Arbuscular mycorrhizal fungal communities colonising the roots of indigenous legumes of South Africa as revealed by high-throughput DNA metabarcoding

The important ecological role of arbuscular mycorrhizal (AM) fungi on plant communities necessitates an understanding of the diversity and the factors that shape the community composition of AM fungi associated with plants. Therefore, this study investigated the diversity and composition of arbuscular mycorrhizal fungal (AMF) communities colonising the roots of eleven indigenous legumes in two South African provinces using high-throughput sequencing of the partial SSU rRNA gene. The analysis revealed 172 operational taxonomic units (OTUs, at 97% sequence similarity) belonging to eight genera. Arbuscular mycorrhizal fungal community composition varied among legumes within and between provinces, with the genus Glomus dominant. The AMF OTU richness and Shannon-Wiener index were significantly correlated with potassium, copper, manganese, zinc, and silt content. Canonical correspondence analysis indicated that nitrates, pH, manganese, and organic C were the principal soil properties significantly influencing AMF community composition. Overall, findings from this study elucidate that soil factors are pertinent environmental cues that shape legume-AMF symbiosis in semi-arid ecosystems.