Role of Combined Use of Mycorrhizae Fungi and Plant Growth Promoting Rhizobacteria in the Tolerance of Quinoa Plants Under Salt Stress

The main objective of this study was to evaluate the effect of biofertilizers based on plant growth-promoting rhizobacteria (PGPR) and arbuscular mycorrhizal fungi (AMF) on the tolerance of quinoa, (var. Titikaka) Titicaca under non-saline and saline conditions (0, 200 and 400 mM NaCl). The two microbial symbiotes were applied individually and/or in combination in the greenhouse. Several morphological and physiological parameters were evaluated under normal and stress conditions. The high level of salinity (400 mM NaCl) had deleterious effects on the growth and physiology of quinoa compared to unstressed conditions (0 Mm NaCl). However, non-inoculated quinoa plants grown under 400 mM NaCl conditions showed a significant decrease in total dry biomass, leaf water potential, stomatal conductance, and chlorophyll fluorescence compared to unstressed control plants (0 Mm NaCl). Under 400 mM NaCl, co-inoculation with PGPR and AMF improved dry biomass, leaf water potential, stomatal conductance, and chlorophyll fluorescence by 930, 38, 266 and 7%, respectively compared to the stressed control (400 Mm NaCl). Thus, the biofertilizers used improved plant growth and physiology by activating the photosynthetic machinery under salt stress conditions. These findings suggest that the combination of PGPR and AMF could be used for the improvement of quinoa tolerance to salt stress.