Environmental heterogeneity and soil properties influence fungal communities in Amazonian ferruginous fields

Fungi are crucial for ecosystem functioning, but there is a lack of data regarding their role in tropical ferruginous ecosystems. This study aims to characterize fungal communities across a vegetation gradient in the ferricretes of the southeastern Amazon, using metabarcoding of the second subunit of the internal transcribed spacer (ITS2). Soil samples were collected from different vegetation formations from previously identified ferricretes in the Lower Araguaia Watershed, Brazil. In total, 2,237 operational taxonomic units were obtained, with a predominance of Ascomycota and Basidiomycota. The taxonomic and functional groups differed between grasslands, shrublands and adjacent forests. Saprotrophic fungi and plant pathogens are predominant across all ferricrete formations, with notable dominance of melanized fungi such as Chaetothyriales and Pleosporales that are highly tolerant to adverse environmental conditions. The distribution of fungal communities is influenced by factors such as soil pH, nutrients, and texture. These results provide new insight into the dynamics of fungal communities in ferruginous fields and their importance for the maintenance of plant communities established in Amazonian ferricretes.