DNA barcoding in Mucorales: an inventory of biodiversity

Alternative ergosterol biosynthetic pathways confer antifungal drug resistance in the human pathogens within the Mucor species complex

Mucormycoses are emerging fungal infections caused by a variety of heterogeneous species within the Mucorales order. Among the Mucor species complex, Mucor circinelloides is the most frequently isolated pathogen in mucormycosis patients and despite its clinical significance, there is an absence of established genome manipulation techniques to conduct molecular pathogenesis studies. In this study, we generated a spontaneous uracil auxotrophic strain and developed a genetic transformation procedure to analyze molecular mechanisms conferring antifungal drug resistance. With this new model, phenotypic analyses of gene deletion mutants were conducted to define Erg3 and Erg6a as key biosynthetic enzymes in the M. circinelloides ergosterol pathway. Erg3 is a C-5 sterol desaturase involved in growth, sporulation, virulence, and azole susceptibility. In other fungal pathogens, erg3 mutations confer azole resistance because Erg3 catalyzes the production of a toxic diol upon azole exposure. Surprisingly, M. circinelloides produces only trace amounts of this toxic diol and yet, it is still susceptible to posaconazole and isavuconazole due to alterations in membrane sterol composition. These alterations are severely aggravated by erg3Δ mutations, resulting in ergosterol depletion and, consequently, hypersusceptibility to azoles. We also identified Erg6a as the main C-24 sterol methyltransferase, whose activity may be partially rescued by the paralogs Erg6b and Erg6c. Loss of Erg6a function diverts ergosterol synthesis to the production of cholesta-type sterols, resulting in resistance to amphotericin B. Our findings suggest that mutations or epimutations causing loss of Erg6 function may arise during human infections, resulting in antifungal drug resistance to first-line treatments against mucormycosis.

IMPORTANCE

The Mucor species complex comprises a variety of opportunistic pathogens known to cause mucormycosis, a potentially lethal fungal infection with limited therapeutic options. The only effective first-line treatments against mucormycosis consist of liposomal formulations of amphotericin B and the triazoles posaconazole and isavuconazole, all of which target components within the ergosterol biosynthetic pathway. This study uncovered M. circinelloides Erg3 and Erg6a as key enzymes to produce ergosterol, a vital constituent of fungal membranes. Absence of any of those enzymes leads to decreased ergosterol and consequently, resistance to ergosterol-binding polyenes such as amphotericin B. Particularly, losing Erg6a function poses a higher threat as the ergosterol pathway is channeled into alternative sterols similar to cholesterol, which maintain membrane permeability. As a result, erg6a mutants survive within the host and disseminate the infection, indicating that Erg6a deficiency may arise during human infections and confer resistance to the most effective treatment against mucormycoses.

Mucor germinans, a novel dimorphic species resembling Paracoccidioides in a clinical sample: questions on ecological strategy

Dimorphism is known among the etiologic agents of endemic mycoses as well as in filamentous Mucorales. Under appropriate thermal conditions, mononuclear yeast forms alternate with multi-nucleate hyphae. Here, we describe a dimorphic mucoralean fungus obtained from the sputum of a patient with Burkitt lymphoma and ongoing graft-versus-host reactions. The fungus is described as Mucor germinans sp. nov. Laboratory studies were performed to simulate temperature-dependent dimorphism, with two environmental strains Mucor circinelloides and Mucor kunryangriensis as controls. Both strains could be induced to form multinucleate arthrospores and subsequent yeast-like cells in vitro. Multilateral yeast cells emerge in all three Mucor species at elevated temperatures. This morphological transformation appears to occur at body temperature since the yeast-like cells were observed in the lungs of our immunocompromised patient. The microscopic appearance of the yeast-like cells in the clinical samples is easily confused with that of Paracoccidioides. The ecological role of yeast forms in Mucorales is discussed.IMPORTANCEMucormycosis is a devastating disease with high morbidity and mortality in susceptible patients. Accurate diagnosis is required for timely clinical management since antifungal susceptibility differs between species. Irregular hyphal elements are usually taken as the hallmark of mucormycosis, but here, we show that some species may also produce yeast-like cells, potentially being mistaken for Candida or Paracoccidioides. We demonstrate that the dimorphic transition is common in Mucor species and can be driven by many factors. The multi-nucleate yeast-like cells provide an effective parameter to distinguish mucoralean infections from similar yeast-like species in clinical samples.

What are the 100 most cited fungal genera?

The global diversity of fungi has been estimated between 2 to 11 million species, of which only about 155 000 have been named. Most fungi are invisible to the unaided eye, but they represent a major component of biodiversity on our planet, and play essential ecological roles, supporting life as we know it. Although approximately 20 000 fungal genera are presently recognised, the ecology of most remains undetermined. Despite all this diversity, the mycological community actively researches some fungal genera more commonly than others. This poses an interesting question: why have some fungal genera impacted mycology and related fields more than others? To address this issue, we conducted a bibliometric analysis to identify the top 100 most cited fungal genera. A thorough database search of the Web of Science, Google Scholar, and PubMed was performed to establish which genera are most cited. The most cited 10 genera are Saccharomyces, Candida, Aspergillus, Fusarium, Penicillium, Trichoderma, Botrytis, Pichia, Cryptococcus and Alternaria. Case studies are presented for the 100 most cited genera with general background, notes on their ecology and economic significance and important research advances. This paper provides a historic overview of scientific research of these genera and the prospect for further research. Citation: Bhunjun CS, Chen YJ, Phukhamsakda C, Boekhout T, Groenewald JZ, McKenzie EHC, Francisco EC, Frisvad JC, Groenewald M, Hurdeal VG, Luangsa-ard J, Perrone G, Visagie CM, Bai FY, Błaszkowski J, Braun U, de Souza FA, de Queiroz MB, Dutta AK, Gonkhom D, Goto BT, Guarnaccia V, Hagen F, Houbraken J, Lachance MA, Li JJ, Luo KY, Magurno F, Mongkolsamrit S, Robert V, Roy N, Tibpromma S, Wanasinghe DN, Wang DQ, Wei DP, Zhao CL, Aiphuk W, Ajayi-Oyetunde O, Arantes TD, Araujo JC, Begerow D, Bakhshi M, Barbosa RN, Behrens FH, Bensch K, Bezerra JDP, Bilański P, Bradley CA, Bubner B, Burgess TI, Buyck B, Čadež N, Cai L, Calaça FJS, Campbell LJ, Chaverri P, Chen YY, Chethana KWT, Coetzee B, Costa MM, Chen Q, Custódio FA, Dai YC, Damm U, de Azevedo Santiago ALCM, De Miccolis Angelini RM, Dijksterhuis J, Dissanayake AJ, Doilom M, Dong W, Alvarez-Duarte E, Fischer M, Gajanayake AJ, Gené J, Gomdola D, Gomes AAM, Hausner G, He MQ, Hou L, Iturrieta-González I, Jami F, Jankowiak R, Jayawardena RS, Kandemir H, Kiss L, Kobmoo N, Kowalski T, Landi L, Lin CG, Liu JK, Liu XB, Loizides M, Luangharn T, Maharachchikumbura SSN, Makhathini Mkhwanazi GJ, Manawasinghe IS, Marin-Felix Y, McTaggart AR, Moreau PA, Morozova OV, Mostert L, Osiewacz HD, Pem D, Phookamsak R, Pollastro S, Pordel A, Poyntner C, Phillips AJL, Phonemany M, Promputtha I, Rathnayaka AR, Rodrigues AM, Romanazzi G, Rothmann L, Salgado-Salazar C, Sandoval-Denis M, Saupe SJ, Scholler M, Scott P, Shivas RG, Silar P, Souza-Motta CM, Silva-Filho AGS, Spies CFJ, Stchigel AM, Sterflinger K, Summerbell RC, Svetasheva TY, Takamatsu S, Theelen B, Theodoro RC, Thines M, Thongklang N, Torres R, Turchetti B, van den Brule T, Wang XW, Wartchow F, Welti S, Wijesinghe SN, Wu F, Xu R, Yang ZL, Yilmaz N, Yurkov A, Zhao L, Zhao RL, Zhou N, Hyde KD, Crous PW (2024). What are the 100 most cited fungal genera? Studies in Mycology 108: 1-411. doi: 10.3114/sim.2024.108.01.

Identification of Food Spoilage Fungi Using MALDI-TOF MS: Spectral Database Development and Application to Species Complex

Fungi, including filamentous fungi and yeasts, are major contributors to global food losses and waste due to their ability to colonize a very large diversity of food raw materials and processed foods throughout the food chain. In addition, numerous fungal species are mycotoxin producers and can also be responsible for opportunistic infections. In recent years, MALDI-TOF MS has emerged as a valuable, rapid and reliable asset for fungal identification in order to ensure food safety and quality. In this context, this study aimed at expanding the VITEK® MS database with food-relevant fungal species and evaluate its performance, with a specific emphasis on species differentiation within species complexes. To this end, a total of 380 yeast and mold strains belonging to 51 genera and 133 species were added into the spectral database including species from five species complexes corresponding to Colletotrichum acutatum, Colletotrichum gloeosporioides, Fusarium dimerum, Mucor circinelloides complexes and Aspergillus series nigri. Database performances were evaluated by cross-validation and external validation using 78 fungal isolates with 96.55% and 90.48% correct identification, respectively. This study also showed the capacity of MALDI-TOF MS to differentiate closely related species within species complexes and further demonstrated the potential of this technique for the routine identification of fungi in an industrial context.

