Long-term Degradation from Marshes into Meadows Shifts Microbial Functional Diversity of Soil Phosphorus Cycling in an Alpine Wetland of the Tibetan Plateau

Soil microbes greatly contribute to the regulating of phosphorus (P) cycling, which plays a significant role in maintaining wetland ecosystem processes and function. The microbial functional diversity of soil P cycling in response to wetland degradation, however, remains largely unknown. We used metagenomic sequencing to investigate the microbial community and genes related to soil P cycling in un-degraded marshes and meadows derived from long-term marsh degradation in the Lalu alpine wetland of the Tibetan Plateau. When the marsh degraded into meadow, organic P (OP) mineralization genes increased while genes related to P-starvation response regulation decreased. Proteobacteria (20.5-74.3%) and Actinobacteria (5.6-59.7%) were the dominant phyla in soils and were also the main contributors (39.7-84.1% in total) to soil P-cycling genes. Soil pH was the primary factor influencing the P-cycling functional genes. Soil pH negatively affected the genes related to the P-uptake and transport system and had negative effects on the genes related to P-starvation response regulation, OP mineralization, and inorganic P solubilization. These findings may deepen our understanding of the biogeochemical process of soil OP and may be beneficial for wetland management.