Geographic location shapes fungal communities associated with Epidendrum roots

Abstract

Fungal biodiversity significantly influences ecosystem dynamics through various interactions with plants, ranging from pathogenic to mutually beneficial associations. This study explores the fungal diversity associated with an ornamental orchid genus Epidendrum that is widely propagated globally but native to northern South America. Root samples were collected from Epidendrum in diverse geographic locations: Brazil, Colombia, Germany, Spain and six South African provinces. Fungal biodiversity was catalogued from the genomic DNA extracted from these roots using fungal-specific primers and Illumina MiSeq sequencing. Bioinformatic and statistical analyses revealed significant fungal diversity in the roots, with distinct dominant orders in each geographic region. Among the South African samples, significant differences were found in alpha diversity indices and species richness. Even though samples originating from different provinces overlapped in the PCoA plot, PERMANOVA indicated a significant difference in the fungal biodiversity, which was further supported by PERMDISP. In the global dataset, alpha diversity indices were insignificant, but species richness was. In the PCoA plot, data points clustered by sampling sites, indicating substantial differences in fungal biodiversity between the samples. This was validated by PERMANOVA and PERMDISP analyses. Outcomes from the core fungal analyses showed Epidendrum retained a conserved set of fungal orders from its native habitat when it transitioned to exotic regions, while it also formed new associations with local fungal communities in these introduced regions. These findings highlight the role of both core and region-specific fungal communities in the ecological adaptability and success of this widely planted orchid genus.