Can Phosphate-Solubilizing Microorganisms Unlock the Path to Sustainable Amazonian Forest Restoration?

Phosphorus (P) availability is a critical constraint for plant growth in tropical ecosystems, primarily due to its low mobility and high fixation by soil colloids. The use of phosphate-solubilizing microorganisms (PSMs) is a sustainable strategy to enhance phosphorus bioavailability, particularly in highly weathered and nutrient-depleted soils. These microorganisms, including bacteria, fungi, actinobacteria (Phylum Actinomycetota), and cyanobacteria, convert insoluble phosphorus into plant-available forms through biochemical pathways such as organic acid production, enzyme secretion, and siderophore release. Although widely studied in agricultural systems, the role of PSMs in forest ecosystems, especially in the Amazon, remains poorly explored. This review synthesizes current knowledge on the diversity, solubilization mechanisms, and applications of PSMs, emphasizing their potential to improve seedling establishment and promote ecosystem resilience in forest restoration efforts. The integration of microbial biofertilization into silvicultural and agroforestry practices may reduce dependence on chemical fertilizers, mitigate environmental impacts, and restore soil fertility in degraded Amazonian landscapes. We underscore the urgent need for further research on locally adapted PSM strains and their functional interactions with native tree species. Ultimately, PSMs represent a promising biotechnological tool for restoring the structure and function of tropical forest ecosystems.