Molecular assessment of oat head blight fungus, including a new genus and species in a family of Nectriaceae

Head blight (HB) of oat (Avena sativa) has caused significant production losses in oats growing areas of western China. A total of 314 isolates, associated with HB were collected from the major oat cultivating areas of Gansu, Qinghai, and Yunnan Provinces in western China. Based on morphological characters, the isolates were initially classified into three genera, as differentiation to species was a bit difficult. Taxonomic analysis of these isolates based on muti-gene phylogenetic analyses (ITS, TEF1, TUB2, and RPB2) revealed four known Fusarium species, F. proliferatum, F. avenaceum, F. poae, and F. sibiricum, and one Acremonium specie (A. sclerotigenum). In addition, a new genus Neonalanthamala gen. nov., similar to genus Nalanthamala was introduced herein with a new combination, Neonalanthamala graminearum sp. nov., to accommodate the HB fungus. The molecular clock analyses estimated the divergence time of the Neonalanthamala and Nalanthamala based on a dataset (ITS, TUB2, RPB2), and we recognized the mean stem ages of the two genera are 98.95 Mya, which showed that they evolved from the same ancestor. N. graminearum was the most prevalent throughout the surveyed provinces. Pathogenicity test was carried out by using two different methods: seed inoculation and head inoculation. Results showed that F. sibiricum isolates were the most aggressive on the seed and head. A. sclerotigenum isolates were not pathogenic to seeds, and were developed less symptoms to the head compared to other species. Data analyses showed that the correlation of the germination potential, germination index, and dry weight of seed inoculation and disease index of plant inoculation had a highly significant negative correlation (P < 0.001). These results showed that the development of HB might be predicted by seed tests for this species. A. sclerotigenum and N. graminearum causing HB are being firstly reported on oat in the world. Similarly, F. proliferatum, F. avenaceum, F. poae and F. sibiricum causing oat HB are firstly reported in China.

First report of basal stem rot caused by three Fusarium species on Chinese yam in China

The cultivated variety of Chinese yam (Dioscorea polystachya Turcz. cv. Tiegun) is an economically important plant, capable of producing tubers that are used as food and traditional Chinese medicine. The basal stem rot was found on approximately 65% of yam (tuber expansion stage) in a total of 10 ha field in Wuzhi, Wen, and Hua counties, Henan, China (Sep 2021). Dark brown fusiform lesions initially occurred at the stems basal, irregularly extending to join together and leading to loop-stem necrotic indentation. Three diseased samples from Wuzhi county were collected, cut into 5 × 5 mm pieces, surface sterilized in 75% ethanol (30 s) and 1% NaClO (1 min), washed in sterile water 3 times, and placed on PDA in the dark for 3 days at 28℃. A total of 44 isolates forming three groups of Fusarium colonies were obtained using monosporic isolation, of which 19, 8, and 17 isolates were identified as F. oxysporum, F. solani, and F. proliferatum based on colony morphology, respectively. Typical isolates SYJJ6, 9, and 10 for each group were further studied. The SYJJ6 colonies showed gray white abundant fluffy aerial mycelium with rough edges, formation of ellipsoid, unicellular microconidia without septa, 5.6 to 13.4 × 2.4 to 4.7 μm (n = 50), and sickle-shaped, slightly curved macroconidia with 2 to 4 septa, 14.0 to 23.9 × 3.4 to 5.1 μm (n = 50). Isolate SYJJ9 produced flocculent white colonies, grew in a circular pattern with a sharp edge, forming oval or oblong microconidia with zero or one septum, 11.2 to 18.8 × 3.4 to 6.2 μm (n = 50), and slightly curved macroconidia with 2 to 3 septa, 27.6 to 44.0 × 3.9 to 7.4 μm (n = 50). SYJJ10 produced whitish or pinkish white colonies with fluffy aerial mycelium and a red pigmentation, produced renal or oval microconidia with no septa, 5.1 to 11.8 × 1.8 to 4.2 μm (n = 50), and falcate, slightly curved macroconidia with 3 to 4 septa, 16.1 to 30.2 × 3.1 to 5.9 μm (n = 50). Additionally, TUB, EF-1α, and RPB2 genes were amplified with primers BT2a/BT2b, EF1/EF2, and 5f2/-7cr, respectively (Glass and Donaldson 1995; O'Donnell et al. 1998, 2010). BLASTn analysis on SYJJ6 (OR047663, OR047666, OR047669), SYJJ9 (OR047665, OR047667, OR047670), and SYJJ10 (OR047664, OR047668, OR047671) gene sequences were over 99% identical to those of F. oxysporum (100%, MK432917; 100%, MN417196; 99.61%, MN457531), F. solani (100%, MF662662; 100%, MN223440; 99.80%, CP104055), and F. proliferatum (100%, ON557521; 100%, ON458137; 99.90%, LT841266), respectively. Pathogenicity tests of three isolates were separately performed on 60-day-old yam seedlings. The basal stems were wounded using needle, and the wounds were wrapped with cotton balls soaked with conidial suspension (1 mL, 3×106 conidia/mL) or water (control). Each isolate treated three plants and repeated three times. All plants were grown at 28℃ under a 16/8-h light/dark cycle. Typical symptoms emerged on basal stems at 16, 13, and 17 days after inoculation with the conidia of isolates SYJJ6, 9, and 10, while the control basal stems appeared healthy. The re-isolated fungi were identical to the original three isolates. Fusarium species (F. oxysporum, F. commune, F. humuli, etc.)were previously reported to cause wilt or stem rot on different D. polystachya cultivars (Fang et al. 2020; Li et al. 2023; Zhao et al. 2013), or basal stem rot on Panax ginseng (Ma et al. 2020). This is the first report of Chinese yam basal stem rot caused by Fusarium species, which threatens the production of Chinese yam 'Tiegun' and should be further studied.

