Conocybe belongs to the Bolbitiaceae. The morphological classification and molecular phylogenetics of Conocybe section Pilosellae are not in agreement. In this study, based on the specimens from China, we investigated the sect. Pilosellae and identified 17 species, including 7 new species: Conocybe pilosa, with a densely hairy pileus and stipe; C. reniformis, with reniform spores; C. ceracea, with waxy dehydration of the lamellae; C. muscicola, growing on moss; C. sinobispora, with two-spored basidia; C. hydrophila, with a hygrophanous pileus; C. rufostipes, growing on dung with a brown stipe; and C. pseudocrispa, one new record for China. A key was compiled for the sect. Pilosellae in China. Here, the sect. Pilosellae, and new species and records from China are morphologically described and illustrated. Maximum likelihood and Bayesian analyses were performed using a combined nuc rDNA internal transcribed spacer region (ITS) and nuc 28S rDNA (nrLSU), and translation elongation factor 1-alpha (tef1-α) dataset to reconstruct the relationships of this section. We found that the sect. Pilosellae was the basal clade of Conocybe, and its evolutionary features may shed light on the characteristics of Conocybe. By integrating morphological classification and phylogenetic analysis, we explored the possible phylogenetic relationships among the species of the sect. Pilosellae in China.

This study is based on the phylogenetic framework of Conocybe section Pilosellae and incorporates materials from Jilin Province. A systematic phylogenetic tree was constructed using maximum likelihood and Bayesian analyses of internal transcribed spacer region (ITS) and nuclear large subunit ribosomal DNA (nrLSU), and translation elongation factor 1-alpha (tef1-α) sequences. As a result, three new species were discovered in Jilin Province: Conocybe verna, which emerges in broad-leaved forests during spring; C. angulispora, characterized by angular and submitriform or slightly hexagonal basidiospores; and C. rubrocyanea, with basidiomata displaying a reddish hue when fresh and a bluish hue when dry. Additionally, a new record for China, C. hexagonospora was identified, characterized by the lack of distinct pubescence on the pileus and slightly hexagonal basidiospores, increasing the total number of species within sect. Pilosellae to 22. Key for sect. Pilosellae is provided, accompanied by morphological descriptions and line drawings for the new species and a new record for China.

Gene fusion is a process through which two or more distinct genes are fused into a single chimeric gene. Unlike most harmful fusion genes in cancer cells, in this study, we first found that spermidine synthetase- (SPDS, catalyst of spermidine biosynthesis) and saccharopine reductase- (SR, catalyst of the penultimate step of lysine biosynthesis) encoding genes form a natural chimeric gene, FfSpdsSr, in Flammulina filiformis. Through the cloning of full-length ORFs in different strains and the analysis of alternative splicing in developmental stages, FfSpdsSr has only one copy and unique transcript encoding chimeric SPDS-SR in F. filiformis. By an orthologous gene search of SpdsSr in more than 80 fungi, we found that the chimeric SpdsSr exists in basidiomycetes, while the two separate Spds and Sr independently exist in ascomycetes, chytridiomycetes, and oomycetes. Further, the transcript level of FfSpdsSr was investigated in different developmental stages and under some common environmental factors and stresses by RT-qPCR. The results showed that FfSpdsSr mainly up-regulated in the elongation stage and pileus development of F. filiformis, as well as under blue light, high temperature, H₂O₂, and MeJA treatments. Moreover, a total of 15 sets of RNA-Seq data, including 218 samples of Neurospora crassa, were downloaded from the GEO database and used to analyze the expression correlation of NcSpds and NcSr. The results showed that the separate NcSpds and NcSr shared highly similar co-expression patterns in the samples with different strains and different nutritional and environmental condition treatments. The chimeric SpdsSr in basidiomycetes and the co-expression pattern of the Spds and Sr in N. crassa indicate the special link of spermidine and lysine in fungi, which may play an important role in the growth and development of fruiting body and in response to the multiple environmental factors and abiotic stresses.

Conobolbitina is a morphologically diverse transitional genus within the Bolbitiaceae. However, taxonomic confusion persists, as some of its species remain classified under other genera, and its section Verrucisporae has been recovered as paraphyletic. This study revises the subdivision of Conobolbitina using integrated morphological and phylogenetic analyses of specimens from Jilin Province, China. A combined dataset of the internal transcribed spacer (ITS), nuclear large subunit ribosomal DNA (nrLSU), and translation elongation factor 1-alpha ( tef 1-α) sequences was analyzed using maximum likelihood (ML) and Bayesian inference (BI). Phylogenetic results revealed four major monophyletic clades within Conobolbitina , corresponding to its four sections. In sect. Conobolbitina , new combinations are proposed for two species, Con. sulcata and Con. striipes . In sect. Aeruginosa , Con. atrocyanea is newly combined. For sect. Verrucisporae , its circumscription is revised by excluding the taxa responsible for its paraphyly, and a new combination, Con. australis , is proposed. To accommodate the excluded taxa from sect. Verrucisporae , a new section, sect. Lignicola , is established based on morphological and phylogenetic evidence. Within this new section, three species, Con. glutinosa , Con. viscosa , and Con. sibirica , are newly combined, and two new species, Con. lignicola sp. nov . and Con. fuscoviolacea sp. nov ., are described. Through these revisions, the taxonomic positions of several species are clarified, and the paraphyly of sect. Verrucisporae is resolved. In total, this study revises and recognizes 10 new taxonomic entities, including one new section, two new species, and seven new combinations. An identification key to the Chinese species of Conobolbitina is provided, along with morphological descriptions and line drawings for the two new species.

A new species Pholiotina sphagnicola sp. nov., was discovered in Mongolia. Its identification was based on phylogenetic analyses of combined nuclear ribosomal DNA internal transcribed spacer region (ITS), nuclear ribosomal DNA 28S subunit (nrLSU), and translation elongation factor 1-alpha (tef1-α), as well as the morphological analyses. The species is characterized by a pileus ranging from hemispherical to convex, with indistinct striae on the margin. The ring is located above the stipe, and the upper sides crenulate-striate. Basidia, which resemble rabbit ears, are 2(1)-spored and have sterigmata ranging from 3 to 13 μm in length. Cheilocystidia are lageniform with a long neck and lanceolate shape; some may exhibit slight swelling at the apex.

Based on morphological observations, this study reports the first discovery of species from section Ochromarasmius in China. Using combined internal transcribed spacer (ITS), nuclear large subunit ribosomal DNA (nrLSU), and translation elongation factor 1-alpha ( tef 1-α) sequences, Bayesian and maximum likelihood phylogenies were reconstructed for sect. Ochromarasmius . The resulting phylogenetic trees indicate that subsect. Dumetorae forms a monophyletic group. Subsect. Subdumetorae , in terms of both its definition and phylogenetic placement, is entirely nested within subsect. Dumetorae ; therefore, it is treated as a later synonym. Furthermore, subsect. Dumetorae encompasses three new species from northern China: Conocybe verrucosa , C. arenicola , and C. subfusispora . Thus, the total number of species in subsect. Dumetorae is increased to 11 and that in sect. Ochromarasmius to 14. Additionally, based on morphological characteristics, putative phylogenetic positions are discussed for the other subsections and species within sect. Ochromarasmius that currently lack molecular sequence data. The study also provides an identification key for sect. Ochromarasmius subsect. Dumetorae , accompanied by morphological descriptions and line drawings of the new species.