Stipe gradient elongation is an important and remarkable feature in the development of most mushroom fruiting bodies. However, its molecular mechanism has rarely been described. Here, the decreasing trend of stipe elongation and increasing trend of cell length in a gradient from the top to the base of the stipe were determined in a model basidiomycete mushroom: Flammulina filiformis. According to RNA-seq results, 1409 differentially expressed genes (DEGs) were identified among elongation region (ER), transition region (TR), and stable region (SR) samples, including 26 transcription factors (TFs). Based on Short Time-series Expression Miner (STEM) clustering of DEGs, clusters 1 and 3, with obvious expression trends that were consistent with or in contrast to the elongation rate, were screened. The cluster 1 DEGs were mainly involved in the GO cellular component category and KEGG genetic information processing class; however, the cluster 3 DEGs were mainly involved in metabolic processes. Furthermore, qRT-PCR confirmed that key genes of the long-chain fatty acid synthesis pathway were involved in stipe gradient elongation and regulated by NADPH oxidase-derived ROS signaling molecules. These findings provide an essential basis for understanding the molecular mechanism of stipe gradient elongation.

The Chinese pepper Zanthoxylum bungeanum Maxim is a special economically important species and a traditional spice in China. It is widely used in medicine, food, timber, tourism, soil and water con...

Morels (Morchella spp.) are a kind of rare and precious edible fungus and have been successfully cultivated in many places. Currently, the widespread cultivation of morels poses a significant challenge owing to their demanding environmental requirements. Soil properties and the soil microbiome are thought to play pivotal roles in morel growth. However, it remains unknown what factors exert a decisive influence on morel growth. In this study, soils with different morel yields were studied in nine sites from four locations. The basic soil physical and chemical properties were measured. In addition, the soil microbiome was analyzed using high-throughput metagenomic sequencing. We found that soil pH, nitrogen, carbon and conductivity were key indicators for the impact on microbial communities in soil for cultivating morels. Among these, nitrate was more positively associated with morel yield. The soil microbial diversity was more abundant in the soil with a high morel yield. Moreover, certain unknown archaea might be unfavorable to morel growth. The microbes that perform incomplete denitrification (no step of N₂O reduction to N₂) and nitrogen fixation were positively and negatively correlated with morel growth, respectively. In summary, morels prefer to live in nutrient-rich soils with a variety of microbes and are supported by nitrate and microbiome components involved in denitrification. The findings elucidate a pivotal mechanism in eliciting morel fructification and provide valuable insights for guiding production practices.

Devastating fungi are one of the most important biotic factors associated with numerous infectious diseases not only in plants but in animals and humans too. Arthrinium rasikravindrae a devastating fungus is responsible for severe infections in a large number of host plants all over the world. In the present study, we analyzed the whole genome sequence of devastating fungus A. rasikravindrae strain AQZ-20, using Illumina Technology from the Novogene Bio-informatics Co., Ltd. Beijing, China. To identify associated annotation results, various corresponding functional annotations databases were utilized. The genome size was 48.24 MB with an N90 (scaffolds) length of 2,184,859 bp and encoded putative genes were 11,101, respectively. In addition, we evaluated the comparative genomic analyses with 4 fungal strains of Ascomycetes. Two related species showed a strong correlation while others exhibited a weak correlation with the A. rasikravindrae AQZ-20 fungus. This study is a discovery of the genome-scale assembly, as well as annotation for A. rasikravindrae. The results obtained from the whole genome sequencing and genomic resources developed in this study will contribute significantly to genetic improvement applications against diseases caused by A. rasikravindrae. In addition, the phylogenetic tree, followed by genomic RNA, transcriptomic, proteomic, metabolic, as well as pathogenic data reported in current research will provide deep insight for further studies in the future.

