Fungal diversity associated with the mycorrhizosphere soil of Brachycorythis conica subsp. transvaalensis, a critically endangered and endemic terrestrial orchid from South Africa

Abstract

The Albertina Sisulu orchid, Brachycorythis conica subsp. transvaalensis is a critically endangered terrestrial orchid with a single population remaining in the Gauteng Province of South Africa. For the conservation of this endemic orchid, several strategies are being implemented such as protection of habitat, identifying pollinators and in vitro propagation. For symbiotic germination, it is essential to identify the mycorrhizal associates of this orchid using non-destructive sampling. In this study, high-throughput sequencing was used to catalogue and compare the diversity of fungi associated with the mycorrhizosphere of this orchid and non-mycorrhizosphere soils collected from the same coordinates. Bioinformatics and statistical analyses of the data showed that, despite the substantial overlap in the community composition of fungi associated with these two soil types, several exclusive fungal species were identified from the mycorrhizosphere of the orchid. These included an assortment of potential orchid mycorrhizal species from the orders Agaricales, Cantharellales and Sebacinales. This study provides the first insight into the soil fungal diversity associated with the mycorrhizosphere of this critically endangered orchid. In the future, data from this study can be used for optimising conservation measures and isolation of suitable mycorrhizal species required for in vitro symbiotic germination of this orchid.