Alternative ergosterol biosynthetic pathways confer antifungal drug resistance in the human pathogens within the Mucor species complex

Mucormycoses are emerging fungal infections caused by a variety of heterogeneous species within the Mucorales order. Among the Mucor species complex, Mucor circinelloides is the most frequently isolated pathogen in mucormycosis patients and despite its clinical significance, there is an absence of established genome manipulation techniques to conduct molecular pathogenesis studies. In this study, we generated a spontaneous uracil auxotrophic strain and developed a genetic transformation procedure to analyze molecular mechanisms conferring antifungal drug resistance. With this new model, phenotypic analyses of gene deletion mutants were conducted to define Erg3 and Erg6a as key biosynthetic enzymes in the M. circinelloides ergosterol pathway. Erg3 is a C-5 sterol desaturase involved in growth, sporulation, virulence, and azole susceptibility. In other fungal pathogens, erg3 mutations confer azole resistance because Erg3 catalyzes the production of a toxic diol upon azole exposure. Surprisingly, M. circinelloides produces only trace amounts of this toxic diol and yet, it is still susceptible to posaconazole and isavuconazole due to alterations in membrane sterol composition. These alterations are severely aggravated by erg3Δ mutations, resulting in ergosterol depletion and consequently, hypersusceptibility to azoles. We also identified Erg6a as the main C-24 sterol methyltransferase, whose activity may be partially rescued by the paralogs Erg6b and Erg6c. Loss of Erg6a function diverts ergosterol synthesis to the production of cholesta-type sterols, resulting in resistance to amphotericin B. Our findings suggest that mutations or epimutations causing loss of Erg6 function may arise during human infections, resulting in antifungal drug resistance to first-line treatments against mucormycosis.

Mucor thermorhizoides-A New Species from Post-mining Site in Sudety Mountains (Poland)

Mucor representatives are mostly rapidly growing cosmopolitan soil saprotrophs of early diverged Mucoromycotina subphylum. Although this is the most speciose genus within the group, some lineages are still understudied. In this study, new species of Mucor was isolated from the post-mining area in southwestern Poland, where soil chemical composition analysis revealed high concentration of hydrocarbons and heavy metals. Phylogenetic analysis based on multigene phylogeny showed that the new isolate clusters distinctly from other Mucor species as a sister group to Mucor microsporus. New species Mucor thermorhizoides Abramczyk (Mucorales, Mucoromycota) is characterized by the extensive rhizoid production in elevated temperatures and formation of two layers of sporangiophores. It also significantly differs from M. microsporus in the shape of spores and the size of sporangia. M. thermorhizoides was shown to be able to grow in oligotrophic conditions at low temperatures. Together with M. microsporus they represent understudied and highly variable lineage of the Mucor genus.

Molecular phylogeny and morphology of Sporodiniella sinensis sp. nov. (Syzygitaceae, Mucorales), an invertebrate-associated species from Yunnan, China

During investigations of invertebrate-associated fungi in Yunnan Province of China, a new species, Sporodiniella sinensis sp. nov., was collected. Morphologically, S. sinensis is similar to Sporodiniella umbellata; however, it is distinguished from S. umbellata by its greater number of sporangiophore branches, longer sporangiophores, larger sporangiospores, and columellae. The novel species exhibits similarities of 91.62 % for internal transcribed spacer (ITS), 98.66-99.10 % for ribosomal small subunit (nrSSU), and 96.36-98.22 % for ribosomal large subunit (nrLSU) sequences, respectively, compared to S. umbellata. Furthermore, phylogenetic analyses based on combined sequences of ITS, nrLSU and nrSSU show that it forms a separate clade in Sporodiniella, and clusters closely with S. umbellata with high statistical support. The phylogenetic and morphological evidence support S. sinensis as a distinct species. Here, it is formally described and illustrated, and compared with other relatives.

Thamnostylum piriforme, a novel etiological agent of superficial mycosis

Fungi are opportunistic eukaryotic entities often taking advantage of susceptibilities offered by a host due to its immunocompromised status, changed microbiome, or ruptured physical barriers and eventually cause infections. They either invade the skin superficially or are deep-seated. Superficial mycosis affects the skin, hair, and nails inhabiting the outermost layer, stratum corneum. In the present study, we report a case of superficial mycosis (onychomycosis in particular) in a 45-year-old immunocompetent man who was an ex-defense personnel and presently serving as a security guard at the University of Jammu, District Jammu, Jammu and Kashmir, India. The infection evolved 17 years ago and negatively affected the quality of life of the patient. For the identification of the causal agent, direct microscopy, cultural, micro-morphological, molecular characterization (ITS sequencing), and phylogenetic analysis were taken into account. A mucoralean fungal species, Thamnostylum piriforme, was isolated from the fingernails (left hand) of the investigated patient, which represents a new global report as the causal agent of superficial mycosis. In vitro antifungal susceptibility testing showed T. piriforme sensitivity to itraconazole, amphotericin B and ketoconazole while resistance to fluconazole. Careful selection of optimal therapy for fungal infection based primarily on correct identification and antifungal susceptibility testing could provide effective results during treatment against these opportunistic human fungal pathogens.

Cold adapted and closely related mucoraceae species colonise dry-aged beef (DAB)

The dry ageing is a historically relevant method of meat preservation, now used as a way to produce the dry-aged beef (DAB) known for its pronounced flavour. Partially responsible for the taste of the DAB may be various microorganisms that grow on the surface of the meat. Historically, the fungal species colonising the DAB were described as members of the genera Thamnidium and Mucor. In this study we used both culture based approach as well as ITS2 rDNA metabarcoding analysis to investigate the fungal community of the DAB, with special emphasis on the mucoralean taxa. Isolated fungi were members of 6 different species from the family Mucoraceae, belonging to the genera Mucor and Helicostylum. Metabarcoding data provided supplementary information regarding the presence of other fungi including those from the Thamnidium genus. In both approaches used in this study isolates closely related to the Mucor flavus strain CBS 992.68 dominated.

Fungicolous Mucor on mushrooms: One novel species and six host records from southwest China and northern Thailand

Mucor species are a group of common soil-borne fungi, known to cause infections on humans and animals, interfere in food production, and act as useful agents in biotechnological applications. This study reports one new Mucor species, M. yunnanensis, which was found to be fungicolous on an Armillaria sp. from southwest China. Further, M. circinelloides on Phlebopus sp., M. hiemalis on Ramaria sp. and Boletus sp., M. irregularis on Pleurotus sp., M. nederlandicus on Russula sp., and M. yunnanensis on Boletus sp. are reported as new host records. Mucor yunnanensis and M. hiemalis have been collected from Yunnan Province in China, whereas M. circinelloides, M. irregularis, and M. nederlandicus have been collected from Chiang Mai and Chiang Rai Provinces in Thailand. All the Mucor taxa reported herein were identified based on both morphology and phylogenetic analyses of a combined nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS) and partial nuc 28S rDNA (28S) sequence matrix. Comprehensive descriptions, illustrations, and a phylogenetic tree are provided for all the taxa reported in the study to show the placements of taxa, and the new taxon is compared with its sister taxa.

In silico and in vitro safety assessment of a fungal biomass from Rhizomucor pusillus for use as a novel food ingredient

To address the growing world population and reduce the impact of environmental changes on the global food supply, ingredients are being produced using microorganisms to yield sustainable and innovative products. Food ingredients manufactured using modern biotechnology must be produced by non-toxigenic and nonpathogenic production organisms that do not harbor antimicrobial resistance (AMR). Several fungal species represent attractive targets as sources of alternative food products. One such product is a fungal biomass obtained from the fermentation of Rhizomucor pusillus strain CBS 143028. The whole genome sequence of this strain was annotated and subjected to sequence homology searches and in silico phenotype prediction tools to identify genetic elements encoding for protein toxins active via oral consumption, virulence factors associated with pathogenicity, and determinants of AMR. The in silico investigation revealed no genetic elements sharing significant sequence homology with putative virulence factors, protein toxins, or AMR determinants, including the absence of mucoricin, an essential toxin in the pathogenesis of mucormycosis. These in silico findings were corroborated in vitro based on the absence of clinically relevant mycotoxin or antibacterial secondary metabolites. Consequently, it is unlikely that R. pusillis strain CBS 143028 would pose a safety concern for use in food for human consumption.

First Report on Choanephora cucurbitarum Causing Choanephora Rot in Chenopodium Plants and Its Sensitivity to Fungicide

Choanephora rot of Chenopodium plants (CRC) was observed at the flowering stages in seven plantations of Shanxi Province, China. CRC had caused leaf, stem, and panicle neck rot of C. quinoa, panicle neck and stem rot of C. formosanum, and stem rot of C. album. Typical symptoms included water-soaked, rapid soft rotting, and abundant sporulation on the whole panicle necks, stems, and leaves. Based on morphological characteristics, phylogenetic analyses, and pathogenicity tests, the pathogens were identified as Choanephoraceae cucurbitarum. Sporangiola and sporangiospore of C. cucurbitarum germinated at 30 °C and were able to germinate by two h post-inoculation (hpi). The germination rates of sporangiola and sporangiospore significantly increased at 3 to 4 hpi, and the germination rates ranged from 91.53 to 97.67%. The temperature had a significant effect on the pathogenicity of C. cucurbitarum the optimum pathogenic temperatures for stems of C. quinoa, C. formosanum and C. album were 30 °C after one day post-inoculation. Choanephoraceae cucurbitarum could infect white and red quinoa panicle necks between 20 and 30 °C, and the average lesion lengths were 0.21 to 3.62 cm. Among the five tested fungicides (boscalid, dimethomorph, isopyrazam, propiconazole, and tebuconazole), isopyrazam showed higher sensitivity to sporangiola germination of C. cucurbitarum, with an EC50 value of 0.6550 μg/mL. Isopyrazam and tebuconazole strongly inhibited the sporangiospore germination of C. cucurbitarum, which showed EC50 values of 0.4406 and 0.3857 μg/mL. To our knowledge, the present study found for the first time that C. cucurbitarum is a pathogen causing panicle neck of C. formosanum and stem rot of C. formosanum and C. album, while CRC first appeared in the quinoa panicle necks, and gradually expanded to stems and leaves.

