Many antibiotics, chemotherapeutics, crop protection agents and food preservatives originate from molecules produced by bacteria, fungi or plants. In recent years, genome mining methodologies have been widely adopted to identify and characterize the biosynthetic gene clusters encoding the production of such compounds. Since 2011, the ‘antibiotics and secondary metabolite analysis shell—antiSMASH’ has assisted researchers in efficiently performing this, both as a web server and a standalone tool. Here, we present the thoroughly updated antiSMASH version 4, which adds several novel features, including prediction of gene cluster boundaries using the ClusterFinder method or the newly integrated CASSIS algorithm, improved substrate specificity prediction for non-ribosomal peptide synthetase adenylation domains based on the new SANDPUMA algorithm, improved predictions for terpene and ribosomally synthesized and post-translationally modified peptides cluster products, reporting of sequence similarity to proteins encoded in experimentally characterized gene clusters on a per-protein basis and a domain-level alignment tool for comparative analysis of trans-AT polyketide synthase assembly line architectures. Additionally, several usability features have been updated and improved. Together, these improvements make antiSMASH up-to-date with the latest developments in natural product research and will further facilitate computational genome mining for the discovery of novel bioactive molecules.

Fungi produce numerous low molecular weight molecules endowed with a multitude of biological activities. However, mining the full-genome sequences of fungi indicates that their potential to produce secondary metabolites is greatly underestimated. Because most of the biosynthesis gene clusters are silent under laboratory conditions, one of the major challenges is to understand the physiological conditions under which these genes are activated. Thus, we cocultivated the important model fungusAspergillus nidulanswith a collection of 58 soil-dwelling actinomycetes. By microarray analyses of bothAspergillussecondary metabolism and full-genome arrays and Northern blot and quantitative RT-PCR analyses, we demonstrate at the molecular level that a distinct fungal-bacterial interaction leads to the specific activation of fungal secondary metabolism genes. Most surprisingly, dialysis experiments and electron microscopy indicated that an intimate physical interaction of the bacterial and fungal mycelia is required to elicit the specific response. Gene knockout experiments provided evidence that one induced gene cluster codes for the long-sought after polyketide synthase (PKS) required for the biosynthesis of the archetypal polyketide orsellinic acid, the typical lichen metabolite lecanoric acid, and the cathepsin K inhibitors F-9775A and F-9775B. A phylogenetic analysis demonstrates that orthologs of this PKS are widespread in nature in all major fungal groups, including mycobionts of lichens. These results provide evidence of specific interaction among microorganisms belonging to different domains and support the hypothesis that not only diffusible signals but intimate physical interactions contribute to the communication among microorganisms and induction of otherwise silent biosynthesis genes.

The fungal genus Aspergillus is of critical importance to humankind. Species include those with industrial applications, important pathogens of humans, animals and crops, a source of potent carcinogenic contaminants of food, and an important genetic model. The genome sequences of eight aspergilli have already been explored to investigate aspects of fungal biology, raising questions about evolution and specialization within this genus. We have generated genome sequences for ten novel, highly diverse Aspergillus species and compared these in detail to sister and more distant genera. Comparative studies of key aspects of fungal biology, including primary and secondary metabolism, stress response, biomass degradation, and signal transduction, revealed both conservation and diversity among the species. Observed genomic differences were validated with experimental studies. This revealed several highlights, such as the potential for sex in asexual species, organic acid production genes being a key feature of black aspergilli, alternative approaches for degrading plant biomass, and indications for the genetic basis of stress response. A genome-wide phylogenetic analysis demonstrated in detail the relationship of the newly genome sequenced species with other aspergilli. Many aspects of biological differences between fungal species cannot be explained by current knowledge obtained from genome sequences. The comparative genomics and experimental study, presented here, allows for the first time a genus-wide view of the biological diversity of the aspergilli and in many, but not all, cases linked genome differences to phenotype. Insights gained could be exploited for biotechnological and medical applications of fungi.

