Molecular analysis of Ganoderma and Amauroderma species in the tropical rainforest of Sarawak, Borneo

This study aimed to record the genetic types of both Ganoderma australe
sensu lato and Amauroderma subrugosum sensu lato with their morphological
and ecological traits. Ganoderma australe sensu lato and Amauroderma
subrugosum sensu lato were studied in three national parks in Sarawak:
Santubong, Kubah (western area) and Lambir Hill (northeastern area). The
decay stage and diameter of fallen logs from which fungal fruiting bodies
appeared were recorded. The size of the pores and length of the tube of
fruiting bodies were measured and recorded in the laboratory. Molecular
phylogenetic trees were inferred from nucleotide sequence of the internal
transcribed spacer (ITS) region of ribosomal RNA. In the phylogenetic tree
analysis, Amauroderma subrugosum was grouped into a single genetic type
while Ganoderma australe has been divided and classified into four genetic
types: type 1, type 2, type 3, and type 5. All genetic types of Ganoderma
australe fruiting bodies frequently appear in the intermediate stages of
decayed wood (stage 3) from small and medium-sized (diameter) fallen trees
or logs. In this study, no novel genetic types of Ganoderma australe were
observed, and several genetic types were not observed in Amauroderma
subrugosum. All genetic types of Ganoderma australe were found in the
northeast (Lambir Hills) and west (Kubah, Santubong) areas of Sarawak.
This suggests that these genetic types are widely distributed across
Sarawak. Further study is needed to reveal the mechanisms that drive
speciation and maintain genetic diversity in Ganoderma australe and the
mechanisms that prevent speciation in Amauroderma subrugosum.