Biogeography of Fungal Communities Associated with Pinus sylvestris L. and Picea abies (L.) H. Karst. along the Latitudinal Gradient in Europe

We assessed the diversity and composition of fungal communities in different functional tissues and the rhizosphere soil of Pinus sylvestris and Picea abies stands along the latitudinal gradient of these tree species distributions in Europe to model possible changes in fungal communities imposed by climate change. For each tree species, living needles, shoots, roots, and the rhizosphere soil were sampled and subjected to high-throughput sequencing. Results showed that the latitude and the host tree species had a limited effect on the diversity and composition of fungal communities, which were largely explained by the environmental variables of each site and the substrate they colonize. The mean annual temperature and mean annual precipitation had a strong effect on root fungal communities, isothermality on needle fungal communities, mean temperature of the warmest quarter and precipitation of the driest month on shoot fungal communities, and precipitation seasonality on soil fungal communities. Fungal communities of both tree species are predicted to shift to habitats with a lower annual temperature amplitude and with increasing precipitation during the driest month, but the suitability of these habitats as compared to the present conditions is predicted to decrease in the future.

Safety evaluation of the food enzyme triacylglycerol lipase from the non-genetically modified Rhizopus arrhizus strain AE-TL(B)

The food enzyme triacylglycerol lipase (triacylglycerol acylhydrolase; EC 3.1.1.3) is produced with the non-genetically modified Rhizopus arrhizus strain AE-TL(B) by Amano Enzyme Inc. The food enzyme was considered free from viable cells of the production organism. It is intended to be used in the modification of fats and oils by interesterification and in the manufacture of enzyme-modified dairy ingredients. Dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 0.057 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not indicate a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 1,960 mg TOS/kg bw per day, the highest dose tested, which, when compared with the estimated dietary exposure, resulted in a margin of exposure of at least 34,386. A search for the similarity of the amino acid sequence of the food enzyme to known allergens was made and no match found. The Panel considered that, under the intended conditions of use, the risk of allergic reactions upon dietary exposure cannot be excluded, but the likelihood is low. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns, under the intended conditions of use.

Epidemiology of Mucormycosis in Greece; Results from a Nationwide Prospective Survey and Published Case Reports

Mucormycosis has emerged as a group of severe infections mainly in immunocompromised patients. We analysed the epidemiology of mucormycosis in Greece in a multicentre, nationwide prospective survey of patients of all ages, during 2005–2022. A total of 108 cases were recorded. The annual incidence declined after 2009 and appeared stable thereafter, at 0.54 cases/million population. The most common forms were rhinocerebral (51.8%), cutaneous (32.4%), and pulmonary (11.1%). Main underlying conditions were haematologic malignancy/neutropenia (29.9%), haematopoietic stem cell transplantation (4.7%), diabetes mellitus (DM) (15.9%), other immunodeficiencies (23.4%), while 22.4% of cases involved immunocompetent individuals with cutaneous/soft-tissue infections after motor vehicle accident, surgical/iatrogenic trauma, burns, and injuries associated with natural disasters. Additionally, DM or steroid-induced DM was reported as a comorbidity in 21.5% of cases with various main conditions. Rhizopus (mostly R. arrhizus) predominated (67.1%), followed by Lichtheimia (8.5%) and Mucor (6.1%). Antifungal treatment consisted mainly of liposomal amphotericin B (86.3%), median dose 7 mg/kg/day, range 3–10 mg/kg/day, with or without posaconazole. Crude mortality was 62.8% during 2005–2008 but decreased significantly after 2009, at 34.9% (p = 0.02), with four times fewer haematological cases, fewer iatrogenic infections, and fewer cases with advanced rhinocerebral form. The increased DM prevalence should alert clinicians for timely diagnosis of mucormycosis in this patient population.

Discovery of a New Lichtheimia (Lichtheimiaceae, Mucorales) from Invertebrate Niche and Its Phylogenetic Status and Physiological Characteristics

Species of Lichtheimia are important opportunistic fungal pathogens in the order Mucorales that are isolated from various sources such as soil, indoor air, food products, feces, and decaying vegetables. In recent years, species of Lichtheimia have become an emerging causative agent of invasive mucormycosis. In Europe and USA, Lichtheimia are the second and third most common causal fungus of mucormycosis, respectively. Thus, the aim of this study was to survey the diversity of species of Lichtheimia hidden in poorly studied hosts, such as invertebrates, in Korea. Eight Lichtheimia strains were isolated from invertebrate samples. Based on morphology, physiology, and phylogenetic analyses of ITS and LSU rDNA sequence data, the strains were identified as L. hyalospora, L. ornata, L. ramosa, and a novel species, L. koreana sp. nov. Lichtheimia koreana is characterized by a variable columellae, sporangiophores arising solitarily or up to three at one place from stolons, and slow growth on MEA and PDA at all temperatures tested. The new species grows best at 30 and 35 °C and has a maximum growth temperature of 40 °C. Detailed descriptions, illustrations, and a phylogenetic tree are provided.

A LAMP-Based Toolbox Developed for Detecting the Major Pathogens Affecting the Production and Quality of the Chinese Medicinal Crop Aconitum carmichaelii

Aconitum carmichaelii Debeaux is a traditional Chinese medicinal herb that has been utilized for approximately 2,000 years. However, as cultivation has increased, there have been more reports of A. carmichaelii infections caused by four major pathogenic fungal species, Fusarium oxysporum, F. solani, Mucor circinelloides, and Sclerotium rolfsii, resulting in increased disease incidences and limited production and quality. To detect these infections, we developed a LAMP-based toolbox in this study. The cytochrome c oxidase subunit 1 (cox1) gene, translation elongation factor-1α (EF-1α), internal transcribed spacer (ITS) regions of rDNA, and alcohol dehydrogenase 1 (ADH1) gene, respectively, were used to design species-specific LAMP primer sets for F. oxysporum, F. solani, S. rolfsii, and M. circinelloides. The results showed that the LAMP-based toolbox was effective at detecting pathogens in soil and plant materials. We also used this toolbox to investigate pathogen infection in the main planting regions of A. carmichaelii. Before harvesting, F. oxysporum, M. circinelloides, and S. rolfsii were commonly found in the planting fields and in infected A. carmichaelii plants. Therefore, the toolbox we developed will be useful for tracking these infections, as well as for disease control in A. carmichaelii.

Antifungal Activity of Isavuconazole and Comparator Agents against Contemporaneous Mucorales Isolates from USA, Europe, and Asia-Pacific

Isavuconazole is the only US FDA-approved antifungal for treating invasive mucormycosis. We evaluated isavuconazole activity against a global collection of Mucorales isolates. Fifty-two isolates were collected during 2017-2020 from hospitals located in the USA, Europe, and the Asia-Pacific. Isolates were identified by MALDI-TOF MS and/or DNA sequencing and susceptibility tested by the broth microdilution method following CLSI guidelines. Isavuconazole (MIC_50/90, 2/>8 mg/L) inhibited 59.6% and 71.2% of all Mucorales isolates at ≤2 mg/L and ≤4 mg/L, respectively. Among comparators, amphotericin B (MIC_50/90, 0.5/1 mg/L) displayed the highest activity, followed by posaconazole (MIC_50/90, 0.5/8 mg/L). Voriconazole (MIC_50/90, >8/>8 mg/L) and the echinocandins (MIC_50/90, >4/>4 mg/L) had limited activity against Mucorales isolates. Isavuconazole activity varied by species and this agent inhibited at ≤4 mg/L 85.2%, 72.7%, and 25% of Rhizopus spp. (n = 27; MIC_50/90, 1/>8 mg/L), Lichtheimia spp. (n = 11; MIC_50/90, 4/8 mg/L), and Mucor spp. (n = 8; MIC₅₀, >8 mg/L) isolates, respectively. Posaconazole MIC_50/90 values against Rhizopus, Lichtheimia, and Mucor species were 0.5/8 mg/L, 0.5/1 mg/L, and 2/- mg/L, respectively; amphotericin B MIC_50/90 values were 1/1 mg/L, 0.5/1 mg/L, and 0.5/- mg/L, respectively. As susceptibility profiles varied among Mucorales genera, species identification and antifungal susceptibility testing are advised whenever possible to manage and monitor mucormycosis.