Fusarium sacchari hypovirus 1, a Member of Hypoviridae with Virulence Attenuation Capacity in Phytopathogenic Fusarium Species

In a survey of mycoviruses in Fusarium species that cause sugarcane Pokkah boeng disease, twelve Fusarium strains from three Fusarium species (F. sacchari, F. andiyazi, and F. solani) were found to contain Fusarium sacchari hypovirus 1 (FsHV1), which we reported previously. The genomes of these variants range from 13,966 to 13,983 nucleotides, with 98.6% to 99.9% nucleotide sequence identity and 98.70% to 99.9% protein sequence similarity. Phylogenetic analysis placed these FsHV1 variants within the Alphahypovirus cluster of Hypoviridae. Intriguingly, no clear correlation was found between the geographic origin and host specificity of these viral variants. Additionally, six out of the twelve variants displayed segmental deletions of 1.5 to 1.8 kilobases, suggesting the existence of defective viral dsRNA. The presence of defective viral dsRNA led to a two-thirds reduction in the dsRNA of the wild-type viral genome, yet a tenfold increase in the total viral dsRNA content. To standardize virulence across natural strains, all FsHV1 strains were transferred into a single, virus-free Fusarium recipient strain, FZ06-VF, via mycelial fusion. Strains of Fusarium carrying FsHV1 exhibited suppressed pigment synthesis, diminished microspore production, and a marked decrease in virulence. Inoculation tests revealed varying capacities among different FsHV1 variants to modulate fungal virulence, with the strain harboring the FsHV1-FSA1 showing the lowest virulence, with a disease severity index (DSI) of 3.33, and the FsHV1-FS1 the highest (DSI = 17.66). The identification of highly virulent FsHV1 variants holds promise for the development of biocontrol agents for Pokkah boeng management.

Optimization of green silver nanoparticles as nanofungicides for management of rice bakanae disease

Rice bakanae, a devastating seed-borne disease caused by Fusarium species requires a more attractive and eco-friendly management strategy. The optimization of plant-mediated silver nanoparticles (AgNPs) as nanofungicides by targeting Fusarium species may be a rational approach. In this study, Azadirachta indica leaf aqueous extract-based AgNPs (AiLAE-AgNPs) were synthesized through the optimization of three reaction parameters: A. indica leaf amount, plant extract-to-AgNO3 ratio (reactant ratio), and incubation time. The optimized green AgNPs were characterized using ultraviolet-visible light (UV-Vis) spectroscopy, field emission scanning electron microscopy (FESEM) with energy dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS), and powder X-ray diffraction (XRD) techniques. The optimal conditions for producing spherical, unique, and diminutive-sized AgNPs ranging from 4 to 27 nm, with an average size of 15 nm, were 2 g AiLAE at a 1:19 ratio (extract-to-AgNO3) and incubated for 4 h. Fusarium isolates collected from infected soils and identified as F. fujikuroi (40) and F. proliferatum (58 and 65) by PCR were used for seed infestation. The AgNPs exhibited concentration-dependent mycelial growth inhibition with EC50 values ranging from 2.95 to 5.50 μg/mL. The AgNPs displayed exposure time-dependent seed disinfectant potential (complete CFU reduction in F. fujikuroi (40) and F. proliferatum (58) was observed at a concentration of 17.24 μg/mL). The optimized green AgNPs were non-toxic to germinating seeds, and completely cured bakanae under net-house conditions, suggesting their great nano-fungicidal potency for food security and sustainable agriculture.

