Capturing the fungal diversity hidden in Eastern Cape dairy pastures

Abstract

Fungi in dairy pastures impact cattle health, yet the diversity of fungal species present in South African pastures remains understudied. Following an outbreak of Sporidesmin-Induced Liver Disease (SILD; caused by the mycotoxin sporidesmin produced by Pseudopithomyces toxicarius) in the Eastern Cape in 2020, we collected mixed pasture samples from 14 dairy farms affected by this disease. Our aim was to investigate what fungal species are present in communities and whether species like Ps. toxicarius are present that may play a role in cattle health. A total of 708 strains were isolated from 95 mixed pasture samples and identified based on DNA sequence data to 132 species representing 55 genera. Fusarium was the most isolated (207 strains; 21 species; 55 samples), followed by Penicillium (75 strains; 22 species; 27 samples), Pseudopithomyces (69 strains; 2 species; 21 samples), Cladosporium (54 strains; 6 species; 23 samples), Epicoccum (52 strains; 6 species; 24 samples) and Bipolaris (38 strains; 3 species; 19 samples). Several strains could not be identified and represent potentially new or previously uncharacterised species. Additionally, phylogenetic analyses revealed the presence of Ps. palmicola and Ps. toxicarius in the Eastern Cape dairy pastures. Our findings underscore the ecological complexity of pasture environments and raise important questions about the role of fungal diversity in livestock health.