Long-term nutrient inputs shift soil microbial functional profiles of phosphorus cycling in diverse agroecosystems

• Published in: The ISME Journal Vol. 14; no. 3; pp. 757 - 770
• Main Authors: Dai, Zhongmin, Liu, Guofei, Chen, Huaihai, Chen, Chengrong, Wang, Jingkuan, Ai, Shaoying, Wei, Dan, Li, Daming, Ma, Bin, Tang, Caixian, Brookes, Philip C., Xu, Jianming
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.03.2020; Oxford University Press; Nature Publishing Group
• Subjects: 45; 45/22; 45/23; 631/208/191; 631/326/2565/2142; 631/326/47; 704/158/855; Abundance; Agricultural ecosystems; Alkaline phosphatase; Bacteria - classification; Bacteria - genetics; Bacteria - isolation & purification; Bacteria - metabolism; BASIC BIOLOGICAL SCIENCES; Biomedical and Life Sciences; Cycles; Ecology; ENVIRONMENTAL SCIENCES; Environmental Sciences & Ecology; Evolutionary Biology; Genes; Immobilization; Life Sciences; Metagenomics; Microbial Ecology; Microbial Genetics and Genomics; Microbiology; Microorganisms; Nitrogen; Nitrogen - analysis; Nitrogen - metabolism; Nutrients; Nutrients - metabolism; Phosphate transporter; Phosphorus; Phosphorus - analysis; Phosphorus - metabolism; Relative abundance; Soil - chemistry; Soil Microbiology; Soil pH; Soils; Solubilization; Stoichiometry
• ISSN: 1751-7362; 1751-7370; 1751-7370
• DOI: 10.1038/s41396-019-0567-9

Microorganisms play an important role in soil phosphorus (P) cycling and regulation of P availability in agroecosystems. However, the responses of the functional and ecological traits of P-transformation microorganisms to long-term nutrient inputs are largely unknown. This study used metagenomics to investigate changes in the relative abundance of microbial P-transformation genes at four long-term experimental sites that received various inputs of N and P nutrients (up to 39 years). Long-term P input increased microbial P immobilization by decreasing the relative abundance of the P-starvation response gene ( phoR ) and increasing that of the low-affinity inorganic phosphate transporter gene ( pit ). This contrasts with previous findings that low-P conditions facilitate P immobilization in culturable microorganisms in short-term studies. In comparison, long-term nitrogen (N) input significantly decreased soil pH, and consequently decreased the relative abundances of total microbial P-solubilizing genes and the abundances of Actinobacteria , Gammaproteobacteria , and Alphaproteobacteria containing genes coding for alkaline phosphatase, and weakened the connection of relevant key genes. This challenges the concept that microbial P-solubilization capacity is mainly regulated by N:P stoichiometry. It is concluded that long-term N inputs decreased microbial P-solubilizing and mineralizing capacity while P inputs favored microbial immobilization via altering the microbial functional profiles, providing a novel insight into the regulation of P cycling in sustainable agroecosystems from a microbial perspective.