The symbiotic association with Piriformospora indica and Pseudomonas fluorescens improves salt tolerance in sage (Salvia officinalis) plants

Background and aims In sustainable agricultural systems, different beneficial soil microorganisms are explored to improve crop production and tolerance of plants to different environmental stresses. The present research aimed to examine the potential of plant beneficial rhizospheric microorganisms (PBRMs) for ameliorate the negative effects of salinity stress on sage (Salvia officinalis).Methods In this study, the effect of symbiosis with Piriformospora indica and Pseudomonas fluorescens in counteracting salinity stress on sage plants was quantified. The biomass production, physiological and biochemical markers and essential oil content and composition were evaluated under four salinity levels (0, 25, 50 and100 mM NaCl) in inoculated and non-inoculated sage plants.Results Fresh and dry herb yield, relative water content (RWC), chlorophyll and essential oil content exhibited a reduction in response to salinity. In contrast, salinity increased electrolyte leakage (EL), amount of malondialdehyde (MDA), accumulation of proline and total soluble sugars (TSS), activity of catalase (CAT), ascorbate peroxidase (APX) and guaiacol peroxidase (GPX) enzymes, total antioxidant activity, total phenol and flavonoids. Inoculation with microorganisms increased fresh and dry herb yield, RWC, chlorophyll content, accumulation of proline and TSS, antioxidant enzymes activity, total antioxidant activity, total phenol and flavonoids and essential oil content and decreased EL and amount of MDA. The dominant constituents of essential oils (alpha-thujone, beta-thujone, camphor, 1,8-cineole, alpha-pinene, camphene and viridiflorol) showed changes in response to salinity stress.Conclusion he findings of this study showed that symbiotic association with PBRMs can help sage plants overcome the adverse effects of salinity stress.