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Lyophyllum decastes is a type of edible and medicinal mushroom with high nutritional value. However, it can be infected by fungi during the fruiting process, which impairs the development of the industry. In this study, one pathogenic fungus was isolated from the diseased fruiting bodies of L. decastes. Morphological and molecular identification clarified that the causal agent of the disease was Cladobotryum mycophilum. Koch’s postulates showed that C. mycophilum could infect L. decastes, and seriously affect mushroom yields. The biological properties of C. mycophilum were investigated. The data showed that the most suitable temperature for the growth of C. mycophilum was 25 °C with a mean growth rate of 21.45 mm d− 1 on PDA. C. mycophilum was better suited to growing in neutral or slightly acidic environments. The suitable carbon source and nitrogen source for C. mycophilum growth were lactose and peptone or yeast extract respectively. The IC50s (Half maximal inhibitory concentration) values of carbendazim and prochloraz for inhibiting C. mycophilum are respectively 1.244 µg.mL− 1 and 3.323 µg.mL− 1. 10 µg.mL− 1 carbendazim can effectively control C. mycophilum during the L. decastes fruiting process. The results of this study can provide knowledge for the control of cobweb disease during the L. decastes fruiting process. [ABSTRACT FROM AUTHOR]

Cobweb disease in white button mushroom (Agaricus bisporus) is a newly identified disease caused by Cladobotryum mycophilum in China. Currently, there are few highly effective and safe fungicides for controlling this disease in the field. This study assessed the fungicidal effect of prochloraz–manganese chloride complex and seboctylamine acetate against C. mycophilum, as well as their ability to control cobweb disease. Additionally, the residues of these fungicides in the mycelium and the mushroom were evaluated. The extent of the fungicidal effect against the pathogen was determined based on the efficiency of crop production. The results revealed that, in addition to the potent inhibitory effect of prochloraz–manganese chloride complex on the hyphae of C. mycophilum, the domestically developed seboctylamine acetate exhibited high toxicity, inhibiting both mycelial growth and spore germination of C. mycophilum, with EC50 values of 0.990 mg/L and 0.652 mg/L, respectively. Furthermore, the application of the two chemical agents had no adverse effects on the mycelial growth and fruiting body growth of A. bisporus, and the residual amount of chemical agent was lower than the maximum residue limit standard. The field application results showed that 400 mg/L of prochloraz–manganese chloride complex and 6 mg/L of seboctylamine acetate resulted in 61.38% and 81.17% disease control respectively. This study presents efficient and safe fungicides for controlling cobweb disease in white button mushroom. Additionally, a residue determination analysis of the fungicide seboctylamine acetate in mushroom crops is described. [ABSTRACT FROM AUTHOR]

Mycophilic or fungicolous fungi can be found wherever fungi exist since they are able to colonize other fungi, which occupy a diverse range of habitats. Some fungicolous species cause important diseases on Basidiomycetes, and thus, they are the main reason for the destruction of mushroom cultivations. Nonetheless, despite their ecological significance, their genomic data remain limited. Cladobotryum mycophilum is one of the most aggressive species of the genus, destroying the economically important Agaricus bisporus cultivations. The 40.7 Mb whole genome of the Greek isolate ATHUM6906 is assembled in 16 fragments, including the mitochondrial genome and 2 small circular mitochondrial plasmids, in this study. This genome includes a comprehensive set of 12,282 protein coding, 56 rRNA, and 273 tRNA genes. Transposable elements, CAZymes, and pathogenicity related genes were also examined. The genome of C. mycophilum contained a diverse arsenal of genes involved in secondary metabolism, forming 106 biosynthetic gene clusters, which renders this genome as one of the most BGC abundant among fungicolous species. Comparative analyses were performed for genomes of species of the family Hypocreaceae. Some BGCs identified in C. mycophilum genome exhibited similarities to clusters found in the family Hypocreaceae, suggesting vertical heritage. In contrast, certain BGCs showed a scattered distribution among Hypocreaceae species or were solely found in Cladobotryum genomes. This work provides evidence of extensive BGC losses, horizontal gene transfer events, and formation of novel BGCs during evolution, potentially driven by neutral or even positive selection pressures. These events may increase Cladobotryum fitness under various environmental conditions and potentially during host–fungus interaction. [ABSTRACT FROM AUTHOR]

