Amelioration of Soil Salinity Through Plant Growth-Promoting Bacteria: A Sustainable Solution

Soil salinity is a growing agricultural challenge affecting millions of hectares of arable land globally.Excessive salt accumulation in the soil disrupts plant growth by limiting water uptake, causing ion toxicity, and reducing soil fertility.Traditional methods to address soil salinity, such as chemical amendments and physical leaching, are often costly, time-consuming, and environmentally taxing.An emerging and sustainable alternative is the use of plant growth-promoting bacteria (PGPB) to improve plant salt tolerance.Soil salinity has emerged as a formidable challenge to sustainable agriculture worldwide.The accumulation of soluble salts in the soil profile adversely affects soil structure, nutrient availability, and plant growth, ultimately reducing agricultural productivity.Soil salinity arises from both natural and anthropogenic factors [1-3].Naturally, saline soils develop in arid and semi-arid regions where evaporation exceeds precipitation, leaving salts to accumulate near the surface.Salinity negatively affects plant metabolism, leading to stunted growth, reduced yield, and, in severe cases, complete crop failure [4][5][6][7].Addressing this issue is critical given the increasing demand for food security and sustainable agriculture.Plant growth-promoting bacteria are naturally occurring microorganisms that enhance plant growth by various mechanisms [8][9][10][11].PGPB can thrive in saline environments and offer a sustainable approach to mitigate soil salinity as shown in Figure 1.Key benefits of PGPB include: Soil Structure Stabilization: Exopolysaccharides secreted by PGPB bind soil particles, improving soil structure and water retention capacity.PGPB contribute to soil improvement in several ways:1. Salt Tolerance Induction: PGPB produce metabolites like exopolysaccharides (EPS) that help plants maintain ionic balance and reduce salt stress.2. Nutrient Bioavailability: These bacteria solubilize essential nutrients like phosphorus and potassium, making them more accessible to plants.3. Phytohormone Production: PGPB synthesize hormones such as auxins, gibberellins, and cytokinins, which promote root growth and enhance plant resilience.4. ACC Deaminase Activity: By breaking down the stress hormone ethylene precursor (1-aminocyclopropane-1carboxylic acid), PGPB alleviate plant stress and promote growth under saline conditions.