Talaromyces Species Research Articles

Alligamycin A, an antifungal β-lactone spiroketal macrolide from Streptomyces iranensis

Fungal infections pose a great threat to public health and there are only four main types of antifungal drugs, which are often limited with toxicity, drug-drug interactions and antibiotic resistance. Streptomyces is an important source of antibiotics, represented by the clinical drug amphotericin B. Here we report the discovery of alligamycin A (1) as an antifungal compound from the rapamycin-producer Streptomyces iranensis through genome-mining, genetics and natural product chemistry approaches. Alligamycin A harbors a unique chemical scaffold with 13 chiral centers, featuring a β-lactone moiety, a [6,6]-spiroketal ring, and an unreported 7-oxo-octylmalonyl-CoA extender unit incorporated by a potential crotonyl-CoA carboxylase/reductase. It is biosynthesized by a type I polyketide synthase which is confirmed through CRISPR-based gene editing. Alligamycin A displayed potent antifungal effects against numerous clinically relevant filamentous fungi, including resistant Aspergillus and Talaromyces species. β-Lactone ring is essential for the antifungal activity since alligamycin B (2) with disruption in the ring abolished the antifungal effect. Proteomics analysis revealed alligamycin A potentially disrupts the integrity of fungal cell walls and induces the expression of stress-response proteins in Aspergillus niger. Discovery of the potent antifungal candidate alligamycin A expands the limited antifungal chemical space.

Xerophilic Aspergillaceae Dominate the Communities of Culturable Fungi in the Mound Nests of the Western Thatching Ant (Formica obscuripes)

The nests of mound-building ants are unexplored reservoirs of fungal diversity. A previous assessment of this diversity in the nests of Formica ulkei suggested that water availability may be a determinant of the composition of this mycota. To investigate this question, we recovered 3594 isolates of filamentous Ascomycota from the nests of Formica obscuripes and adjacent, non-nest sites, employing Dichloran Rose Bengal agar (DRBA), Dichloran Rose Bengal agar containing glycerol (DRBAG), and malt extract agar containing sucrose (MEA20S). Higher numbers of fungi were isolated from the tops of mounds than from within mounds and non-mound sites. Mound nest soils were dominated by members of the family Aspergillaceae, and up to 50% of the colonies isolated on DRBAG belonged to the genus Aspergillus. Pseudogymnoascus pannorum and species of Talaromyces were also present in higher numbers in mound soils. Species of Penicillium were more abundant in non-nest soils, where they accounted for over 66% of isolates on DRBA. All Aspergillaceae assessed for xerotolerance on a medium augmented with glycerol or sucrose were xerophilic. These results, and our observation that the nests of F. obscuripes are low-water environments, indicate that water availability influences the structure of the fungal communities in these animal-modified habitats.

Three new species of Talaromyces sect. Talaromyces discovered in China.

Talaromyces species play an important role in the nutrient cycle in natural ecosystems, degradation of vegetal biomass in industries and the implications in medicine. However, the species diversity of this genus is still far from fully understood. The polyphasic taxonomic approach integrating morphological comparisons and molecular phylogenetic analyses based on BenA, CaM, Rpb2 and ITS sequences was used to propose three new Talaromyces species. Three new species of sect. Talaromyces isolated from soil are proposed, namely, T. disparis (ex-type AS3.26221), T. funiformis (ex-type AS3.26220) and T. jianfengicus (ex-type AS3.26253). T. disparis is unique in low growth rate, velvety texture, limited to moderate sporulation, biverticillate, monoverticillate and irregular penicilli bearing a portion of abnormally large globose conidia, it has no close relatives in phylogeny. Being a member of T. pinophilus complex, T. funiformis produces mycelial funicles on Czapek yeast autolysate agar (CYA), 5% malt extract agar (MEA) and yeast extract (YES), sparse sporulation on Czapek agar (Cz), CYA, MEA and YES while abundant on oatmeal agar (OA), bearing appressed biverticillate penicilli and globose to pyriform conida with smooth to finely rough walls. T. jianfengicus belongs to T. verruculosus complex, is characterized by velvety colony texture with moderate to abundant elm-green conidia en masse, producing biverticillate penicilli, globose conidia with verrucose walls. It is now a common practice in establishing new species of Aspergillus, Penicillium and Talaromyces based on morphological characters and phylogenetic analyses of BenA, CaM, Rpb2 and ITS sequences. The proposal of the three novelties of Talaromyces in this article is not only supported by their morphological distinctiveness, but also confirmed by the phylogenetic analyses of the concatenated BenA-CaM-Rpb2 and BenA-CaM-ITS, as well as the individual BenA, CaM, Rpb2 and ITS sequence matrices.

