Journal of Fungi

12 pages, 495 KiB

Open AccessArticle

Fusarium musae from Diseased Bananas and Human Patients: Susceptibility to Fungicides Used in Clinical and Agricultural Settings

by Valeria Tava, Anna Prigitano, Paolo Cortesi, Maria Carmela Esposto and Matias Pasquali

J. Fungi 2021, 7(9), 784; https://doi.org/10.3390/jof7090784 - 21 Sep 2021

Cited by 11 | Viewed by 2672

Abstract

Fusarium musae belongs to the Fusarium fujikuroi species complex. It causes crown rot disease in banana but also keratitis and skin infections as well as systemic infections in immunocompromised patients. Antifungal treatments in clinical and agricultural settings rely mostly on molecules belonging to [...] Read more.

Fusarium musae belongs to the Fusarium fujikuroi species complex. It causes crown rot disease in banana but also keratitis and skin infections as well as systemic infections in immunocompromised patients. Antifungal treatments in clinical and agricultural settings rely mostly on molecules belonging to the azole class. Given the potential risk of pathogen spread from food to clinical settings, the goal of the work was to define the level of susceptibility to different azoles of a worldwide population of F. musae. Eight fungicides used in agriculture and five antifungals used in clinical settings (4 azoles and amphotericin B) were tested using the CLSI (Clinical and Laboratory Standards Institute) protocol methodology on 19 F. musae strains collected from both infected patients and bananas. The level of susceptibility to the different active molecules was not dependent on the source of isolation with the exception of fenbuconazole and difenoconazole which had a higher efficiency on banana-isolated strains. Minimal inhibitory concentrations (MICs) of the different molecules ranged from 0.12–0.25 mg/L for prochloraz to more than 16 mg/L for tetraconazole and fenbuconazole. Compared to the F. verticillioides, F. musae MICs were higher suggesting the importance of monitoring the potential future spread of this species also in clinical settings. Full article

(This article belongs to the Special Issue Clinically Relevant Fusarium Species)

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18 pages, 2293 KiB

Open AccessReview

Molecular Mechanisms Underlying Fungicide Resistance in Citrus Postharvest Green Mold

by Paloma Sánchez-Torres

J. Fungi 2021, 7(9), 783; https://doi.org/10.3390/jof7090783 - 21 Sep 2021

Cited by 35 | Viewed by 5610

Abstract

The necrotrophic fungus Penicillium digitatum (Pd) is responsible for the green mold disease that occurs during postharvest of citrus and causes enormous economic losses around the world. Fungicides remain the main method used to control postharvest green mold in citrus fruit storage despite [...] Read more.

The necrotrophic fungus Penicillium digitatum (Pd) is responsible for the green mold disease that occurs during postharvest of citrus and causes enormous economic losses around the world. Fungicides remain the main method used to control postharvest green mold in citrus fruit storage despite numerous occurrences of resistance to them. Hence, it is necessary to find new and more effective strategies to control this type of disease. This involves delving into the molecular mechanisms underlying the appearance of resistance to fungicides during the plant–pathogen interaction. Although mechanisms involved in resistance to fungicides have been studied for many years, there have now been great advances in the molecular aspects that drive fungicide resistance, which facilitates the design of new means to control green mold. A wide review allows the mechanisms underlying fungicide resistance in Pd to be unveiled, taking into account not only the chemical nature of the compounds and their target of action but also the general mechanism that could contribute to resistance to others compounds to generate what we call multidrug resistance (MDR) phenotypes. In this context, fungal transporters seem to play a relevant role, and their mode of action may be controlled along with other processes of interest, such as oxidative stress and fungal pathogenicity. Thus, the mechanisms for acquisition of resistance to fungicides seem to be part of a complex framework involving aspects of response to stress and processes of fungal virulence. Full article

(This article belongs to the Section Fungal Pathogenesis and Disease Control)

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16 pages, 1069 KiB

Open AccessArticle

Intake of Koji Amazake Improves Defecation Frequency in Healthy Adults

by Atsushi Kurahashi, Toshihiko Enomoto, Yoshifumi Oguro, Ayana Kojima-Nakamura, Kazuya Kodaira, Kenichi Watanabe, Nobuhiro Ozaki, Hiroshi Goto and Masao Hirayama

J. Fungi 2021, 7(9), 782; https://doi.org/10.3390/jof7090782 - 21 Sep 2021

Cited by 7 | Viewed by 4194

Abstract

Reportedly, the intake of koji amazake, a beverage made from steamed rice fermented by Aspergillus oryzae, improves defecation frequency. However, its functional ingredients and mechanism of action remain unclear. To compare the effects of koji amazake and a placebo beverage on [...] Read more.

Reportedly, the intake of koji amazake, a beverage made from steamed rice fermented by Aspergillus oryzae, improves defecation frequency. However, its functional ingredients and mechanism of action remain unclear. To compare the effects of koji amazake and a placebo beverage on defecation frequency and to identify the functional ingredients and mechanism of action, a randomized, placebo-controlled, double-blind parallel-group comparative trial was performed on two groups. The koji amazake had 302 ± 15.5 mg/118 g of A. oryzae cells, which was not in the placebo. Compared with the placebo group, the koji amazake group showed a significant increase in weekly defecation frequency at 2 weeks (5.09 days vs. 4.14 days), 3 weeks (5.41 days vs. 4.18 days), and 4 weeks (5.09 days vs. 3.95 days), along with an increase in the weekly fecal weight at 4 weeks (724 g vs. 501 g). The intake of koji amazake did not induce significant intergroup differences in the fecal SCFA concentration, whereas it significantly decreased the relative abundance of Blautia and significantly increased that of Bacteroides at 3 weeks. Therefore, koji amazake intake improved defecation frequency, and A. oryzae cells played potentially important roles as functional ingredients. Full article

(This article belongs to the Special Issue Aspergillus oryzae and related Koji molds)

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16 pages, 3643 KiB

Open AccessArticle

Analysis of Stored Wheat Grain-Associated Microbiota Reveals Biocontrol Activity among Microorganisms against Mycotoxigenic Fungi

by Manoj Kumar Solanki, Ahmed Abdelfattah, Sudharsan Sadhasivam, Varda Zakin, Michael Wisniewski, Samir Droby and Edward Sionov

J. Fungi 2021, 7(9), 781; https://doi.org/10.3390/jof7090781 - 20 Sep 2021

Cited by 13 | Viewed by 4215

Abstract

Wheat grains are colonized by complex microbial communities that have the potential to affect seed quality and susceptibility to disease. Some of the beneficial microbes in these communities have been shown to protect plants against pathogens through antagonism. We evaluated the role of [...] Read more.

Wheat grains are colonized by complex microbial communities that have the potential to affect seed quality and susceptibility to disease. Some of the beneficial microbes in these communities have been shown to protect plants against pathogens through antagonism. We evaluated the role of the microbiome in seed health: in particular, against mycotoxin-producing fungi. Amplicon sequencing was used to characterize the seed microbiome and determine if epiphytes and endophytes differ in their fungal and bacterial diversity and community composition. We then isolated culturable fungal and bacterial species and evaluated their antagonistic activity against mycotoxigenic fungi. The most prevalent taxa were found to be shared between the epiphytic and endophytic microbiota of stored wheat seeds. Among the isolated bacteria, Bacillus strains exhibited strong antagonistic properties against fungal pathogens with noteworthy fungal load reduction in wheat grain samples of up to a 3.59 log₁₀ CFU/g compared to untreated controls. We also found that a strain of the yeast, Rhodotorula glutinis, isolated from wheat grains, degrades and/or metabolizes aflatoxin B₁, one of the most dangerous mycotoxins that negatively affects physiological processes in animals and humans. The mycotoxin level in grain samples was significantly reduced up to 65% in the presence of the yeast strain, compared to the untreated control. Our study demonstrates that stored wheat grains are a rich source of bacterial and yeast antagonists with strong inhibitory and biodegradation potential against mycotoxigenic fungi and the mycotoxins they produce, respectively. Utilization of these antagonistic microorganisms may help reduce fungal and mycotoxin contamination, and potentially replace traditionally used synthetic chemicals. Full article

(This article belongs to the Special Issue Mycotoxins and Toxigenic Fungi)

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16 pages, 1420 KiB

Open AccessReview

Insights into the Role of Fungi in Pine Wilt Disease

by Cláudia S. L. Vicente, Miguel Soares, Jorge M. S. Faria, Ana P. Ramos and Maria L. Inácio

J. Fungi 2021, 7(9), 780; https://doi.org/10.3390/jof7090780 - 20 Sep 2021

Cited by 24 | Viewed by 4668

Abstract

Pine wilt disease (PWD) is a complex disease that severely affects the biodiversity and economy of Eurasian coniferous forests. Three factors are described as the main elements of the disease: the pinewood nematode (PWN) Bursaphelenchus xylophilus, the insect-vector Monochamus spp., and the [...] Read more.

