Effect of plant growth regulators and salt stress on secondary metabolite composition in Lamiaceae species

Abstract

Medicinal and aromatic plants (MAPs) are a natural resource for secondary metabolite compounds that are used in the pharmaceutical, cosmetic and food industries due totheir therapeutic properties, nutritional and flavor values or as main natural inputs to the perfumery andchemical industries. The Lamiaceae (mint) family contains many plant species rich in essential oils comprising terpenoid and phenolic components. The quality and quantity of secondary metabolites in Lamiaceae species is affected by salinity and depends on the severity, duration and timing of the salt stress. In accordance with the exogenous treatments of plant growth regulators (PGRs), secondary metabolites, terpenoids and phenolic acid, in particular reach to a desired level. Along with the present study, the most commonly employed PGRs were discussed for their impacts on terpenoid and phenolic acids. Overall, it can be deduced that moderate levels of salinity and PGRs have triggering roles on secondary metabolites and we can utter that interactive or combined impacts of the relevant stress and PGRs are still at their infancy since there is lacking issues to be clarified due to differences regarding concentration, conditions of experiment, application method and genetic background (cultivar) of the species. The relevant reports have been mostly oriented and addressed on metabolite content and composition with couple of basic biochemical parameters. However, profiling the metabolites might not be adequate to explain the responses of the plant secondary metabolites against exogenous treatments. Those results suggest more detailed researches including omic based approaches for revealing the changes at biosynthesis pathways. After revealing the action mechanism of stress and PGRs, it might seem be possible to obtain the desired content and composition of metabolites.