Forestry treatments alter plant pathogenic fungal community composition in mosses, sedges, and oak trees in a sessile oak-hornbeam forest

Abstract We investigated how silvicultural practices affect leaf-associated plant pathogenic fungal communities in a Pannonian oak-hornbeam forest. We generated and analyzed DNA metabarcoding data from leaves of three plant species that are common throughout the study area and represent different growth forms as well as three major phylogenetic clades of plants: epiphytic bryophyte Hypnum cupressiforme , understory monocot Carex pilosa , and woody dicot Quercus petraea . We sequenced the ITS2 rDNA region of leaf samples of all three plant species collected from six replicate plots of the four treatments and the control: clear-cutting (CC), gap-cutting (G), preparation cutting (P), retention tree group (R), and closed-forest control (C). Plant pathogenic fungal communities strongly differed among plant species, particularly between mosses and angiosperms. Several fungal genera showed clear preferences for specific plant hosts. Members of the Devriesia genus exhibited a strong preference for mosses. The Pseudopesicula and Naevala genera were primarily found in the sampled angiosperms, while Ascochyta taxa were present in all three plant hosts. The composition of plant pathogenic fungi strongly correlated with silvicultural treatments, accounting for between 21% and 43% of the compositional variance. Of the abiotic environmental variables known to be affected by silvicultural practices, relative humidity, temperature, and vapour pressure deficit correlated significantly with fungal compositional differences among the sampled plots.