Pine wilt disease (PWD) is a complex disease that severely affects the biodiversity and economy of Eurasian coniferous forests. Three factors are described as the main elements of the disease: the pinewood nematode (PWN) Bursaphelenchus xylophilus, the insect-vector Monochamus spp., and the host tree, mainly Pinus spp. Nonetheless, other microbial interactors have also been considered. The study of mycoflora in PWD dates back the late seventies. Culturomic studies have revealed diverse fungal communities associated with all PWD key players, composed frequently of saprophytic fungi (i.e., Aspergillus, Fusarium, Trichoderma) but also of necrotrophic pathogens associated with bark beetles, such as ophiostomatoid or blue-stain fungi. In particular, the ophiostomatoid fungi often recovered from wilted pine trees or insect pupal chambers/tunnels, are considered crucial for nematode multiplication and distribution in the host tree. Naturally occurring mycoflora, reported as possible biocontrol agents of the nematode, are also discussed in this review. This review discloses the contrasting effects of fungal communities in PWD and highlights promising fungal species as sources of PWD biocontrol in the framework of sustainable pest management actions. Full article

(This article belongs to the Section Environmental and Ecological Interactions of Fungi)

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17 pages, 3319 KiB

Open AccessArticle

In Vitro Effects of Leaf Extracts from Brassica rapa on the Growth of Two Entomopathogenic Fungi

by Daniel G. Cerritos-Garcia, Pasco B. Avery, Xavier Martini, Valentina Candian, Liliana M. Cano and Ronald D. Cave

J. Fungi 2021, 7(9), 779; https://doi.org/10.3390/jof7090779 - 19 Sep 2021

Cited by 3 | Viewed by 3294

Abstract

This study aimed to determine the inhibitive or stimulatory effects of leaf extracts from two Brassica rapa subspecies on the hyphal growth of two well-known entomopathogenic fungi, Cordyceps fumosorosea and Beauveria bassiana. Extract concentrations of 50, 25, and 10% w/v based [...] Read more.

This study aimed to determine the inhibitive or stimulatory effects of leaf extracts from two Brassica rapa subspecies on the hyphal growth of two well-known entomopathogenic fungi, Cordyceps fumosorosea and Beauveria bassiana. Extract concentrations of 50, 25, and 10% w/v based on leaf fresh weight were prepared from turnip (B. rapa subspecies rapa) and bok choy (B. rapa subspecies chinensis) leaves. Each concentration was individually incorporated into potato dextrose agar plates for in vitro bioassays. The center of each plate was inoculated with 20 µL of a fungal suspension that was allowed 24 h to soak into the agar before sealing the plates and incubating them at 25 °C under a 14-h photophase. The fungal colony perimeter was marked 5 days after inoculation on two perpendicular lines drawn on the bottom of each plate. Radial colony growth was measured from 4 marks per plate 5, 10, and 15 days later. Radial growth rates for both fungi were 1.3–2.0 and 0.9–1.4 times faster with bok choy and turnip extracts, respectively, at the 25% and 50% concentrations compared to the no-extract control treatment. Therefore, bok choy and turnip leaf extracts can stimulate entomopathogenic fungus growth within 15 days. Biochemical compounds in the extracts include sesquiterpenes, α-copaene, β-selinene, γ-gurjunene, calamenene, cubenene, and α-calacorene. Full article

(This article belongs to the Special Issue Fungal Pathogen as Potent Toxin for Pest and Disease Control)

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7 pages, 1173 KiB

Open AccessCase Report

Disseminated Geosmithia argillacea Infection in a Patient with Ph-Positive Acute Lymphoblastic Leukemia. Case Report and Literature Review

by Antonio Giordano, Francesca Di Landro, Elena De Carolis, Marianna Criscuolo, Giulia Dragonetti, Luana Fianchi and Livio Pagano

J. Fungi 2021, 7(9), 778; https://doi.org/10.3390/jof7090778 - 19 Sep 2021

Cited by 1 | Viewed by 2084

Abstract

Invasive fungal infection (IFI) remains the major complication in patients with either acute leukemia, allogeneic stem cell transplantation setting, or both, especially regarding pulmonary localization. We report an experience of a 74-year-old Caucasian male with a Philadelphia-positive (BCR-ABL p190) Common B-acute lymphoblastic leukemia [...] Read more.

Invasive fungal infection (IFI) remains the major complication in patients with either acute leukemia, allogeneic stem cell transplantation setting, or both, especially regarding pulmonary localization. We report an experience of a 74-year-old Caucasian male with a Philadelphia-positive (BCR-ABL p190) Common B-acute lymphoblastic leukemia (ALL) who developed a pulmonary infection due to Geosmithia argillacea. Furthermore, we describe the management of this complication and the results of microbiological tests useful to guide the treatment. All cases reported show failure of voriconazole treatment. In the majority of cases a good susceptibility to posaconazole has been reported, which seems to have a good clinical impact; however, only L-AmB shows a clinical effect to produce quick clinical improvement and so it should be a drug of choice. A literature revision shows that only a few papers have thus far described this infection, at present only one case was reported in a hematological setting like a gastrointestinal graft versus host disease in an allogeneic HSCT recipient. The severity of clinical conditions in hematological malignancy settings requires improving the management of this emerging invasive fungal infection. Indeed, a molecular diagnostic approach with a tight laboratory collaboration and targeted therapy should become the gold standard. Full article

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20 pages, 4758 KiB

Open AccessArticle

Weather-Based Predictive Modeling of Cercospora beticola Infection Events in Sugar Beet in Belgium

by Moussa El Jarroudi, Fadia Chairi, Louis Kouadio, Kathleen Antoons, Abdoul-Hamid Mohamed Sallah and Xavier Fettweis

J. Fungi 2021, 7(9), 777; https://doi.org/10.3390/jof7090777 - 18 Sep 2021

Cited by 2 | Viewed by 3293

Abstract

Cercospora leaf spot (CLS; caused by Cercospora beticola Sacc.) is the most widespread and damaging foliar disease of sugar beet. Early assessments of CLS risk are thus pivotal to the success of disease management and farm profitability. In this study, we propose a [...] Read more.