Revealing the diversity of bacteria and fungi in the active layer of permafrost at Spitsbergen island (Arctic) - Combining classical microbiology and metabarcoding for ecological and bioprospecting exploration

Arctic soils are constantly subjected to extreme environmental conditions such as low humidity, strong winds, high salinity, freeze-thaw cycles, UV exposition, and low nutrient availability, therefore, they have developed unique microbial ecosystems. These environments provide excellent opportunities to study microbial ecology and evolution within pristine (i.e. with limited anthropogenic influence) regions since the High Arctic is still considered one of the wildest and least explored environments on the planet. This environment is also of interest for the screening and recovery of unique microbial strains suitable for various biotechnological applications. In this study, a combination of culture-depended and culture-independent approaches was used to determine the cultivation bias in studies of the diversity of cold-active microorganisms. Cultivation bias is a reduction in recovered diversity, introduced when applying a classical culturing technique. Six different soil types, collected in the vicinity of the Polish Polar Station Hornsund (Spitsbergen, Norway), were tested. It was revealed that the used media allowed recovery of only 6.37 % of bacterial and 20 % of fungal genera when compared with a culture-independent approach. Moreover, it was shown that a combination of R2A and Marine Broth media recovered as much as 93.6 % of all cultivable bacterial genera detected in this study. Based on these results, a novel protocol for genome-guided bioprospecting, combining a culture-dependent approach, metabarcoding, next-generation sequencing, and genomic data reuse was developed. With this methodology, 14 psychrotolerant, multi-metal-resistant strains, including the highly promising Rhodococcus spp., were obtained. These strains, besides increased metal tolerance, have a petroleum hydrocarbon utilization capacity, and thus may be good candidates for future bioremediation technologies, also suited to permanently cold regions.

Mapping the human oral and gut fungal microbiota in patients with metabolic dysfunction-associated fatty liver disease

Metabolic dysfunction-associated fatty liver disease (MAFLD) is a phenotype of liver diseases associated with metabolic syndrome. The pathogenesis MAFLD remains unclear. The liver maintains is located near the intestine and is physiologically interdependent with the intestine via metabolic exchange and microbial transmission, underpinning the recently proposed "oral-gut-liver axis" concept. However, little is known about the roles of commensal fungi in the disease development. This study aimed to characterize the alterations of oral and gut mycobiota and their roles in MAFLD. Twenty-one MAFLD participants and 20 healthy controls were enrolled. Metagenomics analyses of saliva, supragingival plaques, and feces revealed significant alterations in the gut fungal composition of MAFLD patients. Although no statistical difference was evident in the oral mycobiome diversity within MAFLD and healthy group, significantly decreased diversities were observed in fecal samples of MAFLD patients. The relative abundance of one salivary species, five supragingival species, and seven fecal species was significantly altered in MAFLD patients. Twenty-two salivary, 23 supragingival, and 22 fecal species were associated with clinical parameters. Concerning the different functions of fungal species, pathways involved in metabolic pathways, biosynthesis of secondary metabolites, microbial metabolism in diverse environments, and carbon metabolism were abundant both in the oral and gut mycobiomes. Moreover, different fungal contributions in core functions were observed between MAFLD patients and the healthy controls, especially in the supragingival plaque and fecal samples. Finally, correlation analysis between oral/gut mycobiome and clinical parameters identified correlations of certain fungal species in both oral and gut niches. Particularly, Mucor ambiguus, which was abundant both in saliva and feces, was positively correlated with body mass index, total cholesterol, low-density lipoprotein, alanine aminotransferase, and aspartate aminotransferase, providing evidence of a possible "oral-gut-liver" axis. The findings illustrate the potential correlation between core mycobiome and the development of MAFLD and could propose potential therapeutic strategies.

First report of Alternaria alternata causing leaf yellow spot on Heteropanax fragrans in China

Heteropanax fragrans (Roxb.) Seem is a common garden landscape tree in China. In December 2020, a leaf disease on H. fragrans was observed in a 2 ha field in Zhanjiang (20.85° N, 109.28° E), Guangdong province, China. Early symptoms were small yellow spots on leaves. Later, the spots gradually expanded and turned into necrotic tissues with a clear yellow halo and a white center. The disease incidence on plants was 100%. Twenty diseased leaves were collected from the field. The margin of the diseased tissues was cut into 2 mm × 2 mm pieces, surface disinfected with 75% ethanol and 2% sodium hypochlorite for 30 and 60 s, respectively, and rinsed thrice with sterile water before isolation. The tissues were plated onto potato dextrose agar (PDA) medium and incubated at 28 ℃. After 2-day incubation, grayish fungal colonies appeared on the PDA, then pure cultures were produced by transferring hyphal tips to new PDA plates. Single-spore isolation method was used to recover pure cultures for three isolates (HFA-1, HFA-2, and HFA-3). The colonies first produced a light-grayish aerial mycelia, which turned dark grayish upon maturity. Conidiophores were branched. Conidia numbered from two to four in chains, were dark brown, ovoid, or ellipsoid and mostly beakless; had 1-4 transverse and 0-3 longitudinal septa; measured within 7.2-17.8 (average = 10.2) × 2.5-7.5 (average = 4.3) µm (n = 30). Molecular identification was performed using the colony polymerase chain reaction method with MightyAmp DNA Polymerase (Takara-Bio, Dalian, China) (Lu et al. 2012) to amplify the large subunit (LSU), internal transcribed spacer (ITS) region, translation elongation factor (TEF) , and Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) with NL1/LR3, ITS1/ITS4, EF-1α-F/EF-1α-R, and GDF1/GDR1 (Walther et al. 2013;Woudenberg et al. 2015; Nishikawa and Nakashima. 2020). Amplicons of the isolates were sequenced and submitted to GenBank (LSU, ON088978-ON088980; ITS, MW629797, ON417005 and ON417006; TEF, MW654167, ON497264,and ON497265;GAPDH, MW654166, ON497262,and ON497263). The obtained sequences were 100% identical with those of Alternaria alternata strain CBS 102600 upon BLAST analysis . The sequences were also concatenated for phylogenetic analysis by maximum likelihood. The isolates clustered with A. alternata (CBS 102600, CBS 102598, CBS 118814, CBS 918.96,CBS 106.24, CBS 119543, CBS 916.96). The fungus associated with leaf yellow spot on H. fragrans was thus identified as A. alternata. Pathogenicity tests were conducted in a greenhouse at 24 ℃-30 ℃ with 80% relative humidity. Individual plants were grown in pots (n = 5, 1 month old). The unwounded leaflets were inoculated with 5 mm-diameter mycelial plugs of the isolates or agar plugs (as control). The test was performed thrice. Disease symptoms were found on the leaves after 7 days, whereas the controls remained healthy. The pathogen was re-isolated from infected leaves and phenotypically identical to the original isolates to fulfill Koch's postulates. To our knowledge, this report is the first one on A. alternata causing leaf yellow spot on H. fragrans. Thus, this work provides an important reference for the control of this disease in the future.

Aspergillus Was the Dominant Genus Found during Diversity Tracking of Potentially Pathogenic Indoor Fungal Isolates

Viable airborne pathogenic fungi represent a potential health hazard when exposing vulnerable persons in quantities exceeding their resilience. In this study, 284 indoor fungal isolates from a strain collection of indoor fungi were screened for pathogenic potential through the ability to grow in neutral pH at 37 °C and 30 °C. The isolates were collected from 20 locations including 14 problematic and 6 non-problematic ordinary buildings. Out of the screened isolates, 170 isolates were unable to grow at 37 °C, whereas 67 isolates growing at pH 7.2 at 37 °C were considered as potential opportunistic pathogens. Forty-seven isolates growing at 30 °C but not at 37 °C were considered as less likely pathogens. Out of these categories, 33 and 33 strains, respectively, were identified to the species level. The problematic buildings included known opportunistic pathogens: Aspergillus calidoustus, Trichoderma longibrachiatum, Rhizopus arrhizus and Paecilomyces variotii, as well as less likely pathogens: Aspergillus versicolor, Chaetomium cochliodes, Chaetomium globosum and Chaetomium rectangulare. Opportunistic pathogens such as Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger and Aspergillus tubingensis and less likely pathogens such as Aspergillus westerdijkiae, Chaetomium globosum and Dichotomopilus finlandicus were isolated both from ordinary and from problematic buildings. Aspergillus was the dominant, most diverse genus found during screening for potentially pathogenic isolates in the indoor strain collection. Studies on Aspergillus niger and Aspergillus calidodoustus revealed that tolerance to cleaning chemicals may contribute to the adaptation of Aspergillus species to indoor environments.

Two New Species of Backusella (Mucorales, Mucoromycota) from Soil in an Upland Forest in Northeastern Brazil with an Identification Key of Backusella from the Americas

During a survey of Mucorales from a forest located in Pernambuco state, Brazil, two new Backusella species were discovered and described based on morphological and molecular data (internal transcribed spacer and large subunit ribosomal DNA sequences). Both species were characterized as unbranched sporangiophores and sporangia with columellae of varied shapes forming. Multispored sporangiola were frequent, whereas unispored sporangiola were rare. URM 8395 forms sporangiophores that may support hyaline, slightly curved or circinate pedicels with multispored sporangiola at their apical portion, and abundant giant cells and chlamydospores. Columellae of sporangia are hyaline, conical (majority), or ellipsoidal with a truncate base, globose to subglobose or subglobose to conical, and, rarely, with slight medial constriction. URM 8427 does not form sporangiola from pedicels, giant cells are not observed, and columellae of sporangia are globose to subglobose, cylindrical with a truncate base, some with a slight constriction, applanate, obovoid, ellipsoidal, or, rarely, conical. Some columellae may have one side more swollen than the other and some are arranged obliquely on the sporangiophores. Sterile sporangia may or may not be formed on short sporophores. The detailed description and illustration of both novel species as well as an identification key for Backusella from the Americas are provided.

