Additions to Lyophyllaceae s.l. from China

Multiple evidence reveals two new species and new distributions of Calocybe species (Lyophyllaceae) from northeastern China

The Calocybe species possess notable economic and medicinal value, demonstrating substantial potential for resource utilization. The taxonomic studies of Calocybe are lacking in quality and depth. Based on the specimens collected from northeast China, this study provides a detailed description of two newly discovered species, namely Calocybebetulicola and Calocybecystidiosa, as well as two commonly found species, Calocybedecolorata and Calocybeionides. Additionally, a previously unrecorded species, C.decolorata, has recently been discovered in Jilin Province, China. The two newly discovered species can be accurately distinguished from other species within the genus Calocybe based on their distinct morphological characteristics. The primary distinguishing features of C.betulicola include its grayish-purple pileus, grayish-brown to dark purple stipe, smaller basidiomata, absence of cellular pileipellis, and its habitat on leaf litter within birch forests. Calocybecystidiosa is distinguished by its growth on the leaf litter of coniferous forests, a flesh-pink pileus, a fibrous stipe with a white tomentose covering at the base, non-cellular pileipellis, larger basidiospores, and the presence of cheilocystidia. The reconstruction of phylogenetic trees using combined ITS, nLSU, and tef1-α sequences, employing maximum likelihood and Bayesian inference analyses, showed that C.betulicola formed a cluster with C.decurrens, while C.cystidiosa clustered with C.vinacea. However, these two clusters formed separate branches themselves, which also supported the results obtained from our morphological studies. A key to the Calocybe species reported from northeast China is provided to facilitate future studies of the genus.

Transcriptome and Hormonal Analysis of Agaricus bisporus Basidiome Response to Hypomyces perniciosus Infection

Agaricus bisporus (Lange) Imbach is the most widely cultivated mushroom in the world. A. bisporus wet bubble disease is one of the most severe diseases of white button mushrooms and is caused by the fungal pathogen Hypomyces perniciosus. The pathogen causes a drastic reduction in mushroom yield because of malformation and deterioration of the basidiomes. However, the mechanism of the button mushroom's malformation development after infection with H. perniciosus remains obscure. Therefore, to reveal the mechanism of A. bisporus malformation caused by H. perniciosus, the interaction between the pathogen and host was investigated in this study using histopathological, physiological, and transcriptomic analyses. Results showed that irrespective of the growth stages of A. bisporus basidiomes infected with H. perniciosus, the host's malformed basidiomes and enlarged mycelia and basidia indicated that the earlier the infection with H. perniciosus, the more the malformation of the basidiomes. Analyzing physiological and transcriptomic results in tandem, we concluded that H. perniciosus causes malformation development of A. bisporus mainly by affecting the metabolism level of phytohormones (N6-isopentenyladenosine, cis-zeatin, and N6-[delta 2-isopentenyl]-adenine) of the host's fruiting bodies rather than using toxins. Our findings revealed the mechanism of the button mushroom's malformation development after infection with H. perniciosus, providing a reference for developing realistic approaches to control mushroom diseases. Our results further clarified the interaction between A. bisporus and H. perniciosus and identified the candidate genes for A. bisporus wet bubble disease resistance breeding. Additionally, our work provides a valuable theoretical basis and technical support for studying the interaction between other pathogenic fungi and their fungal hosts.

Morphology and Phylogeny of Lyophylloid Mushrooms in China with Description of Four New Species

The lyophylloid agarics are a group of ecologically highly diversified macrofungi, some of which are very popular edible mushrooms. However, we know little about lyophylloid species diversity in China. In this study, we described four new species from China: Lyophyllum atrofuscum, L. subalpinarum, L. subdecastes, and Ossicaulis sichuanensis. We conducted molecular phylogenetic analyses of Lyophyllaceae based on the nuclear ribosomal RNA gene (nLSU) and the internal transcribed spacer regions (ITS). Phylogenetic analyses by the maximum likelihood method and Bayesian inference showed that the four new species are unique monophyletic species. A key to the species of Lyophyllum from China and a key to Ossicaulis worldwide were given.