Updated taxonomy of LactifluussectionLuteoli: L.russulisporus from Australia and L.caliendrifer from Thailand

What Quality Suffices for Nanopore Metabarcoding? Reconsidering Methodology and Ectomycorrhizae in Decaying Fagus sylvatica Bark as Case Study

Nanopore raw read accuracy has improved to over 99%, making it a potential tool for metabarcoding. For broad adoption, guidelines on quality filtering are needed to ensure reliable taxonomic unit recovery. This study aims to provide those guidelines for a fungal metabarcoding context and to apply them to a case study of ectomycorrhizae in the decaying bark of Fagus sylvatica. We introduce the eNano pipeline to test two standard metabarcoding approaches: (1) Reference-based mapping leveraging UNITE's species hypothesis system (SH approach); (2) Constructing 98% OTUs (OTU approach). Our results demonstrate that both approaches are effective with Nanopore data. When using a reference database, we recommend strict mapping criteria rather than Phred-based filtering. Leveraging the SH-system further enhances reproducibility and facilitates cross-study communication. For the 98% OTUs, filtering reads at ≥Q25 is recommended. Our case study reveals that the decay gradient is a primary determinant of community composition and that specific mycorrhizal fungi colonize decaying bark. Complementing our metabarcoding results with root tip morphotypification, we identify Laccaria amethystina and Tomentella sublilacina as key ectomycorrhizae of saplings on decaying logs. These findings demonstrate that Nanopore sequencing can provide valuable ecological insights and support its broader use in fungal metabarcoding as read quality continues to improve.

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.

Untangling the Lactifluus clarkeae - Lf. flocktoniae(Russulaceae) species complex in Australasia

The Lactifluus clarkeae complex is a commonly observed, generally brightly coloured, group of mushrooms that are usually associated with Nothofagus or Myrtaceous hosts in Australia and New Zealand. For this study collections labelled as 'Lactarius clarkeae', 'Russula flocktoniae' and 'Lactarius subclarkeae' were examined morphologically and molecularly. Analyses of molecular data showed a high cryptic diversity, with sequences scattered across 11 clades in three subgenera within Lactifluus, and a single collection in Russula. We select epitypes to anchor the currently accepted concepts of Lf. clarkeae s.str. and Lf. flocktoniae s.str. The name Lf. subclarkeae could not be applied to any of the collections examined, as none had a lamprotrichoderm pileipellis. Lactifluus clarkeae var. aurantioruber is raised to species level, and six new species are described, three in subg. Lactifluus: Lf. jetiae, Lf. pagodicystidiatus, and Lf. rugulostipitatus, and three in subg. Gymnocarpi: Lf. albens, Lf. psammophilus, and Lf. pseudoflocktoniae. A new collection of Lf. russulisporus provides a significant range extension for the species. Untangling this complex will enable better identification of species and increase understanding of diversity and specific habitat associations of macrofungi. Citation: Lebel T, Douch J, Tegart L, et al. 2021. Untangling the Lactifluus clarkeae - Lf. flocktoniae (Russulaceae) species complex in Australasia. Persoonia 47: 1-44. https://doi.org/10.3767/persoonia.2021.47.01.

Untangling the Lactifluus clarkeae - Lf. flocktoniae(Russulaceae) species complex in Australasia

The Lactifluus clarkeae complex is a commonly observed, generally brightly coloured, group of mushrooms that are usually associated with Nothofagus or Myrtaceous hosts in Australia and New Zealand. For this study collections labelled as 'Lactarius clarkeae', 'Russula flocktoniae' and 'Lactarius subclarkeae' were examined morphologically and molecularly. Analyses of molecular data showed a high cryptic diversity, with sequences scattered across 11 clades in three subgenera within Lactifluus, and a single collection in Russula. We select epitypes to anchor the currently accepted concepts of Lf. clarkeae s.str. and Lf. flocktoniae s.str. The name Lf. subclarkeae could not be applied to any of the collections examined, as none had a lamprotrichoderm pileipellis. Lactifluus clarkeae var. aurantioruber is raised to species level, and six new species are described, three in subg. Lactifluus: Lf. jetiae, Lf. pagodicystidiatus, and Lf. rugulostipitatus, and three in subg. Gymnocarpi: Lf. albens, Lf. psammophilus, and Lf. pseudoflocktoniae. A new collection of Lf. russulisporus provides a significant range extension for the species. Untangling this complex will enable better identification of species and increase understanding of diversity and specific habitat associations of macrofungi. Citation: Lebel T, Douch J, Tegart L, et al. 2021. Untangling the Lactifluus clarkeae - Lf. flocktoniae (Russulaceae) species complex in Australasia. Persoonia 47: 1-44. https://doi.org/10.3767/persoonia.2021.47.01.

A short story of nearly everything in Lactifluus (Russulaceae)

Fungi are a large and hyper-diverse group with major taxa present in every ecosystem on earth. However, compared to other eukaryotic organisms, their diversity is largely understudied. Since the rise of molecular techniques, new lineages are being discovered at an increasing rate, but many are not accurately characterised. Access to comprehensive and reliable taxonomic information of organisms is fundamental for research in different disciplines exploring a variety of questions. A globally dominant ectomycorrhizal (ECM) fungal family in terrestrial ecosystems is the Russulaceae (Russulales, Basidiomycota) family. Amongst the mainly agaricoid Russulaceae genera, the ectomycorrhizal genus Lactifluus was historically least studied due to its largely tropical distribution in many underexplored areas and the apparent occurrence of several species complexes. Due to increased studies in the tropics, with a focus on this genus, knowledge on Lactifluus grew. We demonstrate here that Lactifluus is now one of the best-known ECM genera. This paper aims to provide a thorough overview of the current knowledge of Lactifluus, with information on diversity, distribution, ecology, phylogeny, taxonomy, morphology, and ethnomycological uses of species in this genus. This is a result of our larger study, aimed at building a comprehensive and complete dataset or taxonomic framework for Lactifluus, based on molecular, morphological, biogeographical, and taxonomical data as a tool and reference for other researchers. Citation: De Crop E, Delgat L, Nuytinck J, Halling RE, Verbeken A (2021). A short story of nearly everything in Lactifluus (Russulaceae). Fungal Systematics and Evolution 7: 133-164. doi: 10.3114/fuse.2021.07.07.