Promoting Sustainable Agriculture: PGPR-Driven Enhancement of Plant Growth and Salinity Stress Tolerance

Salinity poses a major challenge to agriculture, especially in arid environments such as those found in Algeria, by significantly reducing crop yield. This study investigates the use of native Plant Growth-Promoting Rhizobacteria to improve the growth and stress tolerance of durum wheat (Triticum durum L.) under saline conditions. A bacterial isolate, designated BSSM27, was recovered from saline soils and assessed for key biofertilizer traits, including indole-3-acetic acid (IAA) production, siderophore secretion, ammonium generation, and phosphate solubilization. Its biocontrol potential was also evaluated through antagonism against Fusarium spp.

Wheat seeds were inoculated with this strain and grown in pots filled with sandy soil from the Oued Souf region in Southern Algeria. Plants were irrigated with bacterial suspensions under different salinity levels (0, 0.1 M, and 0.2 M NaCl). Inoculated plants showed enhanced germination, increased shoot and root biomass, and a higher number of lateral roots compared to non-inoculated controls. Physiological assessments revealed improved chlorophyll content, relative water content, and membrane stability. Moreover, lower levels of proline and malondialdehyde (MDA) indicated reduced oxidative stress. Hormonal profiling demonstrated a favorable balance, with reduced abscisic acid (ABA) and elevated IAA levels, supporting improved growth under stress.

These results highlight the multifunctional role of native PGPR in promoting plant growth and mitigating salinity stress through nutrient mobilization, hormonal regulation, and physiological enhancement. The use of such bio-inoculants represents a sustainable and environmentally friendly strategy for improving crop performance in saline soils.