Spectrum of Mucormycosis Before and During COVID-19: Epidemiology, Diagnosis, and Current Therapeutic Interventions

Purpose of Review

More than half a billion people have been infected and 6.2 million killed by the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) since the start of the pandemic in 2019. Systemic glucocorticoids are a double-edged sword, on the one hand, life-saving in treating COVID-19 complications while on the other hand, potentially leading to life-and-limb-threatening opportunistic fungal infections. Mucormycosis (MM) is caused by the mucormycetes family. Although rare, it is characterized by high mortality and significant morbidity. The gross similarities observed with other fungal infections which respond to different treatment regimens have made it all the more imperative to quickly and sensitively diagnose and treat MM. This review discusses the epidemiology of MM before and during the COVID-19 pandemic, associated risk factors, COVID-19-associated MM, diagnosis, and current therapeutic interventions.

Recent Findings

There has been a widespread and worrisome trend of rising in cases of MM, worldwide, but more so in the Indian subcontinent, where it is nicknamed the “black fungus.” This upsurge has picked up the pace ever since the start of the COVID-19 pandemic. Necrosis is secondary to the angio-invasive and pro-thrombotic nature of the mold resulting in extensive lesions presenting mostly as rhino-orbital MM (ROM) and rhino-orbito-cerebral MM (ROCM). Infection is mostly observed in subjects with underlying risk factors such as uncontrolled diabetes, those receiving hematopoietic stem cell transplant, and/or on corticosteroid or immunosuppressive therapy, although it is widely suspected that other factors such as iron and zinc may play a role in the pathogenesis of MM. The “One world one guideline” strategy advocates both prophylactic anti-fungal therapy along with aggressive, prompt, and individualized treatment with anti-fungal drugs such as amphotericin B in addition to vigorous surgical intervention. High-risk groups need particularly rapid diagnosis although empirical anti-fungal therapy may not be delayed. Speeding diagnostic turnaround times are essential to institute early therapy, and there is much scope for newer modalities such as PCR, matrix-assisted laser desorption ionization-time of flight mass spectrometry, and whole-genome sequencing in such endeavors. The results of strict monitoring of blood glucose levels along with rational and limited use of steroids and immunomodulatory drugs have proven to be a significant preventive measure.

Summary

The significant rise in cases of MM worldwide has necessitated viewing each case with a strong index of suspicion. Adoption of rapid diagnostics, early antifungal therapy, and prompt surgical interventions are essential, while high-risk groups need particular focused care which may include prophylactic anti-fungal therapy, limited steroid use, and meticulous control of the underlying disease. Developing quicker and more sensitive diagnostic modalities has great potential to improve the detection and management of MM.

High tolerance and degradation of fungicides by fungal strains isolated from contaminated soils

The aim of this work was to isolate fungal strains from phytotoxic agricultural soils, screen them, categorize the most tolerant fungi to three fungicides, and identify them by a molecular approach. In this study, 28 fungal strains were isolated from phytotoxic agricultural soil with intensive use of pesticides. The capacity of fungi to resist and degrade different concentrations of carbendazim, captan, and zineb was determined by an exploratory multivariate analysis. Actinomucor elegans LBM 239 was identified as the most tolerant fungus to these fungicides, degrading a 86.62% of carbendazim after 7 days of treatment. In conclusion, A. elegans LBM 239 demonstrated the highest tolerance and capacity to biodegrade carbendazim, becoming a potential candidate for bioremediation of contaminated soils with carbendazim, captan, or zineb.

First Report of Rhizopus arrhizus (syn. R. oryzae) Causing Garlic Bulb Soft Rot in Hebei Province, China

Rhizopus soft rot occurs on the succulent tissues of vegetables, fruits, and ornamental plants throughout the world (Cui et al. 2019). When the garlic is in the seedling stage in the fields (Fig. S1) in November 2021, a disease outbreak on garlic bulbs suspected as Rhizopus soft rot occurred in Daming County, Handan City, Hebei Province of China (N 36°17', E 115° 13'). This disease symptom was first found in the garlic seedling stage in China. Disease incidence was 10% to 30% in cultivated garlic bulbs. There were soft water-soaked lesions on the surface of diseased garlic bulbs and the interiors were brown and soft. In the disease severe field, white to gray mycelia were observed on the diseased garlic bulbs. Infected garlic bulbs were sampled to isolate and determine the identity of the disease-causing organism. Symptomatic bulbs were surface sterilized with 1% NaClO for 2 min, dipped in 75% ethanol for 3 min and rinsed three times with autoclaved distilled water. Small pieces of the inner decayed tissue were removed and cultured on potato dextrose agar (PDA) at 28°C for 2 to 3 days. Five white colonies grew on PDA and then they became brownish gray to blackish-gray mycelium. The fungal strains were purified by hyphal-tip isolation method. To determine the identity of the five isolated fungi, we analyzed their internal transcribed spacer (ITS) region sequences (Jung et al. 2012). BLAST analysis of the ITS sequences from DSF-0-2 (accession no. ON706022), DSF-0-3 (accession no. ON706021), DSF-0-4 (accession no. ON706020), DSF-0-5 (accession no. ON706019) and DSF-0-6 (accession no. ON706018) were all 100% identical with Rhizopus arrhizus (syn. Rhizopus oryzae). Phylogenetic trees were constructed using the neighbor-joining method of MEGA11 based on the sequences of ITS rRNA gene (Walther et al. 2013). Phylogenetic trees indicated that isolates were most likely Rhizopus arrhizus (syn. Rhizopus oryzae) (Fig. S2). We selected one isolated strain, DSF-0-2, for characterize the morphology and test its ability to cause garlic bulb soft rot. Under the microscope, nonseptate rhizoids, sporangia, and sporangiospores were observed (Fig. S1). Sporangiospores were unequal, subglobose, numerous irregular, or oval, and 9.7 (6.2 - 12.5) × 6.5 (4.1 - 8.5) μm (n = 50) in diameter. The sporangia were globose, black, 121.5 (65 - 198) μm (n = 50) in diameter. Based on the rDNA-ITS sequencing and the morphological characteristics, the DSF-0-2 isolate was identified as Rhizopus arrhizus (syn. Rhizopus oryzae) (Zheng et al. 2007; Abeywickrama et al. 2020). To complete Koch's postulates, surface-sterilized healthy garlic bulbs were inoculated with R. arrhizus isolate DSF-0-2. A 1.0-ml sterile syringe was used to inject 50 μl of a 106 conidia/ml suspension into each of five healthy bulbs. As a control, garlic bulbs were treated with sterile distilled water. The inoculated and control bulbs were incubated at 28°C for 7 days. The bulbs inoculated with R. arrhizus DSF-0-2 showed symptoms of water soaking, and the tissues were brown and soft throughout the bulb at 7 days (Fig. S1). Results of the three trials were the same. No symptoms were observed in the control group. R. arrhizus was reisolated from the symptomatic garlic bulb and confirmed as such based-on colony and sporangia morphology and ITS sequence. There were some reports that R. arrhizus infects cassava tubers and potato tubers (Amadioha and Markson 2007; Cui et al. 2019). To our knowledge, this is the first report of R. arrhizus (syn. Rhizopus oryzae) associated with soft rot on garlic bulb in the seedling stage in China. This disease has posed a potential threat during garlic seedling stage in the field. Management measures should be considered before this disease outbreaks widely. Garlic bulbs died in the seedling stage, which caused production reduction, serious economic loss and soil pollution. This finding may help to take effective control measures for this disease.

Discovery of Three New Mucor Species Associated with Cricket Insects in Korea

Species in the genus Mucor have a worldwide distribution and are isolated from various substrata and hosts, including soil, dung, freshwater, and fruits. However, their diversity from insects is still much too little explored. The aim of this study was to characterize three new species of Mucor: Mucor grylli sp. nov., M. hyangburmii sp. nov., and M. kunryangriensis sp. nov., discovered in Kunryang-ri, Cheongyang in the Chungnam Province of Korea, during an investigation of Mucorales from cricket insects. The new species are described using morphological characters and molecular data including ITS and LSU rDNA regions. Mucor grylli is characterized by the highly variable shape of its columellae, which are subglobose to oblong, obovoid, strawberry-shaped, and sometimes slightly or strongly constricted in the center. Mucor hyangburmii is characterized by the production of azygospores and growth at 40 °C. Mucor kunryangriensis is characterized by the variable shape of its columellae, which are elongated-conical, obovoid, cylindrical ellipsoid, cylindrical, and production of abundant yeast-like cells on PDA, MEA, and SMA media. Based on the sequence analysis of two genetic markers, our phylogenic assessment strongly supported M. grylli, M. hyangburmii, and M. kunryangriensis as new species. Detailed descriptions, illustrations, and phylogenetic trees are provided.

