Laboratory conditions can change the complexity and composition of the natural aquatic mycobiome on Alnus glutinosa leaf litter

Abstract

Community structure is of major interest when aquatic fungi are studied, particularly in leaf decomposition experiments. Although such studies are often conducted as laboratory experiments with microbial communities taken from the field, it remains unclear to what extent natural fungal communities can be sustained under experimental conditions. Here, we used DNA metabarcoding to investigate the development of fungal communities on alder leaves both under laboratory and field conditions. Five leaf conditioning treatments were compared by colonizing leaves in a stream, exposing stream colonized leaves to a defined medium or filtered stream water and using stream colonized leaves to inoculate sterile leaves in the defined medium or stream water. Fewer species were found on leaves that were inoculated under laboratory conditions, whereas differences in fungal community composition were comparably low in the other treatments, irrespective of the chosen medium. Possible shifts in fungal communities should therefore be considered in laboratory experiments. • A high taxonomic resolution was achieved during in depth analysis of the mycobiome. • Fewer species were found on leaves inoculated under laboratory conditions. • Low community changes appeared in treatments with stream conditioned leaves. • Only low differences in community composition were found between chosen media.