Phylogenetic analysis ofAspergillusspecies using DNA sequences from four loci

Characterization of Aspergillus section Flavi associated with stored grains

Increased frequencies of Aspergillus section Flavi and aflatoxins in cereal grains have been seen in recent years due to changes in climate circumstances, such as high temperatures and drought. To assess the microbiological risks of contamination, it is critical to have a reliable and accurate means of identifying the fungi. The main goal of this study was to characterize Aspergillus species from section Flavi obtained from twenty-three samples of barley and maize grains, gathered from different markets in Qena, Egypt, using morphological and molecular techniques. Twenty-three isolates were chosen, one isolate from each sample; they were identified as A. aflatoxiformans (4 isolates), A. flavus (18), and A. parasiticus (1). The existence of four aflatoxin biosynthesis genes was also investigated in relation to the strains' ability to produce total aflatoxins and aflatoxin B1, focusing on the regulatory gene aflR and the structural genes aflD and aflM. All strains producing aflatoxins were linked to the presence of aflR1 and/or aflR2, except two isolates that exhibited aflatoxins but from which aflR1 or aflR2 were not detected, which may be due to one or more missing or unstudied additional genes involved in aflatoxin production. AflD and aflM genes were amplified by 10 and 9 isolates, respectively. Five samples of barley and maize were contaminated by aflatoxins. Fifteen isolates were positive for producing total aflatoxins in the range of 0.1-240 ppm. Antagonistic activity of Trichoderma viride against A. flavus (F5) was assessed at 31.3%. Trichoderma reduced total aflatoxins in all treated seeds, particularly those subjected to Trichoderma formulation.

Depletion of protective microbiota promotes the incidence of fruit disease

Plant-associated microbiomes play important roles in plant health and productivity. However, despite fruits being directly linked to plant productivity, little is known about the microbiomes of fruits and their potential association with fruit health. Here, by integrating 16S rRNA gene, ITS high-throughput sequencing data, and microbiological culturable approaches, we reported that roots and fruits (pods) of peanut, a typical plant that bears fruits underground, recruit different bacterial and fungal communities independently of cropping conditions and that the incidence of pod disease under monocropping conditions is attributed to the depletion of Bacillus genus and enrichment of Aspergillus genus in geocarposphere. On this basis, we constructed a synthetic community (SynCom) consisting of three Bacillus strains from geocarposphere soil under rotation conditions with high culturable abundance. Comparative transcriptome, microbiome profiling, and plant phytohormone signaling analysis reveal that the SynCom exhibited more effective Aspergillus growth inhibition and pod disease control than individual strain, which was underpinned by a combination of molecular mechanisms related to fungal cell proliferation interference, mycotoxins biosynthesis impairment, and jasmonic acid-mediated plant immunity activation. Overall, our results reveal the filter effect of plant organs on the microbiome and that depletion of key protective microbial community promotes the fruit disease incidence.

Long-Term Investigation of Marine-Derived Aspergillus Diversity in the Republic of Korea

Aspergillus species play a crucial role in terrestrial environments as degraders and are well known for producing various secondary metabolites. Recently, Aspergillus species have been discovered in marine environments, exhibiting adaptability to high salinity and producing diverse secondary metabolites with valuable properties. However, limited research has focused on their marine diversity, leading to inaccurate species identification. The current study addresses this gap by investigating diverse marine habitats in the Republic of Korea, including sediment, seawater, seaweed, and marine animals. From three coasts of the Korean Peninsula, 472 Aspergillus strains were isolated from the various marine habitats. A total of 41 species were accurately identified using multigenetic markers: internal transcribed spacer, calmodulin, and β-tubulin. The findings underscore the importance of accurate identification and provide a basis for elucidating the functional role of marine-derived Aspergillus species in marine ecosystems.

Simultaneous detection of mycotoxigenic Aspergillus species of sections Circumdati and Flavi using multiplex digital PCR

Populations of ochratoxin-producing Aspergillus section Circumdati species and aflatoxin-producing Aspergillus section Flavi species frequently coexist in soil and are the main sources of mycotoxin contamination of tree nuts. Identification of mycotoxigenic Aspergillus species in these sections is difficult using traditional isolation and culture methods. We developed a multiplex digital PCR (dPCR) assay to detect and quantify Aspergillus ochraceus, Aspergillus westerdijkiae, and Aspergillus steynii (section Circumdati), as well as Aspergillus flavus and Aspergillus parasiticus (section Flavi), in environmental samples based on species-specific calmodulin gene sequences. Relative quantification of each species by dPCR of mixed-species templates correlated with corresponding DNA input ratios. Target species could be detected in soil inoculated with conidia from each species. Non-target species of sections Circumdati, Flavi, and Nigri were generally not detectable using this dPCR method. Detected non-target species (Aspergillus fresenii, Aspergillus melleus, Aspergillus sclerotiorum, and Aspergillus subramanianii) were discernible from A. ochraceus in dual-template dPCR reactions based on differential fluorescence intensity.

A New Species and Five New Records of Talaromyces (Eurotiales, Aspergillaceae) Belonging to Section Talaromyces in Korea

Talaromyces is a genus within the phylum Ascomycota (class Eurotiomycetes, order Eurotiales, family Trichocomaceae). Many species in this genus are known to produce diverse secondary metabolites with great potential for agricultural, medical, and pharmaceutical applications. During a survey on fungal diversity in the genus Talaromyces in Korea, six strains were isolated from soil, indoor air, and freshwater environments. Based on morphological, physiological, and multi-locus (ITS, BenA, CaM, and RPB2) phylogenetic analyses, we identified five previously unrecorded species in Korea (T. brevis, T. fusiformis, T. muroii, T. ruber, and T. soli) and a new species (T. echinulatus sp. nov.) belonging to section Talaromyces. Herein, detailed descriptions, illustrations, and phylogenetic tree are provided.

Spectrometric Characterization of Clinical and Environmental Isolates of Aspergillus Series Versicolores

Aspergillus series Versicolores are molds distributed among 17 species, commonly found in our environment, and responsible for infections. Since 2022, a new taxonomy has grouped them into 4 major lineages: A. versicolor, A. subversicolor, A. sydowii, and A. creber. Matrix-Assisted Laser Desorption/Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) could be a faster and more cost-effective alternative to molecular techniques for identifying them by developing a local database. To evaluate this technique, 30 isolates from Aspergillus series Versicolores were used. A total of 59 main spectra profiles (MSPs) were created in the local database. This protocol enabled accurate identification of 100% of the extracted isolates, of which 97% (29/30) were correctly identified with a log score ≥ 2.00. Some MSPs recorded as Aspergillus versicolor in the supplier's database could lead to false identifications as they did not match with the correct lineages. Although the local database is still limited in the number and diversity of species of Aspergillus series Versicolores, it is sufficiently effective for correct lineage identification according to the latest taxonomic revision, and better than the MALDI-TOF MS supplier's database. This technology could improve the speed and accuracy of routine fungal identification for these species.

Vitis vinifera genotyping toolbox to highlight diversity and germplasm identification

The contribution of vine cultivation to human welfare as well as the stimulation of basic social and cultural features of civilization has been great. The wide temporal and regional distribution created a wide array of genetic variants that have been used as propagating material to promote cultivation. Information on the origin and relationships among cultivars is of great interest from a phylogenetics and biotechnology perspective. Fingerprinting and exploration of the complicated genetic background of varieties may contribute to future breeding programs. In this review, we present the most frequently used molecular markers, which have been used on Vitis germplasm. We discuss the scientific progress that led to the new strategies being implemented utilizing state-of-the-art next generation sequencing technologies. Additionally, we attempted to delimit the discussion on the algorithms used in phylogenetic analyses and differentiation of grape varieties. Lastly, the contribution of epigenetics is highlighted to tackle future roadmaps for breeding and exploitation of Vitis germplasm. The latter will remain in the top of the edge for future breeding and cultivation and the molecular tools presented herein, will serve as a reference point in the challenging years to come.