Fusariosis in patients with hematological malignancies: Two case reports

Immunosuppressed patients with hematological malignancies are at risk for invasive fungal infections (IFI), including infections with Fusarium species (spp.), which are increasingly reported. Particularly at risk are patients with acute myeloid leukemia (AML) treated with high-dose cytarabine as remission-induction therapy. Whether cytarabine increases the risk of IFI in comparison to other chemotherapy remains not fully determined. Additionally, no clear correlation between the in vitro established minimal inhibitory concentrations (MICs) of antifungal agents and clinical outcome has been established for fusariosis. To increase awareness and knowledge of invasive fusariosis, we report two cases of Fusarium spp. infections in neutropenic patients following treatment with cytarabine for AML. Despite high MICs for azoles both patients were treated with an azole in combination with liposomal amphotericin B. The combination therapy was successful in one patient, however the other patient did not survive the disseminated Fusarium infection.

Distribution and Pathogenicity of Fusarium Species Associated with Soybean Root Rot in Northeast China

Fusarium root rot is an increasingly severe problem in soybean cultivation. Although several Fusarium species have been reported to infect soybean roots in Heilongjiang province, their frequency and aggressiveness have not been systematically quantified in the region. This study aimed to investigate the diversity and distribution of Fusarium species that cause soybean root rot in Heilongjiang province over two years. A total of 485 isolates belonging to nine Fusarium species were identified, with F. oxysporum and F. solani being the most prevalent. Pot experiments were conducted to examine the relative aggressiveness of different Fusarium species on soybean roots, revealing that F. oxysporum and F. solani were the most aggressive pathogens, causing the most severe root rot symptoms. The study also assessed the susceptibility of different soybean cultivars to Fusarium root rot caused by F. oxysporum and F. solani. The results indicated that the soybean cultivar DN51 exhibited the most resistance to both pathogens, indicating that it may possess genetic traits that make it less susceptible to Fusarium root rot. These findings provide valuable insights into the diversity and distribution of Fusarium species that cause soybean root rot and could facilitate the development of effective management strategies for this disease.

Possibly the first case of onychomycosis by Fusarium lactis: Case presentation and literature review of onychomycosis by Fusarium species

Fusarium species (spp.) is frequently found in soil and plant residues and on plant bodies in all climatic zones worldwide. Although there have been few reports of onychomycosis caused by Fusarium spp., it is characterized by drug sensitivity and other characteristics. Here, we report what may be the first case of onychomycosis caused by Fusarium lactis. We analyzed the mycology and characterized previously reported cases of onychomycosis caused by Fusarium spp. A 73-year-old otherwise healthy woman presented with discoloration and thickening of her right thumbnail with paronychia. Direct microscopy revealed unevenly swollen hyphae, and a Grocott-stained nail specimen showed septate hyphae. Based on the morphological features and gene analysis of fungus isolated from the nail, we diagnosed onychomycosis caused by F. lactis belonging to Fusarium fujikuroi species complex. Partial nail removal and topical application of 1% luliconazole solution resolved the condition in 6 months. Minimum inhibitory concentrations for isolated F. lactis showed high sensitivity to luliconazole but not itraconazole or terbinafine. The isolated F. lactis was temperature-sensitive. A search of the literature revealed 57 cases of onychomycosis caused by Fusarium spp. with delineated clinical characteristics. Since those cases were investigated using morphological and/or molecular methods, we analyzed them by species complex as well as species. Onychomycosis caused by Fusarium spp. is predominantly found on the big toe, with Fusarium solani species complex and Fusarium oxysporum species complex accounting for over 70% of cases. Infection of only one digit with paronychia is a characteristic clinical manifestation of onychomycosis caused by Fusarium spp. Since there has been an increase in instances of molecular determination of Fusarium spp., it is deemed necessary to clarify its clinical and fungal nature. Due to its characteristic drug sensitivity and temperature-sensitive nature, new treatments are expected to be developed.

