Figure 1.

Fungal P-solubilization and potential beneficial side effects on plants. Fungal acidification by H⁺ extrusion and organic acid production can improve plant access to P by the solubilization of low-reactivity P-sources and P-desorption from soil minerals. In the first case, phosphate-solubilizing fungi (PSF) can increase the fertilizer value of low-reactivity P-sources by treatment before application to the soil or by direct inoculation to the soil fertilized with the source. In the second scenario, PSF can revert P-fixation by soil, improving the fertilizer use efficiency and allowing reducing P-fertilizer rates. Moreover, PSF inoculation can promote plant growth by additional mechanisms, such as nutrient cycling, biocontrol of plant pathogens, synthesis of plant hormones such as indoleacetic acid (IAA) and gibberellins (GA), volatile organic compounds (VOCs), and enzymes.