Elicitation of Stevia Glycosides Using Salicylic Acid and Silver Nanoparticles Under Callus Culture

Abstract

Development of biosynthesis of phytochemicals, especially medicinal products, is highly important due to their broad bioactivity properties. In this study, optimization of callus growth was initially carried out using various combinations of plant growth regulators. Callus with the highest fresh weight was produced on Murashige and Skoog (MS) medium containing 1 (mg/l) naphthalene acetic acid + 0.5 (mg/l) benzyl aminopurine. The effect of different concentrations of salicylic acid (SA) (0.25, 0.5 and 0.75 mg/l) and silver nanoparticles (Ag NPs) (15, 30, 45 and 60 mg/l) on callus growth as well as the possibility of stevia glycosides (SGs) production in callus culture was subsequently evaluated. The SA elicitation, at a concentration of 0.75 (mg/l), resulted in the highest level of callus growth rate (0.1 cm/day), callus diameter (0.79 cm) and relative callus fresh weight (0.085). Likewise, 45 (mg/l) of Ag NPs led to the highest amount of stevioside (32.34 mg/g dry weight callus). The addition of 0.25 (mg/l) of SA to the MS medium led to production of the highest amount of rebaudioside A (3.40 mg/g dry weight callus). The results of this study may enhance the commercial application of important glycosides prevalent in Stevia by highlighting that the nano-elicitors and SA should be utilized at optimized concentrations.