The major cause of athlete’s foot is Trichophyton rubrum , a dermatophyte or fungal pathogen of human skin. To facilitate molecular analyses of the dermatophytes, we sequenced T. rubrum and four related species, Trichophyton tonsurans , Trichophyton equinum , Microsporum canis , and Microsporum gypseum . These species differ in host range, mating, and disease progression. The dermatophyte genomes are highly colinear yet contain gene family expansions not found in other human-associated fungi. Dermatophyte genomes are enriched for gene families containing the LysM domain, which binds chitin and potentially related carbohydrates. These LysM domains differ in sequence from those in other species in regions of the peptide that could affect substrate binding. The dermatophytes also encode novel sets of fungus-specific kinases with unknown specificity, including nonfunctional pseudokinases, which may inhibit phosphorylation by competing for kinase sites within substrates, acting as allosteric effectors, or acting as scaffolds for signaling. The dermatophytes are also enriched for a large number of enzymes that synthesize secondary metabolites, including dermatophyte-specific genes that could synthesize novel compounds. Finally, dermatophytes are enriched in several classes of proteases that are necessary for fungal growth and nutrient acquisition on keratinized tissues. Despite differences in mating ability, genes involved in mating and meiosis are conserved across species, suggesting the possibility of cryptic mating in species where it has not been previously detected. These genome analyses identify gene families that are important to our understanding of how dermatophytes cause chronic infections, how they interact with epithelial cells, and how they respond to the host immune response. IMPORTANCE Athlete’s foot, jock itch, ringworm, and nail infections are common fungal infections, all caused by fungi known as dermatophytes (fungi that infect skin). This report presents the genome sequences of Trichophyton rubrum , the most frequent cause of athlete’s foot, as well as four other common dermatophytes. Dermatophyte genomes are enriched for four gene classes that may contribute to the ability of these fungi to cause disease. These include (i) proteases secreted to degrade skin; (ii) kinases, including pseudokinases, that are involved in signaling necessary for adapting to skin; (iii) secondary metabolites, compounds that act as toxins or signals in the interactions between fungus and host; and (iv) a class of proteins (LysM) that appear to bind and mask cell wall components and carbohydrates, thus avoiding the host’s immune response to the fungi. These genome sequences provide a strong foundation for future work in understanding how dermatophytes cause disease.

Background: Millions of humans and animals suffer from superficial infections caused by a group of highly specialized filamentous fungi, the dermatophytes, which exclusively infect keratinized host structures. To provide broad insights into the molecular basis of the pathogenicity-associated traits, we report the first genome sequences of two closely phylogenetically related dermatophytes, Arthroderma benhamiae and Trichophyton verrucosum, both of which induce highly inflammatory infections in humans. Results: 97% of the 22.5 megabase genome sequences of A. benhamiae and T. verrucosum are unambiguously alignable and collinear. To unravel dermatophyte-specific virulence-associated traits, we compared sets of potentially pathogenicity-associated proteins, such as secreted proteases and enzymes involved in secondary metabolite production, with those of closely related onygenales (Coccidioides species) and the mould Aspergillus fumigatus. The comparisons revealed expansion of several gene families in dermatophytes and disclosed the peculiarities of the dermatophyte secondary metabolite gene sets. Secretion of proteases and other hydrolytic enzymes by A. benhamiae was proven experimentally by a global secretome analysis during keratin degradation. Molecular insights into the interaction of A. benhamiae with human keratinocytes were obtained for the first time by global transcriptome profiling. Given that A. benhamiae is able to undergo mating, a detailed comparison of the genomes further unraveled the genetic basis of sexual reproduction in this species. Conclusions: Our results enlighten the genetic basis of fundamental and putatively virulence-related traits of dermatophytes, advancing future research on these medically important pathogens.

Filamentous fungi produce numerous natural products that constitute a consistent source of potential drug leads, yet it seems that the majority of natural products are overlooked since most biosynthesis gene clusters are silent under standard cultivation conditions. Screening secondary metabolite genes of the model fungus Aspergillus nidulans , we noted a silent gene cluster on chromosome II comprising two nonribosomal peptide synthetase (NRPS) genes, inpA and inpB , flanked by a regulatory gene that we named scpR for secondary metabolism cross-pathway regulator. The induced expression of the scpR gene using the promoter of the alcohol dehydrogenase AlcA led to the transcriptional activation of both the endogenous scpR gene and the NRPS genes. Surprisingly, metabolic profiling of the supernatant of mycelia overexpressing scpR revealed the production of the polyketide asperfuranone. Through transcriptome analysis we found that another silent secondary metabolite gene cluster located on chromosome VIII coding for asperfuranone biosynthesis was specifically induced. Quantitative reverse transcription-PCR proved the transcription not only of the corresponding polyketide synthase (PKS) biosynthesis genes, afoE and afoG , but also of their activator, afoA , under alcAp - scpR -inducing conditions. To exclude the possibility that the product of the inp cluster induced the asperfuranone gene cluster, a strain carrying a deletion of the NRPS gene inpB and, in addition, the alcAp - scpR overexpression cassette was generated. In this strain, under inducing conditions, transcripts of the biosynthesis genes of both the NRPS-containing gene cluster inp and the asperfuranone gene cluster except gene inpB were detected. Moreover, the existence of the polyketide product asperfuranone indicates that the transcription factor ScpR controls the expression of the asperfuranone biosynthesis gene cluster. This expression as well as the biosynthesis of asperfuranone was abolished after the deletion of the asperfuranone activator gene afoA , indicating that ScpR binds to the afoA promoter. To the best of our knowledge, this is the first report of regulatory cross talk between two biosynthesis gene clusters located on different chromosomes.