Unlocking the plant growth-promoting potential of yeast spp.: exploring species from the Moroccan extremophilic environment for enhanced plant growth and sustainable farming

Abstract

In this study, we successfully isolated two distinct yeasts from Moroccan extreme environments. These yeasts were subjected to molecular characterization by analyzing their ITS regions. Our research thoroughly characterizes plant growth-promoting (PGP) abilities and their drought and salt stress tolerance. In a greenhouse assay, we examined the impact of selected yeasts on Medicago sativa’s growth. Four treatments were employed: i) control without inoculation (NI), ii) inoculation with L1, iii) inoculation with L2, and iv) inoculation with the mixture L1+L2. L1 isolated from Toubkal Mountain shared 99.83% sequence similarity to Rhodotorula mucilaginosa. Meanwhile, L2, thriving in the arid Merzouga desert, displayed a similar identity to Naganishia albida (99.84%). Yeast strains were tolerant to NaCl (2 M) and 60% PEG (polyethylene glycol P6000) in case of drought. Both strains could solubilize P and K (in the case of L2), produce IAA (up to 135 µl mL−1), have siderophores ability, and produce ACC deaminase. Isolates L1, L2, and their consortium showed that the single or combined strains inoculation of M. sativa improved plant growth, development, and nutrient assimilation. Those findings pave the way for harnessing yeast-based solutions in agricultural practices, contributing to enhanced crop productivity and environmental sustainability.