Species Distribution and Antifungal Susceptibilities of Aspergillus Section Terrei Isolates in Clinical Samples from the United States and Description of Aspergillus pseudoalabamensis sp. nov

Aspergillus section Terrei consists of numerous cryptic species in addition to A. terreus sensu stricto. The treatment of invasive infections caused by these fungi may pose a unique challenge prior to diagnosis and species identification, in that they are often clinically resistant to amphotericin B, with poor outcomes and low survival rates in patients treated with this polyene. Data on the species distributions and susceptibility profiles of isolates within section Terrei from the United States (U.S.) are limited. Here, we report the species distributions and susceptibility profiles for amphotericin B, isavuconazole, itraconazole, posaconazole, voriconazole, and micafungin against 278 clinical isolates of this section from institutions across the U.S. collected over a 52-month period. Species identification was performed by DNA sequence analysis and phenotypic characterization. Susceptibility testing was performed using the CLSI broth microdilution method. The majority of isolates were identified as Aspergillus terreus sensu stricto (69.8%), although several other cryptic species were also identified. Most were cultured from specimens collected from the respiratory tract. Posaconazole demonstrated the most potent activity of the azoles (MIC range ≤ 0.03-1 mg/L), followed by itraconazole (≤0.03-2 mg/L), voriconazole, and isavuconazole (0.125-8 mg/L for each). Amphotericin B demonstrated reduced in vitro susceptibility against this section (MIC range 0.25-8 mg/L), although this appeared to be species-dependent. A new species within this section, A. pseudoalabamensis, is also described. Our results, which are specific to the U.S., are similar to previous surveillance studies of the Aspergillus section Terrei.

Current status of secondary metabolite pathways linked to their related biosynthetic gene clusters in Aspergillus section Nigri

Covering: up to the end of 2021Aspergilli are biosynthetically 'talented' micro-organisms and therefore the natural products community has continually been interested in the wealth of biosynthetic gene clusters (BGCs) encoding numerous secondary metabolites related to these fungi. With the rapid increase in sequenced fungal genomes combined with the continuous development of bioinformatics tools such as antiSMASH, linking new structures to unknown BGCs has become much easier when taking retro-biosynthetic considerations into account. On the other hand, in most cases it is not as straightforward to prove proposed biosynthetic pathways due to the lack of implemented genetic tools in a given fungal species. As a result, very few secondary metabolite biosynthetic pathways have been characterized even amongst some of the most well studied Aspergillus spp., section Nigri (black aspergilli). This review will cover all known biosynthetic compound families and their structural diversity known from black aspergilli. We have logically divided this into sub-sections describing major biosynthetic classes (polyketides, non-ribosomal peptides, terpenoids, meroterpenoids and hybrid biosynthesis). Importantly, we will focus the review on metabolites which have been firmly linked to their corresponding BGCs.

Five-year surveillance study of clinical and environmental Triazole-Resistant Aspergillus fumigatus isolates in Iran

BACKGROUND

Invasive aspergillosis is one of the most common fungal infections and azole resistance in Aspergillus fumigatus (ARAf) is a growing medical concern in high-risk patients. To our knowledge, there is no comprehensive epidemiological surveillance study on the prevalence and incidence of ARAf isolates available in Iran.

OBJECTIVES

The study aimed to report a five-year survey of triazole phenotypes and genotype patterns concerning the resistance in clinical and environmental A. fumigatus in Iran.

METHODS

During the study time frame (2016-2021), a total of 1208 clinical and environmental Aspergillus species were collected. Isolates were examined and characterised by in vitro antifungal susceptibility testing (CLSI M38 broth microdilution) and cyp51A sequencing.

RESULTS

In total, 485 Aspergillus section Fumigati strains were recovered (clinical, n = 23; 4.74% and environment, n = 462; 95.26%). Of which A. fumigatus isolates were the most prevalent species (n = 483; 99.59%). Amphotericin B and the echinocandins demonstrated good in vitro activity against the majority of isolates in comparison to triazole. Overall, 16.15% (n = 78) of isolates were phenotypically resistant to at least one of the azoles. However, 9.73% of A. fumigatus isolates for voriconazole were classified as resistant, 89.03% were susceptible, and 1.24% were intermediate. While, for itraconazole and posaconazole, using the epidemiological cut-off value 16.15% and 6.83% of isolates were non-wild types, respectively. Remarkably, in 21.79% (n = 17) phenotypically resistant isolates, no mutations were detected within the cyp51A gene.

CONCLUSION

Although the incidence of ARAf varies from country to country, in Iran the rate has ranged from 3.3% to 18%, significantly increasing from 2013 to 2021. Strikingly, a quarter of the phenotypically resistant isolates harboured no mutations in the cyp51A gene. It seems that other mechanisms of resistance are importantly increasing. To fill a gap in our understanding of the mechanism for azole resistance in the non-cyp51A strains, we highly recommend further and more extensive monitoring of the soil with or without exposure to fungicides in agricultural and hospital areas.

Antarctic fungi with antibiotic potential isolated from Fort William Point, Antarctica

The Antarctic continent is one of the most inhospitable places on earth, where living creatures, mostly represented by microorganisms, have specific physiological characteristics that allow them to adapt to the extreme environmental conditions. These physiological adaptations can result in the production of unique secondary metabolites with potential biotechnological applications. The current study presents a genetic and antibacterial characterization of four Antarctic fungi isolated from soil samples collected in Pedro Vicente Maldonado Scientific Station, at Fort William Point, Greenwich Island, Antarctica. Based on the sequences of the internal transcribed spacer (ITS) region, the fungi were identified as Antarctomyces sp., Thelebolus sp., Penicillium sp., and Cryptococcus gilvescens. The antibacterial activity was assessed against four clinical bacterial strains: Escherichia coli, Klebsiella pneumoniae, Enterococcus faecalis, and Staphylococcus aureus, by a modified bacterial growth inhibition assay on agar plates. Results showed that C. gilvescens and Penicillium sp. have potential antibiotic activity against all bacterial strains. Interestingly, Thelebolus sp. showed potential antibiotic activity only against E. coli. In contrast, Antarctomyces sp. did not show antibiotic activity against any of the bacteria tested under our experimental conditions. This study highlights the importance of conservation of Antarctica as a source of metabolites with important biomedical applications.

Impact of Volatile Organic Compounds on the Growth of Aspergillus flavus and Related Aflatoxin B1 Production: A Review

Volatile organic compounds (VOCs) are secondary metabolites of varied chemical nature that are emitted by living beings and participate in their interactions. In addition, some VOCs called bioactive VOCs cause changes in the metabolism of other living species that share the same environment. In recent years, knowledge on VOCs emitted by Aspergillus flavus, the main species producing aflatoxin B1 (AFB1), a highly harmful mycotoxin, has increased. This review presents an overview of all VOCs identified as a result of A. flavus toxigenic (AFB1-producing) and non-toxigenic (non AFB1-producing) strains growth on different substrates, and the factors influencing their emissions. We also included all bioactive VOCs, mixes of VOCs or volatolomes of microbial species that impact A. flavus growth and/or related AFB1 production. The modes of action of VOCs impacting the fungus development are presented. Finally, the potential applications of VOCs as biocontrol agents in the context of mycotoxin control are discussed.