The Role of Biofilms in Contact Lens Associated Fungal Keratitis

Biofilm formation is an important microbial strategy for fungal pathogens, such as Fusarium, Aspergillus, and Candida, to establish keratitis in patients wearing soft contact lenses. Despite the well-documented 2006 outbreak of Fusarium keratitis that eventually led to the withdrawal of the Bausch & Lomb multipurpose lens care solution ReNu with MoistureLoc ("MoistureLoc") from the global market, contact lens care systems and solutions currently available on the market do not specifically target fungal biofilms. This is partially due to the lack of recognition and understanding of important roles that fungal biofilms play in contact lens associated fungal keratitis (CLAFK). This review aims to reemphasize the link between fungal biofilms and CLAFK, and deepen our comprehension of its importance in pathogenesis and persistence of this medical device-related infection.

Identification and Pathogenicity of Fusarium Isolated from Soybean in Poland

Fungi belonging to the Fusarium genus are commonly isolated from soybean plants and seeds but not all of them are pathogenic. The aim of this study was to compare the pathogenicity among different Fusarium isolates obtained from soybean plants with disease symptoms originating from an experimental field located in the southeast of Poland. Nineteen fungal isolates were selected for the pathogenicity assay, including eight isolates of F. oxysporum, six isolates of F. graminearum, four isolates of F. culmorum and one isolate of F. redolens. Species identification of these isolates was carried out using microscopic methods and sequencing of two genes: translation elongation factor 1-alpha (TEF1) and RNA polymerase second largest subunit (RPB2). To our knowledge, this is the first report of F. redolens being isolated from soybean in Europe. The pathogenicity test was set up by fungal inoculation of healthy soybean seeds of three cultivars: Abelina, Atlanta and Mavka. Symptoms were assessed seven days after inoculation. Disease area percentage of Fusarium inoculated seeds was significantly higher compared to uninoculated control. Nineteen isolates differed in their aggressiveness as the median disease area percentage ranged between 5.0 and 88.0% depending on isolate. The obtained isolates of four Fusarium species may be used in the future screening of soybean cultivars for resistance to these pathogens.

Characterization of the Virulence and Yield Impact of Fusarium Species on Canola (Brassica napus)

Multiple species of Fusarium can contribute to the development of root rot in canola (Brassica napus), making disease management difficult. We conducted field and greenhouse experiments to investigate the impacts of Fusarium avenaceum and Fusarium proliferatum, and the interaction between Fusarium oxysporum and F. proliferatum on root rot severity and canola yields. Inoculation with any of the three Fusarium spp. resulted in significant disease severity and reduced seedling emergence compared with non-inoculated controls, leading to yield reductions of up to 35%. Notably, there was a strong correlation (r = 0.93) between root rot severity at the seedling stage and at maturity. Regression analysis indicated a linear decline in seedling emergence with increasing disease severity. Furthermore, disease severity at maturity adversely affected the pod number per plant and the seed weight per plant, with both parameters ultimately approaching zero at a severity of 4.0 on a 0-4 scale. Co-inoculation with F. oxysporum and F. proliferatum induced more severe root rot than inoculation with each species on its own, suggesting synergistic interactions between these fungi. Knowledge of these interactions and the relative virulence of Fusarium spp. will contribute to the improved management of root rot in canola.

Type A Trichothecene Metabolic Profile Differentiation, Mechanisms, Biosynthetic Pathways, and Evolution in Fusarium Species-A Mini Review

Trichothecenes are the most common Fusarium toxins detected in grains and related products. Type A trichothecenes are among the mycotoxins of greatest concern to food and feed safety due to their high toxicity. Recently, two different trichothecene genotypes within Fusarium species were reported. The available information showed that Tri1 and Tri16 genes are the key determinants of the trichothecene profiles of T-2 and DAS genotypes. In this review, polymorphisms in the Tri1 and Tri16 genes in the two genotypes were investigated. Meanwhile, the functions of genes involved in DAS and NEO biosynthesis are discussed. The possible biosynthetic pathways of DAS and NEO are proposed in this review, which will facilitate the understanding of the synthesis process of trichothecenes in Fusarium strains and may also inspire researchers to design and conduct further research. Together, the review provides insight into trichothecene profile differentiation and Tri gene evolutionary processes responsible for the structural diversification of trichothecene produced by Fusarium.

