International Journal of Plant & Soil Science

Climate change and associated fluctuations in rainfall, temperature and water availability place increasing pressure on agricultural production. Sustainable improvements in crop productivity therefore require approaches that support nutrient acquisition and plant performance without increasing dependence on synthetic inputs. Endophytic bacteria and fungi inhabit internal plant tissues and can influence host growth through several direct and indirect mechanisms. This review examines their reported contributions to nutrient acquisition and the mitigation of abiotic stress. Endophytes may assist nitrogen acquisition through biological nitrogen fixation, improve phosphorus availability through solubilisation and mobilisation, and contribute to potassium and micronutrient nutrition. Additional interactions involve siderophore production, changes in root architecture and the modulation of phytohormones. Under drought, salinity and temperature stress, endophyte-associated plants have been reported to exhibit changes in water relations, antioxidant activity, osmotic adjustment and growth responses. The manuscript also discusses endophyte-assisted responses to heavy-metal stress and the practical constraints affecting agricultural use. These include difficulties in isolation, variability in colonisation and performance under field conditions, competition with native microorganisms, pathogenicity concerns and formulation requirements. Although reported findings indicate potential benefits for sustainable crop production, responses vary with the host, microorganism and environmental conditions. Further work is needed to clarify cellular nutrient-transfer processes and optimise reliable, safe and economical applications of endophytes in agricultural systems.