Taxonomy of Aspergillus series Versicolores: species reduction and lessons learned about intraspecific variability

Aspergillus series Versicolores members occur in a wide range of environments and substrates such as indoor environments, food, clinical materials, soil, caves, marine or hypersaline ecosystems. The taxonomy of the series has undergone numerous re-arrangements including a drastic reduction in the number of species and subsequent recovery to 17 species in the last decade. The identification to species level is however problematic or impossible in some isolates even using DNA sequencing or MALDI-TOF mass spectrometry indicating a problem in the definition of species boundaries. To revise the species limits, we assembled a large dataset of 518 strains. From these, a total of 213 strains were selected for the final analysis according to their calmodulin (CaM) genotype, substrate and geography. This set was used for phylogenetic analysis based on five loci (benA, CaM, RPB2, Mcm7, Tsr1). Apart from the classical phylogenetic methods, we used multispecies coalescence (MSC) model-based methods, including one multilocus method (STACEY) and five single-locus methods (GMYC, bGMYC, PTP, bPTP, ABGD). Almost all species delimitation methods suggested a broad species concept with only four species consistently supported. We also demonstrated that the currently applied concept of species is not sustainable as there are incongruences between single-gene phylogenies resulting in different species identifications when using different gene regions. Morphological and physiological data showed overall lack of good, taxonomically informative characters, which could be used for identification of such a large number of existing species. The characters expressed either low variability across species or significant intraspecific variability exceeding interspecific variability. Based on the above-mentioned results, we reduce series Versicolores to four species, namely A. versicolor, A. creber, A. sydowii and A. subversicolor, and the remaining species are synonymized with either A. versicolor or A. creber. The revised descriptions of the four accepted species are provided. They can all be identified by any of the five genes used in this study. Despite the large reduction in species number, identification based on phenotypic characters remains challenging, because the variation in phenotypic characters is high and overlapping among species, especially between A. versicolor and A. creber. Similar to the 17 narrowly defined species, the four broadly defined species do not have a specific ecology and are distributed worldwide. We expect that the application of comparable methodology with extensive sampling could lead to a similar reduction in the number of cryptic species in other extensively studied Aspergillus species complexes and other fungal genera. Citation: Sklenář F, Glässnerová K, Jurjević Ž, Houbraken J, Samson RA, Visagie CM, Yilmaz N, Gené J, Cano J, Chen AJ, Nováková A, Yaguchi T, Kolařík M, Hubka V (2022). Taxonomy of Aspergillus series Versicolores: species reduction and lessons learned about intraspecific variability. Studies in Mycology 102 : 53-93. doi: 10.3114/sim.2022.102.02.

A monograph of Aspergillus section Candidi

Aspergillus section Candidi encompasses white- or yellow-sporulating species mostly isolated from indoor and cave environments, food, feed, clinical material, soil and dung. Their identification is non-trivial due to largely uniform morphology. This study aims to re-evaluate the species boundaries in the section Candidi and present an overview of all existing species along with information on their ecology. For the analyses, we assembled a set of 113 strains with diverse origin. For the molecular analyses, we used DNA sequences of three house-keeping genes (benA, CaM and RPB2) and employed species delimitation methods based on a multispecies coalescent model. Classical phylogenetic methods and genealogical concordance phylogenetic species recognition (GCPSR) approaches were used for comparison. Phenotypic studies involved comparisons of macromorphology on four cultivation media, seven micromorphological characters and growth at temperatures ranging from 10 to 45 °C. Based on the integrative approach comprising four criteria (phylogenetic and phenotypic), all currently accepted species gained support, while two new species are proposed (A. magnus and A. tenebricus). In addition, we proposed the new name A. neotritici to replace an invalidly described A. tritici. The revised section Candidi now encompasses nine species, some of which manifest a high level of intraspecific genetic and/or phenotypic variability (e.g., A. subalbidus and A. campestris) while others are more uniform (e.g., A. candidus or A. pragensis). The growth rates on different media and at different temperatures, colony colours, production of soluble pigments, stipe dimensions and vesicle diameters contributed the most to the phenotypic species differentiation. Taxonomic novelties: New species: Aspergillus magnus Glässnerová & Hubka; Aspergillus neotritici Glässnerová & Hubka; Aspergillus tenebricus Houbraken, Glässnerová & Hubka. Citation: Glässnerová K, Sklenář F, Jurjević Ž, Houbraken J, Yaguchi T, Visagie CM, Gené J, Siqueira JPZ, Kubátová A, Kolařík M, Hubka V (2022). A monograph of Aspergillus section Candidi. Studies in Mycology 102: 1-51. doi: 10.3114/sim.2022.102.01.

Reducing the number of accepted species in Aspergillus series Nigri

The Aspergillus series Nigri contains biotechnologically and medically important species. They can produce hazardous mycotoxins, which is relevant due to the frequent occurrence of these species on foodstuffs and in the indoor environment. The taxonomy of the series has undergone numerous rearrangements, and currently, there are 14 species accepted in the series, most of which are considered cryptic. Species-level identifications are, however, problematic or impossible for many isolates even when using DNA sequencing or MALDI-TOF mass spectrometry, indicating a possible problem in the definition of species limits or the presence of undescribed species diversity. To re-examine the species boundaries, we collected DNA sequences from three phylogenetic markers (benA, CaM and RPB2) for 276 strains from series Nigri and generated 18 new whole-genome sequences. With the three-gene dataset, we employed phylogenetic methods based on the multispecies coalescence model, including four single-locus methods (GMYC, bGMYC, PTP and bPTP) and one multilocus method (STACEY). From a total of 15 methods and their various settings, 11 supported the recognition of only three species corresponding to the three main phylogenetic lineages: A. niger, A. tubingensis and A. brasiliensis. Similarly, recognition of these three species was supported by the GCPSR approach (Genealogical Concordance Phylogenetic Species Recognition) and analysis in DELINEATE software. We also showed that the phylogeny based on benA, CaM and RPB2 is suboptimal and displays significant differences from a phylogeny constructed using 5 752 single-copy orthologous proteins; therefore, the results of the delimitation methods may be subject to a higher than usual level of uncertainty. To overcome this, we randomly selected 200 genes from these genomes and performed ten independent STACEY analyses, each with 20 genes. All analyses supported the recognition of only one species in the A. niger and A. brasiliensis lineages, while one to four species were inconsistently delimited in the A. tubingensis lineage. After considering all of these results and their practical implications, we propose that the revised series Nigri includes six species: A. brasiliensis, A. eucalypticola, A. luchuensis (syn. A. piperis), A. niger (syn. A. vinaceus and A. welwitschiae), A. tubingensis (syn. A. chiangmaiensis, A. costaricensis, A. neoniger and A. pseudopiperis) and A. vadensis. We also showed that the intraspecific genetic variability in the redefined A. niger and A. tubingensis does not deviate from that commonly found in other aspergilli. We supplemented the study with a list of accepted species, synonyms and unresolved names, some of which may threaten the stability of the current taxonomy. Citation: Bian C, Kusuya Y, Sklenář F, D'hooge E, Yaguchi T, Ban S, Visagie CM, Houbraken J, Takahashi H, Hubka V (2022). Reducing the number of accepted species in Aspergillus series Nigri. Studies in Mycology 102: 95-132. doi: 10.3114/sim.2022.102.03.

Four New Species of Aspergillus Subgenus Nidulantes from China

Aspergillus subgenus Nidulantes includes species with emericella-like ascomata and asexual species. Subgenus Nidulantes is the second largest subgenus of Aspergillus and consists of nine sections. In this study, agricultural soils were sampled from 12 provinces and autonomous regions in China. Based on primary BLAST analyses, seven of 445 Aspergillus isolates showed low similarity with existing species. A polyphasic investigation, including phylogenetic analysis of partial ITS, β-tubulin, calmodulin, and RNA polymerase II second largest subunit genes, provided evidence that these isolates were distributed among four new species (Aspergillus guangdongensis, A. guangxiensis, A. sichuanensis and A. tibetensis) in sections Aenei, Ochraceorosei, and Sparsi of subgenus Nidulantes. Illustrated morphological descriptions are provided for each new taxon.

Seven Undescribed Aspergillus Species from Different Niches in Korea

An investigation of species of the genus Aspergillus present in arthropod, freshwater, and soil led to the discovery of seven undescribed species in Korea. Based on their morphological characteristics and molecular phylogeny analyses using a combined data set of β-tubulin (BenA) and calmodulin (CaM) sequences, the isolated strains CNUFC IGS2-5, CNUFC YJ1-19, CNUFC WD27, CNUFC U8-70, CNUFC AS2-24, CNUFC S32-1, and CNUFC U7-48, were identified as Aspergillus brunneoviolaceus, A. capensis, A. floccosus, A. inflatus, A. parvulus, A. polyporicola, and A. spelaeus, respectively. In the present study, the detailed morphological descriptions and phylogenetic relationships of these species are provided.

