Mineral and Organic Fertilizers Distinctly Affect Fungal Communities in the Crop Rhizosphere

Abstract

Fungi represent a diverse group of organisms that play an essential role in maintaining soil health and ecosystem functioning. Plant root exudates form nutrient-rich niches that harbor specific fungal communities, or so-called rhizosphere mycobiomes. The long-term application of fertilizers supplies the soil with nutrients that may override the plant-related effects on rhizosphere fungal communities. Here, we assessed the effect of contrasting fertilization regimes on the composition, diversity, and abundance of bulk soil and rhizosphere mycobiomes of potato, white mustard, and maize under NPK (mineral fertilizers) or fresh cattle manure (organic fertilizers). Mineral and organic fertilizers led to distinct fungal communities in the rhizospheres of all studied crops, and the plant-related effects on the mycobiome were overridden by the effect of fertilization. The abundances of Ascomycota and Olpidiomycota were higher under manure, while the abundances of Basidiomycota and Monoblepharomycota increased under NPK. Manure input strongly increased fungal abundance but decreased fungal diversity and the total number of species. NPK had a slight effect on fungal diversity, but significantly increased the relative abundances of fungal phytopathogens, such as Alternaria and Fusarium. Our study shows that that potential plant species effects on the abundance and diversity of the rhizosphere mycobiomes are governed by long-term fertilization. Fertilization management could therefore be used to manipulate rhizosphere fungal communities and soilborne pathogen suppressiveness.

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

“…Soil microorganisms are the main engines of agroecosystems because they promote nutrient turnover in soils (Nie et al, 2018 ). In particular, fungi provide favorable conditions for crop growth and development by transforming and transporting nutrients in fertilizers and also by increasing nutrient acquisition from decomposing soil organic matter (Miao et al, 2022 ; Semenov et al, 2022 ). Therefore, the abundance and diversity of rhizosphere fungi have important effects on crop yield and quality (Gao et al, 2019 ).…”

Sugarcane cultivation practices modulate rhizosphere microbial community composition and structure

“…The higher fungal diversity in conventional cultivation suggests the potential of a plant to select fungal communities in the rhizospheric environment through the composition of its root exudates 57 . The collections of rhizospheric material in each crop were carried out at the end of the vegetative growth period (11 months) and the beginning of the maturation of the sugarcane field, and it can be inferred that different stages of plant growth can determine its composition, amount of rhizodeposits present and its associated microbiome 57 , 58 . During plant growth, many ecological succession processes can occur, resulting in new habitats and an increase in the breadth of niches 59 , in our study, we characterized the microbiota only at one specific time point.…”

“…Long-term application of mineral fertilizers provides large amounts of nutrients to the soil. These introduced nutrients can increase exudation and alter the fungal community present 57 . This is because fertilization directly influences the physiological state of the plant and favors the release of these exudates 84 .…”

“…This is because fertilization directly influences the physiological state of the plant and favors the release of these exudates 84 . The use of inorganic nitrogen can reduce the dependence of rhizosphere communities on the use of plant-derived carbon and activate many dormant fungal species 57 . This applies to the fact that most fungi are heterotrophs and highly dependent on exogenous carbon for their growth 85 .…”

“…This genus may have had its abundance favored in a conventional system by the nitrogen fertilization used, which suggestively led to an increase in fungal diversity in this system. The greater diversity may have been driven by the high nutritional increment and the rhizospheric exudation stimulated by the inorganic nitrogen fertilization used 57 , 82 , 84 .…”