Penicillides from Penicillium and Talaromyces: Chemical Structures, Occurrence and Bioactivities.

Penicillide is the founder product of a class of natural products of fungal origin. Although this compound and its analogues have been identified from taxonomically heterogeneous fungi, they are most frequently and typically reported from the species of Talaromyces and Penicillium. The producing strains have been isolated in various ecological contexts, with a notable proportion of endophytes. The occurrence of penicillides in these plant associates may be indicative of a possible role in defensive mutualism based on their bioactive properties, which are also reviewed in this paper. The interesting finding of penicillides in fruits and seeds of Phyllanthus emblica is introductory to a new ground of investigation in view of assessing whether they are produced by the plant directly or as a result of the biosynthetic capacities of some endophytic associates.

Formic acid sandwich method is well-suited for filamentous fungi identification and improves turn around time using Zybio EXS2600 mass spectrometry

ObjectivesMatrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is extensively employed for the identification of filamentous fungi on MALDI Biotyper (Bruker Daltonics) and Vitek MS (biomerieux), but the performance of fungi identification on new EXS2600 (Zybio) is still unknow. Our study aims to evaluate the new EXS2600 system's (Zybio) ability to rapidly identify filamentous fungi and determine its effect on turnaround time (TAT) in our laboratory.MethodsWe tested 117 filamentous fungi using two pretreatment methods: the formic acid sandwich (FA-sandwich) and a commercial mold extraction kit (MEK, Zybio). All isolates were confirmed via sequence analysis. Laboratory data were extracted from our laboratory information system over two 9-month periods: pre-EXS (April to December 2022) and post-EXS (April to December 2023), respectively.ResultsThe total correct identification (at the species, genus, or complex/group level) rate of fungi was high, FA-sandwich (95.73%, 112/117), followed by MEK (94.02%, 110/117). Excluding 6 isolates not in the database, species-level identification accuracy was 92.79% (103/111) for FA-sandwich and 91.89% (102/111) for MEK; genus-level accuracy was 97.29% (108/111) and 96.39% (107/111), respectively. Both methods attained a 100% correct identification rate for Aspergillus, Lichtheimia, Rhizopus Mucor and Talaromyces species, and were able to differentiate between Fusarium verticillioides and Fusarium proliferatum within the Fusarium fujikuroi species complex. Notably, high confidence was observed in the species-level identification of uncommon fungi such as Trichothecium roseum and Geotrichum candidum. The TAT for all positive cultures decreased from pre EXS2600 to post (108.379 VS 102.438, P < 0.05), and the TAT for tissue decreased most (451.538 VS 222.304, P < 0.001).ConclusionsThe FA-sandwich method is more efficient and accurate for identifying filamentous fungi with EXS2600 than the MEK. Our study firstly evaluated the performance of fungi identification on EXS2600 and showed it is suitable for clinical microbiology laboratories use.

A review of recently introduced Aspergillus, Penicillium, Talaromyces and other Eurotiales species.

