Variation in the Microbiomes of the Basidiomycete Fungi Scleroderma citrinum (Pers.) and Pisolithus arhizus (Pers.): a tale of two saprotrophs.

In this study we used high throughput DNA sequencing and ICP-MS to compare the microbiome of the common earthball fungus, Scleroderma citrinum (Pers.) to that of its sister taxon in the Sclerodermataceae, Pisolithus arhizus (Scop.). ICP-MS analysis demonstrates that S. citrinum is enriched in silica, sulfur and zinc relative to P. arhizus, while P. arhizus is enriched in arsenic, calcium, cadmium, cobalt, copper, lithium, magnesium, molybdenum, nickel, potassium and vanadium. Statistical analysis of molecular data indicates that the microbiome of P. arhizus is both richer and more diverse than that of S. citrinum, and that the microbiomes are significantly different with that of S. citrinum being enriched in Cyanobacteria represented by the chloroplast of a photosynthetic, cryptoendolithic red alga, Saccharibacteria (TM-7), and Planctomycetes, while that of P. arhizus is enriched in Gemmatimonadetes, Latescibacteria, Elusomicrobia, and Tectomicrobia. Further, the P. arhizus microbiome is enriched in anaerobes relatives to that of S. citrinum, probably reflecting anaerobic zones previously measured in P. arhizus. Together, the data indicate diverse microbiomes comprised of aromatic hydrocarbon-degrading, metal- and radiotolerant bacteria, indicating that these fungi may provide a rich source of novel microbes suitable for bioremediation strategies.