Soil Microbial Composition and phoD Gene Abundance Are Sensitive to Phosphorus Level in a Long-Term Wheat-Maize Crop System

Abstract

Microbes associated with phosphorus (P) cycling are intrinsic to soil P transformation and availability for plant use but are also influenced by the application of P fertilizer. Nevertheless, the variability in soil P in the field means that integrative analyses of soil P cycling, microbial composition, and microbial functional genes related to P cycling remain very challenging. In the present study in the North China Plain, we subjected the bacterial and fungal communities to amplicon sequencing analysis and characterized the alkaline phosphatase gene (phoD) encoding bacterial alkaline phosphatase in a long-term field experiment (10 years) with six mineral P fertilization rates up to 200 kg P ha–1. Long-term P fertilization increased soil available P, inorganic P, and total P, while soil organic P increased until the applied P rate reached 25 kg ha–1 and then decreased. The fungal alpha-diversity decreased as P rate increased, while there were no significant effects on bacterial alpha-diversity. Community compositions of bacteria and fungi were significantly affected by P rates at order and family levels. The number of keystone taxa decreased from 10 to 3 OTUs under increasing P rates from 0 to 200 kg ha–1. The gene copy numbers of the biomarker of the alkaline phosphatase phoD was higher at moderate P rates (25 and 50 kg ha–1) than at low (0 and 12.5 kg ha–1) and high (100 and 200 kg ha–1) rates of P fertilization, and was positively correlated with soil organic P concentration. One of the keystone taxa named BacOTU3771 belonging to Xanthomonadales was positively correlated with potential functional genes encoding enzymes such as glycerophosphoryl diester phosphodiesterase, acid phosphatase and negatively correlated with guinoprotein glucose dehydrogenase. Altogether, the results show the systematic effect of P gradient fertilization on P forms, the microbial community structure, keystone taxa, and functional genes associated with P cycling and highlight the potential of moderate rates of P fertilization to maintain microbial community composition, specific taxa, and levels of functional genes to achieve and sustain soil health.

Effects of arbuscular mycorrhizal fungi on improvement of degraded landscape soil in an ionized rare earth mining area, subtropical China

“…This finding suggested that under high soil P conditions, host plants reduced carbohydrate transport to mycorrhizal fungi, inhibited mycorrhizal fungal growth, and in turn affected the symbiosis between AMF and host plants. We also found that AMF inoculation significantly increased the absorption and accumulation of P and K in white clover in the absence of starting P, which is similar to previous results (Lang et al., 2020; X. Liu et al., 2016; C. Zheng et al., 2015). This finding indicates that in the absence of P, AMF may enhance the expression of P transporter genes, promote mycelium production and P absorption, and then transform soil to host plants.…”

phoD-harboring bacterial community composition dominates organic P mineralization under long-term P fertilization in acid purple soil

“…The evidence has shown that crop input (root residue) and microbial immobilization are the key ways to form Po in soil ( Condron et al, 2014 ). The changes in root residue and Po show a similar pattern during 10 consecutive years of a wheat-maize rotation system in calcareous soil ( Deng et al, 2017 ; Lang et al, 2021 ), which may be the case in our present study as well.…”

Optimal NPK Fertilizer Combination Increases Panax ginseng Yield and Quality and Affects Diversity and Structure of Rhizosphere Fungal Communities

“…Rather, whether such interactions increase plant adaptability to the environment under specific environmental conditions should be considered (Trivedi et al, 2020 ). In this study, soil fungi were hypothesized to increase NPK transformations and transport of nutrients (Hu et al, 2020 ; Ning et al, 2020 ; Lang et al, 2021 ) and thereby increase nutrient availability for ginseng growth and also protect ginseng from pathogens by competition, production of antibacterial compounds, and hydrolysis (Naik et al, 2019 ; Delgado-Ospina et al, 2021 ).…”