Taxonomic studies of the Penicillium glabrum complex and the description of a new species P. subericola

Understanding the role of bats as fungal vectors in the environment

Bats (Chiroptera), the second largest group of mammals, are known for their unique immune system and their ability to act as vectors for various zoonoses. Bats also act as important carriers of fungi, which include plant, animal, and human pathogens. Their roosting areas, foraging behaviors, and even migration routes make bats ideal vectors for fungi. We isolated 75 culturable fungal species from bats in Yunnan Province, China, with 36 species representing known pathogens of plants, animals, and humans, while 39 species are non-pathogenic fungi. Among these species, 77% (58 species) belonged to Ascomycota, 9% (seven species) belonged to Basidiomycota, and 13% (10 species) belonged to Mucoromycota. Even though several taxonomic studies on fungi associated with bats have been published, studies exploring the role of bats as fungal vectors are lacking. This study discusses the fungi host-specific traits and pathogenicity and the impact and ecological significance of bats as fungal vectors.

Multifactorial action of lavender and lavandin oils against filamentous fungi

AIMS

In this study, five essential oils (EOs) from different species of Lavandula hybrida abrialis, for Lavandula hybrida R.C., Lavandula hybrida 'super A', Lavandula hybrida 'super Z' and Lavandula vera and its hybrids Lavender were evaluated against 26 dust-isolated fungal strains from North Africa.

METHODS AND RESULTS

The composition of the different EOs was determined from volume to dry weight. The photochemical analyses were performed via gas chromatography (GC). The cytotoxic effect of five lavender EOs on human epithelial colorectal adenocarcinoma cells (Caco-2) cell line was done. A total of 26 strains of filamentous fungi including Aspergillus spp., Botrytis cinerea, Ceriporia spp., Fusarium spp. and Penicillium glabrum were isolated from sand dust samples via molecular diagnostic tool of PCR. Fungal strains with the lowest minimal lethal concentration (MLC) were Penicillium glabrum, Ceriporia spp. and a strain of Aspergillus spp.

CONCLUSIONS

More studies are needed to verify the activity of this EO against more different fungal species, and determine the active ingredients.Significance and impact of study: MIC of the antifungal efficacy relating to EOs was evaluated. The EOs tests showed no cytotoxic effect at very low concentrations, ranging from 0.03% (IC50 0.9132 mg/mL) (L. hybrid Abrialis) to 0.001% (IC50 1.631 mg/mL) (L. hybrid R.C.).

A study on the fungal rhinosinusitis: Causative agents, symptoms, and predisposing factors

Background

In natural conditions, inhaled fungi are considered a part of the microflora of nasal cavities and sinuses. However, subsequent to the protracted use of corticosteroids and antibacterial agents, suppression of the immune system by chemotherapy, and poor ventilation, these fungi can become pathogens. Fungal colonization in the nose and paranasal sinuses is a prevalent medical issue in immunocompetent and immunosuppressed patients. In this study, we aimed to categorize fungal rhinosinusitis (FRS) among immunocompetent and immunosuppressed patients and identified the etiologic agents of disease by molecular methods.

Materials and Methods

A total of 74 cases were evaluated for FRS. Functional endoscopic sinus surgery was performed for sampling. The clinical samples were examined by direct microscopy with potassium hydroxide 20% and subcultured on Sabouraud Dextrose Agar with chloramphenicol. Polymerase chain reaction sequencing was applied to identify causative agents.

Results

Thirty-three patients (44.6%) had FRS. Principal predisposing factors were antibiotic consumption (n = 31, 93.9%), corticosteroid therapy (n = 22, 66.6%), and diabetes mellitus (n = 21, 63.6%). Eyesore (n = 22, 66.6%), proptosis (n = 16, 48.5%), and headache (n = 15, 45.4%) were the most common clinical manifestations among patients. Rhizopus oryzae (n = 15, 45.4%) and Aspergillus flavus (n = 10, 30.3%) were the most prevalent fungal species.

Conclusion

Diagnosis and classification of FRS are crucial, and a lack of early precise diagnosis can lead to a delay in any surgical or medical management. Since there are a variety of treatments for FRS, accurate identification of etiologic agents should be performed based on phenotypic and molecular methods.