Atypical Mycosis in Psittacine Birds: A Retrospective Study

A retrospective study was conducted on parrots submitted from necropsy to the Department of Veterinary Pathology, School of Biosciences and Veterinary, University of Camerino, Italy, from 2007 to 2018. From a total of 2,153 parrots examined at post-mortem, four cases were diagnosed with atypical mycosis and were considered for determination of the fungus species by PCR. A Fischer's lovebird (Agapornis fischeri), Peach-faced lovebirds (Agapornis roseicollis), and two Blue and Gold Macaws (Ara ararauna) from four different aviaries died after some days of lethargy and ruffled feathers. Records of gross necropsy and histopathological exams (H&E, PAS, and Grocott stain) were described and biomolecular analyses were carried out. No specific gross lesions were appreciated at necropsy, while histopathology evidenced a systemic mycosis in several organs, particularly in the lungs. In affected organs, broad and non-septate hyphae, suggestive of mycoses, were observed. Molecularly, Mucor racemosus (Fischer's lovebird) and M. circinelloides (Peach-faced lovebirds) were identified from formalin-fixed and paraffin-embedded (FFPE) lung and liver tissue. In addition, Alternaria alternata and Fusicladium spp. (respectively in male and female Blue and Gold macaws) were identified in FFPE tissue from several organs; whereas the role of Mucor spp. as true pathogens is well-demonstrated, and the behavior of A. alternata and Fusicladium spp. in macaws as opportunistic pathogens have been discussed. To our knowledge, this report is the first one reporting mucormycosis caused by M. racemosus and M. circinelloides in lovebirds, and A. alternata and Fusicladium spp. in macaws.

First Molecular Identification of Three Clinical Isolates of Fungi Causing Mucormycosis in Honduras

Mucormycoses are rare but serious opportunistic fungal infections caused by filamentous organisms of the order Mucorales. Here we report the first molecular identification of Rhizopus oryzae (heterotypic synonym Rhizopus arrhizus), R. delemar, and Apophysomyces ossiformis as the etiological agents of three cases of severe mucormycosis in Honduras. Conventional microbiological cultures were carried out, and DNA was extracted from both clinical samples and axenic cultures. The ITS ribosomal region was amplified and sequenced. Molecular tools are suitable strategies for diagnosing and identifying Mucorales in tissues and cultures, especially in middle-income countries lacking routine diagnostic strategies.

First Report of Seedling Rot of Castor (Ricinus communis) caused by Choanephora cucurbitarum in China

Castor (Ricinus communis L.) oil is used in the manufacture of cosmetics, lubricants, plastics, pharmaceuticals, and soaps and is grown in more than 40 countries with India and China leading in oil production(Tunaru et al. 2012). In June 2021, a seedling rot disease was observed on castor cv. Zibi-5 in a plant nursery in Zhanjiang (21°17' N, 110°18' E), China. Initial symptoms on leaves and stems were water-soaked and dark green lesions that resulted in rapid rotting. Disease incidence was 25% and resulted in seedling death. White fungal mycelia developed on the rotting plant tissues. Leaves and stems were collected from 10 diseased plants, surface disinfected in 0.5% sodium hypochlorite and 75% ethyl alcohol, and tissue pieces placed in plates of potato dextrose agar (PDA) which were maintained at 28℃. Hyphal tips from fungal mycelia that developed in the PDA plates were selected to establish pure cultures and three representative fungal isolates, designated RCC-1, RCC-2, and RCC-3, were selected for further study. The fungal isolates produced sporangiophores that were smooth, hyaline, aseptate, and apically swollen. Sporangiophores bore monosporous sporangiola that were broadly ellipsoidal, longitudinally coarsely striate, brown to dark brown, and measured 6.2 to 14.8 x 10.5 to 26.5 um (n=30). Sporangia contained few to many spores that were spherical, brown, and measured 59 to 150 um in diameter (n=20). Sporangiospores were ellipsoid, striate, and brown with multiple hyaline polar appendages and measured 6.6 to 12.3 x 10.6 to 25.5 um (n=30) in size. Based on these morphological characteristics, the fungus was identified as Choanephora cucurbitarum (Berk. & Ravenel) Thaxt. (Kirk, 1984). Molecular identification was done using the colony PCR method with MightyAmp DNA Polymerase (Takara-Bio, Dalian, China) (Lu et al. 2012) used to amplify the internal transcribed spacer (ITS) region and large subunit (LSU) with ITS1/ITS4 and NL1/LR3 (Walther et al. 2013). The amplicons were sequenced and the sequences were deposited in GenBank with accession numbers ITS, OL376748-OL376750, and LSU, OL763430-OL763432. BLAST analysis of these sequences revealed a 100% to 99% identity with the sequences (ITS, MG650194; 573/573, 573/573, and 573/573; LSU, AF157181; 673/676, 673/676, and 673/676) of C. cucurbitarum in GenBank. Pathogenicity tests, to fulfill Koch's postulates, were performed in a greenhouse with a temperature range of 24℃ to 30℃ and 80% relative humidity. Thirty-day-old cv. Zibi-5 castor plants were grown in pots and used for inoculation tests. Ten plants were inoculated by placing agar plugs with mycelia of fungal isolate RCC-1 on leaves or stems. Ten control plants were inoculated with agar plugs only and the test was repeated three times in total. Five days after inoculation, all plants, with either leaf or stem inoculations, became infected and began rotting. Symptom progression was consistent with that observed in the nursery and all control plants remained healthy. C. cucurbitarum was successfully reisolated from all inoculated plants and identified by morphological characteristics and by sequence analysis. This fungus is known to cause serious damage on a wide range of hosts (Liu et al. 2019) and previously was reported on castor in India (Shaw 1984) and Papua New Guinea (Peregrin and Ahmad 1982). We observed that the pathogen grows very rapidly and causes serious damage to castor seedlings, warranting further investigation on the epidemiology and control of this disease.

Biosurfactant-Producing Mucor Strains: Selection, Screening, and Chemical Characterization

Biosurfactants are amphiphilic molecules with surface tension reducing activities. Among biosurfactant producers, fungi have been identified as promising organisms. While many studies have investigated biosurfactant production in fungal species from the Ascomycota and Basidiomycota phyla, less is known concerning species from the Mucoromycota phylum. In this context, the aim of this study was to screen and optimize biosurfactant production in 24 fungal strains, including seven Mucor, three Lichtheimia, and one Absidia species. After cultivation in a medium stimulating surfactant production, the surface activity of cell-free supernatants was measured using both oil spreading and parafilm M tests. Among them, five Mucor strain cell-free supernatants belonging to M. circinelloides, M. lanceolatus, M. mucedo, M. racemosus, and M. plumbeus, showed oil repulsion. Then, the impact of the medium composition on surfactant production was evaluated for eight strains. Three of them, i.e., Mucor circinelloides UBOCC-A-109190, Mucor plumbeus UBOCC-A-111133, and Mucor mucedo UBOCC-A-101353 showed an interesting surfactant production potential, reducing the medium surface tension to 36, 31, and 32 mN/m, respectively. A preliminary characterization of the surfactant molecules produced by these strains was performed and showed that these compounds belonged to the glycolipid family.

The Fungal Microbiome of Wheat Flour Includes Potential Mycotoxin Producers

Consumers are increasingly demanding higher quality and safety standards for the products they consume, and one of this is wheat flour, the basis of a wide variety of processed products. This major component in the diet of many communities can be contaminated by microorganisms before the grain harvest, or during the grain storage right before processing. These microorganisms include several fungal species, many of which produce mycotoxins, secondary metabolites that can cause severe acute and chronic disorders. Yet, we still know little about the overall composition of fungal communities associated with wheat flour. In this study, we contribute to fill this gap by characterizing the fungal microbiome of different types of wheat flour using culture-dependent and -independent techniques. Qualitatively, these approaches suggested similar results, highlighting the presence of several fungal taxa able to produce mycotoxins. In-vitro isolation of fungal species suggest a higher frequency of Penicillium, while metabarcoding suggest a higher abundance of Alternaria. This discrepancy might reside on the targeted portion of the community (alive vs. overall) or in the specific features of each technique. Thus, this study shows that commercial wheat flour hosts a wide fungal diversity with several taxa potentially representing concerns for consumers, aspects that need more attention throughout the food production chain.

Current Insight into Traditional and Modern Methods in Fungal Diversity Estimates

Fungi are an important and diverse component in various ecosystems. The methods to identify different fungi are an important step in any mycological study. Classical methods of fungal identification, which rely mainly on morphological characteristics and modern use of DNA based molecular techniques, have proven to be very helpful to explore their taxonomic identity. In the present compilation, we provide detailed information on estimates of fungi provided by different mycologistsover time. Along with this, a comprehensive analysis of the importance of classical and molecular methods is also presented. In orderto understand the utility of genus and species specific markers in fungal identification, a polyphasic approach to investigate various fungi is also presented in this paper. An account of the study of various fungi based on culture-based and cultureindependent methods is also provided here to understand the development and significance of both approaches. The available information on classical and modern methods compiled in this study revealed that the DNA based molecular studies are still scant, and more studies are required to achieve the accurate estimation of fungi present on earth.

New insights on mucormycosis and its association with the COVID-19 pandemic

COVID-19 continues to cause significant fatality worldwide. Glucocorticoids prove to play essential roles in COVID-19 management; however, the extensive use of steroids together with the virus immune dysregulation may increase the danger of secondary infections with mucormycosis, an angioinvasive fungal infection. Unfortunately, a definite correlation between COVID-19 and elevated mucormycosis infection cases is now clear worldwide. In this review, we discuss the historical record and epidemiology of mucormycosis as well as pathogenesis and associated host immune response, risk factors, clinical presentation, diagnosis and treatment. Special emphasis is given to its association with the current COVID-19 pandemic, including latest updates on COVID-19-associated mucormycosis cases globally, with recommendations for efficacious management.

A definite correlation between COVID-19 and elevated mucormycosis infection cases is now clear worldwide. This article can be used as comprehensive tool to help clinicians and the healthcare team in getting a clearer look on the historical record and epidemiology of mucormycosis as well as pathogenesis and associated host immune response. Risk factors, clinical presentation, diagnosis, treatment options and also the latest updates on COVID-19-associated mucormycosis are also discussed, which will help in the understanding of the fatal mucormycosis infection.