Cercospora leaf spot (CLS; caused by Cercospora beticola Sacc.) is the most widespread and damaging foliar disease of sugar beet. Early assessments of CLS risk are thus pivotal to the success of disease management and farm profitability. In this study, we propose a weather-based modelling approach for predicting infection by C. beticola in sugar beet fields in Belgium. Based on reported weather conditions favoring CLS epidemics and the climate patterns across Belgian sugar beet-growing regions during the critical infection period (June to August), optimum weather conditions conducive to CLS were first identified. Subsequently, 14 models differing according to the combined thresholds of air temperature (T), relative humidity (RH), and rainfall (R) being met simultaneously over uninterrupted hours were evaluated using data collected during the 2018 to 2020 cropping seasons at 13 different sites. Individual model performance was based on the probability of detection (POD), the critical success index (CSI), and the false alarm ratio (FAR). Three models (i.e., M1, M2 and M3) were outstanding in the testing phase of all models. They exhibited similar performance in predicting CLS infection events at the study sites in the independent validation phase; in most cases, the POD, CSI, and FAR values were ≥84%, ≥78%, and ≤15%, respectively. Thus, a combination of uninterrupted rainy conditions during the four hours preceding a likely start of an infection event, RH > 90% during the first four hours and RH > 60% during the following 9 h, daytime T > 16 °C and nighttime T > 10 °C, were the most conducive to CLS development. Integrating such weather-based models within a decision support tool determining fungicide spray application can be a sound basis to protect sugar beet plants against C. beticola, while ensuring fungicides are applied only when needed throughout the season. Full article

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20 pages, 1092 KiB

Open AccessReview

Current Perspectives of Biocontrol Agents for Management of Fusarium verticillioides and Its Fumonisin in Cereals—A Review

by Deepa N, Premila N. Achar and Marikunte Y. Sreenivasa

J. Fungi 2021, 7(9), 776; https://doi.org/10.3390/jof7090776 - 18 Sep 2021

Cited by 35 | Viewed by 5294

Abstract

Fusarium verticillioides is the most predominant fungal phytopathogen of cereals and it is posing great concern from a global perspective. The fungus is mainly associated with maize, rice, sorghum, wheat, sugarcane, banana, and asparagus and causes cob, stalk, ear, root, crown, top, and [...] Read more.

Fusarium verticillioides is the most predominant fungal phytopathogen of cereals and it is posing great concern from a global perspective. The fungus is mainly associated with maize, rice, sorghum, wheat, sugarcane, banana, and asparagus and causes cob, stalk, ear, root, crown, top, and foot rot. F. verticillioides produces fumonisins as the major secondary metabolite along with trace levels of beauvericin, fusaric acid, fusarin C, gibberiliformin, and moniliformin. Being a potential carcinogen, fumonisins continue to receive major attention as they are common contaminants in cereals and its processed food products. The importance of elimination of F. verticillioides growth and its associated fumonisin from cereals cannot be overemphasized considering the significant health hazards associated with its consumption. Physical and chemical approaches have been shown to reduce fumonisin B1 concentrations among feeds and food products but have proved to be ineffective during the production process. Hence, biological control methods using microorganisms, plant extracts, antioxidants, essential oils, phenolic compounds, and other advanced technologies such as growing disease-resistant crops by applying genetic engineering, have become an effective alternative for managing F. verticillioides and its toxin. The different methods, challenges, and concerns regarding the biocontrol of F. verticillioides and production of fumonisin B1 have been addressed in the present review. Full article

(This article belongs to the Special Issue Different Antimycotoxin Strategies)

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20 pages, 5569 KiB

Open AccessArticle

Macrofungi Cultivation in Shady Forest Areas Significantly Increases Microbiome Diversity, Abundance and Functional Capacity in Soil Furrows

by Dong Liu, Yanliang Wang, Peng Zhang, Fuqiang Yu and Jesús Perez-Moreno

J. Fungi 2021, 7(9), 775; https://doi.org/10.3390/jof7090775 - 18 Sep 2021

Cited by 9 | Viewed by 5035

Abstract

Cultivating macrofungi is an important management measure to develop economy in shady forest areas; however, its effect on soil ecology, especially microbial abundance and structure, remains insufficiently studied. Herein, in a subtropical forestland, soil chemical and enzyme analyses, metagenomic sequencing and quantitative real-time [...] Read more.

Cultivating macrofungi is an important management measure to develop economy in shady forest areas; however, its effect on soil ecology, especially microbial abundance and structure, remains insufficiently studied. Herein, in a subtropical forestland, soil chemical and enzyme analyses, metagenomic sequencing and quantitative real-time PCR were employed to evaluate the impact of Stropharia rugosoannulata cultivation on soil microbiomes in three niches: soil below fungal beds, soil from furrows, and control forest soil with no influence from mushroom cultivation. Nutrients were accumulated in the soil below fungal beds with a significant increase (p < 0.05) in SOC, total C, total N, available P, and the activities of glucosidase and cellobiosidase. Non-metric multidimensional scaling and PERMANOVA results indicated that the structure of the microbiomes had been significantly (p < 0.05) shaped among the different niches. Soil furrows were microbial hotspots characterized by the higher microbial diversity and richness. Moreover, the increased microbiome abundance (assessed through qPCR) and the high number of significant stimulated functional types (based on MetaCyc genome database) indicated an enhanced functional capacity in furrows. Together, these results provide a comprehensive understanding of the microbial assemblies and the differently influenced soil properties in mushroom cultivation areas. Full article

(This article belongs to the Special Issue Diversity and Classification of Environmental Fungi)

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22 pages, 3981 KiB

Open AccessArticle

Entomotoxic Activity of the Extracts from the Fungus, Alternaria tenuissima and Its Major Metabolite, Tenuazonic Acid

by Dilara Salimova, Anna Dalinova, Vsevolod Dubovik, Igor Senderskiy, Elena Stepanycheva, Oksana Tomilova, Qiongbo Hu and Alexander Berestetskiy

J. Fungi 2021, 7(9), 774; https://doi.org/10.3390/jof7090774 - 18 Sep 2021

Cited by 11 | Viewed by 3015

Abstract

The study of fungal antibiotics in their competitive interactions with arthropods may lead to the development of novel biorational insecticides. Extracts of Alternaria tenuissima MFP253011 obtained using various methods showed a wide range of biological activities, including entomotoxic properties. Analysis of their composition [...] Read more.

The study of fungal antibiotics in their competitive interactions with arthropods may lead to the development of novel biorational insecticides. Extracts of Alternaria tenuissima MFP253011 obtained using various methods showed a wide range of biological activities, including entomotoxic properties. Analysis of their composition and bioactivity allowed us to reveal several known mycotoxins and unidentified compounds that may be involved in the entomotoxic activity of the extracts. Among them, tenuazonic acid (TeA), which was the major component of the A. tenuissima extracts, was found the most likely to have larvicidal activity against Galleria mellonella. In the intrahaemocoel injection bioassay, TeA was toxic to G. mellonella and of Zophobas morio with an LT₅₀ of 6 and 2 days, respectively, at the level of 50 µg/larva. Administered orally, TeA inhibited the growth of G. mellonella larvae and caused mortality of Acheta domesticus adults (LT₅₀ 7 days) at a concentration of 250 µg/g of feed. TeA showed weak contact intestinal activity against the two phytophages, Tetranychus urticae and Schizaphis graminum, causing 15% and 27% mortality at a concentration of 1 mg/mL, respectively. TeA was cytotoxic to the Sf9 cell line (IC₅₀ 25 µg/mL). Thus, model insects such as G. mellonella could be used for further toxicological characterization of TeA. Full article

(This article belongs to the Special Issue Fungal Pathogen as Potent Toxin for Pest and Disease Control)

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12 pages, 2960 KiB

Open AccessArticle

Selection of Atoxigenic Aspergillus flavus for Potential Use in Aflatoxin Prevention in Shandong Province, China

by Jia Xu, Peng Wang, Zehua Zhou, Peter John Cotty and Qing Kong

J. Fungi 2021, 7(9), 773; https://doi.org/10.3390/jof7090773 - 18 Sep 2021

Cited by 9 | Viewed by 3331

Abstract

Aspergillus flavus is a common filamentous fungus widely present in the soil, air, and in crops. This facultative pathogen of both animals and plants produces aflatoxins, a group of mycotoxins with strong teratogenic and carcinogenic properties. Peanuts are highly susceptible to aflatoxin contamination [...] Read more.