Multiplex PCR Identification of Aspergillus cristatus and Aspergillus chevalieri in Liupao Tea Based on Orphan Genes

“Golden flower” fungi in dark tea are beneficial to human health. The rapid identification method of “golden flower” fungi can verify the quality of dark tea products and ensure food safety. In this study, 6 strains were isolated from Liupao tea. They were respectively identified as A. cristatus, A. chevalieri, and A. pseudoglaucus. A. pseudoglaucus was reported as Liupao tea “golden flower” fungus for the first time. It was found that the ITS and BenA sequences of A. cristatus and A. chevalieri were highly conserved. It is difficult to clearly distinguish these closely related species by ITS sequencing. To rapidly identify species, multiplex PCR species-specific primers were designed based on orphan genes screened by comparative genomics analysis. Multiplex PCR results showed that orphan genes were specific and effective for the identification of A. cristatus and A. chevalieri isolated from Liupao tea and Fu brick tea. We confirmed that orphan genes can be used for identification of closely related Aspergillus species. Validation showed that the method is convenient, rapid, robust, sequencing-free, and economical. This promising method will be greatly beneficial to the dark tea processing industry and consumers.

Aspergilli series Versicolores: importance of species identification in the clinical setting

The moulds of the genus Aspergillus section Nidulantes series Versicolores are ubiquitous and particularly recurrent in indoor air. They are considered present in 70% of the bioaerosols to which we are exposed most of our time spent indoors. With the taxonomic revision proposed in 2012 and the discovery of four new species, the series Versicolores currently includes 18 species. These moulds, although considered as cryptic (except Aspergillus sydowii), are opportunistic pathogens that can exhibit increased minimal inhibitory concentrations to conventional antifungal agents. In this review, we discuss the ecology and clinical implications of each species belonging to the series Versicolores. This survey also highlights the lack of consideration for taxonomic revisions in clinical practice and in scientific studies which greatly limits the acquisition of specific knowledge on species belonging to the series Versicolores.

Mrada3 is required for sexual reproduction and secondary metabolite production in industrial fungi Monascus strain

AIMS

Monascus spp. are valuable industrial fungi for producing beneficial compounds. Since sporulation is often coupled with the production of secondary metabolites, the current study was performed to investigate how Mrada3 regulated asexual and sexual development and the production of edible pigments and mycotoxin.

METHODS AND RESULTS

The functional characteristics of Mrada3 were identified by gene deletion and overexpression in Monascus ruber M7 (the wild-type, WT). The results revealed that the ΔMrada3 strain aborted sexual development, but it produced many more conidia than WT. RNA-Seq data showed the deletion of Mrada3 altered the expression levels of partial genes involved in sexual and asexual development. In addition, the deletion of Mrada3 also resulted in slower growth, lower pigment production, and increased citrinin yield at the late period. For the Mrada3-overexpressed strain, the number of ascospores and pigment content were significantly higher than those of WT, but citrinin was slightly lower than that of WT.

CONCLUSIONS

The Mrada3 gene plays a vital role in the sporulation development and secondary metabolism of Monascus species.

SIGNIFICANCE AND IMPACT OF THE STUDY

Mrada3 is first identified as an essential regulator for sexual development in Monascus species, enriching the regulatory knowledge of sexual development in filamentous fungi.

Unravelling the Molecular Identification and Antifungal Susceptibility Profiles of Aspergillus spp. Isolated from Chronic Pulmonary Aspergillosis Patients in Jakarta, Indonesia: The Emergence of Cryptic Species

Cryptic species of Aspergillus have rapidly increased in the last few decades. Chronic pulmonary aspergillosis (CPA) is a debilitating fungal infection frequently affecting patients with previous TB. The identification and antifungal susceptibility profiles of different species of Aspergillus are important to support the management of CPA. The aim of this study was to describe the molecular and susceptibility profiles of Aspergillus isolated from CPA patients. The species identity of isolates was determined by combined DNA analyses of internal transcribed space (ITS), partial β-tubulin genes, and part of the calmodulin gene. We revealed a high (27%) prevalence of cryptic species among previous tuberculosis patients with persistent symptoms. Twenty-nine (49%) patients met the criteria for diagnosis of CPA with 24% containing Aspergillus cryptic species. This is the first report of five cryptic Aspergillus species from clinical isolates in Indonesia: A. aculea tus, A. neoniger, A. brunneoviolacues, A. welwitschiae, and A. tubingensis. Significantly, there was decreased sensitivity against itraconazole in the CPA group (66% susceptible to itraconazole) compared to the non-CPA group (90% susceptible to itraconazole) (p = 0.003). The species-level characterisation of Aspergillus and its antifungal susceptibility tests demands greater attention to better the management of CPA patients.

Subtyping Options for Microsporum canis Using Microsatellites and MLST: A Case Study from Southern Italy

Microsporum canis is considered one of the most common zoophilic dermatophyte species causing infections in animals and humans worldwide. However, molecular epidemiological studies on this dermatophyte are still rare. In this study, we aimed to analyse the population structure and relationships between M. canis strains (n = 66) collected in southern Italy and those isolated from symptomatic and asymptomatic animals (cats, dogs and rabbits) and humans. For subtyping purposes, using multilocus sequence typing (MLST) and multilocus microsatellite typing (MLMT), we first used a limited set of strains to screen for variability. No intraspecies variability was detected in six out of the eight reference genes tested and only the ITS and IGS regions showed two and three sequence genotypes, respectively, resulting in five MLST genotypes. All of eight genes were, however, useful for discrimination among M. canis, M. audouinii and M. ferrugineum. In total, eighteen microsatellite genotypes (A-R) were recognized using MLMT based on six loci, allowing a subdivision of strains into two clusters based on the Bayesian iterative algorithm. Six MLMT genotypes were from multiple host species, while 12 genotypes were found only in one host. There were no statistically significant differences between clusters in terms of host spectrum and the presence or absence of lesions. Our results confirmed that the MLST approach is not useful for detailed subtyping and examining the population structure of M. canis, while microsatellite analysis is a powerful tool for conducting surveillance studies and gaining insight into the epidemiology of infections due to this pathogen.

Aspergillus niger LBM 134 isolated from rotten wood and its potential cellulolytic ability

Aspergillus

is a genus of filamentous and cosmopolitan fungi that includes important species for medical mycology, food, basic research and agro-industry areas. Aspergillus section Nigri are efficient producers of hydrolytic enzymes such as cellulases that are employed in the cellulose conversion. Hence, the search of new cellulolytic isolates and their correct identification is important for carrying out safe biotechnological processes. This study aimed to characterise the cellulolytic potential of Aspergillus sp. LBM 134, isolated from the Paranaense rainforest (Argentina) and to identify the isolate through a polyphasic approach. The fungus was identified as Aspergillus niger and its cellulolytic potential was evaluated by using Congo red technique and fluorescence plate assays for carboxymethyl cellulase, β-glucosidase and cellobiohydrolase, respectively. All three cellulase activities were positive; this bio-prospective positioned A. niger LBM 134 as a promising alternative for industries that require organisms capable of carrying out cellulosic biomass processing.

Azole-resistant Aspergillus fumigatus is highly prevalent in the environment of Vietnam, with marked variability by land use type

Azole-resistant environmental Aspergillus fumigatus presents a threat to public health but the extent of this threat in Southeast Asia is poorly described. We conducted environmental surveillance in the Mekong Delta region of Vietnam, collecting air and ground samples across key land-use types, and determined antifungal susceptibilities of Aspergillus section Fumigati (ASF) isolates and azole concentrations in soils. Of 119 ASF isolates, 55% were resistant (or non-wild type) to itraconazole, 65% to posaconazole and 50% to voriconazole. Azole resistance was more frequent in A. fumigatus sensu stricto isolates (95%) than other ASF species (32%). Resistant isolates and agricultural azole residues were overrepresented in samples from cultivated land. cyp51A gene sequence analysis showed 38/56 resistant A. fumigatus sensu stricto isolates carried known resistance mutations, with TR₃₄ /L98H most frequent (34/38).