The effect of the use of commercial tempeh starter on the diversity of Rhizopus tempeh in Indonesia

At present, only a single Rhizopus species, R. microsporus, can be found in fresh tempeh produced in Java, Indonesia. The loss of diversity of Rhizopus in tempeh has been associated with the widespread use of commercial tempeh starter in Indonesia since the 2000s. However, the identities of the previous Rhizopus strains associated with tempeh, which have been preserved in a culture collection in Indonesia, have not been verified. The present study aimed to verify the identities of 22 Rhizopus strains isolated from tempeh produced using the traditional tempeh starters from the 1960s to the 2000s. Phylogenetic analysis based on the ITS regions in the rRNA gene sequence data, revealed that the Rhizopus strains belonged to the species R. arrhizus (five strains); R. delemar (14 strains); and R. microsporus (three strains). Verification of the identities of these Rhizopus strains in the present study confirmed the loss of diversity of Rhizopus species in tempeh produced in Indonesia, particularly in Java. Our findings confirmed that the morphological changes in Rhizopus species isolated from tempeh as a result of centuries of domestication.

Fungal diversity notes 1387-1511: taxonomic and phylogenetic contributions on genera and species of fungal taxa

This article is the 13th contribution in the Fungal Diversity Notes series, wherein 125 taxa from four phyla, ten classes, 31 orders, 69 families, 92 genera and three genera incertae sedis are treated, demonstrating worldwide and geographic distribution. Fungal taxa described and illustrated in the present study include three new genera, 69 new species, one new combination, one reference specimen and 51 new records on new hosts and new geographical distributions. Three new genera, Cylindrotorula (Torulaceae), Scolecoleotia (Leotiales genus incertae sedis) and Xenovaginatispora (Lindomycetaceae) are introduced based on distinct phylogenetic lineages and unique morphologies. Newly described species are Aspergillus lannaensis, Cercophora dulciaquae, Cladophialophora aquatica, Coprinellus punjabensis, Cortinarius alutarius, C. mammillatus, C. quercoflocculosus, Coryneum fagi, Cruentomycena uttarakhandina, Cryptocoryneum rosae, Cyathus uniperidiolus, Cylindrotorula indica, Diaporthe chamaeropicola, Didymella azollae, Diplodia alanphillipsii, Dothiora coronicola, Efibula rodriguezarmasiae, Erysiphe salicicola, Fusarium queenslandicum, Geastrum gorgonicum, G. hansagiense, Helicosporium sexualis, Helminthosporium chiangraiensis, Hongkongmyces kokensis, Hydrophilomyces hydraenae, Hygrocybe boertmannii, Hyphoderma australosetigerum, Hyphodontia yunnanensis, Khaleijomyces umikazeana, Laboulbenia divisa, Laboulbenia triarthronis, Laccaria populina, Lactarius pallidozonarius, Lepidosphaeria strobelii, Longipedicellata megafusiformis, Lophiotrema lincangensis, Marasmius benghalensis, M. jinfoshanensis, M. subtropicus, Mariannaea camelliae, Melanographium smilaxii, Microbotryum polycnemoides, Mimeomyces digitatus, Minutisphaera thailandensis, Mortierella solitaria, Mucor harpali, Nigrograna jinghongensis, Odontia huanrenensis, O. parvispina, Paraconiothyrium ajrekarii, Parafuscosporella niloticus, Phaeocytostroma yomensis, Phaeoisaria synnematicus, Phanerochaete hainanensis, Pleopunctum thailandicum, Pleurotheciella dimorphospora, Pseudochaetosphaeronema chiangraiense, Pseudodactylaria albicolonia, Rhexoacrodictys nigrospora, Russula paravioleipes, Scolecoleotia eriocamporesi, Seriascoma honghense, Synandromyces makranczyi, Thyridaria aureobrunnea, Torula lancangjiangensis, Tubeufia longihelicospora, Wicklowia fusiformispora, Xenovaginatispora phichaiensis and Xylaria apiospora. One new combination, Pseudobactrodesmium stilboideus is proposed. A reference specimen of Comoclathris permunda is designated. New host or distribution records are provided for Acrocalymma fici, Aliquandostipite khaoyaiensis, Camarosporidiella laburni, Canalisporium caribense, Chaetoscutula juniperi, Chlorophyllum demangei, C. globosum, C. hortense, Cladophialophora abundans, Dendryphion hydei, Diaporthe foeniculina, D. pseudophoenicicola, D. pyracanthae, Dictyosporium pandanicola, Dyfrolomyces distoseptatus, Ernakulamia tanakae, Eutypa flavovirens, E. lata, Favolus septatus, Fusarium atrovinosum, F. clavum, Helicosporium luteosporum, Hermatomyces nabanheensis, Hermatomyces sphaericoides, Longipedicellata aquatica, Lophiostoma caudata, L. clematidis-vitalbae, Lophiotrema hydei, L. neoarundinaria, Marasmiellus palmivorus, Megacapitula villosa, Micropsalliota globocystis, M. gracilis, Montagnula thailandica, Neohelicosporium irregulare, N. parisporum, Paradictyoarthrinium diffractum, Phaeoisaria aquatica, Poaceascoma taiwanense, Saproamanita manicata, Spegazzinia camelliae, Submersispora variabilis, Thyronectria caudata, T. mackenziei, Tubeufia chiangmaiensis, T. roseohelicospora, Vaginatispora nypae, Wicklowia submersa, Xanthagaricus necopinatus and Xylaria haemorrhoidalis. The data presented herein are based on morphological examination of fresh specimens, coupled with analysis of phylogenetic sequence data to better integrate taxa into appropriate taxonomic ranks and infer their evolutionary relationships.

Antagonistic and plant growth promotion effects of Mucor moelleri, a potential biocontrol agent

With the increasing demand for high quality and environmentally safe or green food, Biological Control Agents (BCAs) are playing critical roles in green agriculture, which in turn has paved the way for the requirement of effective, appropriate microbial antagonists. In this study, Mucor moelleri AA1 was isolated and investigated for its growth promotion and antagonism against Athelia rolfsii and Colletotrichum gloeosporiodes. The results showed a high antagonistic activity of M. moelleri against A. rolfsii and C. gloeosporiodes with percentage inhibitions of 73 % and 86 % respectively using the dual plate method, and the same antagonistic activity was also observed in liquid cocultures. A pot study analysis showed significant suppression of the diseases as well as growth promotion on tomato. Scanning electron microscopy (SEM) indicated that M. moelleri inhibited the growth of mycelium and the production of web-like materials. Based on headspace-solid phase microextraction (HS-SPME) analysis, microbial volatile compounds were determined, which were mainly aromatic compounds and alkaloids. Also, several antagonistic enzymes, such as β-1, 3- glucanase, proteases, catalase and ACC deaminase as well as the phytohormone IAA, were found to be produced by M. moelleri. Overall, these results combine to make M. moelleri a good prospective candidate for biological control and as a plant growth-promoting agent. The present study appears to be the first report identifying M. moelleri as a biological control agent.

Novel Mucor species (Mucoromycetes, Mucoraceae) from northern Thailand

Mucor species are common fast-growing fungi found in soil. Two new species of Mucor and one new geographical record of M.nederlandicus were collected from northern Thailand and are described in this study. Evidence from morphophysiological data and phylogenetic analysis supports the introduction of the new taxa. Phylogenetic analysis based on the internal transcribed spacer (ITS) and large subunit of the nuclear ribosomal RNA (LSU) data showed that the new isolates cluster distinctly from other Mucor species with high or maximum bootstrap support. Mucoraseptatophorus is characterized by aseptate sporangiophores, globose columella, resistant and deliquescent sporangia, has sympodial, and monopodial branches and shows growth at 37 °C. It also differs from M.irregularis in having smaller sporangiospores, and larger sporangia. Mucorchiangraiensis has subglobose or slightly elongated globose columella, produces hyaline sporangiospores, and resistant and deliquescent sporangia. Furthermore, this species has wider sporangiophore, smaller sporangia and lower growth than M.nederlandicus. A detailed description of the species and illustrations are provided for the novel species.

Early-diverging fungal phyla: taxonomy, species concept, ecology, distribution, anthropogenic impact, and novel phylogenetic proposals

The increasing number of new fungal species described from all over the world along with the use of genetics to define taxa, has dramatically changed the classification system of early-diverging fungi over the past several decades. The number of phyla established for non-Dikarya fungi has increased from 2 to 17. However, to date, both the classification and phylogeny of the basal fungi are still unresolved. In this article, we review the recent taxonomy of the basal fungi and re-evaluate the relationships among early-diverging lineages of fungal phyla. We also provide information on the ecology and distribution in Mucoromycota and highlight the impact of chytrids on amphibian populations. Species concepts in Chytridiomycota, Aphelidiomycota, Rozellomycota, Neocallimastigomycota are discussed in this paper. To preserve the current application of the genus Nephridiophaga (Chytridiomycota: Nephridiophagales), a new type species, Nephridiophaga blattellae, is proposed.

