Meta-omics revealed that nitrogen fertilization alters the endophytic fungi divergence in maize field ecosystem

Endophytic mycobiomes are an integral part of crops in agricultural systems. Fertilization is a conventional practice to improve agricultural crops and may alter the mycobiomes of soil and plant systems. In agroecosystems, Nature Based Solutions (NBS) are key strategies for agricultural suitability. Investigating mycobiomes under N flux can provide fundamental data for constructive NBS strategies. In this study, the effects of nitrogen (N) fertilizer treatments on fungal compositions of the soil-maize systems were systematically investigated in field experiments at six N rates (F0, F72, F126, F180, F234, F280 kg N/ha) in northern China. Metaomics amplicon sequencing of the internal transcribed spacer (ITS) region was employed to study community dynamics, network correlation, metabolic functional assemblies, abundance patterns and core fungi. This study found that fungal communities were significantly higher at 72 kg N/ha compared with control and other treatments. Network topology increased in maize fungi (R2 = 0.69) but decreased in the soil (R2 = 0.51). Abundances of carbon-nitrogen metabolizing functional genes (Ure, AMT, gdhA and GDH) were significantly correlated with maize fungal communities and were assembled by stochastic processes. Additionally, the relative abundance of Ascomycota (67.26 %) was dominant in the soil, whereas Basidiomycota (61. 73 %) prevailed in maize samples at 72 kg N/ha. Moreover, Sporidiobolus, Alternaria, Fusarium, and Penicillium served as conserved core genera and were positively correlated with NH4+-N mg/kg, NO2--N mg/kg and NO3--N mg/kg, and pH components. Furthermore, selective genera were tested and confirmed to increase the growth rate and nitrogen utilization in maize. The study highlights the promising role of associated endophytes as Nature-Based Solution for optimizing fertilization to improve crop production in maize-agroecosystem.