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

Abstract

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 Ptransformation 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.

Nitrogen and phosphorus additions accelerate decomposition of slow carbon pool and lower total soil organic carbon pool in alpine meadows

“…Anthropogenic drivers of environmental change such as atmospheric deposition and fertilization induced nitrogen (N) and phosphorus (P) additions to grasslands and affect ecosystem processes and functioning (Dai et al, 2020; Isbell et al, 2013; Riggs & Hobbie, 2016). For example, N and P additions can not only reduce plant diversity and increase productivity (Borer, Grace, Harpole, MacDougall, & Seabloom, 2017; Clark & Tilman, 2008; Isbell et al, 2013) but also reduce soil pH and increase total N and P (TN, TP) contents (Chen et al, 2019; Fang et al, 2014; Li et al, 2018).…”

The Rhizosphere Microbiome of Mikania micrantha Provides Insight Into Adaptation and Invasion

“…The competition of invasive species with native species depends largely on the abilities of accession in resources (Seabloom et al, 2003). P is an essential macronutrient for plant growth and development (Lidbury et al, 2016), and microorganisms play an important role in soil P cycling and in regulating P availability (Dai et al, 2019). In this study, we found that Enterobacter and Pseudomonas might contribute to the increased soil available P content, and helped M. micrantha to outcompete native species and ultimately facilitate plant invasion (Figure 3A).…”

“…The bacteria and genes involved in soil microbial P-solubilizing and mineralization, pathogen, and defense were searched based on previous publications and are shown in Supplementary Tables S1-S6 (Weller et al, 2002;Garbeva et al, 2004;Beth Mudgett, 2005;Raaijmakers and Mazzola, 2012;Sharma et al, 2013;Raj et al, 2014;Alori et al, 2017;Han et al, 2018;Dai et al, 2019). The names, KOs, and functions of the genes associated with P solubilizing and mineralization, type III secretion/effector systems, and polyketide synthase (PKS) are shown in Supplementary Tables S2, S4, S6, respectively.…”

“…Next, the genes generally contained in PSM were analyzed, including those coding for P mineralizing and solubilizing enzymes (Dai et al, 2019). The genes coding for organic P mineralization, such as C-P lyase, phosphonoacetate hydrolase, and phytase, as well as the genes coding for inorganic pyrophosphatase responsible for the inorganic P solubilization, were all enriched in rhizosphere of M. micrantha and two native plants (P < 0.05) ( Figure 3C).…”

Molecular biological methods in environmental engineering

“…Similarly, microorganisms in farmland systems also have such functions. Dai, Liu, Chen, and Chen (2019) used metagenomics to study the effects of long-term application of different types of fertilizers on microbial functional genes transformed by phosphorus. The results showed that no matter long-term application of nitrogen or phosphorus fertilizer, it would affect the gene composition of phosphorus transforming microorganisms and the availability of phosphorus.…”