Fungal frontiers in toxic terrain: Revealing culturable fungal communities in Serpentine paddy fields of Taiwan

Serpentine soils are predominantly distributed along the Circum-Pacific margin and the Mediterranean, including eastern Taiwan. These soils are characterized by high levels of heavy metals, including nickel and chromium, and a low calcium-to-magnesium ratio, creating a unique environment that fosters microorganisms with specialized traits. In this study, culture-dependent isolation methods were used to elucidate the composition of culturable fungal communities in serpentine-characterized paddy fields in eastern Taiwan.

A total of 154 fungal isolates were isolated from serpentine paddy fields in eastern Taiwan. These isolates were grouped into 79 strains based on colony morphology and were subsequently evaluated through morphological and multi-locus phylogenetic analyses. The results revealed that 60 % of the strains belong to the class Dothideomycetes, followed by 21 % in Sordariomycetes and 19 % in Eurotiomycetes.

At the genus level, Westerdykella was the dominant genus, presenting 35 % of the total of isolated strains, followed by Pyrenochaetopsis (20 %), Talaromyces (19 %), and Pseudorhypophila (8 %). The study reports 11 novel species: Cylindrotrichum formosanum sp. nov., Dimorphiseta formosana sp. nov., D. serpentinicola sp. nov., Parasarocladium formosum sp. nov., Phialoparvum formosanum sp. nov., Poaceascoma serpentinum sp. nov., Pseudorhypophila formosana sp. nov., Sarocladium formosanum sp. nov., S. serpentinicola sp. nov., Talaromyces taiwanensis sp. nov., and Westerdykella formosana sp. nov.

Additionally, 11 known species are reported for the first time in Taiwan: Pseudothielavia terricola, Pseudoxylomyces aquaticus, Pyrenochaetopsis oryzicola, Py. paucisetosa, Setophaeosphaeria microspora, Talaromyces adpressus, T. thailandensis, Westerdykella aquatica, W. capitulum, W. dispersa, and W. globosa. In addition, this study presents the first documented asexual morph within the genus Poaceascoma, represented by P. serpentinum.

These discoveries will be valuable for future evaluations of the potential uses and functions of these species as bioremediation agents.