Sparassis crispa, also known as cauliflower mushroom, is a new popularly edible mushroom in China, also a medicinal mushroom, which possesses various biological activities, such as immunopotentiation, anti-diabetes, anti-cancer, and anti-inflammatory effects. (Han et al., 2018). In recent years, the artificial cultivation of S. crispa has gained considerable public attention in China. In 2023, approximately 20% of S. crispa (about 0.05 ha of the planting area) showed obvious rot with white molds symptoms in mushroom hothouse, located in Shuangliu county, Sichuan province, China (GPS, 104°7'51"N, 30°25'2"E). Infected fruiting bodies were covered by white mycelia that later turned red or fuchsia. In the final stages of infection, the S. crispa fruiting bodies turned dark red or brown before rotting. The pathogen was isolated from the margin of the lesions by plating onto potato dextrose agar (PDA), and incubated at 25℃ in the dark for a week. Five pure culture fungal isolates were obtained. Collected isolates with similar morphology were described as Lecanicillium spp. (Zare et al., 2001). The colonies were raised, covered with white, the reverse side were violet brown, produced diffusing reddish-purple pigment. Conidiogenous cells produced singly, in pairs, verticillate or in dense irregular clusters on prostrate hyphae, at first flask-shaped, tapering into threadlike neck, with a size of 3.0-6.2×0.8-2.2 μm. Conidia were solitary, oval to subglobose, and 2.3-4.0×1.1-2.1 μm in size, similar to L. aphanocladii (Higo et al., 2021). For pathogenicity testing, ten fruiting bodies of S. crispa (planted in the bottles) were selected. Fungal cake of the isolate Bx-Ljb of L. aphanocladii were applied to the fruiting body of S. crispa, whereas pieces of sterile PDA medium were used as controls. All the bottles were incubated at 19±1℃, 85-100% relative humidity, and 18 h of light in the mushroom hothouse. A week later, the inoculated fruiting bodies developed brown spots and gradually expanding, with symptoms similar to the original diseased fruiting bodies. The controls remained healthy. The same fungus was reisolated from the infected fruiting bodies and subsequently identified by morphological characteristics and DNA sequence analysis. The pathogenicity test was repeated three times with similar results. For molecular identification, the DNA of the isolates was extracted using a Fungi Genomic DNA Extraction kit (Solarbio, Beijing). The SSU, LSU, and TEF1-α genes were amplified with the primer as previously described (Zhou et al., 2018). The generated sequences were deposited in GenBank with accession numbers OR206377, OR206378, and OR204702, respectively. BLASTn analyses showed >99.2% identity with previously deposited sequences of L. aphanocladii. Based on the maximum likelihood method, phylogenetic analysis revealed 99% bootstrap support values with L. aphanocladii. The fungus was identified as L. aphanocladii based on morphological and multilocus phylogenetic analyses. To our knowledge, there are two reports of L. aphanocladii on fruiting bodies of Tremella fuciformis and Morchella sextelata in China, and this is the first report of this fungus causing rot of S. crispa in China. It may be a reminder that the risk of L. aphanocladii in mushroom production in China is gradually increasing. These results will contribute to developing managemental strategies for this disease in S. crispa.

Cauliflower mushroom (Sparassis latifolia), is widely distributed in Australia, North America, Europe, and East Asia (Bashir et al., 2020). It is known for its medicinal significance due to the availability of various pharmacological substances and their use in health supplements (Bashir et al., 2017). In recent years, with the development of artificial cultivation technology, S. latifolia has been industrialized in China, with an annual output value 50 million dollars. In March 2023, approximately 15% of S. latifolia showed obvious bacterial rot in mushroom hothouse (about 0.05 ha), located in Shuangliu county, Sichuan province, China (104°7'51"N, 30°25'2"E). The affected parts appear water-soaked, and become sunken and softened as the disease progresses. In the finally, all the fruiting body tissues turn into paste, with colors pale yellow, and have a foul smell. The pathogen was isolated from the margin of the lesions by dilution and streaking techniques onto Nutrient Agar, and incubated at 28℃ in the dark for 2-3 days. A single colony was re-streak for purification. Eight isolates were obtained from five samples collected randomly. The representative three isolates were selected for further characterization. For pathogenicity testing, ten health fruit bodies of S. latifolia were selected (for per isolate). Bacterial suspensions (1 × 107 CFU/ml) of the three isolates were applied to the fruiting body until wet, sterile water was used as controls. All the S. latifolia were maintained at 19±1℃, 85-100% relative humidity, and 18 h of light in the mushroom hothouse. Three days later, the inoculated fruiting bodies developed yellow color, and appear water-soaked, five days later, fruiting body gradually turn to soft and part turn to rot, seven days later, the fruiting body tissues completely turn into paste with a foul smell. The symptoms exhibited were similar to those of the original diseased fruiting bodies, while the control group remained healthy. The same bacterial were re-isolated from the infected fruiting bodies and subsequently identified by morphological characteristics and DNA sequenced. The pathogenicity test was conducted three times, each yielding similar results. The colonies of the pathogen are gram-negative rods, medium sized, convex, smooth, opaque, turning yellow after several days at a temperature 28℃. For molecular identification, the DNA of the representative three isolates was extracted using a Bacterial Genomic DNA Extraction Kit (Solarbio, Beijing). The 16S rRNA genes were amplified and sequenced with the primer 27F/1492R (Lane et al., 1985). Finally, the sequences were identical. The generated representative sequence was deposited in GenBank with accession number OR399122. BLASTn analysis showed 100% identity (1404/1404 bp) with previously deposited sequence (accession number CP068224) of S. multivorum FDAARGOS in GenBank. Based on the maximum likelihood method, phylogenetic analysis revealed 100% bootstrap support values with S. multivorum. Finally, the bacterium was identified as S. multivorum. This is the first report of S. multivorum causing bacterial rot of mushroom. The fruiting body of S. multivorum consists of multiple folded flat lobes, which are thin and have large surface area, may facilitate the infection of S. multivorum. Sphingobacterium sp. are named for their synthesize sphingolipids, which play an important role in bacterial infection (Kunz et al., 2019). These results will contribute to developing control strategies for this disease.