Cobweb disease is a fungal disease that can cause serious damage to edible mushrooms worldwide. To investigate cobweb disease in Morchella sextelata in Guizhou Province, China, we isolated and purified the pathogen responsible for the disease. Through morphological and molecular identification and pathogenicity testing on infected M. sextelata, we identified Cladobotryum mycophilum as the cause of cobweb disease in this region. This is the first known occurrence of this pathogen causing cobweb disease in M. sextelata anywhere in the world. We then obtained the genome of C. mycophilum BJWN07 using the HiFi sequencing platform, resulting in a high-quality genome assembly with a size of 38.56 Mb, 10 contigs, and a GC content of 47.84%. We annotated 8428 protein-coding genes in the genome, including many secreted proteins, host interaction-related genes, and carbohydrate-active enzymes (CAZymes) related to the pathogenesis of the disease. Our findings shed new light on the pathogenesis of C. mycophilum and provide a theoretical basis for developing potential prevention and control strategies for cobweb disease. [ABSTRACT FROM AUTHOR]

Cladobotryum mycophilum , the causative agent of cobweb disease on Agaricus bisporus results in significant crop losses for mushroom growers worldwide. Cobweb disease is treated through strict hygiene control methods and the application of chemical fungicides but an increase in fungicide resistant Cladobotryum strains has resulted in a need to develop alternative biocontrol treatment methods. The aim of the work presented here was to evaluate the response of C. mycophilum to a Bacillus velezensis isolate to assess its potential as a novel biocontrol agent. Exposure of 48 hr C. mycophilum cultures to 25% v/v 96 hr B. velezensis culture filtrate resulted in a 57% reduction in biomass (P < 0.0002), a disruption in hyphal structure and morphology, and the appearance of aurofusarin, a secondary metabolite which is a known indicator of oxidative stress, in culture medium. Proteomic analysis of B. velezensis culture filtrate revealed the presence of peptidase 8 (subtilisin), peptide deformylase and probable cytosol aminopeptidase which are known to induce catalytic activity. Characterisation of the proteomic response of C. mycophilum following exposure to B. velezensis culture filtrate revealed an increase in the abundance of a variety of proteins associated with stress response (ISWI chromatin-remodelling complex ATPase ISW2 (+24 fold), carboxypeptidase Y precursor (+3 fold) and calmodulin (+2 fold). There was also a decrease in the abundance of proteins associated with transcription (40 S ribosomal protein S30 (−26 fold), 40 S ribosomal protein S21 (−3 fold) and carbohydrate metabolism (l -xylulose reductase (−10 fold). The results presented here indicate that B. velezensis culture filtrate is capable of inhibiting the growth of C. mycophilum and inducing a stress response, thus indicating its potential to control this important pathogen of mushrooms. • Bacillus velezensis culture filtrate inhibits growth of Cladobotryum mycophilum. • Bacillus velezensis culture filtrate inhibits Cladobotryum mycophilum biomass accumulation. • C. mycophilum exposed to Bacillus velezensis culture filtrate shows oxidative stress response. • Bacillus velezensis culture filtrate contains range of lytic enzymes. • Bacillus velezensis culture filtrate may have potential to control cobweb. [ABSTRACT FROM AUTHOR]

Mushroom cultivation requires effective control of environmental cues to obtain the best yield and high quality. The impact of water content in the casing layer on mushroom yield and the incidence of two of the most important diseases in the mushroom growing farms, dry bubble and cobweb diseases, was evaluated. Different initial water content in the casing and two alternative irrigation programs applied (light or moderate irrigation) were the agronomic parameters under study during five separate button mushroom crop trials. Higher initial humidity content in the casing layer reported a larger yield, with a fewer number of basidiomes but heavier, while no correlation to the dry matter content or the colour of the basidiomes was noted. The incidence of dry bubble disease was not conditioned by the water content of the casing layer, at the high moisture levels established in the study. In the case of Cladobotryum mycophilum, the lower moisture level of the casing layer reported more incidence of cobweb disease, and subsequently harmful yield losses. According to the results obtained, the right management of the moisture level in the casing materials could promote crop yield and preclude the significant impact of dry bubble and cobweb diseases.

Cladobotryum mycophilum is the causal agent of cobweb disease in many important mushroom crops. In this study, we report the complete mitochondrial genome of C. mycophilum for the first time. The genome is 78,729 bp long and comprises 52 protein-coding genes (PCGs), 2 ribosomal RNA genes (rRNA), and 26 transfer RNA (tRNA) genes. The nucleotide composition of C. mycophilum mitochondrial genome is as follows: A (38.06%), T (34.68%), C (12.19%), and G (15.07%). Phylogenetic analysis revealed that C. mycophilum had a close relationship with Cladobotryum varium from Hypocreaceae. This study provided a basis for studies of the mitochondrial evolution of Hypocreaceae.