Re-examination of species limits in Aspergillus section Flavipedes using advanced species delimitation methods and description of four new species

Since the last revision in 2015, the taxonomy of section Flavipedes evolved rapidly along with the availability of new species delimitation techniques. This study aims to re-evaluate the species boundaries of section Flavipedes members using modern delimitation methods applied to an extended set of strains (n = 90) collected from various environments. The analysis used DNA sequences of three house-keeping genes (benA, CaM, RPB2) and consisted of two steps: application of several single-locus (GMYC, bGMYC, PTP, bPTP) and multi-locus (STACEY) species delimitation methods to sort the isolates into putative species, which were subsequently validated using DELINEATE software that was applied for the first time in fungal taxonomy. As a result, four new species are introduced, i.e. A. alboluteus, A. alboviridis, A. inusitatus and A. lanuginosus, and A. capensis is synonymized with A. iizukae. Phenotypic analyses were performed for the new species and their relatives, and the results showed that the growth parameters at different temperatures and colonies characteristics were useful for differentiation of these taxa. The revised section harbors 18 species, most of them are known from soil. However, the most common species from the section are ecologically diverse, occurring in the indoor environment (six species), clinical samples (five species), food and feed (four species), droppings (four species) and other less common substrates/environments. Due to the occurrence of section Flavipedes species in the clinical material/hospital environment, we also evaluated the susceptibility of 67 strains to six antifungals (amphotericin B, itraconazole, posaconazole, voriconazole, isavuconazole, terbinafine) using the reference EUCAST method. These results showed some potentially clinically relevant differences in susceptibility between species. For example, MICs higher than those observed for A. fumigatus wild-type were found for both triazoles and amphotericin B for A. ardalensis, A. iizukae, and A. spelaeus whereas A. lanuginosus, A. luppiae, A. movilensis, A. neoflavipes, A. olivimuriae and A. suttoniae were comparable to or more susceptible as A. fumigatus. Finally, terbinafine was in vitro active against all species except A. alboviridis.

Molecular Markers of Antifungal Resistance: Potential Uses in Routine Practice and Future Perspectives

Antifungal susceptibility testing (AST) has come to establish itself as a mandatory routine in clinical practice. At the same time, the mycological diagnosis seems to have headed in the direction of non-culture-based methodologies. The downside of these developments is that the strains that cause these infections are not able to be studied for their sensitivity to antifungals. Therefore, at present, the mycological diagnosis is correctly based on laboratory evidence, but the antifungal treatment is undergoing a growing tendency to revert back to being empirical, as it was in the last century. One of the explored options to circumvent these problems is to couple non-cultured based diagnostics with molecular-based detection of intrinsically resistant organisms and the identification of molecular mechanisms of resistance (secondary resistance). The aim of this work is to review the available molecular tools for antifungal resistance detection, their limitations, and their advantages. A comprehensive description of commercially available and in-house methods is included. In addition, gaps in the development of these molecular technologies are discussed.

Aspergillus Species in Lower Respiratory Tract of Hospitalized Patients from Shanghai, China: Species Diversity and Emerging Azole Resistance

Purpose

To investigate species diversity and prevalence of antifungal resistance among clinical isolates of Aspergillus spp. in Shanghai, China.

Patients and Methods

In this study, the Aspergillus spp. isolates were analyzed by multilocus sequence typing (MLST) targeting the internal transcribed spacer (ITS) regions, and partial β-tubulin (BenA) and calmodulin (CaM) genes. The susceptibilities of these isolates to nine antifungal agents were determined according to the protocol in document M38-A3 established by the Clinical and Laboratory Standards Institute (CLSI).

Results

The most common Aspergillus spp. was A. fumigatus (58.2%), followed by the A. flavus complex (23.5%), and A. niger complex (15.3%). Isolates belonging to A. tamarii and A. effusus of the A. flavus complex and A. tubingensis and A. awamori of the A. niger complex were identified. Moreover, several mutations were found in the azole target cyp51A gene (TR₄₆/Y121F/T289A and F46Y, G89G, M172V, N248T and D255E) in azole-resistant isolates of A. fumigatus.

Conclusion

The results of our study revealed a diversity of species in the lower respiratory tract of inpatients in Shanghai and approximately 9% of our isolates were resistant to at least one of the triazole antifungals. Formulation of local treatment strategies to combat emerging azole resistance and species diversity in clinically relevant Aspergillus spp. is needed.

The Genomic Regions That Contain Ochratoxin A Biosynthetic Genes Widely Differ in Aspergillus Section Circumdati Species

Aspergillus section Circumdati includes 27 species, some of which are considered ochratoxin A (OTA) producers. However, there is considerable controversy about their potential OTA synthesis ability. In this work, the complete genomes of 13 species of Aspergillus section Circumdati were analyzed in order to study the cluster of OTA biosynthetic genes and the region was compared to those previously reported in A. steynii and A. westerdijkiae. The results obtained reveal that the genomes of some species in this section, including A. affinis, A. cretensis, A. elegans, A. muricatus, A. pulvericola, A. roseoglobulosus, and A. subramanianii, contain a potentially functional OTA biosynthetic cluster. Therefore, they might be able to synthesize the toxin. On the contrary, A. melleus, A. ochraceus, A. ostianus, A. persii, A. sclerotiorum, A. sesamicola, and A. westlandensis contain a truncated version of the cluster that lacks many of the genes involved in OTA biosynthesis, which might be related to their inability to produce OTA. The gain/loss pattern is different in all species, which suggests that the genetic evolution of this region might be due to independent events.

The Conserved MAP Kinase MpkB Regulates Development and Sporulation without Affecting Aflatoxin Biosynthesis in Aspergillus flavus

In eukaryotes, the MAP kinase signaling pathway plays pivotal roles in regulating the expression of genes required for growth, development, and stress response. Here, we deleted the mpkB gene (AFLA_034170), an ortholog of the Saccharomyces cerevisiae FUS3 gene, to characterize its function in Aspergillus flavus, a cosmopolitan, pathogenic, and aflatoxin-producing fungus. Previous studies revealed that MpkB positively regulates sexual and asexual differentiation in Aspergillus nidulans. In A. flavus, mpkB deletion resulted in an approximately 60% reduction in conidia production compared to the wild type without mycelial growth defects. Moreover, the mutant produced immature and abnormal conidiophores exhibiting vesicular dome-immaturity in the conidiophore head, decreased phialide numbers, and very short stalks. Interestingly, the ΔmpkB mutant could not produce sclerotia but produced aflatoxin B1 normally. Taken together, these results suggest that the A. flavus MpkB MAP kinase positively regulates conidiation and sclerotia formation but is not involved in the production of secondary metabolites such as aflatoxin B1.

Molecular Identification and Characterisation of Aspergillus Flavus Isolates Originating from Serbian Wheat Grains

During previous years, regarding the shifts in climate conditions in temperate region, such as occurrence of high temperatures and prolonged drought, increased occurrence frequencies of Aspergillus flavus and aflatoxins in cereal grains were recorded. A reliable and accurate identification of the fungi is of great importance for evaluating the microbiological risks of contamination. The essential point of the present investigation was molecular characterisation and identification of A. flavus isolates originating from common wheat and spelt grains collected after harvest during the period of three years (2015–2017) in Northern Serbia. A holistic approach that included PCR amplification of two DNA genomic regions and PCR-RFLP assay followed by fragment length analysis, provided complete and comprehensive characterisation of A. flavus isolated from wheat grains. The presented results indicate that there was no difference among the tested Aspergillus isolates on the molecular–genetic level. All 38 strains were identified as A. flavus by sequencing of combined ITS region and β-tubulin gene fragments (acc. no.: MH582473 to MH582510). PCR-RFLP method in combination with a Lab-on-a-chip (LoaC) electrophoresis can be successfully used to rapidly identify A. flavus isolates.