Aspergillus flavus is a common filamentous fungus widely present in the soil, air, and in crops. This facultative pathogen of both animals and plants produces aflatoxins, a group of mycotoxins with strong teratogenic and carcinogenic properties. Peanuts are highly susceptible to aflatoxin contamination and consumption of contaminated peanuts poses serious threats to the health of humans and domestic animals. Currently, the competitive displacement of aflatoxin-producers from agricultural environments by atoxigenic A. flavus is the most effective method of preventing crop aflatoxin contamination. In the current study, 47 isolates of A. flavus collected from peanut samples originating in Shandong Province were characterized with molecular methods and for aflatoxin-producing ability in laboratory studies. Isolates PA04 and PA10 were found to be atoxigenic members of the L strains morphotype. When co-inoculated with A. flavus NRRL3357 at ratios of 1:10, 1:1, and 10:1 (PA04/PA10: NRRL3357), both atoxigenic strains were able to reduce aflatoxin B₁ (AFB₁) levels, on both culture media and peanut kernels, by up to 90%. The extent to which atoxigenic strains reduced contamination was correlated with the inoculation ratio. Abilities to compete of PA04 and PA10 were also independently verified against local aflatoxin-producer PA37. The results suggest that the two identified atoxigenic strains are good candidates for active ingredients of biocontrol products for the prevention of aflatoxin contamination of peanuts in Shandong Province. Full article

(This article belongs to the Special Issue Aspergillus flavus, Aflatoxins, and Their Effects on Crop Production and Food Safety)

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13 pages, 1493 KiB

Open AccessArticle

Mercury in Macrolepiota procera (Scop.) Singer and Its Underlying Substrate—Environmental and Health Risks Assessment

by Ivona Jančo, Marek Šnirc, Martin Hauptvogl, Lenka Demková, Hana Franková, Vladimír Kunca, Tomáš Lošák and Július Árvay

J. Fungi 2021, 7(9), 772; https://doi.org/10.3390/jof7090772 - 18 Sep 2021

Cited by 2 | Viewed by 2395

Abstract

Wild-growing edible mushrooms are valuable food with a high content of proteins, fibers, antioxidants, and they are characterized by their specific taste and flavor. However, from an ecotoxicological point of view, they are a risk commodity because of their extremely high bioaccumulative capacity [...] Read more.

Wild-growing edible mushrooms are valuable food with a high content of proteins, fibers, antioxidants, and they are characterized by their specific taste and flavor. However, from an ecotoxicological point of view, they are a risk commodity because of their extremely high bioaccumulative capacity to accumulate the risk elements and contaminants from the environment. In the present study, we examined mercury (Hg) contamination in 230 fruiting bodies of Macrolepiota procera (Scop.) Singer and 230 soil/substrate samples, which were collected in foraging seasons 2015–2019 from 22 different locations in Slovakia. Total mercury content was determined by cold-vapor AAS analyzer AMA 254. The level of contamination and environmental risks were assessed by contamination factor (C_f), index of geoaccumulation (I_geo), and potential environmental risk index (PER). Bioaccumulation factor (BAF) was calculated for individual anatomical parts of M. procera. Mercury content in the soil/substrate samples varied between 0.02 and 0.89 mg kg⁻¹ DW, and in mushroom samples between 0.03 and 2.83 mg kg⁻¹ DW (stems), and between 0.04 and 6.29 mg kg⁻¹ DW (caps). The obtained results were compared with the provisional tolerable weekly intake for Hg defined by WHO to determine a health risk resulting from regular and long-term consumption of M. procera. Full article

(This article belongs to the Special Issue Edible Mushrooms)

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17 pages, 4221 KiB

Open AccessArticle

Neopestalotiopsis Species Associated with Flower Diseases of Macadamia integrifolia in Australia

by Kandeeparoopan Prasannath, Roger G. Shivas, Victor J. Galea and Olufemi A. Akinsanmi

J. Fungi 2021, 7(9), 771; https://doi.org/10.3390/jof7090771 - 17 Sep 2021

Cited by 24 | Viewed by 5270

Abstract

Macadamia (Macadamia integrifolia) is native to eastern Australia and produces an edible nut that is extensively cultivated in commercial orchards in several countries. Little is known about the diversity of fungi associated with diseases of macadamia inflorescences. A survey of fungi [...] Read more.

Macadamia (Macadamia integrifolia) is native to eastern Australia and produces an edible nut that is extensively cultivated in commercial orchards in several countries. Little is known about the diversity of fungi associated with diseases of macadamia inflorescences. A survey of fungi associated with the dry flower disease of macadamia detected several isolates of Neopestalotiopsis (Pestalotiopsidaceae, Sordariomycetes). Five new species of Neopestalotiopsis were identified based on molecular phylogenetic analyses of concatenated gene sequences of the internal transcribed spacer (ITS), β-tubulin (TUB), and the translation elongation factor 1-alpha (TEF1α). The new species are named Neopestalotiopsis drenthii, N. maddoxii, N. olumideae, N. vheenae, and N. zakeelii, and are described by molecular, morphological, and cultural characteristics. The ecology of the isolates and their pathogenic, saprophytic, or commensal ability were not determined. Full article

(This article belongs to the Section Fungal Evolution, Biodiversity and Systematics)

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13 pages, 17608 KiB

Open AccessReview

White Rot Fungi (Hymenochaetales) and Esca of Grapevine: Insights from Recent Microbiome Studies

by Giovanni Del Frari, Helena Oliveira and Ricardo Boavida Ferreira

J. Fungi 2021, 7(9), 770; https://doi.org/10.3390/jof7090770 - 17 Sep 2021

Cited by 23 | Viewed by 3752

Abstract

Esca is a major grapevine trunk disease that heavily affects vineyards in the Northern hemisphere. The etiology and epidemiology of this disease have been subject of dispute ever since the earliest disease reports. The reason behind such debate is the presence of multiple [...] Read more.

Esca is a major grapevine trunk disease that heavily affects vineyards in the Northern hemisphere. The etiology and epidemiology of this disease have been subject of dispute ever since the earliest disease reports. The reason behind such debate is the presence of multiple internal and external symptoms, as well as several putative and confirmed wood pathogens. While the role of pathogenic fungi, as causal agents of wood symptoms, has been thoroughly assessed, their role in the expression of leaf symptoms remains to be fully elucidated. In this review, we analyzed etiological and epidemiological data, with a special focus on the microbiological aspect of esca and the involvement of Hymenochaetales (Basidiomycota). Vineyard studies have associated leaf symptoms with the presence of white rot, most frequently caused by Fomitiporia mediterranea (Hymenochaetales), while tracheomycotic fungi are commonly found, with similar abundance, in symptomatic and asymptomatic vines. Pathogenicity trials have excluded a direct effect of Hymenochaetales species in triggering leaf symptoms, while the data concerning the role of tracheomycotic fungi remains controversial. Recent microbiome studies confirmed that F. mediterranea is more abundant in leaf-symptomatic vines, and treatments that effectively control leaf symptoms, such as sodium arsenite spray and trunk surgery, act directly on the abundance of F. mediterranea or on the presence of white rot. This suggest that the simultaneous presence of Hymenochaetales and tracheomycotic fungi is a pre-requisite for leaf symptoms; however, the relation among fungal pathogens, grapevine and other biotic and abiotic factors needs further investigation. Full article

(This article belongs to the Special Issue Application of Omics Technologies for a Deeper Insight into the Study of Fungal Trunk Pathogens of Grapevine)

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19 pages, 8974 KiB

Open AccessArticle

Defining Functions of Mannoproteins in Saccharomyces cerevisiae by High-Dimensional Morphological Phenotyping

by Farzan Ghanegolmohammadi, Hiroki Okada, Yaxuan Liu, Kaori Itto-Nakama, Shinsuke Ohnuki, Anna Savchenko, Erfei Bi, Satoshi Yoshida and Yoshikazu Ohya

J. Fungi 2021, 7(9), 769; https://doi.org/10.3390/jof7090769 - 17 Sep 2021

Cited by 8 | Viewed by 3758

Abstract

Mannoproteins are non-filamentous glycoproteins localized to the outermost layer of the yeast cell wall. The physiological roles of these structural components have not been completely elucidated due to the limited availability of appropriate tools. As the perturbation of mannoproteins may affect cell morphology, [...] Read more.

