Beneficial microorganisms: a sustainable horticultural solution to improve the quality of saffron in hydroponics

•Hydroponic cultivation with bioinoculants may increase saffron profitability.•Plant growth promoting bacteria and an arbuscular mycorrhizal fungus were tested.•Bioinoculants improved the spice's safranal concentration.•Mixed formulation increased saffron total phenolic content.•The corm yield resulted enhanced for inoculated plants.