Photoperiod and elicitors increase steviol glycosides, phenolics, and flavonoid contents in root cultures of Stevia rebaudiana

The establishment of green root cultures of Stevia rebaudiana Bertoni, and the effect of elicitors such as hydrogen peroxide (H2O2) and methyl jasmonate (MeJA), is shown in the present study. Stevioside, rebaudioside A, and the isomers steviol/isosteviol were identified through DFI-ESI-IT-MSn and UPLC-TOFMS spectrometric systems, in combination with solid-phase extraction. The accumulation of steviol glycosides increased by 2.4 times (compared to the control value of 22.35 μgSG per gDW), with the addition of 250 μM H2O2. The non-enzymatic antioxidant response, which resulted from production of phenolic and flavonoid compounds, was modified based on the elicitor and the dose used. The maximum accumulation of flavonoids was induced on the third day with the addition of H2O2 (250 or 500 μM), and with MeJA (250 or 500 μM); the increase was observed on the fifth day. The enzymatic antioxidant response of the catalase and peroxidase from the roots under elicitation confirmed the stress conditions.