Absence of Azole Antifungal Resistance in Aspergillus fumigatus Isolated from Root Vegetables Harvested from UK Arable and Horticultural Soils

The emergence of azole-resistant Aspergillus fumigatus (ARAf) complicates the treatment of aspergillosis and can nearly double the mortality from invasive aspergillosis (IA). ARAf has been isolated from many different environmental sites and indoor environments and thus presents a significant risk for susceptible patients. Local surveillance of environmental ARAf can guide antifungal prescribing and improve patient outcomes. In this study, seventy-four soils samples collected from the surface of a variety of root vegetables from farm shops and private gardens covering a wide geographical area of the UK, were cultured to assess the presence of A. fumigatus, and the prevalence and nature of any resistance mechanisms. A high-throughput in-house antifungal susceptibility screening method was developed and validated using the EUCAST MIC reference method, E.DEF 9.3.1. A total of 146 isolates were recovered and analysed. Even though the study premise was that soil-covered root vegetables and other fresh produce could represent a conduit for ARAf exposure in vulnerable patients, no ARAf were found in the soil samples despite 55% of samples harbouring A. fumigatus. The sample type and screening method used could be suitable for more extensive monitoring of the soil to detect trends in the prevalence of ARAf.

Two New Aspergillus flavus Reference Genomes Reveal a Large Insertion Potentially Contributing to Isolate Stress Tolerance and Aflatoxin Production

Efforts in genome sequencing in the Aspergillus genus have led to the development of quality reference genomes for several important species including A. nidulans, A. fumigatus, and A. oryzae However, less progress has been made for A. flavus As part of the effort of the USDA-ARS Annual Aflatoxin Workshop Fungal Genome Project, the isolate NRRL3357 was sequenced and resulted in a scaffold-level genome released in 2005. Our goal has been biologically driven, focusing on two areas: isolate variation in aflatoxin production and drought stress exacerbating aflatoxin production by A. flavus Therefore, we developed two reference pseudomolecule genome assemblies derived from chromosome arms for two isolates: AF13, a MAT1-2, highly stress tolerant, and highly aflatoxigenic isolate; and NRRL3357, a MAT1-1, less stress tolerant, and moderate aflatoxin producer in comparison to AF13. Here, we report these two reference-grade assemblies for these isolates through a combination of PacBio long-read sequencing and optical mapping, and coupled them with comparative, functional, and phylogenetic analyses. This analysis resulted in the identification of 153 and 45 unique genes in AF13 and NRRL3357, respectively. We also confirmed the presence of a unique 310 Kb insertion in AF13 containing 60 genes. Analysis of this insertion revealed the presence of a bZIP transcription factor, named atfC, which may contribute to isolate pathogenicity and stress tolerance. Phylogenomic analyses comparing these and other available assemblies also suggest that the species complex of A. flavus is polyphyletic.

Characterization and Pathogenicity of Colletotrichum Species on Philodendron tatei cv. Congo in Gansu Province, China

In recent years in China, leaf spot caused by Colletotrichum species has been an emerging disease of Philodendron tatei cv. Congo. From 2016 to 2019, typical symptoms, appearing as circular or ovoid, sunken, and brown lesions with a yellow halo, were commonly observed on P. tatei cv. Congo in and around Lanzhou, Gansu Province, China. Conidiomata were often visible on infected leaf surfaces. Leaf disease incidence was approximately 5 to 20%. A total of 126 single-spored Colletotrichum isolates were obtained from leaf lesions. Multilocus phylogenetic relationships were analyzed based on seven genomic loci (ITS, ACT, GAPDH, HIS3, CAL, CHS-1, and TUB2) and the morphological characters of the isolates determined. These isolates were identified as three Colletotrichum species in this study. A further 93 isolates, accounting for 74% of all Colletotrichum isolates, were described as new species and named as Colletotrichum philodendricola sp. nov. after the host plant genus name, Philodendron; another two isolates were named as C. pseudoboninense sp. nov. based on phylogenetic and morphological relativeness to C. boninense; the other 31 isolates, belonging to the C. orchidearum species complex, were identified as a known species-C. orchidearum. Both novel species C. philodendricola and C. pseudoboninense belong to the C. boninense species complex. Pathogenicity tests by both spray and point inoculations confirmed that all three species could infect leaves of P. tatei cv. Congo. For spray inoculation, the mean infection rate of leaves on the three species was only 4.7% (0 to 12%), and the size on lesions was mostly 1 to 2 mm in length. For point inoculation, 30 days after nonwounding inoculation, the infection rate on leaves was 0 to 35%; in wounding inoculation, the infection rate of leaves was 35 to 65%; wounding in healthy leaves greatly enhanced the pathogenicity of these three species to P. tatei cv. Congo; however, the sizes of lesions among the three species were not significantly different. To our knowledge, this is the first report of Colletotrichum species associated with anthracnose diseases on P. tatei cv. Congo. Results obtained in this study will assist the disease prevention and appropriate management strategies.

New species in Aspergillus section Usti and an overview of Aspergillus section Cavernicolarum

Aspergillus sections Usti and Cavernicolarum are accommodated in the subgenus Nidulantes. In the present study, a polyphasic approach using morphology and multi-gene phylogeny was applied to investigate the taxonomy of these two sections. Based on the phylogenetic analysis, Aspergillus section Usti includes 25 species, which can be assigned to four series: Calidousti, Deflecti, Monodiorum and Usti. Aspergillus sigarelli is newly described in this section and this species was isolated from a cigarette from PR China and belongs to series Calidousti. It is clearly distinct from other members in this series based on ITS, BenA, CaM and RPB2 sequences. Aspergillus section Usti members like A. calidoustus and A. granulosus are important opportunistic pathogens, it is speculative that more pathogenetic species will be found by using polyphasic taxonomy approaches. Aspergillus section Cavernicolarum includes five species, the growth rates on agar media and size and ornamentation of conidia are important characters for differentiating species in section Cavernicolarum.

verA Gene is Involved in the Step to Make the Xanthone Structure of Demethylsterigmatocystin in Aflatoxin Biosynthesis

In the biosynthesis of aflatoxin, verA, ver-1, ordB, and hypA genes of the aflatoxin gene cluster are involved in the pathway from versicolorin A (VA) to demethylsterigmatocystin (DMST). We herein isolated each disruptant of these four genes to determine their functions in more detail. Disruptants of ver-1, ordB, and hypA genes commonly accumulated VA in their mycelia. In contrast, the verA gene disruptant accumulated a novel yellow fluorescent substance (which we named HAMA) in the mycelia as well as culture medium. Feeding HAMA to the other disruptants commonly caused the production of aflatoxins B₁ (AFB₁) and G₁ (AFG₁). These results indicate that HAMA pigment is a novel aflatoxin precursor which is involved at a certain step after those of ver-1, ordB, and hypA genes between VA and DMST. HAMA was found to be an unstable substance to easily convert to DMST and sterigmatin. A liquid chromatography-mass spectrometry (LC-MS) analysis showed that the molecular mass of HAMA was 374, and HAMA gave two close major peaks in the LC chromatogram in some LC conditions. We suggest that these peaks correspond to the two conformers of HAMA; one of them would be selectively bound on the substrate binding site of VerA enzyme and then converted to DMST. VerA enzyme may work as a key enzyme in the creation of the xanthone structure of DMST from HAMA.