Biocontrol of Fusarium Species Utilizing Indigenous Rooibos and Honeybush Extracts

Mycotoxins produced by several Fusarium species have a significant effect on reducing maize yield and grain quality and have led to food safety concerns. The antifungal activities of rooibos (Aspalathus linearis) and honeybush (Cyclopia species) tea extracts reduced the growth of plant pathogen Botrytis cinerea, but their efficacy against Fusarium spp. is unknown. In this study, we examined the effects of fermented and unfermented rooibos (A. linearis) and honeybush (Cyclopia subternata) aqueous extracts as well as green tea (Camellia sinensis) against 10 Fusarium species. Conidial viability was assessed by fluorescence microscopy dyes, ATP production was determined using the BacTiter-Glo assay, the mode of action was analyzed by scanning electron microscopy (SEM), and quantification of polyphenols was done using high-performance liquid chromatography with diode array detection (HPLC-DAD). Fermented rooibos extract demonstrated the highest antifungal activity (P < 0.0001) against Fusarium verticillioides MRC 826-E, Fusarium subglutinans MRC 8553, Fusarium proliferatum MRC 8549, and Fusarium globosum MRC 6647, with only 9.53%, 9.26%, 11.0%, and 12.7% ATP production, respectively, followed by antifungal activity of the fermented C. subternata extract against F. subglutinans MRC 8553, F. subglutinans MRC 8554, F. proliferatum MRC 8550, and F. verticillioides MRC 826-E with 3.79%, 6.04%, 6.04%, and 8.40% ATP production, respectively. Extract-treated conidia examined by SEM exhibited disruption of conidial hyphae and collapsed spores. Overall, the fermented rooibos and C. subternata extracts showed higher antifungal activity against the Fusarium species than the unfermented extracts. IMPORTANCE In maize subsistence farming areas in South Africa, daily consumption of maize contaminated by high level of mycotoxins contributes to long-term health effects such as immune deficiency and cancer. Biocontrol methods that are safe and cost-effective are critical to addressing this public health problem. Plant extracts known as biocides or green pesticides are alternatives to chemical pesticides due to their safety and eco-friendly properties. In South Africa, rooibos (Aspalathus linearis) and honeybush (Cyclopia species) contain polyphenols with significant antioxidant and antimicrobial properties. These indigenous herbal teas are widely available and consumed in South Africa and have potential as an innovative approach to reduce mycotoxin levels and, subsequently, human and animal exposure to these toxins. This study evaluates the efficacy of the antifungal activities of several aqueous extracts prepared from fermented and unfermented rooibos (A. linearis), honeybush (Cyclopia subternata), and green tea (Camellia sinensis) on 10 Fusarium strains.

Effect of Crop Rotation on Fusarium Mycotoxins and Fusarium Species in Cereals in Sichuan Province (China)

The present study was performed to evaluate the effect of crop rotation on Fusarium mycotoxins and species in cereals in Sichuan Province. A total of 311 cereal samples were randomly collected and analyzed from 2018 to 2019 in Sichuan Province. The results of mycotoxin analysis showed that the major trichothecene mycotoxins in Sichuan Province were nivalenol (NIV) and deoxynivalenol (DON), and the mean concentration of total trichothecenes (including NIV, fusarenone X [4ANIV], DON, 3-acetyldeoxynivalenol [3ADON], and 15-acetyldeoxynivalenol [15ADON]) in wheat was significantly higher than that in maize and rice. The concentration of total trichothecenes in the succeeding crops was significantly higher than that in the previous crops. In addition, wheat grown after maize had reduced incidence and concentration of trichothecene mycotoxins compared with that grown after rice, and ratooning rice grown after rice had increased incidence and concentration of trichothecene mycotoxins. Our data indicated that Fusarium asiaticum with the NIV chemotype was predominant in wheat and rice samples, while the number of the NIV chemotypes of F. asiaticum and Fusarium meridionale and the 15ADON chemotype of Fusarium graminearum in maize were almost the same. Although the composition of Fusarium species was affected by crop rotations, there were no differences when comparing the same crop rotation except for the maize-wheat rotation. Moreover, the same species and chemotype of Fusarium strains originated from different crops in various rotations, but there were no significant differences in pathogenicity in wheat and rice. These results contribute to the knowledge of the effect of crop rotation on Fusarium mycotoxins and species affecting cereals in Sichuan Province, which may lead to improved strategies for control of Fusarium mycotoxins and fungal disease in China.

