The impact of microorganisms, specifically their functional activities, on geological processes on the Earth’s surface is undeniably significant. Currently, most of our knowledge about these critical biogeochemical processes and the environmental relevance is limited to the study of bacterial and archaeal microbes because they are abundant, have diverse metabolic functions, and are readily manipulated using modern genomics techniques. Increasing evidence illustrates that highly abundant and metabolically active micro-eukaryotes, such as fungi, also promote numerous geochemical transformation reactions, and their contributions may be equal to or greater than that of bacteria in some environments, particularly in anthropogenically compromised systems. For example, fungi are the primary drivers of wood and leaf litter decay that influence the global carbon cycle and they also promote biogeochemical cycling in metal-polluted and constructed environments. Fungi, although limited to heterotrophic metabolisms, are key drivers of diverse nutrient and metal(loid) redox transformations and their impact on geobiological processes should be more critically examined.
Research to uncover the processes and pathways by which fungi promote mineral dissolution, mineral precipitation, and metal(loid) phase transformations are imperative for better understanding fungal contributions to the fate and distribution of environmentally relevant elements. Our work examines diverse filamentous fungi and the biological pathways by which they promote the transformation of metals like manganese (Mn) and selenium (Se) from a toxic aqueous phase to solid or volatile phases that are less bioavailable and less hazardous to most living organisms. Paired profiling of the geochemical transformations and fungal gene expression due to Se exposure, for example, is revealing the complex myriad pathways by which fungi can both sequester nutrients as well as detoxify elements from cells and, ultimately, from Earth surface environments.