Three-gene phylogeny of the genus Arthroderma: Basis for future taxonomic studies

Arthroderma is the most diverse genus among dermatophytes encompassing species occurring in soil, caves, animal burrows, clinical material and other environments. In this study, we collected ex-type, reference and authentic strains of all currently accepted Arthroderma species and generated sequences of three highly variable loci (ITS rDNA, β-tubulin, and translation elongation factor 1-α). The number of accepted species was expanded to 27. One novel species, A. melbournense (ex-type strain CCF 6162T = CBS 145858T), is described. This species was isolated from toenail dust collected by a podiatrist in Melbourne, during an epidemiological study of four geographical regions of Eastern Australia. Trichophyton terrestre, Chrysosporium magnisporum, and Chrysosporium oceanitis are transferred to Arthroderma. Typification is provided for T. terrestre that is not conspecific with any of the supposed biological species from the former T. terrestre complex, that is, A. insingulare, A. lenticulare and A. quadrifidum. A multi-gene phylogeny and reference sequences provided in this study should serve as a basis for future phylogenetic studies and facilitate species identification in practice.

LAY ABSTRACT

The genus Arthroderma encompasses geophilic dermatophyte species that infrequently cause human and animal superficial infections. Reference sequences from three genetic loci were generated for all currently accepted Arthroderma species and phylogeny was constructed. Several taxonomic novelties are introduced. The newly provided data will facilitate species identification and future taxonomic studies.

Black aspergilli: A remaining challenge in fungal taxonomy?

Aspergillus section Nigri is a taxonomically difficult but medically and economically important group. In this study, an update of the taxonomy of A. section Nigri strains within the BCCM/IHEM collection has been conducted. The identification accuracy of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was tested and the antifungal susceptibilities of clinical isolates were evaluated. A total of 175 strains were molecularly analyzed. Three regions were amplified (ITS, benA, and caM) and a multi-locus phylogeny of the combined loci was created by using maximum likelihood analysis. The in-house MALDI-TOF MS reference database was extended and an identification data set of 135 strains was run against a reference data set. Antifungal susceptibility was tested for voriconazole, itraconazole, and amphotericin B, using the EUCAST method. Phylogenetic analysis revealed 18 species in our data set. MALDI-TOF MS was able to distinguish between A. brasiliensis, A. brunneoviolaceus, A. neoniger, A. niger, A. tubingensis, and A. welwitschiae of A. sect. Nigri. In the routine clinical lab, isolates of A. sect. Nigri are often identified as A. niger. However, in the clinical isolates of our data set, A. tubingensis (n = 35) and A. welwitschiae (n = 34) are more common than A. niger (n = 9). Decreased antifungal susceptibility to azoles was observed in clinical isolates of the /tubingensis clade. This emphasizes the importance of identification up to species level or at least up to clade level in the clinical lab. Our results indicate that MALDI-TOF MS can be a powerful tool to replace classical morphology.

Identification of toxigenic fungal species associated with maize ear rot: Calmodulin as single informative gene

Accurate identification of fungi occurring on agrofood products is the key aspect of any prevention and pest management program, offering valuable information in leading crop health and food safety. Fungal species misidentification can dramatically impact biodiversity assessment, ecological studies, management decisions, and, concerning toxigenic fungi, health risk assessment, since they can produce a wide range of toxic secondary metabolites, referred to as mycotoxins. Since each toxigenic fungal species can have its own mycotoxin profile, a correct species identification, hereby attempted with universal DNA barcoding approach, could have a key role in mycotoxins prevention strategies. Currently, identification of single marker for species resolution in fungi has not been achieved and the analysis of multiple genes is used, with the advantage of an accurate species identification and disadvantage of difficult setting up of PCR-based diagnostic assays. In the present paper, we describe our strategy to set up a DNA-based species identification of fungal species associated with maize ear rot, combining DNA barcoding approach and species-specific primers design for PCR based assays. We have (i) investigated the appropriate molecular marker for species identification, limited to mycobiota possibly occurring on maize, identifying calmodulin gene as single taxonomically informative entity; (ii) designed 17 sets of primers for rapid identification of 14 Fusarium, 10 Aspergillus, 2 Penicillium, and 2 Talaromyces species or species groups, and finally (iii) tested specificity of the 17 set of primers, in combination with 3 additional sets previously developed.

Cryptic species of Aspergillus section Terrei display essential physiological features to cause infection and are similar in their virulence potential in Galleria mellonella

Aspergillus species account for the majority of invasive mold infections in immunocompromised patients. Most commonly, members of the Aspergillus section Fumigati are isolated from clinical material, followed by isolates belonging to section Terrei. The section Terrei contains 16 accepted species. Six species were found to be of clinical relevance and studied for differences in growth adaptability and virulence potential. Therefore, a set of 73 isolates (22 A. terreus s.s., 8 A. alabamensis, 27 A. citrinoterreus, 2 A. floccosus, 13 A. hortai, and 1 A. neoafricanus) was studied to determine differences in (a) germination kinetics, (b) temperature tolerance, (c) oxygen stress tolerance (1% O₂), and (d) a combination of the latter two. Virulence potential of phialidic (PC) and accessory conidia (AC) was studied in G. mellonella larvae, using survival as read out. Further, the formation of AC was evaluated in larval tissue. All isolates were able to grow at elevated temperature and hypoxia, with highest growth and germination rates at 37°C. A. terreus s.s., A. citrinoterreus, and A. hortai exhibited highest growth rates. Virulence potential in larvae was inoculum and temperature dependent. All species except A. floccosus formed AC and germination kinetics of AC was variable. Significantly higher virulence potential of AC was found for one A. hortai isolate. AC could be detected in larval tissue 96 h post infection. Based on these findings, cryptic species of section Terrei are well adapted to the host environment and have similar potential to cause infections.

Arboricolonus simplex gen. et sp. nov. and novelties in Cadophora, Minutiella and Proliferodiscus from Prunus wood in Germany

During a survey on fungi associated with wood necroses of Prunus trees in Germany, strains belonging to the Leotiomycetes and Eurotiomycetes were detected by preliminary analyses of ITS sequences. Multi-locus phylogenetic analyses (LSU, ITS, TUB, EF-1α, depending on genus) of 31 of the 45 strains from Prunus and reference strains revealed several new taxa, including Arboricolonus gen. nov., a new genus in the Helotiales (Leotiomycetes) with a collophorina-like asexual morph. Seven Cadophora species (Helotiales, Leotiomycetes) were treated. The 29 strains from Prunus belonged to five species, of which C. luteo-olivacea and C. novi-eboraci were dominating; C. africana sp. nov., C. prunicola sp. nov. and C. ramosa sp. nov. were revealed as new species. The genus Cadophora was reported from Prunus for the first time. Phialophora bubakii was combined in Cadophora and differentiated from C. obscura, which was resurrected. Asexual morphs of two Proliferodiscus species (Helotiales, Leotiomycetes) were described, including one new species, Pr. ingens sp. nov. Two Minutiella species (Phaeomoniellales, Eurotiomycetes) were detected, including the new species M. pruni-avium sp. nov. Prunus avium and P. domestica are reported as host plants of Minutiella.

Updating the taxonomy of Aspergillus in South Africa

The taxonomy and nomenclature of the genus Aspergillus and its associated sexual (teleomorphic) genera have been greatly stabilised over the last decade. This was in large thanks to the accepted species list published in 2014 and associated metadata such as DNA reference sequences released at the time. It had a great impact on the community and it has never been easier to identify, publish and describe the missing Aspergillus diversity. To further stabilise its taxonomy, it is crucial to not only discover and publish new species but also to capture infraspecies variation in the form of DNA sequences. This data will help to better characterise and distinguish existing species and make future identifications more robust. South Africa has diverse fungal communities but remains largely unexplored in terms of Aspergillus with very few sequences available for local strains. In this paper, we re-identify Aspergillus previously accessioned in the PPRI and MRC culture collections using modern taxonomic approaches. In the process, we re-identify strains to 63 species, describe seven new species and release a large number of new DNA reference sequences.