First report of Fusarium concentricum as a causal agent of Fusarium leaf blotch on pecan (Carya illinoinensis) in Southeast China

The economically important nut crop pecan (Carya illinoinensis (Wangenh.) K. Koch) is seriously affected by increasing incidence of fungal disease worldwide (Xiao et al 2021). The top leaves of the pecan variety 'Pawnee' in the orchard of Zhejiang A&F University, Zhejiang, China were damaged by massive dark brown plaques in summer to autumn 2021. The causal agent was isolated from leaves with target plaques following the steps: sterilized with 70% alcohol (30 s × 2), rinsed with sterilized water (3 ×) before and after 5% sodium hypochlorite (30 s), excised the plaques, and placed on PDA medium at 28℃ in a dark incubator for 3-d. The mycelium on the edge of each colony was transferred to fresh SNA medium in dark for 2 weeks to induce conidia formation. A few conidia-germinated mycelia were transferredand inoculated on new plates containing fresh PDA medium to obtain the purified cultures. Koch's postulates were applied to validate the pathogenicity of the purified isolates. Non-woundedly healthy leaves (disinfected with 5% sodium hypochlorite) of 'Pawnee' seedlings were inoculated with 5 mm 7-d old purified cultures. Dark-brown spots appeared on the leaves 2 days post inoculation at 25℃. The spots became larger accompanied by partially cracking and slight deformation of inoculated leaves from day 2 to day 4, while the control leaves remained asymptomatic. A re-isolated strain ZJ-6 from these infected leaves was identified as the pathogenic isolate with the same symptom as the previous one. Morphologically, aerial mycelia of the pathogenic isolate ZJ-6 cashmere and white. The reverse of colony orange. The edge of the colony appeared gradually thinner, the aerial mycelia loose and flocky, and the matrix mycelium whitened. Hyphae were septate, translucent with smooth wall and 1.47-7.14 µm in width. Microconidia (n = 20) obovoid to fusoid, mainly with 0-septate, 4.45-7.78×4.79-16.25 µm. Macroconidia (n = 20) sickle, mainly with 3-5 septa, 5.56-10.28×56.67-114.54 µm. Simultaneous of monophialidic and polyphialidic conidiophores. Conidiophore width 1.47-3.68 µm, slightly smaller than vegetative hyphae. The morphological characteristics matched with previous descriptions of Fusarium species (Nirenberg and O'Donnell 1998; Wang et al 2013). The identity of ZJ-6 was confirmed by phylogenetic reconstruction using the concatenated sequences of the ATP citrate lyase (ACL1), Calmodulin (CaM), the internal transcribed spacer (ITS) rDNA region, ribosomal RNA gene (LSU), the largest subunit of DNA-dependent RNA polymerase II (RPB1), partial translation elongation factor-1 alpha (TEF) and β-Tubulin (TUB). To this end, the genomic DNA of ZJ-6 was extracted by the M5 hipermix-MF859 (Mei5 Biotechnology) and submitted to GenBank under the accession numbers OP933646, OP933647, OP925890, OP925889, OP933396, OP933648, and OP933397, respectively. The obtained sequences of ZJ-6 were used for nucleotide BLAST against thetandard databases, respectively, and the strains with sequence identification values above 98% were selected to construct multiple alignment for building a phylogenetic tree. This analyses allowed the identification of ZJ-6 as Fusarium concentricum Nirenberg & O'Donnell, a species with few reports that can cause serious damage to the fruits and branches of other hosts (Hasan et al 2020; Huda-Shakirah et al 2020; Wang et al 2013). This is the first report of pathogenic F. concentricum on pecan in Southeast China that caused no harvest of infected plants.