Incidence, Speciation, and Morpho-Genetic Diversity of Penicillium spp. Causing Blue Mold of Stored Pome Fruits in Serbia

Blue mold, caused by Penicillium spp., is one of the most economically important postharvest diseases of pome fruits, globally. Pome fruits, in particular apple, is the most widely grown pome fruit in Serbia, and the distribution of Penicillium spp. responsible for postharvest decay is unknown. A two-year survey was conducted in 2014 and 2015, where four pome fruits (apple, pear, quince, and medlar) with blue mold symptoms were collected from 20 storage locations throughout Serbia. Detailed morphological characterization, analysis of virulence in three apple cultivars, and multilocus phylogeny revealed three main Penicillium spp. in order of abundance: P. expansum, P. crustosum, and P. solitum. Interestingly, P. expansum split into two distinct clades with strong statistical support that coincided with several morphological observations. Findings from this study are significant and showed previously undocumented diversity in blue mold fungi responsible for postharvest decay including the first finding of P. crustosum, and P. solitum as postharvest pathogens of quince and P. crustosum of medlar fruit in the world, and P. expansum of quince in Serbia. Data from this study provide timely information regarding phenotypic, morphological and genotypic plasticity in P. expansum that will impact the design of species-specific detection tools and guide the development of blue mold management strategies.

Production of Mycophenolic Acid by a Newly Isolated Indigenous Penicillium glabrum

Soil-occupant fungi produce a variety of mycotoxins as secondary metabolites, one of which is mycophenolic acid (MPA), an antibiotic and immunosuppressive agent. MPA is mainly produced by several species of Penicillium, especially Penicillium brevicompactum. Here, we present the first report of MPA production by a local strain belonging to Penicillium glabrum species. We screened ascomycete cultures isolated from moldy food and fruits, as well as soils, collected from different parts of Iran. MPA production of one hundred and forty Penicillium isolates was analyzed using HPLC. Three MPA producer isolates were identified, among which the most producer was subjected to further characterization, based on morphological and microscopic analysis, as well as molecular approach (ITS, rDNA and beta-tubulin gene sequences). The results revealed that the best MPA producer belongs to P. glabrum IBRC-M 30518, and can produce 1079 mg/L MPA in Czapek-Dox medium.

Mycobiota in Chilean chilli Capsicum annuum L. used for production of Merkén

This work aims to provide the first study on the mycobiota present in Chilean pepper Capsicum annuum L. cv. "Cacho de Cabra" throughout the early production stages. Two hundred and forty berry fruits were sampled: 1) at the ripe fruits harvest day; 2) during drying; and 3) smoking processes. A total of 192 strains, encompassing 11 genera and 44 species, were identified through analysis of β-tubulin (benA) gene and internal transcribed spacer of ribosomal DNA (ITS) region. All collection points showed samples with high fungal contamination, but the mycobiota composition varied as a result of different environmental conditions. Alternaria spp. and Fusarium spp. were predominantly isolated from fresh fruits of C. annuum. Penicillium spp. was the most frequent genus in all analysed points. Penicillium brevicompactum and P. crustosum were the most abundant species. Among Aspergillus, A. niger and A. flavus were dominant after the drying phase. In our study, none of the analysed strains of Penicillium (113) and Aspergillus (35) produced Ochratoxin A at detectable levels. The broad characterization of the fungal community of C. annuum carried out in this study, could be a guideline for future mycotoxin analyses performed directly on the pod. Understanding the role and dynamics of mycobiota and its relationship with the toxins present in this substrate, will be useful to establish and improve control measures considering the specificities of each point in the C. annuum production chain.

HPLC-MS/MS Method for the Detection of Selected Toxic Metabolites Produced by Penicillium spp. in Nuts

Penicillium spp. are emerging as producers of mycotoxins and other toxic metabolites in nuts. A HPLC-MS/MS method was developed to detect 19 metabolites produced by Penicillium spp. on chestnuts, hazelnuts, walnuts and almonds. Two extraction methods were developed, one for chestnuts and one for the other three nuts. The recovery, LOD, LOQ and matrix effect were determined for each analyte and matrix. Correlation coefficients were always >99.99%. In walnuts, a strong signal suppression was observed for most analytes and patulin could not be detected. Six strains: Penicillium bialowiezense, P. brevicompactum, P. crustosum, P. expansum, P. glabrum and P. solitum, isolated from chestnuts, were inoculated on four nuts. Chestnuts favored the production of the largest number of Penicillium toxic metabolites. The method was used for the analysis of 41 commercial samples: 71% showed to be contaminated by Penicillium-toxins. Cyclopenin and cyclopenol were the most frequently detected metabolites, with an incidence of 32% and 68%, respectively. Due to the risk of contamination of nuts with Penicillium-toxins, future studies and legislation should consider a larger number of mycotoxins.