The order Eurotiales is diverse and includes species that impact our daily lives in many ways. In the past, its taxonomy was difficult due to morphological similarities, which made accurate identification of species difficult. This situation improved and stabilised with recent taxonomic and nomenclatural revisions that modernised Aspergillus, Penicillium and Talaromyces. This was mainly due to the availability of curated accepted species lists and the publication of comprehensive DNA sequence reference datasets. This has also led to a sharp increase in the number of new species described each year with the accepted species lists in turn also needing regular updates. The focus of this study was to review the 160 species described between the last list of accepted species published in 2020 until 31 December 2022. To review these species, single-gene phylogenies were constructed and GCPSR (Genealogical Concordance Phylogenetic Species Recognition) was applied. Multi-gene phylogenetic analyses were performed to further determine the relationships of the newly introduced species. As a result, we accepted 133 species (37 Aspergillus, two Paecilomyces, 59 Penicillium, two Rasamsonia, 32 Talaromyces and one Xerochrysium), synonymised 22, classified four as doubtful and created a new combination for Paraxerochrysium coryli, which is classified in Xerochrysium. This brings the number of accepted species to 453 for Aspergillus, 12 for Paecilomyces, 535 for Penicillium, 14 for Rasamsonia, 203 for Talaromyces and four for Xerochrysium. We accept the newly introduced section Tenues (in Talaromyces), and series Hainanici (in Aspergillus sect. Cavernicolarum) and Vascosobrinhoana (in Penicillium sect. Citrina). In addition, we validate the invalidly described species Aspergillus annui and A. saccharicola, and series Annuorum (in Aspergillus sect. Flavi), introduce a new combination for Dichlaena lentisci (type of the genus) and place it in a new section in Aspergillus subgenus Circumdati, provide an updated description for Rasamsonia oblata, and list excluded and recently synonymised species that were previously accepted. This study represents an important update of the accepted species lists in Eurotiales. Taxonomic novelties: New sections: Aspergillus section Dichlaena Visagie, Kocsubé & Houbraken. New series: Aspergillus series Annuorum J.J. Silva, B.T. Iamanaka, Frisvad. New species: Aspergillus annui J.J. Silva, M.H.P. Fungaro, Frisvad, M.H. Taniwaki & B.T. Iamanaka; Aspergillus saccharicola J.J. Silva, Frisvad, M.H.P. Fungaro, M.H. Taniwaki & B.T. Iamanaka. New combinations: Aspergillus lentisci (Durieu & Mont.) Visagie, Malloch, L. Kriegsteiner, Samson & Houbraken; Xerochrysium coryli (Crous & Decock) Visagie & Houbraken. Citation: Visagie CM, Yilmaz N, Kocsubé S, Frisvad JC, Hubka V, Samson RA, Houbraken J (2024). A review of recently introduced Aspergillus, Penicillium, Talaromyces and other Eurotiales species. Studies in Mycology 107: 1-66. doi: 10.3114/sim.2024.107.01.

Characterization and Effect of a Nematophagous Fungus Talaromyces cystophila sp. nov. for the Biological Control of Corn Cyst Nematode.

The dynamic of plant-parasitic nematode populations in soil is closely related to soil microorganisms. Fungi from Heterodera zeae cysts were isolated to explore the phenomenon of decline in the H. zeae population in the soil. Phylogenetic study of partial ITS, BenA, CaM, and RPB2 gene sequences, in addition to morphological investigations, was utilized to identify a nematode-destroyingfungus. The nematicidal activity of a novel strain GX1 against H. zeae was assessed in vitro and in the greenhouse. Our findings revealed that strain GX1 is a new species of Talaromyces, named Talaromyces cystophila. It has a strong parasitic and lethal effect on H. zeae cysts, with 91.11% parasitism on cysts at 3 days after treatment. The contents of second-stage juveniles (J2s) and eggs inside the cysts were degraded and formed dense vacuoles, and the damaged eggs could not hatch normally. The spore suspension exhibited high nematophagous activity against nematodes, and fermentation filtrate exhibited marked inhibition of egg hatching and nematicidal activities on J2s. The hatching inhibition rates of eggs exposed to 1 × 108 CFU/ml spore suspensions or 20% 1-week fermentation filtrate (1-WF) for 15 days were 98.56 and 100%, respectively. The mortality of J2s exposed to 1 × 108 CFU/ml spore suspension reached 100% at 24 h; exposure to 50% 2-WF was 98.65 and 100% at 24 and 48 h, respectively. Greenhouse experiments revealed that the spore suspension and fermentation broth considerably decreased H. zeae reproduction by 56.17 to 78.76%. T. cystophila is a potential biocontrol strain with nematophagous and nematicidal activity that deserves attention and application.

