Multilocus phylogenies and morphological analyses revealed new and previously described Ganoderma species in South Africa

TCHOTET TCHOUMI, J.M.; COETZEE M.P.A.; RAJCHENBERG M.; ROUX, J.

Johanesburgo

Congreso; 45th South African Association of Botanists Conference; 2019

South African Association of Botanists

Ganoderma is a cosmopolitan genus of Polypores that encompasses species important for forestry, medicine and cultural traditions. Despite the importance of this genus, knowledge pertaining to the species diversity of Ganoderma in South Africa is limited. This study aimed at elucidating the identity and phylogenetic placements of a large collection of Ganoderma samples obtained from the Garden Route National Park (GRNP) of South Africa and during earlier fieldwork at other localities. Identification was done based on phylogenetic analyses of DNA sequences obtained from the Internally Transcribed Spacer (ITS) regions, a region of the β-tubulin and Translation Elongation Factor 1-alpha (TEF) genes, respectively, as well as morphological characters. Results from these analyses revealed that isolates from the collections belong to eight Ganoderma species. Of these, G. applanatum, G. austroafricanum, G. destructans and G. enigmaticum have previously been reported from South Africa, while G. cupreum and G. resinaceum are new records for the country. The remaining two species are novel taxa belonging to subgen. Elfvingia and described as G. acacicola sp. nov. and G. knysnamense sp. nov. Ganoderma acacicola occurs on native and non-native hosts, including Acacia cyclops, Celtis africana, Prunus africana and an unknown palm species in four provinces of the country. The fungus is characterised by a perennial, triquetrous and broadly attached basidiome, a sulcate up to zonate yellowish brown to brown pilear surface, and ovoid to ellipsoid basidiospores. Ganoderma knysnamense was collected only in the GRNP where it was also the most abundant fungus among the species identified. It is distinguished by its applanate to ungulate, sometimes convex, and dimidiate to broadly attached basidiome, its chocolate-brown pilear surface covered with a hard woody-like crust and ellipsoid, broadly ellipsoid to ovoid basidiospores. The discovery of two new Ganoderma species as well as the two newly-recorded species raises the total known Ganoderma species in South Africa to 15. The continual discovery of new species, as is shown in this study and other recent studies, suggest that many more Ganoderma species are likely to be discovered in South Africa and indicates that further research is warranted on this important genus in the country and in Africa.