Mannoproteins are non-filamentous glycoproteins localized to the outermost layer of the yeast cell wall. The physiological roles of these structural components have not been completely elucidated due to the limited availability of appropriate tools. As the perturbation of mannoproteins may affect cell morphology, we investigated mannoprotein mutants in Saccharomyces cerevisiae via high-dimensional morphological phenotyping. The mannoprotein mutants were morphologically classified into seven groups using clustering analysis with Gaussian mixture modeling. The pleiotropic phenotypes of cluster I mutant cells (ccw12Δ) indicated that CCW12 plays major roles in cell wall organization. Cluster II (ccw14Δ, flo11Δ, srl1Δ, and tir3Δ) mutants exhibited altered mother cell size and shape. Mutants of cluster III and IV exhibited no or very small morphological defects. Cluster V (dse2Δ, egt2Δ, and sun4Δ) consisted of endoglucanase mutants with cell separation defects due to incomplete septum digestion. The cluster VI mutant cells (ecm33Δ) exhibited perturbation of apical bud growth. Cluster VII mutant cells (sag1Δ) exhibited differences in cell size and actin organization. Biochemical assays further confirmed the observed morphological defects. Further investigations based on various omics data indicated that morphological phenotyping is a complementary tool that can help with gaining a deeper understanding of the functions of mannoproteins. Full article

(This article belongs to the Special Issue The Fungal Cell Wall Integrity Pathway)

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16 pages, 2395 KiB

Open AccessArticle

The Siderophore Transporters Sit1 and Sit2 Are Essential for Utilization of Ferrichrome-, Ferrioxamine- and Coprogen-Type Siderophores in Aspergillus fumigatus

by Mario Aguiar, Thomas Orasch, Matthias Misslinger, Anna-Maria Dietl, Fabio Gsaller and Hubertus Haas

J. Fungi 2021, 7(9), 768; https://doi.org/10.3390/jof7090768 - 16 Sep 2021

Cited by 25 | Viewed by 3987

Abstract

Siderophore-mediated acquisition of iron has been shown to be indispensable for the virulence of several fungal pathogens, the siderophore transporter Sit1 was found to mediate uptake of the novel antifungal drug VL-2397, and siderophores were shown to be useful as biomarkers as well [...] Read more.

Siderophore-mediated acquisition of iron has been shown to be indispensable for the virulence of several fungal pathogens, the siderophore transporter Sit1 was found to mediate uptake of the novel antifungal drug VL-2397, and siderophores were shown to be useful as biomarkers as well as for imaging of fungal infections. However, siderophore uptake in filamentous fungi is poorly characterized. The opportunistic human pathogen Aspergillus fumigatus possesses five putative siderophore transporters. Here, we demonstrate that the siderophore transporters Sit1 and Sit2 have overlapping, as well as unique, substrate specificities. With respect to ferrichrome-type siderophores, the utilization of ferrirhodin and ferrirubin depended exclusively on Sit2, use of ferrichrome A depended mainly on Sit1, and utilization of ferrichrome, ferricrocin, and ferrichrysin was mediated by both transporters. Moreover, both Sit1 and Sit2 mediated use of the coprogen-type siderophores coprogen and coprogen B, while only Sit1 transported the bacterial ferrioxamine-type xenosiderophores ferrioxamines B, G, and E. Neither Sit1 nor Sit2 were important for the utilization of the endogenous siderophores fusarinine C and triacetylfusarinine C. Furthermore, A. fumigatus was found to lack utilization of the xenosiderophores schizokinen, basidiochrome, rhizoferrin, ornibactin, rhodotorulic acid, and enterobactin. Taken together, this study characterized siderophore use by A. fumigatus and substrate characteristics of Sit1 and Sit2. Full article

(This article belongs to the Special Issue Molecular Processes of Fungi)

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20 pages, 3073 KiB

Open AccessArticle

Using High-Throughput Amplicon Sequencing to Evaluate Intragenomic Variation and Accuracy in Species Identification of Cordyceps Species

by Soumitra Paloi, Wuttichai Mhuantong, Janet Jennifer Luangsa-ard and Noppol Kobmoo

J. Fungi 2021, 7(9), 767; https://doi.org/10.3390/jof7090767 - 16 Sep 2021

Cited by 4 | Viewed by 3193

Abstract

While recent sequencing technologies (third generation sequencing) can successfully sequence all copies of nuclear ribosomal DNA (rDNA) markers present within a genome and offer insights into the intragenomic variation of these markers, high intragenomic variation can be a source of confusion for high-throughput [...] Read more.

While recent sequencing technologies (third generation sequencing) can successfully sequence all copies of nuclear ribosomal DNA (rDNA) markers present within a genome and offer insights into the intragenomic variation of these markers, high intragenomic variation can be a source of confusion for high-throughput species identification using such technologies. High-throughput (HT) amplicon sequencing via PacBio SEQUEL I was used to evaluate the intragenomic variation of the ITS region and D1–D2 LSU domains in nine Cordyceps species, and the accuracy of such technology to identify these species based on molecular phylogenies was also assessed. PacBio sequences within strains showed variable level of intragenomic variation among the studied Cordyceps species with C. blackwelliae showing greater variation than the others. Some variants from a mix of species clustered together outside their respective species of origin, indicative of intragenomic variation that escaped concerted evolution shared between species. Proper selection of consensus sequences from HT amplicon sequencing is a challenge for interpretation of correct species identification. PacBio consensus sequences with the highest number of reads represent the major variants within a genome and gave the best results in terms of species identification. Full article

(This article belongs to the Section Fungal Evolution, Biodiversity and Systematics)

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15 pages, 1222 KiB

Open AccessArticle

Integration of Solid State and Submerged Fermentations for the Valorization of Organic Municipal Solid Waste

by Gheorghe-Adrian Martău, Peter Unger, Roland Schneider, Joachim Venus, Dan Cristian Vodnar and José Pablo López-Gómez

J. Fungi 2021, 7(9), 766; https://doi.org/10.3390/jof7090766 - 16 Sep 2021

Cited by 36 | Viewed by 5120

Abstract

Solid state fermentation (SsF) is recognized as a suitable process for the production of enzymes using organic residues as substrates. However, only a few studies have integrated an evaluation of the feasibility of applying enzymes produced by SsF into subsequent hydrolyses followed by [...] Read more.

Solid state fermentation (SsF) is recognized as a suitable process for the production of enzymes using organic residues as substrates. However, only a few studies have integrated an evaluation of the feasibility of applying enzymes produced by SsF into subsequent hydrolyses followed by the production of target compounds, e.g., lactic acid (LA), through submerged-liquid fermentations (SmF). In this study, wheat bran (WB) was used as the substrate for the production of enzymes via SsF by Aspergillus awamori DSM No. 63272. Following optimization, cellulase and glucoamylase activities were 73.63 ± 5.47 FPU/g_ds and 107.10 ± 2.63 U/g_db after 7 days and 5 days of fermentation, respectively. Enzymes were then used for the hydrolysis of the organic fraction of municipal solid waste (OFMSW). During hydrolysis, glucose increased considerably with a final value of 19.77 ± 1.56 g/L. Subsequently, hydrolysates were fermented in SmF by Bacillus coagulans A166 increasing the LA concentration by 15.59 g/L. The data reported in this study provides an example of how SsF and SmF technologies can be combined for the valorization of WB and OFMSW. Full article

(This article belongs to the Special Issue Fungal Biotechnology and Application)

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24 pages, 5362 KiB

Open AccessArticle

Metabolic Profiling and Metabolite Correlation Network Analysis Reveal That Fusarium solani Induces Differential Metabolic Responses in Lotus japonicus and Lotus tenuis against Severe Phosphate Starvation

by Amira Susana Nieva, Fernando Matías Romero, Alexander Erban, Pedro Carrasco, Oscar Adolfo Ruiz and Joachim Kopka

J. Fungi 2021, 7(9), 765; https://doi.org/10.3390/jof7090765 - 16 Sep 2021

Cited by 6 | Viewed by 3708

Abstract

Root fungal endophytes are essential mediators of plant nutrition under mild stress conditions. However, variations in the rhizosphere environment, such as nutrient depletion, could result in a stressful situation for both partners, shifting mutualistic to nonconvenient interactions. Mycorrhizal fungi and dark septate endophytes [...] Read more.

