Inoculation of Arbuscular Mycorrhizal Fungi and Plant Growth Promoting Rhizobacteria Mediated Water Stress Tolerance in Quinoa Seeds by Modulating the Phenolics Compounds, Stress Markers, Osmolytes Accumulation and Antioxidant Defense

Several research studies have highlighted the benefits of biofertilizers for plant productivity and soil fertility. Arbuscular mycorrhizal fungi (AMF) and Plant growth promoting rhizobacteria (PGPR) have been shown to confer on plants the potential to overcome water stress conditions. The objective of this study is to evaluate the impact of AMF (M) and PGPR (R) on the quality of quinoa seeds under water deficit. The experiment consisted in the application of M and R consortium and their combination (MR) on quinoa plants subjected to two water regimes: well-watered (WW) (75% field capacity (FC)) and water-stress (WS) (25% FC). The combination MR increased the dry weight by 25% compared to the control under WS. The application of R alone reduces the accumulation of reactive oxygen species (H2O2) by 47% compared to the stressed control. Our results revealed that separate and/or combined application of M and R mitigated the effect of water stress by increasing polyphenol and flavonoid content compared to the water-stressed control. Furthermore, R‑inoculated quinoa showed the highest improvement in 1,1-diphenyl-2-picrylhydrazyl in water-stressed quinoa grains. In addition, M‑ and R‑application alone and/or combined can be a sustainable and effective strategy to improve seed quality and tolerance of quinoa under drought.