Talaromyces sedimenticola sp. nov., isolated from the Mariana Trench.

Two fungal strains (K-2T and S1) were isolated from the deepest ocean sediment of the Challenger Deep located in the Mariana Trench. The internal transcribed spacer (ITS) gene sequences of the isolates K-2T and S1 differed from those of closely related species, such as Talaromyces assiutensis and T. trachyspermus. Phylogenetic analyses based on single and concatenated alignments of the genes, namely ITS, β-tubulin (benA), calmodulin (cam), and the second-largest subunit fragment of the RNA polymerase II (rpb2) showed that the isolates K-2T and S1 were clustered together with other Talaromyces species, such as T. trachyspermus and T. assiutensis, as evidenced by the position on a terminal branch with high bootstrap support. They could also be distinguished from their closest relatives with valid published names via morphological and physiological characteristics, for example, growth at 4°C-50°C with a pH in the range of 1.5-12. Based on their phylogenetic, morphological, and physicochemical properties, the isolates K-2T and S1 represent a novel species in the genus Talaromyces, and the proposed name is Talaromyces sedimenticola sp. nov. The type strain is K-2T (= GDMCC 3.746T = JCM 39451T).

Talaromyces mellisjaponici sp. nov., a xerophilic species isolated from honey in Japan.

Five isolates of a xerophilic Talaromyces species were obtained from honey in Japan. Molecular phylogenetic analysis based on a combined dataset for four regions (rRNA internal transcribed spacer, β-tubulin, calmodulin and RNA polymerase II second largest subunit) revealed that the strains formed an independent clade in section Trachyspermi, which is sister to Talaromyces affinitatimellis, Talaromyces basipetosporus and Talaromyces speluncarum. The strains and their relatives have different growth on creatine agar, yeast extract sucrose agar and dichloran 18 % glycerol agar, different branching patterns (mostly monoverticillate or biverticillate, less frequently divaricate or terverticillate), and different sizes and surface structures of conidia. Xerotolerance tests were also conducted using media adjusted to five different sucrose concentrations (0, 20, 40, 60 and 80 %). The colony diameters of the strains were larger than those of T. affinitatimellis, T. basipetosporus and T. speluncarum at each sucrose concentration. Altogether, the obtained morphological, molecular and physiological data allowed the proposal of Talaromyces mellisjaponici sp. nov. for this novel species, with NBRC 116048T as the type strain.

Aspergillus, Penicillium, and Talaromyces (Eurotiales) in Brazilian caves, with the description of four new species

