Establishment and elicitation of adventitious root cultures in Phryma leptostachya for enhanced furofuran lignan production

The development of efficient in vitro culture systems for sustainable production of plant secondary metabolites is a central goal in plant biotechnology. Phryma leptostachya is a medicinal plant rich in bioactive furofuran lignans; however, large-scale production is constrained by field cultivation. In this study, an adventitious root culture system was established as an alternative platform for controlled lignan production. Adventitious roots were successfully induced and maintained by optimizing auxin concentrations, with 2.0 mg L⁻¹ indole-3-butyric acid (IBA) supporting optimal biomass accumulation and lignan yield. To further enhance secondary metabolite production, three elicitors, including methyl jasmonate (MeJA), chitosan, and L-phenylalanine were evaluated. Among these, treatment with 100 µM MeJA significantly increased the levels of four major furofuran lignans by 1.5‑fold for (+)-leptostachyol acetate, 3.2‑fold for (+)-6-demethoxyleptostachyol acetate, 7.4‑fold for (+)-phrymarolin I, and 2.6‑fold for (+)-phrymarolin II, respectively, compared with the control. Insecticidal bioassays showed that crude extracts from elicited roots synergistically enhanced the efficacy of cyhalothrin, avermectin, and indocarb against Mythimna separata, with synergistic ratios of 2.37, 1.55, and 1.61, respectively. These findings confirm the functional integrity of lignans produced in vitro. Overall, this study demonstrates that P. leptostachya adventitious root cultures represent a stable and sustainable experimental system for enhanced lignan production.