Aspergillus, Penicillium and Cladosporium species associated with dried date fruits collected in the Perugia (Umbria, Central Italy) market

A total of 20 dried date samples, chosen as representative among those available on the Perugia (Umbria, Central Italy) market, were analyzed for the possible occurrence of fungal species and related contamination by fungal secondary metabolites. Twenty-six isolates, representative of the total mycobiota, were obtained and morphologically identified as belonging to the genera Aspergillus, Penicillium and Cladosporium. Inside each genus, molecular characterization (by partial sequencing of ITS region and/or β-tubulin and calmodulin regions for Aspergillus and Penicillium isolates or actin region for Cladosporium isolates) and in vitro mycotoxigenic profile characterization (by LC-MS/MS analysis) showed the presence of the following species: A. flavus, A. tubingensis, P. brevicompactum, P. chrysogenum, P. crustosum, P. glabrum, P. solitum, P. venetum, C. cladosporioides, C. limoniforme and C. halotolerans, with A. tubingensis as the prevalent species and P. crustosum, P. solitum, P. venetum and C. limoniforme first reported here on dates. Date packaging and format showed an effect on the incidence of isolated fungi, with the lowest incidence recovered from whole dates and in hermetic bag packaging. These findings can be useful both for dried dates producers and consumers, guiding them towards choices of packaging and format with a lower risk of mycotoxigenic species presence. However, no fungal metabolites were detected in the dried date samples analyzed, which were therefore regarded as safe for human consumption, underlining the absence of correspondence between fungal isolation and mycotoxin contaminations.

Several species of Penicillium isolated from chestnut flour processing are pathogenic on fresh chestnuts and produce mycotoxins

A collection of 124 isolates of Penicillium spp. was created by monitoring fresh chestnuts, dried chestnuts, chestnut granulates, chestnut flour and indoor chestnut mills. Sequencing of the ITS region, β-tubulin and calmodulin, macro-morphology and secondary metabolite production made it possible to determine 20 species of Penicillium. P. bialowiezense was dominant in the fresh chestnuts, while P. crustosum was more frequent in the other sources. A pathogenicity test on chestnut showed that around 70% of the isolates were virulent. P. corylophilum and P. yezoense were not pathogenic, while the other 18 species had at least one virulent isolate. P. expansum and P. crustosum were the most virulent. The isolates were characterized to establish their ability to produce 14 toxic metabolites in vivo: 59% were able to produce at least one mycotoxin. P. expansum was able to produce patulin, chaetoglobosin A and roquefortine, while P. bialowiezense produced C. Mycophenolic acid. Cyclopenins and viridicatins were produced by most of the P. crustosum, P. polonicum, P. solitum and P. discolour isolates. Some of the P. crustosum isolates were also able to produce roquefortine C or penitrem A. Information about the occurrence of Penicillium spp. and their mycotoxins will help producers to set up management procedures that can help to control the fungal growth and the mycotoxin production of chestnuts.

Genetic and Morphological Diversity of the Genus Penicillium From Mazandaran and Tehran Provinces, Iran

Background:

The genus Penicillium contains a large number of ubiquitous environmental taxa, of which some species are clinically important. Identification of Penicillium down to the species level is currently based on polyphasic criteria, including phenotypic features and genetic markers. Biodiversity of the genus Penicillium from Mazandaran and Tehran provinces has not been described.

Objectives:

The current paper focused on the environmental biodiversity of Penicillium isolates within some areas of Mazandaran and Tehran provinces, based on morphological traits and the molecular data from partial sequence of the β-tubulin (BT2) gene.

Materials and Methods:

A total of 400 strains were isolated from the environment and investigated using morphological tests and sequencing of BT2, in order to characterize the spectrum of the Penicillium species.

Results:

Sequence analysis of BT2 and morphological criteria of 20 strains representative of 10 species showed that Penicillium chrysogenum was the most prevalent species (n = 6), followed by P. polonicum (n = 3), P. glabrum (n = 2), P. palitans (n = 2), P. melanoconidium (n = 2), and other species, including P. expansum, P. canescense, P. griseofulvum, P. italicum, and P. raistrickii with one case each.