The study of the Brazilian cave mycobiota has revealed a rich but highly diverse assemblage of fungi, with Aspergillus, Penicillium, and Talaromyces being the most frequently reported genera. The present study investigated the airborne fungi and fungi obtained from the bodies of bats, guano, and the soil/sediment from the caves Urubu (in the Atlantic Forest) and Furna Feia (in the Caatinga dryland forest) in the Northeast region of Brazil. Fungal strains were identified based on morphological features and multilocus phylogenetic analyses of ITS, beta-tubulin (BenA), calmodulin (CaM), and RNA polymerase II second largest subunit (RPB2) sequences. A total of 86 isolates were obtained, representing Aspergillus (34), Penicillium (20), Talaromyces (2), and 30 isolates belonging to other genera that will be reported on elsewhere. These isolates were identified as 18 Aspergillus, nine Penicillium, and one Talaromyces species. Eight of the species identified are reported for the first time from a cave environment. Four species showed unique morphological features and phylogenetic relationships, and are newly described. These include two new species of Aspergillus (A. alvaroi sp. nov. and A. guanovespertilionum sp. nov.), one of Penicillium (P. cecavii sp. nov.), and one ofTalaromyces (T. potiguarorum sp. nov.). Our study increases the awareness and known richness of the Brazilian and global fungal diversity found in caves.

Screening and Characterization of Polycyclic Aromatic Hydrocarbons Tolerant Fungi from Petrochemical Refinery Effluent

Fungi were isolated from effluent released by petrochemical refinery and screened for their tolerance to 50 mg/L concentration of naphthalene, phenanthrene and pyrene under agitation condition of 150 rpm and ambient temperature over a period of 21 days. Samples were analysed for residual PAH concentrations using HPLC and tolerance ability were calculated in percentages. Fungal growth in mineral salt medium supplemented with PAH was measured in dry weight of mycelial biomass was used as index for assessing their tolerance ability. Out of the 22 fungi isolated, only four were identified as Aspergillus, Talaromyces, Fusarium and Trichoderma species to exhibit tolerance to naphthalene (94.6, 96.9, 99.7 and 99.8%), phenanthrene (91.1, 92.2, 99.5 and 99.8%) and pyrene (89.4, 90.5, 92,6 and 94.2%) respectively. Low molecular weight PAHs (naphthalene and phenanthrene) were better tolerated compared to high molecular weight pyrene. Based on findings made in this study, the four isolates with higher tolerance to PAHs could be recommended for bioremediation of PAH contaminated environments.

The Outstanding Chemodiversity of Marine-Derived Talaromyces.

Fungi in the genus Talaromyces occur in every environment in both terrestrial and marine contexts, where they have been quite frequently found in association with plants and animals. The relationships of symbiotic fungi with their hosts are often mediated by bioactive secondary metabolites, and Talaromyces species represent a prolific source of these compounds. This review highlights the biosynthetic potential of marine-derived Talaromyces strains, using accounts from the literature published since 2016. Over 500 secondary metabolites were extracted from axenic cultures of these isolates and about 45% of them were identified as new products, representing a various assortment of chemical classes such as alkaloids, meroterpenoids, isocoumarins, anthraquinones, xanthones, phenalenones, benzofurans, azaphilones, and other polyketides. This impressive chemodiversity and the broad range of biological properties that have been disclosed in preliminary assays qualify these fungi as a valuable source of products to be exploited for manifold biotechnological applications.

Polyketides with potential bioactivities from the mangrove-derived fungus Talaromyces sp. WHUF0362

Metabolites of microorganisms have long been considered as potential sources for drug discovery. In this study, five new depsidone derivatives, talaronins A-E (1–5) and three new xanthone derivatives, talaronins F–H (6–8), together with 16 known compounds (9–24), were isolated from the ethyl acetate extract of the mangrove-derived fungus Talaromyces species WHUF0362. The structures were elucidated by analysis of spectroscopic data and chemical methods including alkaline hydrolysis and Mosher’s method. Compounds 1 and 2 each attached a dimethyl acetal group at the aromatic ring. A putative biogenetic relationship of the isolated metabolites was presented and suggested that the depsidones and the xanthones probably had the same biosynthetic precursors such as chrysophanol or rheochrysidin. The antimicrobial activity assay indicated that compounds 5, 9, 10, and 14 showed potent activity against Helicobacter pylori with minimum inhibitory concentration (MIC) values in the range of 2.42–36.04 μmol/L. While secalonic acid D (19) demonstrated significant antimicrobial activity against four strains of H. pylori with MIC values in the range of 0.20 to 1.57 μmol/L. Furthermore, secalonic acid D (19) exhibited cytotoxicity against cancer cell lines Bel-7402 and HCT-116 with IC50 values of 0.15 and 0.19 μmol/L, respectively. The structure–activity relationship of depsidone derivatives revealed that the presence of the lactone ring and the hydroxyl at C-10 was crucial to the antimicrobial activity against H. pylori. The depsidone derivatives are promising leads to inhibit H. pylori and provide an avenue for further development of novel antibiotics.

