Microbe promotes soil phosphorus bioavailability at the beginning of pedogenesis

The quick accumulation of bioavailable phosphorus (bio-P) promoted the ecosystem development at the very beginning of pedogenesis on the Hailuogou Glacier foreland. It is still unclear what role and how microbe played in bio-P accumulation at the very beginning of pedogenesis.  Using the Hailuogou Glacier foreland on Gongga Mountain as a natural laboratory, microbial community assembly, co-occurrence networks, and PCGs were examined across four successional stages (S1-S4) before the pioneer plant emerged. The results indicated that bacteria were the dominant domain in all four stages. At the very beginning of pedogenesis, microorganisms adapted to scare bio-P conditions by regulating the functional expression of key PCGs. Key genes, including pqqE, gcd, phoD, and 3-Phytase, played a crucial role in mineral phosphorus solubilizing and organic phosphorus mineralizing. Community assembly was predominantly driven by deterministic processes under environmental pressures. Tight cooperative network structures within the microbial communities and dominant microbial taxa were the major factors accelerating the bio-P releasing into the soil. It can be concluded that microbepromoted bio-P accumulation at the very beginning of pedogenesis by regulating PCGs and typical microbial community constructing. These findings provided new insights into the mechanisms by which microbial communities regulate phosphorus dynamics during pedogenesis process.