Salinity-induced modifications on growth, physiology and 20-hydroxyecdysone levels in Brazilian-ginseng [Pfaffia glomerata (Spreng.) Pedersen]

– Salinity is a major threat to agriculture. However, depending on the concentration of soluble salts in soil, increased secondary metabolite levels can occur with no major damages to plant growth and development. The phytoecdysteroid (PE) 20-hydroxyecdysone (20E) is a secondary metabolite with biotechnological, medicinal, pharmaceutical and agrochemical applicability. Here, we characterize the responses (growth and physiology) of Pfaffia glomerata under different NaCl concentrations and examine the production of 20E as affected by salinity. Forty-day-old plants grown in greenhouse were exposed to 0, 120, 240, 360 or 480 mM of NaCl for 11 days. Moderate salinity (i.e., 120 mM of NaCl) led to increased 20E concentrations in leaves (47%) relative to the control with no significant effect on photosynthesis and biomass accumulation, thus allowing improved 20E contents on a per whole-plant basis. In contrast, plants under high salinity (i.e., 240–480 mM of NaCl) displayed similar 20E concentrations in leaves compared to the control, but with marked impairments to biomass accumulation and photosynthetic performance (coupled with decreased sucrose and starch levels) in parallel to nutritional imbalance. High salinity also strongly increased salicylic acid levels, antioxidant enzyme activities, and osmoregulatory status. Regardless of stress severity, 20E production was accompanied by the upregulation of Spook and Phantom genes. Our findings suggest that P. glomerata cultivation in moderate salinity soils can be considered as a suitable agricultural option to increase 20E levels, since metabolic and structural complexity that makes its artificial synthesis very difficult. •Moderate salinity (i.e., 120 mM of NaCl) increases 20-hydroxyecdysone (20E) levels in Pfaffia glomerata.•Expression of genes related to 20E biosynthetic pathways is markedly influenced by salinity.•High salinity (i.e., 240–480 mM of NaCl) inhibits growth, ion balance and photosynthetic performance.•High salinity leads to altered phytohormone levels and enhanced anti-oxidative systems and osmoregulatory status.