Soil fertilization affects the abundance and distribution of carbon and nitrogen cycling genes in the maize rhizosphere

Matthew Chekwube Enebe,Olubukola Oluranti Babalola

doi:10.1186/s13568-021-01182-z

Abstract

Soil microbes perform important functions in nitrogen and carbon cycling in the biosphere. Microbial communities in the rhizosphere enhance plants’ health and promote nutrient turnover and cycling in the soil. In this study, we evaluated the effects of soil fertilization with organic and inorganic fertilizers on the abundances and distribution of carbon and nitrogen cycling genes within the rhizosphere of maize plants. Our result showed that maize plants through rhizosphere effects selected and enriched the same functional genes glnA, gltB, gudB involved in nitrogen cycle as do high compost and low inorganic fertilizer treatments. This observation was significantly different from those of high doses of inorganic fertilizer and low compost manure treated soil. Only alpha amylase encoding genes were selectively enriched by low compost and high inorganic fertilized soil. The other treatments only selected xynB (in Cp8), lacZ (Cp4), bglA, pldB, trpA (N2), uidA (N1) and glgC, vanA (Cn0) carbon cycling genes in the rhizosphere of maize. Also Actinomycetales are selected by high compost, low inorganic fertilizer and control. The control was without any fertilization and the soil was planted with maize. Bacillales are also promoted by low compost and high inorganic fertilizer. This indicated that only microbes capable of tolerating the stress of high dose of inorganic fertilizer will thrive under such condition. Therefore, soil fertilization lowers nitrogen gas emission as seen with the high abundance of nitrogen assimilation genes or microbial anabolic genes, but increases carbon dioxide evolution in the agricultural soil by promoting the abundance of catabolic genes involve in carbon cycling.

Highlights

The need to profile microbial community structure and functions are important for the attainment of a sustainable agriculture because of the roles they play in facilitating the biogeochemical cycling of nutrients such as carbon, phosphorus, nitrogen, sulphur and metals (Falkowski et al 2008)
Actinomycetales were most abundant in low dose inorganic (N1) fertilized soil, the control (Cn0) and the high dose compost (Cp8) manure fertilized maize rhizosphere soil
Rhizobiales Rhodospirillales Enterobacteriales GemmaƟmonadales fertilizers on the functional genes abundance, but none had considered whether these functional genes abundance are influenced by plants’ rhizosphere effect or the fertilization effects

Summary

Introduction

The need to profile microbial community structure and functions are important for the attainment of a sustainable agriculture because of the roles they play in facilitating the biogeochemical cycling of nutrients such as carbon, phosphorus, nitrogen, sulphur and metals (Falkowski et al 2008). Soil microbes are genetically diverse and plants exert influence on them. Enebe and Babalola A MB Expr (2021) 11:24 microbial biomass formation and metabolic activities that will be inherent in the soil. These interactions at the rhizosphere generally control important biogeochemical cycling involved in carbon cycle, emission of greenhouse gases and cycling of other nutrients. Little is known concerning whether fertilizers have greater effects on microbial genes abundance and activities in the soil or is it the plants that shapes and decides which genes should be expressed more in a fertilized soil, and if so, how does it influence nutrient cycling in the agricultural soil

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Conclusion