A Talaromyces Fungal Species with Strong Antimicrobial Activity from Deception Island, Antarctica

Deception Island is well-known for harboring highly diverse microbial communities due to its unique volcanic environment in Antarctica. Most studies focused on bacteria, and relatively little was known about the fungal species on this island. The present study was aimed to determine the antimicrobial production and nutrient utilization profiles of a soil fungus from Deception Island, designated as Im33. Our findings showed that the strain had maximum mycelial growth and sporulation on malt-extract agar (MEA) medium, but it demonstrated the strongest antimicrobial activity in yeast extract-malt extract broth (YMB) medium. Phylogenetic analysis of the internal transcribed spacer 1 and 2 regions showed that it is a species belonging to the genus Talaromyces. It was resistant to cycloheximide concentrations up to 1,000 mg/L and exhibited broad-spectrum antimicrobial activity against Gram-positive and Gram-negative test pathogens, as well as being able to utilize a variety of carbon sources. This is the first report of a Talaromyces species from Deception Island. The capability of the strain to produce broad-spectrum antimicrobial compounds and various enzymes indicated that Antarctic fungi, like their bacterial counterparts, have adopted various adaptation strategies to compete and survive in the extreme environment.

Occurrence and identification of Penicillium and Talaromyces species from beach sand

Occurrence and identification of Penicillium and Talaromyces species from beach sand

Talaromyces santanderensis: A New Cadmium-Tolerant Fungus from Cacao Soils in Colombia.

Inorganic pollutants in Colombian cocoa (Theobroma cacao L.) agrosystems cause problems in the production, quality, and exportation of this raw material worldwide. There has been an increased interest in bioprospecting studies of different fungal species focused on the biosorption of heavy metals. Furthermore, fungi constitute a valuable, profitable, ecological, and efficient natural soil resource that could be considered in the integrated management of cadmium mitigation. This study reports a new species of Talaromyces isolated from a cocoa soil sample collected in San Vicente de Chucurí, Colombia. T. santanderensis is featured by Lemon Yellow (R. Pl. IV) mycelium on CYA, mono-to-biverticillade conidiophores, and acerose phialides. T. santanderensis is distinguished from related species by its growth rate on CYAS and powdery textures on MEA, YES and OA, high acid production on CREA and smaller conidia. It is differentiated from T. lentulus by its growth rate on CYA medium at 37 °C without exudate production, its cream (R. PI. XVI) margin on MEA, and dense sporulation on YES and CYA. Phylogenetic analysis was performed using a polyphasic approach, including different phylogenetic analyses of combined and individual ITS, CaM, BenA, and RPB2 gene sequences that indicate that it is new to science and is named Talaromyces santanderensis sp. nov. This new species belongs to the Talaromyces section and is closely related to T. lentulus, T. soli, T. tumuli, and T. pratensis (inside the T. pinophilus species complex) in the inferred phylogeny. Mycelia growth of the fungal strains was subjected to a range of 0–400 mg/kg Cd and incorporated into malt extract agar (MEA) in triplicates. Fungal radial growth was recorded every three days over a 13-day incubation period and In vitro cadmium tolerance tests showed a high tolerance index (0.81) when the mycelium was exposed to 300 mg/kg of Cd. Results suggest that T. santanderensis showed tolerance to Cd concentrations that exceed the permissible limits for contaminated soils, and it is promising for its use in bioremediation strategies to eliminate Cd from highly contaminated agricultural soils.

