Sustainable Release of Phosphorus and Potassium by Phosphate-Solubilizing Fungi: From Microbiology to Application

Phosphorus (P) and potassium (K) are essential nutrients for plant growth, but most soil P and K exist in insoluble minerals, restricting plant uptake and driving higher chemical fertilizer use. Phosphate-solubilizing fungi (PSF) are recognized as effective bioinoculants due to their high ability to concurrently mobilize poorly soluble P and K via biomechanical and biochemical pathways. The mechanisms of P and K release by PSF include the secretion of low molecular weight organic acids, acidification, chelation, enzymatic mineralization, and mycelium network erosion. However, the growth and metabolism of PSF are usually influenced by various environmental factors, such as soil pH, temperature, mineral type, and fungal source. These factors determine the efficiency of P and K release and the contribution of PSF to plant nutrient uptake and crop yield. This article reviews the potential practical and biotechnological strategies to enhance PSF performance and highlights priorities for future research on its sustainable application.