Phylogenetic assessment and taxonomic revision of Scytalidium (Helotiales, Leotiomycetes)

Members of Scytalidium are primarily saprotrophic and are known for their ability to colonize a variety of substrates, including soil, decaying plant material, and wood. During an investigation of soil microfungi in Capsicum annuum cultivation areas of China, seven Scytalidium isolates were obtained from soil samples collected in Guizhou. In this study, we revised the genus Scytalidium by combining morphological characteristics and phylogenetic analyses based on concatenated ITS – LSU sequences.

The results showed that Scytalidium sensu stricto comprises 16 species, including the type species S. lignicola and four novel species proposed in this study (S. chlamydosporum, S. guizhouense, S. rodionovae, and S. tongrenense). Ten species were excluded, and six species were treated as uncertain due to the lack of available molecular sequences. This study revised the genus Scytalidium, expanded its species diversity and geographical distribution, and lays the foundation for future taxonomic research on this genus.