Yu Lan Chen ¹ xieluyao Wei ¹ leitao qin ¹ yong wang ¹ lingzi zhang ¹ Quanju Xiang ¹ ke Zhao ¹ Xiumei Yu ¹ Qiang Chen ¹ xue Gao ² Tashi Nyima ² Petri Penttinen ^1* Yunfu Gu ^1*

• ¹ Sichuan Agricultural University, Ya'an, Sichuan, China
• ² Tibet Academy of Agricultural and Animal Husbandry Sciences, Lhasa, China

Phosphorus (P) is a crucial growth-limiting nutrient in soil, much of which remains challenging for plants to absorb and use. Unlike chemical phosphate fertilizers, phosphate-solubilizing microorganisms (PSMs) offer a means to address available phosphorus deficiency without causing environmental harm. PSMs possess multiple mechanisms for phosphorus solubilization. Although the phosphorus-solubilizing mechanisms of phosphatesolubilizing bacteria (PSB) have been well characterized, the mechanisms utilized by phosphate-solubilizing fungi (PSF) remain largely unexplored. This study isolated a PSF strain Trametes gibbosa T-41 from the soil. T-41 exhibited varying phosphorus solubilizing capacity when grown with organic (calcium phytin) (Phytin-P) and inorganic (tricalcium phosphate) (Ca-P) phosphorus sources (109.80±8.9 mg/L vs. 57.5±7.9 mg/L, P<0.05).Compared with the Ca-P treatment, T-41 demonstrated a stronger alkaline phosphatase (ALP) production capacity under Phytin-P treatment (34.5±1.2 μmol/L/h vs. 19.8±0.8 μmol/L/h, P<0.05). Meanwhile, the production of oxalic acid, maleic acid, and succinic acid was higher under Phytin-P treatment (P<0.05). Transcriptomic and metabolomic analysis revealed that different phosphorus sources altered metabolic pathways such as galactose metabolism, glyoxylate and dicarboxylic acid metabolism, and ascorbate and aldolate metabolism. Key metabolites like myo-inositol, 2-oxoglutarate, and pyruvate were found to impact the performance of T. gibbosa T-41 differently under the two P sources. Notably, synthesis in Ca-P vs Pytin-P, T-41 upregulated genes involved in myo-inositol synthesis, potentially enhancing its P-solubilizing ability. These results provide new insights into the molecular mechanisms of PSF at the transcriptomic and metabolomic levels, laying a theoretical foundation for the broader application of PSF as bio-phosphorus fertilizers in the future.