Integrative effects of phytohormones in the phenolic acids production in Salvia verticillata L. under multi-walled carbon nanotubes and methyl jasmonate elicitation

Abstract

Abstract Salvia verticillata L. is a well-known herbal medicine rich in rosmarinic acid (RA) and with therapeutic values. Some physiological and biochemical responses of S. verticillata to methyl jasmonate (MJ) and multi-walled carbon nanotubes (MWCNTs) were investigated in this work. It has been supposed that the stimulants could change the level of phenolic compounds, especially RA, and activate their signaling pathways in S. verticillata. The leaves were sprayed with aqueous solutions containing 100 mg L-1 MWCNTs and 100 μM MJ and then harvested from 0 to 96 hours after treatment. Obtained data revealed significant variations in the levels of some phytohormones, as well as the content of H2O2 and the amount of lipid peroxidation, during the initial hours of harvesting. The content of phenolic acids positively correlated with the transcription levels of key enzymes involved in their biosynthesis, especially rosmarinic acid synthase. The content of RA increased more than 2.7- and 11.5-fold following exposure to MJ and MWCNTs, respectively. The patterns of changes in phytohormone levels in the treated leaves with MWCNTs were different from those in leaves elicited with MJ. It is reasonable to conclude that putative linkages between changes in some phytohormone pools, notably jasmonic acid and salicylic acid, and applied elicitors lead to the accumulation of phenolic acids in the leaves of S. verticillata. Overall, the present findings help us to improve our understanding of the signal transduction pathways of the applied stimulants that led to the enhancement of phenolic acids in S. verticillata.