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Continuous passaging in vitro can lead to the accumulation of changes in DNA sequence that potentially affect the properties of microbes, making them different from the original isolates. The identification of such genetic alterations is rare in fungi. A set of insertional mutants in the plant pathogenic fungus Leptosphaeria maculans, all derived from the same transformation experiment, had independent Agrobacterium T-DNA insertions and reduced pathogenicity on canola (Brassica napus). None of the insertions co-segregated in progeny from crosses with the reduction in pathogenicity. Genome sequences of three strains were analysed, and a mutation identified in a gene (ptf1, for pathogenicity-associated transcription factor 1) encoding a putative Zn2(II)Cys6 transcription factor. Homologs are found in other ascomycetes, and are required for pathogenicity by Fusarium graminearum, Fusarium oxysporum and Magnaporthe oryzae. The mutation in the L. maculans ptf1 gene co-segregates in progeny from crosses with the reduction in pathogenicity, a strain with an independent mutant allele isolated using CRISPR-Cas9 editing has reduced pathogenicity, and addition of wild type copies of the gene restores pathogenicity. Thus, this work defines a base pair substitution that occurred during in vitro passaging of a fungus that contributed to an attenuation of pathogenicity.The N-end rule pathway is a regulated protein degradation system. [https://www.selleckchem.com/products/proxalutamide-gt0918.html click here] Arthrobotrys oligospora, a typical nematode-trapping fungus, switches its life strategies from saprophytism to carnivorism when capturing free-living nematodes by means of adhesive networks. In this study, a putative E3-ligase AoUBR1 involved in N-end rule pathway was characterized in A. oligospora during vegetative growth and trap formation. Expression of AoUBR1 coding gene was down-regulated during trap formation. Compared with wild type, the AoUBR1 knock-out mutants decreased the vegetative growth, formed less traps, and turned to be sensitive to cold stress, while, AoUBR1 overexpression mutants lost the capacity to produce conidia and also formed less traps. A number of genes differentially expressed by knock-out and overexpression of AoUBR1, which lead to the transcriptional responses associated with plasma membrane, transportation, oxidation, and proteolysis. AoUBR1 knock-out also resulted in the down-regulation of numerous secreted proteins associated with carnivorism and nutrient utilization from nematodes. In addition, AoUBR1 homologs were conserved in nematode-trapping fungi based on the genome searching. Therefore, the results suggested AoUBR1 in A. oligospora and its homologs in other trapping fungi are involved in the lifestyle switch between saprophytism and carnivorism.The formation of propagules is the critical stage for transmission of the pathogenic fungus Stemphylium eturmiunum. However, how the development of these propagules is regulated remains to be fully understood. Here, we show that nitric oxide (NO) is necessary for reproduction in S. eturmiunum.Application of NO scavenger carboxy-CPTIO (cPTIO) or soluble guanylate cyclase (sGC) inhibitor NS-2028 abolishes propagules formation, which was increased by a supplement of sodium nitroprusside (SNP). SNP supplement also triggered increased biosynthesis of melanin, which can be inhibited upon the addition of arbutin or tricyclazole, the specific inhibitors for DOPA and DHN synthetic pathway, respectively. Intriguingly, enhanced melanin biosynthesis corelates with an increased propagules formation; The SNP-induced increment propagules formation can be also compromised upon the supplement of cPTIO or NS-2028. RT-PCR analysis showed that SNP promoted transcription of brlA, abA and wetA at 0.2 mmol/L, but inhibited at 2 mmol/L. In contrast, SNP increased transcription of mat1, and mat2, and the synthetic genes for DHN and DOPA melanins at 2 mmol/L. However, the increased transcription of these genes is down-regulated upon the supplement of cPTIO or NS-2028. Thus, NO regulates reproduction and melanin synthesis in S. eturmiunum possibly through the NO-sGC-GMP signaling pathway.Delimitation of species boundaries within the fungal genus Diaporthe has been challenging, but the analyses of combined multilocus DNA sequences has become an important tool to infer phylogenetic relationships and to circumscribe species. However, analyses of congruence between individual gene genealogies and the application of the genealogical concordance principle have been somehow overlooked. We noted that a group of species including D. amygdali, D. garethjonesii, D. sterilis, D. kadsurae, D. ternstroemia, D. ovoicicola, D. fusicola, D. chongqingensis and D. mediterranea, commonly known as D. amygdali complex, occupy a monophyletic clade in Diaporthe phylogenies but the limits of all species within the complex are not entirely clear. To assess the boundaries of species within this complex we employed the Genealogical Concordance Phylogenetic Species Recognition principle (GCPSR) and coalescence-based models General Mixed Yule-Coalescent (GMYC) and Poisson Tree Processes (PTP). The incongruence detected between individual gene phylogenies, as well as the results of coalescent methods do not support the recognition of lineages within the complex as distinct species. Moreover, results support the absence of reproductive isolation and barriers to gene flow in this complex, thus providing further evidence that the D. amygdali species complex constitutes a single species. This study highlights the relevance of the application of the GCPSR principle, showing that concatenation analysis of multilocus DNA sequences, although being a powerful tool, might lead to an erroneous definition of species limits. Additionally, it further shows that coalescent methods are useful tools to assist in a more robust delimitation of species boundaries in the genus Diaporthe.The lichen, to which the name Lecidea lichenicola is found to have been misapplied, was first described from England and is an extreme specialist of chalk pebbles. It has long been known that it is not closely related to Lecidea in the strict sense, but its true evolutionary relationships have been unknown. Here we use metagenome-assembled genome data to place this fungus in a six-locus phylogeny of Ascomycota, and find strong support for its placement in the class Lichinomycetes. Multiple gene trees using existing data from Lichinomycetes support its further placement within the family Lichinaceae. Based on a revision of types and original descriptions, we conclude that the earliest name for this species is Lecidea obsoleta (syn. Thrombium cretaceum). We neotypify that name by a modern collection and accommodate it in the new genus Watsoniomyces. Type and other original material of L. lichenicola (syn. Discocera lichenicola) was re-examined and found not to be on chalk and to represent a different lichen, Trapelia glebulosa.