Classification of Aspergillus, Penicillium, Talaromyces and related genera (Eurotiales): An overview of families, genera, subgenera, sections, series and species

The Eurotiales is a relatively large order of Ascomycetes with members frequently having positive and negative impact on human activities. Species within this order gain attention from various research fields such as food, indoor and medical mycology and biotechnology. In this article we give an overview of families and genera present in the Eurotiales and introduce an updated subgeneric, sectional and series classification for Aspergillus and Penicillium. Finally, a comprehensive list of accepted species in the Eurotiales is given. The classification of the Eurotiales at family and genus level is traditionally based on phenotypic characters, and this classification has since been challenged using sequence-based approaches. Here, we re-evaluated the relationships between families and genera of the Eurotiales using a nine-gene sequence dataset. Based on this analysis, the new family Penicillaginaceae is introduced and four known families are accepted: Aspergillaceae, Elaphomycetaceae, Thermoascaceae and Trichocomaceae. The Eurotiales includes 28 genera: 15 genera are accommodated in the Aspergillaceae (Aspergillago, Aspergillus, Evansstolkia, Hamigera, Leiothecium, Monascus, Penicilliopsis, Penicillium, Phialomyces, Pseudohamigera, Pseudopenicillium, Sclerocleista, Warcupiella, Xerochrysium and Xeromyces), eight in the Trichocomaceae (Acidotalaromyces, Ascospirella, Dendrosphaera, Rasamsonia, Sagenomella, Talaromyces, Thermomyces, Trichocoma), two in the Thermoascaceae (Paecilomyces, Thermoascus) and one in the Penicillaginaceae (Penicillago). The classification of the Elaphomycetaceae was not part of this study, but according to literature two genera are present in this family (Elaphomyces and Pseudotulostoma). The use of an infrageneric classification system has a long tradition in Aspergillus and Penicillium. Most recent taxonomic studies focused on the sectional level, resulting in a well-established sectional classification in these genera. In contrast, a series classification in Aspergillus and Penicillium is often outdated or lacking, but is still relevant, e.g., the allocation of a species to a series can be highly predictive in what functional characters the species might have and might be useful when using a phenotype-based identification. The majority of the series in Aspergillus and Penicillium are invalidly described and here we introduce a new series classification. Using a phylogenetic approach, often supported by phenotypic, physiologic and/or extrolite data, Aspergillus is subdivided in six subgenera, 27 sections (five new) and 75 series (73 new, one new combination), and Penicillium in two subgenera, 32 sections (seven new) and 89 series (57 new, six new combinations). Correct identification of species belonging to the Eurotiales is difficult, but crucial, as the species name is the linking pin to information. Lists of accepted species are a helpful aid for researchers to obtain a correct identification using the current taxonomic schemes. In the most recent list from 2014, 339 Aspergillus, 354 Penicillium and 88 Talaromyces species were accepted. These numbers increased significantly, and the current list includes 446 Aspergillus (32 % increase), 483 Penicillium (36 % increase) and 171 Talaromyces (94 % increase) species, showing the large diversity and high interest in these genera. We expanded this list with all genera and species belonging to the Eurotiales (except those belonging to Elaphomycetaceae). The list includes 1 187 species, distributed over 27 genera, and contains MycoBank numbers, collection numbers of type and ex-type cultures, subgenus, section and series classification data, information on the mode of reproduction, and GenBank accession numbers of ITS, beta-tubulin (BenA), calmodulin (CaM) and RNA polymerase II second largest subunit (RPB2) gene sequences.

Increasing the species diversity in the Aspergillus section Nidulantes: Six novel species mainly from the indoor environment

Aspergillus section Nidulantes encompasses almost 80 homothallic and anamorphic species, mostly isolated from soil, plant material, or the indoor environment. Some species are clinically relevant or produce mycotoxins. This study reevaluated the species boundaries within several clades of section Nidulantes. Five data sets were assembled, each containing presumptive new species and their closest relatives, and phylogenetic and phenotypic analyses were performed. We tested the hypotheses that the newly isolated or reexamined strains constitute separate species (splitting approach) or should be treated as part of broadly defined species (lumping approach). Four DNA sequence loci were amplified, internal transcribed spacer (ITS) and large subunit (LSU) regions of the rDNA and partial sequences of the β-tubulin (benA), calmodulin (CaM), and RNA polymerase II second largest subunit (RPB2) genes. The latter three loci were used for the phylogenetic analysis and served as input for single-locus (GMYC, bGMYC, PTP, and bPTP) and multilocus (STACEY and BP&P) species delimitation analyses. The phenotypic analysis comprised macro- and micromorphology (including scanning electron microscopy) and comparison of cardinal growth temperatures. The phylogenetic analysis supported the splitting hypothesis in all cases, and based on the combined approach, we propose six new species, four that are homothallic and two anamorphic. Four new species were isolated from the indoor environment (Jamaica, Trinidad and Tobago, USA), one originated from soil (Australia), and one from a kangaroo rat cheek pouch (USA).

Occurrence and Characterization of Fungi and Mycotoxins in Contaminated Medicinal Herbs

Traditional medicinal herbs are widely used and may be contaminated with mycotoxigenic fungi during cultivation, harvesting, and storage, causing spoilage and mycotoxin production. We evaluated the predominant mycoflora and extent of mycotoxin contaminations in 48 contaminated samples of 13 different medicinal herbs. In total, 70.8% of herbs were slightly contaminated with aflatoxins (<5 μg kg-1). Codonopsis radix samples contained ochratoxin A (OTA) (360-515 μg kg-1), and Scutellariae radix samples contained OTA (49-231 μg kg-1) and citrinin (15-53 μg kg-1). Forty samples (83.3%) contained fungal contamination. Sixty-nine strains were characterized via morphological and molecular identification. The predominant mycoflora comprised four genera, Aspergillus spp. (26.1%), Penicillium spp. (24.6%), Rhizopus spp. (14.5%), and Trichoderma spp. (11.6%). Aflatoxins, OTA, and citrinin were detected in 37 cultures by high-performance liquid chromatography-tandem mass spectrometry. Approximately 21.6% of Aspergillus and Penicillium isolates produced mycotoxins. One Penicillium polonicum strain isolated from Scutellariae radix synthesized citrinin. Multiplex PCR analysis showed that three Aspergillus flavus strains harbored aflatoxin biosynthesis genes. One Aspergillus flavus strain isolated from Amomi fructus produced AFB1 and AFB2. To the best of our knowledge, the citrinin production by Aspergillus chevalieri and Penicillium sacculum was first reported in this study, which poses a potential risk of mycotoxin contamination in medicinal herbs.

Aspergillus incahuasiensis sp. nov., isolated from soil in the semi-arid region of northern Chile

During a study of the fungi from a semi-arid region of northern Chile, a novel species of Aspergillus was encountered in the soil from an area where pepper trees (Schinusmolle) were growing. Marker genes were sequenced to identify these isolates. The β-tubulin, calmodulin and DNA-dependent RNA polymerase loci all indicated that this was a novel species in Aspergillus section Nidulantes and in the Aspergillus multicolorclade. The new species was studied morphologically and differences between it and the other members of the A. multicolor clade are described. We provide a name and description for these isolates as Aspergillus incahuasiensis sp. nov.

Dispersion, persistence, and stability of the biocontrol agent Penicillium frequentans strain 909 after stone fruit tree applications

The capacity of dispersion, persistence, and stability from biocontrol agents is essential before these organisms can be developed into a commercial product. Interactions that microorganisms establish with stone fruit trees may be beneficial in the exploitation of trees in agriculture as crop production. The natural background levels of Penicillium frequentans strain 909 dispersion, persistence, and stability were assessed after tree applications and postharvest conditions. A fingerprinting-based approach to trace genetic stability of P. frequentans along stored time and its release in the field was developed. P. frequentans was successfully traced and discriminated. This strain was dispersed well in treated trees, persisting in the ecosystem up to 2 weeks and staying genetically stable after 36 months of storage. However, the dispersal of P. frequentans was very limited on around untreated trees and soil. P. frequentans dispersed randomly into the air, and its presence reduced from the first day to disappear completely at 15-21 days after application. Great losses of P. frequentans and its increased dispersal in open field conditions probably resulted from rainfall. Biological control strategies with Pf909 were discussed.