Root fungal endophytes are essential mediators of plant nutrition under mild stress conditions. However, variations in the rhizosphere environment, such as nutrient depletion, could result in a stressful situation for both partners, shifting mutualistic to nonconvenient interactions. Mycorrhizal fungi and dark septate endophytes (DSEs) have demonstrated their ability to facilitate phosphate (Pi) acquisition. However, few studies have investigated other plant–fungal interactions that take place in the root environment with regard to phosphate nutrition. In the present research work, we aimed to analyze the effect of extreme Pi starvation and the fungal endophyte Fusarium solani on the model Lotus japonicus and the crop L. tenuis. We conducted metabolomics analysis based on gas chromatography-mass spectrometry (GC-MS) on plant tissues under optimal conditions, severe Pi starvation and F.solani presence. By combining statistical and correlation network analysis strategies, we demonstrated the differential outcomes of the two plant species against the combination of treatments. The combination of nutritional stress and Fusarium presence activated significant modifications in the metabolism of L. japonicus affecting the levels of sugars, polyols and some amino acids. Our results display potential markers for further inspection of the factors related to plant nutrition and plant–fungal interactions. Full article

(This article belongs to the Special Issue Plant and Fungal Interactions)

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23 pages, 4328 KiB

Open AccessArticle

Variations in the Community Structure of Fungal Microbiota Associated with Apple Fruit Shaped by Fruit Bagging-Based Practice

by Punda Khwantongyim, Somying Wansee, Xi Lu, Wei Zhang and Guangyu Sun

J. Fungi 2021, 7(9), 764; https://doi.org/10.3390/jof7090764 - 15 Sep 2021

Cited by 7 | Viewed by 3014

Abstract

The various fungal communities that adhere to apple fruit are influenced by agricultural practices. However, the effects of fruit bagging-based management practice on the fungal microbiota are still unknown, and little is known about the fungal communities of bagged apple fruit. We conducted [...] Read more.

The various fungal communities that adhere to apple fruit are influenced by agricultural practices. However, the effects of fruit bagging-based management practice on the fungal microbiota are still unknown, and little is known about the fungal communities of bagged apple fruit. We conducted a study using apple fruit grown in a conventionally managed orchard where pesticide use is an indispensable practice. Fungal communities were collected from the calyx-end and peel tissues of bagged and unbagged fruit and characterized using barcode-type next-generation sequencing. Fruit bagging had a stronger effect on fungal richness, abundance, and diversity of the fungal microbiota in comparison to non-bagging. In addition, bagging also impacted the compositional variation of the fungal communities inhabiting each fruit part. We observed that fruit bagging had a tendency to maintain ecological equilibrium since Ascomycota and Basidiomycota were more distributed in bagged fruit than in unbagged fruit. These fungal communities consist of beneficial fungi rather than potentially harmful fungi. Approximately 50 dominant taxa were detected in bagged fruit, for example, beneficial genera such as Articulospora, Bullera, Cryptococcus, Dioszegia, Erythrobasidium, and Sporobolomyces, as well as pathogenic genera such as Aureobasidium and Taphrina. These results suggested that fruit bagging could significantly increase fungal richness and promote healthy fungal communities, especially the harmless fungal communities, which might be helpful for protecting fruit from the effects of pathogens. This study provides a foundation for understanding the impacts of bagging-based practice on the associated fungal microbiota. Full article

(This article belongs to the Special Issue Fungal Biodiversity and Ecology 2.0)

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22 pages, 5763 KiB

Open AccessArticle

Antifungal Activity of the Phenolic Compounds Ellagic Acid (EA) and Caffeic Acid Phenethyl Ester (CAPE) against Drug-Resistant Candida auris

by Fernanda Cristina Possamai Rossatto, Nagendran Tharmalingam, Iliana E. Escobar, Pedro Alves d’Azevedo, Karine Rigon Zimmer and Eleftherios Mylonakis

J. Fungi 2021, 7(9), 763; https://doi.org/10.3390/jof7090763 - 15 Sep 2021

Cited by 33 | Viewed by 4915

Abstract

Candida auris is an emerging healthcare-associated fungal pathogen that has become a serious global health threat. Current treatment options are limited due to drug resistance. New therapeutic strategies are required to target this organism and its pathogenicity. Plant polyphenols are structurally diverse compounds [...] Read more.

Candida auris is an emerging healthcare-associated fungal pathogen that has become a serious global health threat. Current treatment options are limited due to drug resistance. New therapeutic strategies are required to target this organism and its pathogenicity. Plant polyphenols are structurally diverse compounds that present a vast range of biological properties. In the present study, plant-derived molecules ellagic acid (EA) and caffeic acid phenethyl ester (CAPE) were investigated for their antifungal and antivirulence activities against Candida auris. We also tested against C. albicans. The minimum inhibitory concentration (MIC) for EA ranged from 0.125 to 0.25 µg/mL and for CAPE ranged from 1 to 64 µg/mL against drug-resistant C. auris strains. Killing kinetics determined that after 4 h treatment with CAPE, there was a complete reduction of viable C. auris cells compared to fluconazole. Both compounds might act by modifying the fungal cell wall. CAPE significantly reduced the biomass and the metabolic activity of C. auris biofilm and impaired C. auris adhesion to cultured human epithelial cells. Furthermore, both compounds prolonged the survival rate of Galleria mellonella infected by C. auris (p = 0.0088 for EA at 32 mg/kg and p = 0.0028 for CAPE at 4 mg/kg). In addition, EA at 4 μg/mL prolonged the survival of C. albicans-infected Caenorhabditis elegans (p < 0.0001). CAPE was not able to prolong the survival of C. albicans-infected C. elegans. These findings highlight the antifungal and antivirulence effects of EA and CAPE against C. auris, and warrant further investigation as novel antifungal agents against drug-resistant infections. Full article

(This article belongs to the Special Issue Alternative Therapeutic Approaches of Candida Infections)

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11 pages, 1466 KiB

Open AccessArticle

Functional Characterization of Melanin Decolorizing Extracellular Peroxidase of Bjerkandera adusta

by Jina Baik, Anwesha Purkayastha, Kyung Hye Park and Taek Jin Kang

J. Fungi 2021, 7(9), 762; https://doi.org/10.3390/jof7090762 - 15 Sep 2021

Cited by 5 | Viewed by 3242

Abstract

Melanin pigmentation in the human skin results from complicated cellular mechanisms that remain to be entirely understood. Uneven melanin pigmentation has been counteracted by inhibiting synthesis or transfer of melanin in the skin. Recently, an enzymatic approach has been proposed, wherein the melanin [...] Read more.

Melanin pigmentation in the human skin results from complicated cellular mechanisms that remain to be entirely understood. Uneven melanin pigmentation has been counteracted by inhibiting synthesis or transfer of melanin in the skin. Recently, an enzymatic approach has been proposed, wherein the melanin in the skin is decolorized using lignin peroxidase. However, not many enzymes are available for decolorizing melanin; the most studied one is lignin peroxidase derived from a lignin degrading fungus, Phanerochaete chrysosporium. Our current study reveals that versatile peroxidase from Bjerkandera adusta can decolorize synthetic melanin. Melanin decolorization was found to be dependent on veratryl alcohol and hydrogen peroxide, but not on Mn²⁺. The degree of decolorization reached over 40% in 10 min at 37 °C and a pH of 4.5. Optimized storage conditions were slightly different from those for the reaction; crude enzyme preparation was the most stable at 25 °C at pH 5.5. Since the enzyme rapidly lost its activity at 50 °C, stabilizers were screened. As a result, glycerol, a major component in several cosmetic formulations, was found to be a promising excipient. Our results suggest that B. adusta versatile peroxidase can be considered for future cosmetic applications aimed at melanin decolorization. Full article

(This article belongs to the Section Fungi in Agriculture and Biotechnology)

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11 pages, 2053 KiB

Open AccessArticle

Invasive Fungal Disease in Patients with Newly Diagnosed Acute Myeloid Leukemia

by Anastasia I. Wasylyshyn, Kathleen A. Linder, Carol A. Kauffman, Blair J. Richards, Stephen M. Maurer, Virginia M. Sheffield, Lydia Benitez Colon and Marisa H. Miceli

J. Fungi 2021, 7(9), 761; https://doi.org/10.3390/jof7090761 - 15 Sep 2021

Cited by 7 | Viewed by 2706

Abstract

This single-center retrospective study of invasive fungal disease (IFD) enrolled 251 adult patients undergoing induction chemotherapy for newly diagnosed acute myeloid leukemia (AML) from 2014–2019. Patients had primary AML (n = 148, 59%); antecedent myelodysplastic syndrome (n = 76, 30%), or [...] Read more.