Research advances in the structures and biological activities of secondary metabolites from Talaromyces.

The genus Talaromyces belongs to the phylum Ascomycota of the kingdom Fungi. Studies have shown that Talaromyces species yield many kinds of secondary metabolites, including esters, terpenes, steroids, alkaloids, polyketides, and anthraquinones, some of which have biological activities such as anti-inflammatory, bacteriostatic, and antitumor activities. The chemical constituents of fungi belonging to the genus Talaromyces that have been studied by researchers over the past several years, as well as their biological activities, are reviewed here to provide a reference for the development of high-value natural products and innovative uses of these resources.

Two Novel Species of Talaromyces Discovered in a Karst Cave in the Satun UNESCO Global Geopark of Southern Thailand.

Karst caves are oligotrophic environments that appear to support a high diversity of fungi. Studies of fungi in Thailand’s caves are limited. During a 2019 exploration of the mycobiota associated with soil samples from a karst cave, namely, Phu Pha Phet in the Satun UNESCO Global Geopark in Satun Province, southern Thailand, two previously undescribed fungi belonging to Talaromyces (Trichocomaceae, Eurotiales, Eurotiomycetes) were studied using a polyphasic approach combining phenotypic and molecular data. Based on datasets of four loci (ITS, BenA, CaM, and RPB2), phylogenetic trees of the section Trachyspermi were constructed, and two new species—Talaromyces phuphaphetensis sp. nov. and T. satunensis sp. nov.—phylogenetically related to T. subericola, T. resinae, and T. brasiliensis, are described. Detailed descriptions and illustrations of the new species are provided. This study increases the number of cave-dwelling soil fungi discovered in Thailand’s Satun UNESCO Global Geopark, which appears to be a unique environment with a high potential for discovering fungal species previously undescribed.

New Species of Talaromyces (Trichocomaceae, Eurotiales) from Southwestern China

Species of Talaromyces are cosmopolitan and ubiquitous, and some are of industrial and medicinal importance. Species of Talaromyces have been successively reported in China. During our examinations of samples collected from southwestern China, two new species belonging to Talaromyces sect. Talaromyces were further discovered based on phylogenetic analyses and morphological comparisons. Talaromyces ginkgonis sp. nov., isolated from a partially colonized fruit of Ginkgo biloba, differs from closely-related fungi in the combination of conidia ellipsoidal, smooth and 3.5−4 × 2−3 μm, no growth on CYA at 37 °C and sequence divergences; T. shilinensis sp. nov. is distinguished from its related allies in the combination of smooth conidia, colonies 10−11 mm diameter on CYA at 25 °C and sequence differences. Detailed descriptions and illustrations of the new taxa are given.

Key thermally dimorphic fungal pathogens: shaping host immunity.

Exposure to fungal pathogens from the environment is inevitable and with the number of at-risk populations increasing, the prevalence of invasive fungal infection is on the rise. An interesting group of fungal organisms known as thermally dimorphic fungi predominantly infects immunocompromised individuals. These potential pathogens are intriguing in that they survive in the environment in one form, mycelial phase, but when entering the host, they are triggered by the change in temperature to switch to a new pathogenic form. Considering the growing prevalence of infection and the need for improved diagnostic and treatment approaches, studies identifying key components of fungal recognition and the innate immune response to these pathogens will significantly contribute to our understanding of disease progression. This review focuses on key endemic dimorphic fungal pathogens that significantly contribute to disease, including Histoplasma, Coccidioides and Talaromyces species. We briefly describe their prevalence, route of infection and clinical presentation. Importantly, we have reviewed the major fungal cell wall components of these dimorphic fungi, the host pattern recognition receptors responsible for recognition and important innate immune responses supporting adaptive immunity and fungal clearance or the failure thereof.