Seminar of the Department of Microbiology

Bacterial-fungal interactions in glacier forefields: to the Alps and beyond

Edoardo Mandolini - AG Ursula Peintner, Department of Microbiology, University of Innsbruck

20.10.2022, 11:00 - Online & in presence - Join online - or in presence: Seminarraum Mikrobiologie, (Bauteil V)

Abstract

Bacterial-fungal interactions in recently deglaciated ecosystems promote biogeochemical cycles, mineral soil fertility, and pioneer plant growth, but the diversity of keystone microbes and the quality of their interactions remain largely unexplored. Here, we investigated the diversity of both fungal and bacterial communities to predict core microbial networks and to estimate conserved interactions across comparable deglaciated systems.

We studied the soil fungal and bacterial communities at the early stages of soil development (0-25 years) in four receding calcareous glaciers of the Alps (>200 samples). High-resolution marker-gene (16S and ITS) analysis were performed alongside detailed soil geochemical analysis. Furthermore, we included 13 datasets from publicly available projects on forefields of receding glaciers (world-wide) whose sequencing libraries resembled the criteria of our own dataset. Network analysis (FlashWeave/SpiecEasi) was performed for each dataset. Then, core microbial interactions were identified across glacier forefields.

Bacterial and fungal communities differed in a location-specific manner, sharing remarkably few common taxa.

We found extremely dense networks in all locations, with fungi clearly dominating the keystone nodes for all major interactive clusters. We speculate that conserved interactions across glacier forefields are rather based on trophic preferences than on phylogenetic diversity.

Our data emphasize (i) the unique diversity of soil microbial communities in glacier forefields likely depending on stochastic processes of dispersion, but provide (ii) evidence for common ecological roles based on conserved microbial interactions.