Insights into the Metabolomic Capacity of Podaxis and Isolation of Podaxisterols A-D, Ergosterol Derivatives Carrying Nitrosyl Cyanide-Derived Modifications

Microbial landscapes in Trinervitermes trinervoides termite colonies are affected by mound compartments and soil properties but not by symbiotic Podaxis fungi

Termites are important ecosystem engineers and play key roles in modulating microbial communities within and outside their mounds. Microbial diversity within termite mounds is generally lower than surrounding soils, due to termite-associated antimicrobial compounds and active sanitary behaviours. Microbial symbionts of termites can also influence the microbial landscape, by inhibiting or out-competing other microbes. Certain members of the arid habitat fungal genus Podaxis (Agaricomycetes; Agaricaceae) are symbiotic with savannah specialist grass-cutting termites, and have the potential to influence mound-associated microbiomes. To test this, we characterized fungal (ITS2) and bacterial (16S rRNA) communities within and outside 49 Trinervitermes trinervoides mounds with and without Podaxis fruiting bodies across a 1000 km transect in South Africa. We predicted that Podaxis would be a dominant member of the fungal communities in mounds and negatively impact microbial diversity. Further, we explored how environmental variables shaped microbial communities, including whether soil elemental composition affected Podaxis presence. As expected, we observed less diverse fungal communities, but not bacterial communities, within than outside mounds, while microbial communities differed by sampling regions and mound compartments. Podaxis sequences were present in 48 out of 49 mounds in low relative abundances, and neither fruiting body presence nor sequence abundance were associated with microbial diversity or composition. There was, however, an overall association between the presence of Podaxis fruiting bodies and elemental composition, with different elements displaying varying associations depending on geographic region. Both environmental variables and soil elements were associated with fungal and bacterial taxa, indicating that they are key drivers of microbial community composition. Taken together, our findings suggest that microbial landscapes in termite mounds are not strongly influenced by Podaxis but mainly driven by termite filtering and regional abiotic variables and elemental compositions.

Current Biological Knowledge, Applications, and Potential Use of the Desert Shaggy Mane Mushroom Podaxis pistillaris (Agaricomycetes): A Review

Podaxis pistillaris, an abundant gasteroid mushroom, has become an important biological element in arid and semiarid communities worldwide. This mushroom possesses cosmetic, edible, and medicinal attributes, playing a crucial role in communities in countries such as Australia, India, Saudi Arabia, Yemen, and Mexico. Proximate studies highlight the nutritional richness of P. pistillaris, characterized by high protein content and essential bioelements such as K, P, and Mg. Furthermore, P. pistillaris is integral to the traditional medicine of indigenous communities in America, Asia, and Africa, where it is revered for its purported wound-healing, anti-inflammatory, and coagulant properties. In the case of Mexico, the Seri community uses and markets P. pistillaris in various forms, including ointments and, within the region, its spores. Chemical analysis of this species reveals notable compounds, including epicorazines A-C exhibiting antimicrobial properties, along with polysaccharides such as β-glucans, and a recently identified ergosterol derivative named podaxisterol. Despite its importance, the chemical characterization and assessment of the biological activity of its compounds have been largely understudied. Consequently, there are currently no wound-healing products on the market derived from fungi, as the majority originate from plant sources. This work aims to present the essential aspects of P. pistillaris's ethnobiological use, medicinal properties, bioactive compounds, and biotechnological applications. In addition, it underscores the overlooked status of P. pistillaris among fungi inhabiting arid areas, emphasizing its potential as a valuable subject for further research.

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