Outbreaks of wet bubble disease (WBD) caused by Mycogone perniciosa are increasing across the world and seriously affecting the yield of Agaricus bisporus. However, highly WBD-resistant strains are rare. Here, we tested 28 A. bisporus strains for WBD resistance by inoculating M. perniciosa spore suspension on casing soil, and assessed genetic diversity of these strains using 17 new simple sequence repeat (SSR) markers developed in this study. We found that 10 wild strains originating from the Tibetan Plateau in China were highly WBD-resistant strains, and 13 cultivated strains from six countries were highly susceptible strains. A total of 88 alleles were detected in these 28 strains, and the observed number of alleles per locus ranged from 2 to 8. Cluster and genetic structure analysis results revealed the wild resources from China have a relatively high level of genetic diversity and occur at low level of gene flow and introgression with cultivated strains. Moreover, the wild strains from China potentially have the consensus ancestral genotypes different from the cultivated strains and evolved independently. Therefore, the highly WBD-resistant wild strains from China and newly developed SSR markers could be used as novel sources for WBD-resistant breeding and quantitative trait locus (QTL) mapping of WBD-resistant gene of A. bisporus.

Agaricus bisporus is widely consumed on the world market. The easy browning of mushroom surface is one of the most intuitive factors affecting consumer purchase. A certain cognition on browning mechanism has been made after years of research. At present, people slow down the browning of mushrooms mainly by improving preservation methods. In addition, breeding is also a reliable way. In the production practice, we have identified some browning-resistant varieties, and we selected a browning-resistant variety to compare with an ordinary variety to reveal the resistance mechanism. Using transcriptomics and metabolomics, the differences in gene expression and metabolite levels were revealed, respectively. The results showed that differentially expressed genes (DEGs) like AbPPO4, AbPPO3 and AbPPO2 were differently expressed and these DEGs were involved in many pathways related to browning. The expression of AbPPO expression play an important role in the browning of A. bisporus and multiple PPO family members are involved in the regulation of browning. However, the resistance to browning cannot be judged only by the expression level of AbPPOs. For metabolomics, most of the different metabolites were organic acids. These organic acids had a higher level in anti-browning (BT) than easy-browning varieties (BS), although the profile was very heterogeneous. On the contrary, the content of trehalose in BS was significantly higher than that in BT. Higher organic acids decreased pH and further inhibited PPO activity. In addition, the BS had a higher content of trehalose, which might play roles in maintaining PPO activity. The difference of browning resistance between BS and BT is mainly due to the differential regulation mechanism of PPO.

Agaricus blazei, a type of edible straw‐rotting mushroom with somewhat sweet taste and fragrance of almonds, has attracted considerable scientific and practical attention. High‐throughput Illumina PE150 and PacBio RSII platform were employed to generate a genomic sequence. De novo assembly generated 36 contigs with 38,686,133 bp in size, containing 10,119 putative predicted genes. Additionally, we also studied transcriptional regulation of the mycelia and the primordia for exploration of genes involved in fruiting body formation. Expression profiling analysis revealed that 2,164 genes were upregulated in mycelia and 1,557 in primordia. Functional enrichment showed that differentially expressed genes associated with response to stress, ribosome biogenesis, arginine biosynthesis, and steroid biosynthesis pathway were more active in fruiting body. The genome and transcriptome analysis of A. blazei provide valuable sequence resources and contribute to our understanding of genes related to the biosynthesis pathway of polysaccharide and benzaldehyde, as well as the fruiting body formation.

Agaricus bisporus, belonging to the genus Agaricus and the family Agaricaceae, is a popular commercially cultivated mushroom with rich nutritional and medical values. Cultivation of A. bisporus requires superior cultivars. Understanding the differences between wild and cultivated accession at the genetic level is crucial for mining loci and genes associated with cultivation-related traits, informing future breeding directions. Additionally, the identification of loci and genes associated with important agronomic traits (e.g., yield and quality) facilitates mushroom molecular breeding. In this study, we conducted sequencing of 200 strains of A. bisporus and analyzed genomic variations. Population structure and genetic relationships were investigated for 200 strains. Selection signs and genes were also obtained after selection sweep analysis. Thirteen candidate genes in the selective elimination regions had significantly different expression patterns at the fruit body stage. Moreover, six genes were identified for the esterase isozyme type through a combination of GWAS and RNA data. This study provides insight into environmental adaptation at the genetic base, providing valuable genetic resources for button mushroom molecular breeding to improve environmental adaptation, quality, or yield.

Accurate strain identification is essential for economically significant fungi, as it aids in understanding their diverse agronomic traits, pathogenicity, and other important characteristics. However, traditional methods often face challenges related to limited accuracy, high workloads, and reproducibility issues. Recently, multiple nucleotide polymorphism (MNP) markers have been employed in mushroom strain identification, demonstrating significantly improved accuracy and reproducibility. Nevertheless, the identification of strains across different species still heavily depends on specific and often overly complex MNP markers. In this study, we address these challenges by developing a novel method for constructing high‐resolution phylogenomic topologies using core gene‐associated multiple nucleotide polymorphism (cgMNP) markers, focusing on Agaricus bisporus (button mushroom). Utilising resequencing data from 213 cultivated and wild strains of A. bisporus , we identified 84 cgMNP markers within 83 core genes from 1011 MNP markers. Phylogenetic analysis based on cgMNP sequences and the genetic distance between strain pairs allowed for precise identification of all strains. Moreover, the successful transferability of these cgMNP markers to an additional 385 A. bisporus strains and other fungal species, including Flammulina filiformis (enoki mushroom) and Saccharomyces cerevisiae (yeast), highlights their cross‐species applicability. The high resolution and strong congruence of cgMNP markers with whole‐genome data provide a robust and reliable method for strain‐level discrimination in fungi. The success of this approach in A. bisporus sets a promising precedent for its application to a broader range of fungal taxa.