Conclusions:

It was shown that partial β-tubulin sequence, as a reliable genetic target, supported specific morphological criteria for identification of the Penicillium species. Like other assessments throughout the world, P. chrysogenum remains the most frequent environmental Penicillium species in Mazandaran and Tehran Provinces.

A combined approach to assess the microbial contamination of the archimedes palimpsest

A combined approach, using molecular and microscopic techniques, was used to identify the microbiota associated with the Archimedes Palimpsest, an unusual parchment manuscript. SEM analyses revealed the microbial damage to the collagen fibers and the presence of characteristic cell chains typical of filamentous bacteria and fungal spores. Molecular analysis confirmed a homogeneous bacterial community colonizing the manuscript. The phyla Proteobacteria and Actinobacteria were associated with this ancient parchment; the sequences were most related to uncultured clones detected in the human skin microbiome and in ephitelium, and to cultivated species of the genera Acinetobacter and Nocardiopsis. Nevertheless, a great variation was observed among the different sampled areas indicating fungal diversity. Blumeria spp. dominated in the healthy areas of the parchment while degraded areas showed disparate fungal communities, with dominant members of the genera Mucor and Cladosporium. In addition, the quantification of the β-actin gene by real-time PCR analyses (qPCR) revealed a higher fungal abundance on degraded areas than on the healthy ones.

Identification and nomenclature of the genus Penicillium

Penicillium is a diverse genus occurring worldwide and its species play important roles as decomposers of organic materials and cause destructive rots in the food industry where they produce a wide range of mycotoxins. Other species are considered enzyme factories or are common indoor air allergens. Although DNA sequences are essential for robust identification of Penicillium species, there is currently no comprehensive, verified reference database for the genus. To coincide with the move to one fungus one name in the International Code of Nomenclature for algae, fungi and plants, the generic concept of Penicillium was re-defined to accommodate species from other genera, such as Chromocleista, Eladia, Eupenicillium, Torulomyces and Thysanophora, which together comprise a large monophyletic clade. As a result of this, and the many new species described in recent years, it was necessary to update the list of accepted species in Penicillium. The genus currently contains 354 accepted species, including new combinations for Aspergillus crystallinus, A. malodoratus and A. paradoxus, which belong to Penicillium section Paradoxa. To add to the taxonomic value of the list, we also provide information on each accepted species MycoBank number, living ex-type strains and provide GenBank accession numbers to ITS, β-tubulin, calmodulin and RPB2 sequences, thereby supplying a verified set of sequences for each species of the genus. In addition to the nomenclatural list, we recommend a standard working method for species descriptions and identifications to be adopted by laboratories working on this genus.

A taxonomic and phylogenetic revision of Penicillium section Aspergilloides

Species belonging to Penicillium section Aspergilloides have a world-wide distribution with P. glabrum, P. spinulosum and P. thomii the most well-known species of this section. These species occur commonly and can be isolated from many substrates including soil, food, bark and indoor environments. The taxonomy of these species has been investigated several times using various techniques, but species delimitation remains difficult. In the present study, 349 strains belonging to section Aspergilloides were subjected to multilocus molecular phylogenetic analyses using partial β-tubulin (BenA), calmodulin (CaM) and RNA polymerase II second largest subunit (RPB2) sequences. Section Aspergilloides is subdivided into 12 clades and 51 species. Twenty-five species are described here as new and P. yezoense, a species originally described without a Latin diagnosis, is validated. Species belonging to section Aspergilloides are phenotypically similar and most have monoverticillate conidiophores and grow moderately or quickly on agar media. The most important characters to distinguish these species were colony sizes on agar media, growth at 30 °C, ornamentation and shape of conidia, sclerotium production and stipe roughness.

Penicillium fusisporum and P. zhuangii, two new monoverticillate species with apical-swelling stipes of section Aspergilloides isolated from plant leaves in China

Two new Penicillium species isolated from plant leaves are reported here, namely, P. fusisporum (type strain AS3.15338^T = NRRL 62805^T = CBS 137463^T) and P. zhuangii (type strain AS3.15341^T = NRRL 62806^T = CBS 137464^T). P. fusisporum is characterized by fast growth rate, apical-swelling monoverticillate penicilli, verrucose stipes, fusiform to oblong conidia about 3.5–4×2–2.5 µm and cinnamon-colored sclerotia. While P. zhuangii presents a moderate growth rate, it also bears apical-swelling monoverticillate penicilli but its stipes are smooth-walled, and produces ovoid to globose smooth-walled conidia about 3–3.5 µm. Both species belong to section Aspergilloides, and P. fusisporum is related to “P. thomii var. flavescens”, while P. zhuangii is morphologically similar to P. lividum. Phylogenetic analyses of sequences of calmodulin and beta-tubulin genes both show that the two new taxa form distinct monophyletic clades.

