Evaluating the Plant-Growth-Promoting Endophytes for the Reclamation of Saline Soils in Coastal Agriculture

Soil salinization is a major threat to food security in the coastal regions of Pakistan, necessitating innovative and sustainable reclamation strategies. This study investigated the efficacy of indigenous plant-growth-promoting endophytes (PGPEs), isolated from native halophytes of the Indus Delta, to enhance wheat (Triticum aestivum) resilience and rehabilitate saline soils in Sindh province. A consortium of three potent endophytic strains, selected for high salt tolerance and multifunctional PGP traits (including phosphate solubilization and indole-3-acetic acid production), was developed. A field trial was conducted in naturally saline soils near Thatta using a randomized complete block design with four treatments: an untreated control, chemical fertilizer alone, PGPE inoculation alone, and a combined PGPE and reduced fertilizer application. Inoculation with the PGPE consortium significantly improved soil health, reducing electrical conductivity by 18% and increasing soil organic matter content by 22% compared to the control. Wheat plants treated with PGPEs exhibited superior growth, with a 35% increase in root length and a 28% increase in shoot biomass, attributable to enhanced nutrient acquisition and water use efficiency. The combined treatment (PGPE + fertilizer) yielded the highest grain production, surpassing the control by 42%. Biochemical analyses confirmed elevated proline content and antioxidant enzyme activities, indicating robust induced systemic tolerance to salinity stress. This research provides compelling evidence that locally sourced PGPE consortia are a highly effective, sustainable, and economically viable bio-strategy for mitigating salt stress and improving productivity in saline agroecosystems, with significant potential for global application.