Type B Trichothecenes in Cereal Grains and Their Products: Recent Advances on Occurrence, Toxicology, Analysis and Post-Harvest Decontamination Strategies

Type B trichothecenes (deoxynivalenol, nivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol) and deoxynivalenol-3-glucoside (DON-3G) are secondary toxic metabolites produced mainly by mycotoxigenic Fusarium fungi and have been recognized as natural contaminants in cereals and cereal-based foods. The latest studies have proven the various negative effects of type B trichothecenes on human health. Due to the widespread occurrence of Fusarium species, contamination by these mycotoxins has become an important aspect for public health and agro-food systems worldwide. Hence, their monitoring and surveillance in various foods have received a significant deal of attention in recent years. In this review, an up-to-date overview of the occurrence profile of major type B trichothecenes and DON-3G in cereal grains and their toxicological implications are outlined. Furthermore, current trends in analytical methodologies for their determination are overviewed. This review also covers the factors affecting the production of these mycotoxins, as well as the management strategies currently employed to mitigate their contamination in foods. Information presented in this review provides good insight into the progress that has been achieved in the last years for monitoring type B trichothecenes and DON-3G, and also would help the researchers in their further investigations on metabolic pathway analysis and toxicological studies of these Fusarium mycotoxins.

Lantadene A and boswellic acid isolated from the leaves of Lantana camara L. have the potential to control phytopathogenic Fusarium species

Phytopathogenic Fusarium species are restricting factors causing diseases and yield loss in crop production. As part of exploration for pesticides from medicinal plants, this study aimed to isolate and characterize bioactive compounds from Lantana camara L. and evaluate their efficiency against Fusarium phytopathogens. Phytochemical investigation of ethyl acetate leaf extract led to separation of lantadene A (22-angeloyloxy-9-hydroxy-3-oxo-olean-12-en-28-oic acid) and boswellic acid (11-keto-β-boswellic acid). The chemical structures of the aforementioned compounds were confirmed using physical properties, spectroscopic analysis, and published data. Lantadene A exhibited significant antifungal activity against F. subglutinans, F. proliferatum, F. solani, F. graminearum, and F. semitectum with minimum inhibitory concentration (MIC) less than or equal to 0.63 mg/mL. Boswellic acid exhibited strong activity (MIC = 0.63 mg/mL) against F. subglutinans and F. semitectum. In terms of their toxicity towards Raw 264.7 cells, lantadene A and boswellic acid recorded half-maximal inhibitory concentration values of 84.2 μg/mL and 186.6 μg/mL, respectively. Both lantadene A and boswellic acid had no phytotoxic effect against seed germination and seedling root length. Lantadene A and boswellic acid have strong potential to be further investigated as lead natural fungicides (biopesticides) to control Fusarium crop diseases.

Genome mining of Fusarium reveals structural and functional diversity of pectin lyases: a bioinformatics approach

Pectin lyase (PNL) is an important enzyme of the pectinases group which degrades pectin polymer to 4,5-unsaturated oligogalacturonides by a unique β-elimination mechanism and is used in several industries. The existence of multigene families of pectin lyases has been investigated by mining microbial genomes. In the present study, 52 pectin lyase genes were predicted from sequenced six species of Fusarium, namely F. fujikuroi, F. graminearum, F. proliferatum, F. oxysporum, F. verticillioides and F. virguliforme. These sequences were in silico characterized for several physico-chemical, structural and functional attributes. The translated PNL proteins showed variability with 344-1142 amino acid residues, 35.44-127.41 kDa molecular weight, and pI ranging from 4.63 to 9.28. The aliphatic index ranged from 75.33 to 84.75. Multiple sequence alignment analysis showed several conserved amino acid residues and five distinct groups marked as I, II, III, IV, and V were observed in the phylogenetic tree. The Three-dimensional Structure of five of these PNLs, each representing a distinct group of phylogenetic trees was predicted using I-TASSER Server and validated. The pectin lyase proteins of Fusarium species revealed close similarity with pectin lyase of Aspergillus niger PelA(1IDJ) and PelB(1QCX). Diversity in the structural motifs was observed among Fusarium species with 2 β-sheets, 1 β-hairpin, 7-12 β bulges, 18-25 strands, 6 -11 helices, 1 helix-helix interaction, 32-49 β turns, 2-6 γ turns and 2- 3 disulfide bonds. The unique Pec_lyase domain was uniformly observed among all PNL proteins confirming its identity. The genome-wide mining of Fusarium species was attempted to provide the diversity of PNL genes, which could be explored for diverse applications after performing cloning and expression studies.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03333-w.