This single-center retrospective study of invasive fungal disease (IFD) enrolled 251 adult patients undergoing induction chemotherapy for newly diagnosed acute myeloid leukemia (AML) from 2014–2019. Patients had primary AML (n = 148, 59%); antecedent myelodysplastic syndrome (n = 76, 30%), or secondary AML (n = 27, 11%). Seventy-five patients (30%) received an allogeneic hematopoietic cell transplant within the first year after induction chemotherapy. Proven/probable IFD occurred in 17 patients (7%). Twelve of the 17 (71%) were mold infections, including aspergillosis (n = 6), fusariosis (n = 3), and mucomycosis (n = 3). Eight breakthrough IFD (B-IFD), seven of which were due to molds, occurred in patients taking antifungal prophylaxis. Patients with proven/probable IFD had a significantly greater number of cumulative neutropenic days than those without an IFD, HR = 1.038 (95% CI 1.018–1.059), p = 0.0001. By cause-specific proportional hazards regression, the risk for IFD increased by 3.8% for each day of neutropenia per 100 days of follow up. Relapsed/refractory AML significantly increased the risk for IFD, HR = 7.562 (2.585–22.123), p = 0.0002, and Kaplan-Meier analysis showed significantly higher mortality at 1 year in patients who developed a proven/probable IFD, p = 0.02. IFD remains an important problem among patients with AML despite the use of antifungal prophylaxis, and development of IFD is associated with increased mortality in these patients. Full article

(This article belongs to the Special Issue Fungal Infections in Immunocompromised Hosts 2.0)

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14 pages, 11350 KiB

Open AccessArticle

Participation of the ABC Transporter CDR1 in Azole Resistance of Candida lusitaniae

by Valentin Borgeat, Danielle Brandalise, Frédéric Grenouillet and Dominique Sanglard

J. Fungi 2021, 7(9), 760; https://doi.org/10.3390/jof7090760 - 15 Sep 2021

Cited by 13 | Viewed by 3016

Abstract

Candida lusitaniae is an opportunistic pathogen in humans that causes infrequent but difficult-to-treat diseases. Antifungal drugs are used in the clinic to treat C. lusitaniae infections, however, this fungus can rapidly acquire antifungal resistance to all known antifungal drugs (multidrug resistance). C. lusitaniae [...] Read more.

Candida lusitaniae is an opportunistic pathogen in humans that causes infrequent but difficult-to-treat diseases. Antifungal drugs are used in the clinic to treat C. lusitaniae infections, however, this fungus can rapidly acquire antifungal resistance to all known antifungal drugs (multidrug resistance). C. lusitaniae acquires azole resistance by gain-of-function (GOF) mutations in the transcriptional regulator MRR1. MRR1 controls the expression of a major facilitator transporter (MFS7) that is important for fluconazole resistance. Here, we addressed the role of the ATP Binding Cassette (ABC) transporter CDR1 as additional mediator of azole resistance in C. lusitaniae. CDR1 expression in isolates with GOF MRR1 mutations was higher compared to wild types, which suggests that CDR1 is an additional (direct or indirect) target of MRR1. CDR1 deletion in the azole-resistant isolate P3 (V688G GOF) revealed that MICs of long-tailed azoles, itraconazole and posaconazole, were decreased compared to P3, which is consistent with the role of this ABC transporter in the efflux of these azoles. Fluconazole MIC was only decreased when CDR1 was deleted in the background of an mfs7Δ mutant from P3, which underpins the dominant role of MFS7 in the resistance of the short-tailed azole fluconazole. With R6G efflux readout as Cdr1 efflux capacity, our data showed that R6G efflux was increased in P3 compared to an azole-susceptible wild type parent, and diminished to background levels in mutant strains lacking CDR1. Milbemycin oxim A3, a known inhibitor of fungal ABC transporters, mimicked efflux phenotypes of cdr1Δ mutants. We therefore provided evidence that CDR1 is an additional mediator of azole resistance in C. lusitaniae, and that CDR1 regulation is dependent on MRR1 and associated GOF mutations. Full article

(This article belongs to the Special Issue Clinical Resistance to Antifungal Mechanism)

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17 pages, 1946 KiB

Open AccessArticle

Population Diversity and Genetic Structure Reveal Patterns of Host Association and Anthropogenic Impact for the Globally Important Fungal Tree Pathogen Ceratocystis manginecans

by Feifei Liu, Tuan A. Duong, Irene Barnes, Michael J. Wingfield and Shuaifei Chen

J. Fungi 2021, 7(9), 759; https://doi.org/10.3390/jof7090759 - 15 Sep 2021

Cited by 9 | Viewed by 3139

Abstract

Species in the Ceratocystis manginecans complex are important fungal pathogens of plantation trees globally. The most important hosts include species of Eucalyptus, Acacia, Mangifera, and Punica. Despite their relevance and widespread occurrence, little is known regarding their population genetics [...] Read more.

Species in the Ceratocystis manginecans complex are important fungal pathogens of plantation trees globally. The most important hosts include species of Eucalyptus, Acacia, Mangifera, and Punica. Despite their relevance and widespread occurrence, little is known regarding their population genetics and how this might relate to their host associations or geographic regions in which they occur. A global collection of 491 isolates representing the C. manginecans complex, from four different plant hosts and nine countries, were genotyped using microsatellite markers. Population genetic analyses using numerous tools were conducted to interrogate how their genetic diversity and structure might be affected by host or areas of occurrence. Results of genetic diversity studies showed that when grouping isolates into populations based on their host associations, the population on Eucalyptus was most diverse, and it also has a broad global distribution. When considering countries of origin as a basis for defining populations, the gene and genotypic diversity were highest in populations from China, Indonesia, and Brazil. In contrast, populations from Oman and Pakistan collected from Mangifera had the lowest genetic diversity and were clonal. Molecular variance, population differentiation, and network and structure analyses showed that the genetic structure of isolates in the C. manginecans complex is influenced by both host association as well as geographical isolation. Furthermore, the results reflected the movement of genotypes between plant hosts and geographic regions that have implications regarding the broad global distribution of this pathogen. Full article

(This article belongs to the Section Environmental and Ecological Interactions of Fungi)

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22 pages, 4844 KiB

Open AccessArticle

Global Transcriptome Profile of the Oleaginous Yeast Saitozyma podzolica DSM 27192 Cultivated in Glucose and Xylose

by Habibu Aliyu, Olga Gorte, Anke Neumann and Katrin Ochsenreither

J. Fungi 2021, 7(9), 758; https://doi.org/10.3390/jof7090758 - 15 Sep 2021

Cited by 14 | Viewed by 3184

Abstract

Unlike conventional yeasts, several oleaginous yeasts, including Saitozyma podzolica DSM 27192, possess the innate ability to grow and produce biochemicals from plant-derived lignocellulosic components such as hexose and pentose sugars. To elucidate the genetic basis of S. podzolica growth and lipid production on [...] Read more.

