Biotic elicitors enhance diosgenin production in Helicteres isora L. suspension cultures via up-regulation of CAS and HMGR genes

Abstract

In an attempt to find an alternative and potent source of diosgenin, a steroidal saponin in great demand for its pharmaceutical importance, Helicteres isora suspension cultures were explored for diosgenin extraction. The effect of biotic elicitors on the biosynthesis of diosgenin, in suspension cultures of H. isora was studied. Bacterial as well as fungal elicitors such as Escherichia coli, Bacillus subtilis, Saccharomyces cerevisiae and Aspergillus niger were applied at varying concentrations to investigate their effects on diosgenin content. The HPLC based quantification of the treated samples proved that amongst the biotic elicitors, E. coli (1.5%) proved best with a 9.1-fold increase in diosgenin content over respective control cultures. Further, the scaling-up of the suspension culture to shake-flask and ultimately to bioreactor level were carried out for production of diosgenin. During all the scaling-up stages, diosgenin yield obtained was in the range between 7.91 and 8.64 mg l -1 , where diosgenin content was increased with volume of the medium. The quantitative real-time PCR (qRT-PCR) analysis showed biotic elicitors induced the expression levels of regulatory genes in diosgenin biosynthetic pathway, the 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) and cycloartenol synthase (CAS), which can be positively correlated with elicited diosgenin contents in those cultures. The study holds significance as H. isora represents a cleaner and easy source of diosgenin where unlike other traditional sources, it is not admixed with other steroidal saponins, and the scaled-up levels of diosgenin achieved herein have the potential to be explored commercially.

Improving the Production of Total Phenolics and Flavonoids and the Antioxidant Capacity of Echinacea purpurea Callus through Biotic Elicitation

“…Increasing levels of A. niger significantly improved the accumulation of TFC compared to the control. These findings are in harmony with Tonk et al [59] on Catharanthus roseus, Ebrahimi et al [60] on Peganum harmal, and Shaikh et al [61] on Helicteres isora. This positive influence might be associated with the endogenous phytohormones such as salicylic acid in the callus tissues, which increased by increasing the elicitation level with A. niger as reported by Ibrahim et al [62].…”

Transcriptome analysis reveals candidate genes related to steroid alkaloid biosynthesis in Fritillaria anhuiensis

“…Inhibition of the activity of CAS leads to more 2,3‐oxidosqualene being available for ginsenoside biosynthesis, which indirectly results in enhanced ginsenoside levels and decreases phytosterol levels (Liang et al, 2009). Biotic elicitors increase the expression levels of CAS and HMGR genes, leading to enhanced diosgenin accumulation (Shaikh et al, 2020). These findings indicate that CAS has important roles in phytosterol synthesis and triterpene biosynthesis.…”

“…Biotic elicitors increase the expression levels of CAS and HMGR genes, leading to enhanced diosgenin accumulation (Shaikh et al, 2020).…”

Plant in vitro Culture Technologies; A Promise Into Factories of Secondary Metabolites Against COVID-19

“…A lot of important medicinal plants have been exploited for the production of useful antiviral medicinal metabolites through callus and cell cultures (Ali et al, 2018a,b). For example, as listed in Table 2, considerable levels of diosgenin (an anti-SARS-CoV metabolite) were detected in the callus cultures of Helicteres isora L (Shaikh et al, 2020). Callus and cell cultures in Gymnema sylvestre have shown an optimal production of gymnemic acid (GA) which possesses the potential to work against SARS-CoV-2 (Veerashree et al, 2012).…”