Evidence for geomycological gold redox transformation under supergene conditions

Gold is one of the most inert elements on Earth but cycles in various chemical species determined by in situ biogeochemical properties. Here, we show that fungi, a major driver of mineral bioweathering, play a crucial role in gold redox transformation under supergene conditions. Our data reveal that indigenous fungi oxidize gold in an auriferous organosol over a secondary gold deposit of Yilgarn Craton, Western Australia. We isolated and characterized a gold-oxidizing fungus, Fusarium verticillioides TA_pink1, that belongs to Hypocreales from the gold anomalous soil. Intriguingly, fungal interspecific interactions vary considerably with the anomalous gold, while Hypocreales was identified as the keystone of the auriferous fungal network. Concomitantly, positive connections among fungal operational taxonomic units (OTUs) were prevalent in the auriferous fungal network. Soil carbon matter, in contrast to its role in the reference area, becomes a minor restricting factor that shapes the microbiome in the auriferous soil, potentially linking mycological gold redox transformation to carbon turnover. We argue that geomycological redox processes and communities should be considered in supergene gold biogeochemical cycling in terrestrial environments, which may exert a pervasive influence on the ecosystem than ever being prospected.