Unlike conventional yeasts, several oleaginous yeasts, including Saitozyma podzolica DSM 27192, possess the innate ability to grow and produce biochemicals from plant-derived lignocellulosic components such as hexose and pentose sugars. To elucidate the genetic basis of S. podzolica growth and lipid production on glucose and xylose, we performed comparative temporal transcriptome analysis using RNA-seq method. Approximately 3.4 and 22.2% of the 10,670 expressed genes were differentially (FDR < 0.05, and log2FC > 1.5) expressed under batch and fed batch modes, respectively. Our analysis revealed that a higher number of sugar transporter genes were significantly overrepresented in xylose relative to glucose-grown cultures. Given the low homology between proteins encoded by most of these genes and those of the well-characterised transporters, it is plausible to conclude that S. podzolica possesses a cache of putatively novel sugar transporters. The analysis also suggests that S. podzolica potentially channels carbon flux from xylose via both the non-oxidative pentose phosphate and potentially via the first steps of the Weimberg pathways to yield xylonic acid. However, only the ATP citrate lyase (ACL) gene showed significant upregulation among the essential oleaginous pathway genes under nitrogen limitation in xylose compared to glucose cultivation. Combined, these findings pave the way toward the design of strategies or the engineering of efficient biomass hydrolysate utilization in S. podzolica for the production of various biochemicals. Full article

(This article belongs to the Section Fungal Genomics, Genetics and Molecular Biology)

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20 pages, 7670 KiB

Open AccessArticle

Candida tropicalis Systemic Infection Redirects Leukocyte Infiltration to the Kidneys Attenuating Encephalomyelitis

by Natália Munhoz-Alves, Luiza Ayumi Nishiyama Mimura, Rosa Marlene Viero, Eduardo Bagagli, Jean Pierre Schatzmann Peron, Alexandrina Sartori and Thais Fernanda de Campos Fraga-Silva

J. Fungi 2021, 7(9), 757; https://doi.org/10.3390/jof7090757 - 14 Sep 2021

Cited by 5 | Viewed by 2754

Abstract

Environmental factors, including infections, are strongly associated with the pathogenesis of multiple sclerosis (MS), which is an autoimmune and demyelinating disease of the central nervous system (CNS). Although classically associated with bacterial and viral agents, fungal species have also been suspected to affect [...] Read more.

Environmental factors, including infections, are strongly associated with the pathogenesis of multiple sclerosis (MS), which is an autoimmune and demyelinating disease of the central nervous system (CNS). Although classically associated with bacterial and viral agents, fungal species have also been suspected to affect the course of the disease. Candida tropicalis is an opportunistic fungus that affects immunocompromised individuals and is also able to spread to vital organs. As C. tropicalis has been increasingly isolated from systemic infections, we aimed to evaluate the effect of this fungus on experimental autoimmune encephalomyelitis (EAE), a murine model to study MS. For this, EAE was induced in female C57BL/6 mice 3 days after infection with 10⁶ viable C. tropicalis yeasts. The infection decreased EAE prevalence and severity, confirmed by the less inflammatory infiltrate and less demyelization in the lumbar spinal cord. Despite this, C. tropicalis infection associated with EAE results in the death of some animals and increased urea and creatinine serum levels. The kidneys of EAE-infected mice showed higher fungal load associated with increased leukocyte infiltration (CD45⁺ cells) and higher expression of T-box transcription factor (Tbx21) and forkhead box P3 (Foxp3). Altogether, our results demonstrate that although C. tropicalis infection reduces the prevalence and severity of EAE, partially due to the sequestration of leukocytes by the inflamed renal tissue, this effect is associated with a poor disease outcome. Full article

(This article belongs to the Special Issue New Perspectives for Candidiasis)

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10 pages, 1354 KiB

Open AccessArticle

Regulation of Copper Metabolism by Nitrogen Utilization in Saccharomyces cerevisiae

by Suzie Kang, Hyewon Seo, Min-Gyu Lee and Cheol-Won Yun

J. Fungi 2021, 7(9), 756; https://doi.org/10.3390/jof7090756 - 14 Sep 2021

Cited by 2 | Viewed by 2577

Abstract

To understand the relationship between carbon or nitrogen utilization and iron homeostasis, we performed an iron uptake assay with several deletion mutants with partial defects in carbon or nitrogen metabolism. Among them, some deletion mutants defective in carbon metabolism partially and the MEP2 [...] Read more.

To understand the relationship between carbon or nitrogen utilization and iron homeostasis, we performed an iron uptake assay with several deletion mutants with partial defects in carbon or nitrogen metabolism. Among them, some deletion mutants defective in carbon metabolism partially and the MEP2 deletion mutant showed lower iron uptake activity than the wild type. Mep2 is known as a high-affinity ammonia transporter in Saccharomyces cerevisiae. Interestingly, we found that nitrogen starvation resulted in lower iron uptake activity than that of wild-type cells without downregulation of the genes involved in the high-affinity iron uptake system FET3/FTR1. However, the gene expression of FRE1 and CTR1 was downregulated by nitrogen starvation. The protein level of Ctr1 was also decreased by nitrogen starvation, and addition of copper to the nitrogen starvation medium partially restored iron uptake activity. However, the expression of MAC1, which is a copper-responsive transcriptional activator, was not downregulated by nitrogen starvation at the transcriptional level but was highly downregulated at the translational level. Mac1 was downregulated dramatically under nitrogen starvation, and treatment with MG132, which is an inhibitor of proteasome-dependent protein degradation, partially attenuated the downregulation of Mac1. Taken together, these results suggest that nitrogen starvation downregulates the high-affinity iron uptake system by degrading Mac1 in a proteasome-dependent manner and eventually downregulates copper metabolism. Full article

(This article belongs to the Special Issue Yeast Genetics 2021)

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17 pages, 4818 KiB

Open AccessArticle

FgSfl1 and Its Conserved PKA Phosphorylation Sites Are Important for Conidiation, Sexual Reproduction, and Pathogenesis in Fusarium graminearum

by Chen Gong, Junqi Huang, Daiyuan Sun, Daiying Xu, Yuqian Guo, Jiangang Kang, Gang Niu and Chenfang Wang

J. Fungi 2021, 7(9), 755; https://doi.org/10.3390/jof7090755 - 14 Sep 2021

Cited by 6 | Viewed by 2427

Abstract

The fungal plant pathogen, Fusarium graminearum, contains two genes, FgCPK1 and FgCPK2, encoding the catalytic subunits of cAMP-dependent protein kinase A. FgCPK1 and FgCPK2 are responsible for most of the PKA activities and have overlapping functions in various cellular processes in [...] Read more.

The fungal plant pathogen, Fusarium graminearum, contains two genes, FgCPK1 and FgCPK2, encoding the catalytic subunits of cAMP-dependent protein kinase A. FgCPK1 and FgCPK2 are responsible for most of the PKA activities and have overlapping functions in various cellular processes in F. graminearum. The cpk1 cpk2 double mutant was significantly reduced in growth, rarely produced conidia, and was non-pathogenic. In this study, we found that the cpk1 cpk2 double mutant was unstable and produced fast-growing spontaneous sectors that were defective in plant infection. All spontaneous suppressor strains had mutations in FgSFL1, a transcription factor gene orthologous to SFL1 in yeast. Thirteen suppressor strains had non-sense mutations at Q501, three suppressor strains had frameshift mutations at W198, and five suppressor strains had mutations in the HSF binding domain of FgSfl1. Only one suppressor strain had both a non-synonymous mutation at H225 and a non-sense mutation at R490. We generated the SFL1 deletion mutant and found that it produced less than 2% of conidia than that of the wild-type strain PH-1. The sfl1 mutant was significantly reduced in the number of perithecia on carrot agar plates at 7 days post-fertilization (dpf). When incubated for more than 12 days, ascospore cirrhi were observed on the sfl1 mutant perithecia. The infection ability of the sfl1 deletion mutant was also obviously defective. Furthermore, we found that in addition to the S223 and S559 phosphorylation sites, FgSFL1 had another predicted phosphorylation site: T452. Interestingly, the S223 phosphorylation site was responsible for sexual reproduction, and the T452 phosphorylation site was responsible for growth and sexual reproduction. Only the S559 phosphorylation site was found to play an important role in conidiation, sexual reproduction, and infection. Overall, our results indicate that FgSFL1 and its conserved PKA phosphorylation sites are important for vegetative growth, conidiation, sexual reproduction, and pathogenesis in F. graminearum. Full article

(This article belongs to the Section Fungi in Agriculture and Biotechnology)

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J. Fungi, Volume 7, Issue 9 (September 2021) – 105 articles

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