Variations of physiological indices and metabolite profiling in Satureja khuzistanica in response to drought stress

Savory (Satureja khuzistanica) is one of the nine endemic species which have phenolic compounds such as carvacrole and thymol in its essential oil and rosmarinic and other phenolic acids in its extract, has strong antioxidant and antimicrobial properties and remarkable effects on several diseases. Drought stress was induced by stopping irrigation at flowering stage. Samples were taken five times with three interval days and several physiological traits were measured. For oil extraction, Clevenger apparatus was used. For determination of essential oil’s components and methanolic extract compounds, GC, GC/MS and HPTLC were utilized. Profiling of volatiles using GC/MS, showed an increasing-decreasing trend at major phenolic and terpenes compounds such as thymol, γ- Terpinene, p- Cymene, Rosmarinic acid and Caffeic acid. Drought stress also led to a significant increase in oil yield, soluble sugars and proline as well as a significant reduction in leaf water potential, relative water content and pigments. Metabolite profiling of Satureja khuzistanica represents the strategies employed by savory in generating different biochemical phenotype. Applicable results of this study for increasing product quality is effective application of drought stress before harvesting. The results verified that drought stress affected physiological characteristics and secondary metabolism of savory which were useful for future work by using metabolic engineering focusing on important species to increase main compounds, such as carvacrol and rosmarinic acid and caffeic acid.