Chitinase production and effects of land use change on fungal communities in the soil of the Brazilian Cerrado.

The Brazilian Cerrado is the world's most biodiverse savanna, yet its rapid conversion to agriculture, including coffee cultivation, may alter soil fungal communities in ways that remain insufficiently characterized. We used ITS metabarcoding to assess fungal diversity and community composition across native Cerrado, conventional coffee, and regenerative coffee systems. Sixty soil samples were analyzed, comprising 20 samples per land-use system distributed among 12 transects arranged in four sampling pairs. In parallel, 1481 fungal isolates obtained by serial dilution were screened for chitinolytic activity. Fungal alpha diversity did not differ significantly among land-use systems, whereas community composition differed after accounting for the paired sampling design. Native Cerrado and coffee soils also differed taxonomically, with Basidiomycota contributing substantially to several Cerrado communities and Ascomycota being prominent in both coffee systems. Community composition was further associated with soil physicochemical gradients, particularly soil acidity, Fe, P, S, and organic matter. Chitinolytic activity varied among isolates, with the highest individual activities observed in regenerative coffee and native Cerrado soils, while conventional coffee yielded a greater number of isolates with relatively high activity. Overall, land-use change was associated with marked restructuring of Cerrado soil fungal communities, while both native and cultivated soils harbored fungi with relevant chitinolytic potential. These findings reinforce the importance of conserving native Cerrado soils as reservoirs of fungal biodiversity and highlight agricultural soils as promising sources for biotechnological prospecting.