In 2009–2010, unusual symptoms were observed on Pleurotus eryngii grown in mushroom farms in Gyeongnam Province, Republic of Korea. One of the main symptoms was a cobweb-like growth of fungal mycelia over the surface of the mushroom. The colonies on the surface rapidly overwhelmed the mushrooms and developed several spores within 3–4 days. The colonized surface turned pale brown or yellow. The fruit body eventually turned dark brown and became rancid. Koch’s postulates were completed by spraying and spotting using isolated strains. The phylogenetic tree obtained from the internal transcribed spacer sequence analysis showed that the isolated fungal pathogen corresponded to Cladobotryum mycophilum (99.5%). In the fungicide sensitivity tests, the ED₅₀ values for the isolate with respect to benomyl and carbendazim were from 0.29 to 0.31 ppm. Benzimidazole fungicides were most effective against C. mycophilum, a causal agent of cobweb disease in P. eryngii.

Abstract: Temperate species of Hypomyces and Cladobotryum that produce the red pigment aurofusarin are common on agaricoid and polyporoid basidiomata of species from five orders of Agaricomycetes. Several cause cobweb disease of commercially cultivated mushrooms resulting in serious losses. We sequenced rpb1, rpb2, tef1, and FG1093 regions in 90 wild strains and 30 strains from mushroom farms, isolated from Europe, North America, Africa, Asia, Australia, and New Zealand. Multigene analyses support the distinctness of five species but reveal Hypomyces rosellus to be paraphyletic, comprising several cryptic lineages. Hypomyces rosellus s. str. is characterised by wide dispersal and gene flow across Eurasia but does not occur in North America. Instead, the lineages from the West and the East Coast appear distinct, having given rise to species inhabiting the Southern Hemisphere. Our results reveal wide misuse of the name H. rosellus, especially for cobweb isolates. The majority of these belong to Hypomyces odoratus, including a weakly supported group of fungicide-resistant strains from Europe and North America sharing identical sequence data. New collections are presented for Cladobotryum rubrobrunnescens and Cladobotryum tenue as well as Cladobotryum multiseptatum and Hypomyces dactylarioides, all previously known only from their type material. The former species pair occurs in Europe and the latter in Australia and New Zealand. Separate lineages appear to be maintained by geographic isolation in North America and temperate Australasia but by host specialisation in the species occurring sympatrically in Europe and Asia. Both specialist and generalist host use strategies have evolved in the group. Although teleomorphs are known in most of the species and unnamed lineages, analyses of the five-gene regions suggest the prevalence of clonal reproduction in H. odoratus. This can be the reason for its success in mushroom farms, also facilitating the spread of fungicide resistance. While tef1 and rpb2 can be recommended for species delimitation, low variation, not exceeding 1 % in the whole ingroup, impeaches the use of ITS as a barcoding gene region in this group of fungi. [Copyright &y& Elsevier]

This report is the first of cobweb disease on Agaricus bisporus in Korea. Cobweb on both fruit bodies and casing soils were observed on several mushroom farms in Gyeongbuk Province, Korea. Classical and molecular characterization indicated that the causal agent is Cladobotryum mycophilum. The isolated fungus was used to inoculate fruiting bodies of A. bisporus and caused the same symptoms. [ABSTRACT FROM AUTHOR]

Cladobotryum mycophilum is the causal agent of cobweb disease in many important mushroom crops. In this study, we report the complete mitochondrial genome of C. mycophilum for the first time. The genome is 78,729 bp long and comprises 52 protein-coding genes (PCGs), 2 ribosomal RNA genes (rRNA), and 26 transfer RNA (tRNA) genes. The nucleotide composition of C. mycophilum mitochondrial genome is as follows: A (38.06%), T (34.68%), C (12.19%), and G (15.07%). Phylogenetic analysis revealed that C. mycophilum had a close relationship with Cladobotryum varium from Hypocreaceae. This study provided a basis for studies of the mitochondrial evolution of Hypocreaceae. [ABSTRACT FROM AUTHOR]

Mushroom cultivation requires effective control of environmental cues to obtain the best yield and high quality. The impact of water content in the casing layer on mushroom yield and the incidence of two of the most important diseases in the mushroom growing farms, dry bubble and cobweb diseases, was evaluated. Different initial water content in the casing and two alternative irrigation programs applied (light or moderate irrigation) were the agronomic parameters under study during five separate button mushroom crop trials. Higher initial humidity content in the casing layer reported a larger yield, with a fewer number of basidiomes but heavier, while no correlation to the dry matter content or the colour of the basidiomes was noted. The incidence of dry bubble disease was not conditioned by the water content of the casing layer, at the high moisture levels established in the study. In the case of Cladobotryum mycophilum, the lower moisture level of the casing layer reported more incidence of cobweb disease, and subsequently harmful yield losses. According to the results obtained, the right management of the moisture level in the casing materials could promote crop yield and preclude the significant impact of dry bubble and cobweb diseases. [ABSTRACT FROM AUTHOR]