Unraveling the plant growth promotion potential of Pseudomonas species isolated from the rhizosphere of Lotus creticus grown in the Mediterranean coastal regions of Morocco

Rhizosphere-associated bacteria play a key role in enhancing plant performance under saline and nutrient-limited soil conditions, where plant establishment is strongly constrained. In this study, we evaluated the plant growth-promoting potential of rhizobacteria isolated from the rhizosphere of wild-growing Lotus creticus along the Mediterranean coast of Morocco. Of the 30 isolates, five bacterial strains (R125, P79, R8, R150, and R15) were selected based on their plant growth-promoting traits. These strains were identified through 16S rRNA gene sequencing as Pseudomonas protegens , Pseudomonas sesami , Pseudomonas versuta , Pseudomonas helleri , and Pseudomonas trivialis . Phenotypic characteristics, including IAA production, phosphate solubilization capacity, cellulase and protease activities, and tolerance to salinity and temperature, were evaluated. Additionally, a pot experiment was conducted to assess the impact of inoculation on L. creticus growth. Pseudomonas protegens P79 was characterized by strong IAA production, high phosphate solubilization capacity (150.5 mg L −1 ), and notable cellulase and protease activities. It also demonstrated high tolerance to salinity (up to 13 % NaCl) and temperature (up to 45 °C). Comparatively, Pseudomonas sesami R8 exhibited broad-spectrum antifungal activity, including strong inhibition of the growth of Aspergillus ochraceus . The pot experiment revealed that inoculation with Pseudomonas helleri R125 and Pseudomonas trivialis R150 significantly ( P < 0.05) enhanced the aerial dry biomass of L. creticus by 300 %. In contrast, Pseudomonas protegens P79 was more effective in promoting root elongation by 8 % under growth chamber conditions. This study highlights the potential of Pseudomonas strains as promising biostimulants for sustainable agriculture and rehabilitation of coastal marginal soils under combined salinity and nutrient stresses.