Ecology of aquatic hyphomycetes and the role of biodiversity
Laboratory of Applied Microbiology, University of Applied Sciences and Arts of Southern Switzerland (SUPSI)
Ecology of aquatic hyphomycetes and the role of biodiversity.
Lundi 03 juin 2019, 11h00, Salle de Conférences, 4R1.
Dr. Andreas BRUDER
Laboratory of Applied Microbiology, University of Applied Sciences and Arts of Southern Switzerland (SUPSI).
Aquatic hyphomycetes represent a polyphyletic group of filamentous fungi, which have their main habitat in well-oxygenated streams, mainly headwaters. The principal ecological roles of aquatic hyphomycetes center on the decomposition of allochthonous plant litter, mainly abscised leaves from the riparian vegetation surrounding the streams. Their activity also benefits feeding by invertebrate detritivores, thus further emphasizing their crucial roles in stream food webs. Headwater stream ecosystems are important in terms of their abundance as a landscape feature, but also because of their disproportionally high biodiversity. However, in terms of microbes, in particular fungi, this biodiversity is not well known. This finding is worrisome since biodiversity of freshwaters has been declining rapidly during the past decades as a consequence of human activities, and it has been doing so faster than that of most other ecosystem types. I will highlight the role of biodiversity at various trophic levels of detritus-based food webs for the activity of aquatic hyphomycetes and for the processes they govern. I will base these notions on examples from field- and laboratory experiments. Some studies suggest that not only interspecific but also intraspecific diversity of aquatic hyphomycetes may influence their activity and their sensitivity to environmental stressors. Studies addressing these questions require quantification of intraspecific diversity, which, however, is challenging with established approaches in fungal taxonomy (i.e. morphological identification and DNA barcoding). I will present a proteomic approach that we are developing based on MALDI TOF mass spectrometry and which may help in addressing this challenge. Due to the broad range of ribosomal proteins analyzed simultaneously, this technique provides vast genomic information. It may thus lend itself for detailed characterization and identification of fungal cultures including measures of inter- and intraspecific diversity. We applied this technique to our collection of aquatic hyphomycete cultures isolated from pristine streams in Southern Switzerland. As an example, this project revealed previously unknown intraspecific patterns in a common and ubiquitous species, i.e. Tetracladium marchalianum.