Stimulating secondary compound accumulation by elicitation: Is it a realistic tool in medicinal plants in vivo?

Abstract

Stimulating the production of secondary metabolites by elicitation seems to be an accepted tool in several in vitro cultures. In vivo application of chemical elicitation is, however, much less frequently discussed. The paper summarizes the experimental findings on the effects of jasmonic acid, methyl-jasmonate (MeJa) and salicylic acid (SA) treatments on medicinal and aromatic plants. Growth behaviour, yield, stress responses, essential oil (EO) and phenolic compounds are discussed. Exogenous application of MeJa or SA mostly by foliar spraying in concentrations between 10−4 and 4 mM, induced various changes in the plants. In most cases, the elicitation enhanced the volatile accumulation, although the opposite reaction was observed too. Numerous in vivo trials also demonstrated an altered EO composition. Positive effects of treatments on the concentration of phenolic type compounds were described, while in some cases the components exhibited contradictory behavior or no significant changes. Unfortunately, phenolic composition was rarely determined. There is evidence for the dose dependency of the reactions to both elicitors, but systematic studies on this issue are missing. Some results indicate that lower concentrations in replication may be at least as effective as higher ones. Changes in secondary metabolite accumulation may be induced by the elicitors directly or through other physiological processes. The in vivo results should be considered in the complex system of plant ontogenesis, environmental conditions, timing of the treatment, type of the elicitor and concentration. Research results indicate a promising aspect of chemical elicitation in vivo, but further well-designed studies are needed for the individual species.

Effect of Biotic Elicitors on the Growth, Antioxidant Activity and Metabolites Accumulation in In Vitro Propagated Shoots of Pueraria tuberosa

“…The use of biotic elicitors has been shown to facilitate cell growth and increase the accumulation of bioactive molecules within cells and tissues [ 30 , 31 , 32 ]. Elicitor concentration is a crucial aspect of productive elicitation, and plant species differ in their optimal concentration [ 33 ]. In this study, different concentrations of YE, PEC, and ALG were evaluated for their effects on the growth of P. tuberosa shoots, as well as their metabolite compositions, such as protein, carbohydrate, chlorophyll, phenolic, and flavonoid contents, and antioxidant activity.…”

Dynamics of alkannin/shikonin biosynthesis in response to jasmonate and salicylic acid in Lithospermum officinale

“…Phytohormones such as jasmonates (JA) and salicylic acid (SA) or their methyl derivatives have promotional effects on the production of various specialized metabolites in plants 45 – 47 . In Boraginaceae, alkannin/shikonin (A/S) respond uniquely to MeJA but not to SA 1 , 23 ) as also supported by the present study.…”

A first approach for the micropropagation of the medicinal halophyte Polygonum maritimum L. and phenolic profile of acclimatized plants

“…Therefore, it can explain the difference found between the previous studies made with sea knotgrass plants collected from the wild or cultivated from seeds gathered from natural sites, and this study with micropropagated plants. However, the in vitro production of secondary metabolites can be stimulated by the addition of biotic (e.g., proteins, fungus, rhizobacteria, and hormones) and/or abiotic (e.g., drought, salinity, light, and temperature) elements to the culture medium to enhance the biosynthesis and accumulation of secondary compounds of interest (Kandoudi and Németh-Zámboriné, 2022 ). In contrast, for the consequent greenhouse cultivation, growth conditions can also be managed to promote the synthesis of the desired compounds.…”