Critical Role of the gcd Gene in Enhancing Soil Phosphorus Availability Under Vegetation Restoration in the Mu Us Sandy Land

Phosphorus (P) is a critical limiting nutrient for plant growth and microbial metabolism in many terrestrial ecosystems, but the global depletion of P reserves poses challenges for soil nutrient cycling. Here, changes and influencing mechanisms of soil phosphorus components and related microbial communities in different vegetation restoration types of Mu Us Sandy Land—bare sandy land (CK), grassland (GL), shrubland (SL), grass and shrubland (GSL), and forest land (FL) were explored. The GSL and FL restoration types exhibited higher SOC levels and enzyme activities, indicating greater microbial activity and nutrient utilization efficiency. The distribution of P‐transforming microbial genes varied among vegetation restoration types, with the phoD gene most abundant in GSL and the gcd gene most abundant in SL. Correlation analyses indicated that the gcd gene, linked to Actinobacteria and Proteobacteria, was strongly associated with the transformation of moderately stable phosphates into plant‐available forms. Mantel test results revealed that phoD gene abundance was significantly correlated with SOC content (p < 0.05), whereas gcd gene abundance was strongly correlated with NaOH‐Pi (p < 0.01) and also significantly correlated with AP content (p < 0.05). Such correlations underscore the critical roles of specific genes in enhancing soil P availability and nutrient cycling. This study highlights that strategic vegetation restoration, particularly GSL and FL, can effectively improve soil nutrient status and microbial functionality. These findings provide valuable insights for ecological restoration and sustainable land management in desertified regions.