Diversity of Penicillium section Citrina within the fynbos biome of South Africa, including a new species from a Protea repens infructescence

During a survey of the fynbos biome in the Western Cape of South Africa, 61 Penicillium species were isolated and nine belong to Penicillium section Citrina. Based on morphology and multigene phylogenies, section Citrina species were identified as P. cairnsense, P. citrinum, P. pancosmium, P. pasqualense, P. sanguifluum, P. sizovae, P. sumatrense and P. ubiquetum. One of the species displayed unique phenotypic characters and DNA sequences and is described here as P. sucrivorum. Multigene phylogenies consistently resolved the new species in a clade with P. aurantiacobrunneum, P. cairnsense, P. miczynksii, P. neomiczynskii and P. quebecense. However, ITS, β-tubulin and calmodulin gene sequences are unique for P. sucrivorum and growth rates on various media, the ability to grow at 30 C, a positive Ehrlich reaction and the absence of sclerotia on all media examined, distinguish P. sucrivorum from all of its close relatives.

Phylogeny of Penicillium and the segregation of Trichocomaceae into three families

Species of Trichocomaceae occur commonly and are important to both industry and medicine. They are associated with food spoilage and mycotoxin production and can occur in the indoor environment, causing health hazards by the formation of β-glucans, mycotoxins and surface proteins. Some species are opportunistic pathogens, while others are exploited in biotechnology for the production of enzymes, antibiotics and other products. Penicillium belongs phylogenetically to Trichocomaceae and more than 250 species are currently accepted in this genus. In this study, we investigated the relationship of Penicillium to other genera of Trichocomaceae and studied in detail the phylogeny of the genus itself. In order to study these relationships, partial RPB1, RPB2 (RNA polymerase II genes), Tsr1 (putative ribosome biogenesis protein) and Cct8 (putative chaperonin complex component TCP-1) gene sequences were obtained. The Trichocomaceae are divided in three separate families: Aspergillaceae, Thermoascaceae and Trichocomaceae. The Aspergillaceae are characterised by the formation flask-shaped or cylindrical phialides, asci produced inside cleistothecia or surrounded by Hülle cells and mainly ascospores with a furrow or slit, while the Trichocomaceae are defined by the formation of lanceolate phialides, asci borne within a tuft or layer of loose hyphae and ascospores lacking a slit. Thermoascus and Paecilomyces, both members of Thermoascaceae, also form ascospores lacking a furrow or slit, but are differentiated from Trichocomaceae by the production of asci from croziers and their thermotolerant or thermophilic nature. Phylogenetic analysis shows that Penicillium is polyphyletic. The genus is re-defined and a monophyletic genus for both anamorphs and teleomorphs is created (Penicillium sensu stricto). The genera Thysanophora, Eupenicillium, Chromocleista, Hemicarpenteles and Torulomyces belong in Penicilliums. str. and new combinations for the species belonging to these genera are proposed. Analysis of Penicillium below genus rank revealed the presence of 25 clades. A new classification system including both anamorph and teleomorph species is proposed and these 25 clades are treated here as sections. An overview of species belonging to each section is presented.

Unveiling the fungal mycobiota present throughout the cork stopper manufacturing process

A particular fungal population is present in the main stages of the manufacturing process of cork discs. Its diversity was studied using both dependent (isolation) and independent culture methods (denaturing gel gradient electrophoresis and cloning of the ITS1-5.8S-ITS2 region). The mycobiota in the samples taken in the stages before and after the first boiling seems to be distinct from the population in the subsequent manufacturing stages. Most isolated fungi belong to the genera Penicillium, Eurotium and Cladosporium. The presence of uncultivable fungi, Ascomycota and endophytes in raw cork was confirmed by sequencing. The samples taken after the first boiling contained uncultivable fungi, but in a few samples some isolated fungi were also detected. The main taxa present in the following stages were Chrysonilia sitophila, Penicillium glabrum and Penicillium spp. All applied techniques had complementary outcomes. The main factors driving the shift in cork fungal colonization seem to be the high levels of humidity and temperature to which the slabs are subjected during the boiling process.