Two new Russula species (fungi) from dry dipterocarp forest in Thailand suggest niche specialization to this habitat type.

Dry dipterocarp forests are among the most common habitat types in Thailand. Russulaceae are known as common ectomycorrhizal symbionts of Dipterocarpaceae trees in this type of habitat. The present study aims to identify collections of Russula subsection Amoeninae Buyck from dry dipterocarp forests in Thailand. A multi-locus phylogenetic analysis placed Thai Amoeninae collections in two novel lineages, and they are described here as R. bellissima sp. nov. and R. luteonana sp. nov. The closest identified relatives of both species were sequestrate species suggesting that they may belong to drought-adapted lineages. An analysis of publicly available ITS sequences in R. subsect. Amoeninae did not confirm evidence of any of the new species occurring in other Asian regions, indicating that dry dipterocarp forests might harbor a novel community of ectomycorrhizal fungi. Macromorphological characters are variable and are not totally reliable for distinguishing the new species from other previously described Asian Amoeninae species. Both new species are defined by a combination of differentiated micromorphological characteristics in spore ornamentation, hymenial cystidia and hyphal terminations in the pileipellis. The new Amoeninae species may correspond to some Russula species collected for consumption in Thailand, and the detailed description of the new species can be used for better identification of edible species and food safety in the region.

Lanostane triterpenoids from cultivated fruiting bodies of basidiomycete Ganoderma mbrekobenum.

In the quest for medicinally active compounds in mushrooms of the genus Ganoderma, eleven undescribed lanostane triterpenoids, including a novel chlorinated derivative, i.e., (20S,24E)-21-chloro-15ß,20,29-trihydroxy-3,7,11-trioxolanosta-8,24-dien-26-oic acid, were isolated from artificially cultivated fruiting bodies of the basidiomycete Ganoderma mbrekobenum. The structures were elucidated on the basis of NMR spectroscopic and mass spectrometry data. The configuration of the C-20 atom in the most abundant 20-hydroxy-lanostane, (20S,24E)-15ß,20,29-trihydroxy-3,7,11-trioxolanosta-8,24-dien-26-oic acid, was established by chemical derivatization, and the absolute configuration of the lanostane skeleton was determined by ECD calculation. Two of the undescribed compounds exhibited moderate antimalarial activity.