A new isolated fungus Talaromyces sp. MC-F2 efficiently solubilizes phosphate through media-dependent metabolic regulation.

This study isolated and identified a new phosphate-solubilizing fungus strain, Talaromyces sp. MC-F2, based on morphological characteristics and phylogenetic analysis, from agricultural soil. Its capacity to solubilize tricalcium phosphate (TCP) was systematically evaluated in Pikovskaya (PVK), National Botanical Research Institute's phosphate growth medium (NBRIP), and potato dextrose broth (PDB) media. MC-F2 demonstrated effective TCP dissolution across all media, and the highest final concentration of soluble phosphorus was observed in NBRIP medium. The solubilization was primarily driven by acidification through secretion of organic acids, notably gluconic and malic acid, leading to the formation of calcium oxalate hydrates (whewellite and weddellite) as secondary minerals. Untargeted metabolomics revealed that medium composition and TCP concentration significantly reshaped central metabolic pathways, particularly enhancing the TCA cycle in NBRIP, which directly underpinned the high organic acid production and superior solubilization performance. These findings not only expand the resources of phosphate-solubilizing fungi but also provide deeper metabolic insights into their environmental adaptability, highlighting the potential of Talaromyces sp. MC-F2 as a promising agent for developing eco-friendly biofertilizers.