Absidia healeyae: a new species of Absidia (Mucorales) isolated from Victoria, Australia

Absidia healeyae is a new species described in the Mucorales genus Absidia after screening 16 strains of Absidia isolated from seven locations in the state of Victoria in Australia. After initial analysis of the large ribosomal subunit sequence, the genomes of representative strains from two clades were sequenced using short paired-reads. Additional taxonomic markers extracted from the genome sequencing data support the novelty of A. healeyae. The identification of a new species in the genus Absidia, from a relatively small collection of isolates, hints at an unexplored diversity in the early diverging lineages of fungi in Australia.

Intraspecific variability in cardinal growth temperatures and water activities within a large diversity of Penicillium roqueforti strains

Different strains of a given fungal species may display heterogeneous growth behavior in response to environmental factors. In predictive mycology, the consideration of such variability during data collection could improve the robustness of predictive models. Among food-borne fungi, Penicillium roqueforti is a major food spoiler species which is also used as a ripening culture for blue cheese manufacturing. In the present study, we investigated the intraspecific variability of cardinal temperatures and water activities (a_w), namely, minimal (T_min and a_wmin), optimal (T_opt and a_wopt) and maximal (T_max) temperatures and/or a_w estimated with the cardinal model for radial growth, of 29 Penicillium roqueforti strains belonging to 3 genetically distinct populations. The mean values of cardinal temperatures and a_w for radial growth varied significantly across the tested strains, except for T_max which was constant. In addition, the relationship between the intraspecific variability of the biological response to temperature and a_w and putative genetic populations (based on microsatellite markers) within the selected P. roqueforti strains was investigated. Even though no clear relationship was identified between growth parameters and ecological characteristics, PCA confirmed that certain strains had marginal growth response to temperature or a_w. Overall, the present data support the idea that a better knowledge of the response to abiotic factors such as temperature and a_w at an intraspecific level would be useful to model fungal growth in predictive mycology approaches.

First Report of Mucor irregularis Causing Postharvest Fruit Rot on Garcinia mangostana in China

Mangosteen (Garcinia mangostana Linn.) is an evergreen fruit tree grown in Southeast Asia. The fruit of Mangosteen is dark purple spherical with a diameter of 5 to 8 centimeter, a hard rind and white flesh. The seeds and pericarps of the fruit have long been utilized as a traditional medicine in Southeast Asia (Ovalle-Magallanes et al. 2017). Surveys were conducted during the months from March to April 2019 of fruit markets located in Wujing Town, Shanghai (31°02'33″ N, 121°28'04″ E), one noteworthy postharvest disease was observed. Overall 116 fruit samples were collected from 5 different supermarkets, 10.3% (12) of the fruits were found infected with the same symptoms during cold storage. The infected fruits were subjected to pathogen isolation and characterization. The junction areas between diseased and healthy tissues were cut into small pieces of diameter 5 mm, which were surface sterilized with 0.5% NaClO solution for 3 min, followed by rinsing in sterile water thrice, and then the tissues were placed on sterilized potato dextrose agar (PDA) plates supplemented with 50 μg/ml streptomycin. The colony edges of resulted fungal cultures were cut and removed to new PDA plates for purification after 2 days incubation at 28°C. After 3 rounds of subculture, a total of 19 purified isolates were obtained and these isolates showed similar phenotypes in morphological characters. The fungal colonies were fast growing (25 mm per day at 28°C on PDA plates) and were circular shaped with massive aerial hyphae, white to ochraceous color. Non-septate hyphae were hyaline and the septa were found only at the branching points. Sporangiophores arose from hyphae or from stolons. Sporangiospores were hyaline, smooth-walled, mostly subspherical to ellipsoidal, and measured 1.34 to 2.73 µm (width) and 3.12 to 6.19 µm (length) (1.98 ± 0.36×4.46 ± 0.69, n=100)(Alvarez et al. 2011). Three independent isolates (GM-07, GM-16, GM-19) were selected used for further genetic analysis and pathogenicity test. The internal transcribed spacer (ITS) and the D1/D2 region of the nuclear large subunit ribosomal RNA gene (LSU) were amplified by primers ITS1/ITS4 and primers NL1/LR3, respectively (Walther et al. 2013). BLASTn analyses of ITS (MN081612, MN081613, MN087659) and LUS (MN080423, MN080422, MN080432) sequences exhibited 99 to 100% identify to Mucor irregularis strains HZ640, extr25 and CBS977.68 (Accession numbers KC461926, MH510278 of ITS and JX976214 of LUS). These observed morphological features and molecular identification indicated that the pathogen possessed identical characteristics as Mucor irregularis Stchigel, Cano, Guarro & Ed. Alvarez (Alvarez et al. 2011). To conduct a pathogenicity test (Al-Sadi et al. 2014), 20 µl of spore suspension (106 spores ml-1) were inoculated into five healthy mangosteen fruits by sterile syringes, meanwhile another five healthy fruits were injected with sterilized water as controls. All inoculated fruits were kept in sealed plastic boxes at 28°C with a 12L/12D illumination cycle and 90% relative humidity. After about 3 to 7 days, the inoculated materials showed similar symptoms to those on the original diseased fruits, while control samples remained symptomless. M. irregularis was successfully re-isolated from symptomatic fruits, fulfilling Koch's postulates. Only three plant species that can be infected by M. irregularis have been reported so far, including key lime from Oman (Al-Sadi et al. 2014), corn from China (Peng et al. 2015), and sorghum from Brazil (Lima et al. 2018). To our knowledge, this is the first report of M. irregularis causing the postharvest rot on mangosteen fruit in China.

Cunninghamella arunalokei a New Species of Cunninghamella from India Causing Disease in an Immunocompetent Individual

Mucormycosis due to Cunninghamella spp. is a rare disease, especially in immunocompetent individuals. Here, we describe the isolation and characterization of a new species of Cunninghamella, causing chronic rhino-orbital-cerebral disease, and review cases of mucormycosis due to Cunninghamella spp. in immunocompetent individuals. The Basic Local Alignment Search Tool (BLAST) analysis of the internal transcribed spacer region (ITS) sequence of isolate NCCPF 890012 showed 90% similarity with Cunninghamella bigelovii, while the large ribosomal subunit (28S) and translation elongation factor-1 alpha (EF-1 alpha) gene sequences showed 98% identity. Further, the phylogenetic analysis with concatenated sequences clustered isolate (NCCPF 890012) closely with C. bigelovii. The ITS sequence showed the maximum variation among three genes analyzed and helped in the new species’ delineation. Comparison of the assembled whole genome of NCCPF 890012 with other Mucorales using 123 single-copy orthologous genes showed clustering within the genus Cunninghamella. Based on these findings, the isolate is considered to be a new species of Cunninghamella and designated as Cunninghamella arunalokei sp. nov. Despite repeated debridement and antifungal treatment, the patient had multiple recurrences with intracranial extension and succumbed to the illness.

Emergence of resistant Candida glabrata in Germany

Background

Candida glabrata is the second leading fungal pathogen causing candidaemia and invasive candidiasis in Europe. This yeast is recognized for its rapid ability to acquire antifungal drug resistance.

Objectives

We systematically evaluated 176 C. glabrata isolates submitted to the German National Reference Center for Invasive Fungal Infections (NRZMyk) between 2015 and 2019 with regard to echinocandin and fluconazole susceptibility.

Methods

Susceptibility testing was performed using a reference protocol (EUCAST) and a range of commercial assays. Hot spot regions of the echinocandin target FKS genes were sequenced using Sanger sequencing.

Results

In total, 84 of 176 isolates were initially classified as anidulafungin-resistant based on EUCAST testing. Of those, 71 harboured mutations in the glucan synthase encoding FKS genes (13% in FKS1, 87% in FKS2). Significant differences in anidulafungin MICs were found between distinct mutation sites. 11 FKS wild-type (WT) isolates initially classified as resistant exhibited anidulafungin MICs fluctuating around the interpretation breakpoint upon re-testing with multiple assays. Two FKS WT isolates consistently showed high anidulafungin MICs and thus must be considered resistant despite the absence of target gene mutations. Over one-third of echinocandin-resistant strains displayed concomitant fluconazole resistance. Of those, isolates linked to bloodstream infection carrying a change at Ser-663 were associated with adverse clinical outcome.

Conclusions

Resistant C. glabrata strains are emerging in Germany. Phenotypic echinocandin testing can result in misclassification of susceptible strains. FKS genotyping aids in detecting these strains, however, echinocandin resistance may occur despite a wild-type FKS genotype.

Discovery of Novel Backusella (Backusellaceae, Mucorales) Isolated from Invertebrates and Toads in Cheongyang, Korea

Three novel fungal species, Backusella chlamydospora sp. nov., B. koreana sp. nov., and B. thermophila sp. nov., as well as two new records, B. oblongielliptica and B. oblongispora, were found in Cheongyang, Korea, during an investigation of fungal species from invertebrates and toads. All species are described here using morphological characters and sequence data from internal transcribed spacer sequences of ribosomal DNA and large subunit of the ribosomal DNA. Backusella chlamydospora is different from other Backusella species by producing chlamydospores. Backusella koreana can be distinguished from other Backusella species by producing abundant yeast-like cells. Backusella thermophila is characterized by a variable (subglobose to oblong, applanate to oval, conical and ellipsoidal to pyriform) columellae and grows well at 37 °C. Multigene phylogenetic analyses of the combined ITS and LSU rDNA sequences data generated from maximum likelihood and MrBayes analyses indicate that B. chlamydospora, B. koreana, and B. thermophila form distinct lineages in the family Backusellaceae. Detailed descriptions, illustrations, phylogenetic tree, and taxonomic key to the Backusella species present in Korea are provided.