased approximately 2-fold in adventitious root samples treated with 50 µM MJ (22.08 mg•g −1 DW) versus the control (10.08 mg•g −1 DW) in Polygonum multiflorum. In addition, hairy root cultures of P. multiflorum, the highest total phenolic content (52.87 mg•g −1 DW) was 3.4-fold higher than the control, especially, MJ treatment led to significantly higher levels of almost all individual phenolics, such as 1.13-fold increase of physcion, 3.83-fold of quercetin, 1.58-fold of kaempferol, 5.48-fold of p-hydroxybenzoic acid, and 4.3-fold of salicylic acid [62]. Level of ginsenoside accumulation showed a seven-fold enhancement in the adventitious root cultures treated with 100 µM MJ when compared to the control [66].…”

Adventitious root culture for secondary metabolite production in medicinal plants: A Review

“…Almost all the studies that have been carried out, aim to compare the various types and concentrations of elicitor in order to obtain the most optimal elicitation strategy to increase the production of bioactive compounds. Among the various types of abiotic elicitors mentioned above, MJ was the most suitable type of abiotic elicitor for most adventitious root culture of medicinal plants such as Fagonia indica, Hypericum perforatum, Panax ginseng, Panax quinquefolium, Polygonum multiforum, and Scopolia parviflora (Khan et al 2017;Cui et al 2010;Wu et al 2008;Wang et al 2016;Ho et al 2018;Kang et al 2004). MJ can increase the synthesis of secondary metabolites in adventitious root culture through signal transduction which will accelerate the enzyme catalysis process, thus bioactive compounds such as alkaloids, flavonoids, terpenoids, and polyphenols will be formed (Zhao et al 2005).…”