Chitosan elicitation of Isatis tinctoria L. hairy root cultures for enhancing flavonoid productivity and gene expression and related antioxidant activity

Abstract

Elicitation for phytochemical enhancement via cost-effective elicitors can overcome the limitation of commercial application faced by plant cell and organ culture technology. Chitosan is a natural, low-cost, and nontoxic elicitor that can trigger plant defense responses with the concomitant enhancement in phytochemical biosynthesis. In this work, the elicitation of Isatis tinctoria L. hairy root cultures by chitosan was conducted to enhance the production of pharmacologically active flavonoids. In comparison with control (2.31 ± 0.29 mg/g DW), a 7.08-fold enhancement of total flavonoids (16.35 ± 0.88 mg/g DW) was achieved in 24 day-old I. tinctoria hairy root cultures elicited by 150 mg/L chitosan for 36 h. Interestingly, the multiple hydroxyl-substituted flavonoids (rutin, quercetin, isorhamnetin, and isoliquiritigenin) were noticed to increase significantly in chitosan-elicited I. tinctoria hairy root cultures. Moreover, the transcription of associated genes involved in flavonoid biosynthesis pathway was significantly up-regulated underlying chitosan elicitation, among which chalcone synthase and flavonoid 3′-hydroxylase might play an important role in flavonoid enhancement. Additionally, extracts from chitosan-elicited I. tinctoria hairy root cultures exhibited higher antioxidant activities with lower IC 50 values as compared with control. Overall, a cost-effective strategy via the simple chitosan elicitation is provided here to enhance the production of high-added value flavonoids in I. tinctoria hairy root cultures, which paves the way toward the successful commercialization of this in vitro culture system in the future.

Chitosan Upregulates the Genes of the ROS Pathway and Enhances the Antioxidant Potential of Grape (Vitis vinifera L. ‘Touriga Franca’ and ’Tinto Cão’) Tissues

“…Exogenous chitosan reportedly interacts with chitin synthase, and chitin deacetylase in plants, to produce chitosan oligomers that are responsible for signal perception in cells, leading to the activation of various genes, including genes of the ROS pathway [50,70,71]. Elicitor molecules have been used to stimulate a broad range of responses including defense mechanism [72] in field conditions as well as in vitro cultures for elicitation of secondary metabolites [73,74,75,76]. However, it was reported earlier that acetic acid alone itself may exert some effect [77].…”

Isatis tinctoria L. (Woad): A Review of Its Botany, Ethnobotanical Uses, Phytochemistry, Biological Activities, and Biotechnological Studies

“…Such promising results prompted the Chinese team to perform the elicitation experiments on these cultures in order to boost the bioactive metabolites' production. The elicitation experiment with chitosan was proven to increase the flavonoid yield in I. tinctoria hairy root biomass [118]. In comparison with the control (2.31 mg/g DW), a 7.08-fold enhancement of total flavonoids (16.35 mg/g DW) was achieved in 24-day-old hairy root cultures elicited by 150 mg/L chitosan for 36 h [118].…”

“…The elicitation experiment with chitosan was proven to increase the flavonoid yield in I. tinctoria hairy root biomass [118]. In comparison with the control (2.31 mg/g DW), a 7.08-fold enhancement of total flavonoids (16.35 mg/g DW) was achieved in 24-day-old hairy root cultures elicited by 150 mg/L chitosan for 36 h [118]. Under another study, the I. tinctoria hairy root cultures were exposed to ultraviolet radiation (UV-A, UV-B, and UV-C) in an attempt to promote the production flavonoids.…”

Enhanced Secondary Metabolite Production in Hairy Root Cultures Through Biotic and Abiotic Elicitors

“…The elicitation by CHI causes the upregulation of flavonoid 3 0 -hydroxylase and chalcone synthase genes which in turn causes the elevated accumulation of flavonoids, i.e., rutin, quercetin, etc. [167]. Talking about the hairy roots of Agastache foeniculum, CHI shows a promotive effect on the hairy root growth.…”