Insights into intracellular signaling network in Fusarium species

Fusarium is a large genus of filamentous fungi including numerous important plant pathogens. In addition to causing huge economic losses of crops, some Fusarium species produce a wide range of mycotoxins in cereal crops that affect human and animal health. The intracellular signaling in Fusarium plays an important role in growth, sexual and asexual developments, pathogenesis, and mycotoxin biosynthesis. In this review, we highlight the recent advances and provide insight into signal sensing and transduction in Fusarium species. G protein-coupled receptors and other conserved membrane receptors mediate recognition of environmental cues and activate complex intracellular signaling. Once activated, the cAMP-PKA and three well-conserved MAP kinase pathways activate downstream transcriptional regulatory networks. The functions of individual signaling pathways have been well characterized in a variety of Fusarium species, showing the conserved components with diverged functions. Furthermore, these signaling pathways crosstalk and coordinately regulate various fungal development and infection-related morphogenesis.

Toxicity and preventive approaches of Fusarium derived mycotoxins using lactic acid bacteria: state of the art

Mycotoxin contamination of food and feed is a serious food safety issue and causes acute and chronic diseases in humans and livestock. Climatic and agronomic changes helps in the proliferation of fungal growth and mycotoxin production in food commodities. Mycotoxin contamination has attracted global attention due to its wide range of toxicity to humans and animals. However, physical and chemical management approaches in practice are unsafe for well-being due to their health-hazardous nature. Various antibiotics and preservatives are in use to reduce the microbial load and improve the shelf life of food products. In addition, the use of antibiotic growth promotors in livestock production may increase the risk of antimicrobial resistance, which is a global health concern. Due to their many uses, probiotics are helpful microbes that have a significant impact on food and nutrition. Furthermore, the probiotic potential of lactic acid bacteria (LAB) is employed in various food and feed preparations to neutralize mycotoxins, antimicrobial activities, balance the gut microbiome, and various immunomodulatory activities in both humans and livestock. In addition, LAB produces various antimicrobials, flavouring agents, peptides, and proteins linked to various food and health care applications. The LAB-based processes for mycotoxin management are more effective, eco-friendly, and low-cost than physical and chemical approaches. The toxicity, novel preventive measures, binding nature, and molecular mechanisms of mycotoxins' detoxification using LAB have been highlighted in this review.

Identification of New Fusarium sulawense Strains Causing Soybean Pod Blight in China and Their Control Using Carbendazim, Dipicolinic Acid and Kojic Acid

Soybean plants are highly susceptible to Fusarium species, which significantly reduce soybean production and quality. Several Fusarium species have been reported to synthesize mycotoxins, such as trichothecene, which have been related to major human diseases. In November 2021, soybean pods in Nantong municipality, China, showed black necrotic lesions during the harvest stage. The disease incidence reached 69%. The pathogen was identified as Fusarium sulawense via morphological analysis and sequencing of ITS, EF1-α and RPB2 genes. A PCR assay with primers targeting the trichothecene biosynthesis genes suggested that the three isolates could synthesize trichothecenes. The effectiveness of fungicide carbendazim and natural metabolites dipicolinic acid and kojic acid was screened for the management of F. sulawense on postharvest soybean pods. The highest efficacy was obtained when combining 3.8 mg/mL carbendazim and 0.84 mg/mL dipicolinic acid (curative efficacy: 49.1% lesion length inhibition; preventive efficacy: 82.7% lesion length inhibition), or 1.9 mg/mL carbendazim and 0.71 mg/mL kojic acid (preventive efficacy: 84.9% lesion length inhibition). Collectively, this report will lead to a better understanding of the safety hazards found in soybean products in China and reveals the application of dipicolinic and kojic acids to reduce the use of carbendazim.

Influence of Maize Residues in Shaping Soil Microbiota and Fusarium spp. Communities

Fusarium head blight (FHB) is a devastating fungal disease of small grain cereals including wheat. Causal fungal agents colonize various components of the field during their life cycle including previous crop residues, soil, and grains. Although soil and residues constitute the main inoculum source, these components have received much less attention than grains. This study aimed at disentangling the role of previous crop residues in shaping soil microbiota, including Fusarium spp. communities, in fields under wheat-maize rotation. Such knowledge may contribute to better understand the complex interactions between Fusarium spp. and soil microbiota. Dynamics of bacterial and fungal communities, with a special focus on Fusarium spp., were monitored in soils at 3 time points: during wheat cultivation (April 2015 and 2017) and after maize harvest (November 2016) and in maize residues taken from fields after harvest. Shifts in microbiota were also evaluated under mesocosm experiments using soils amended with maize residues. Fusarium graminearum and F. avenaceum were predominant on maize residues but did not remain in soils during wheat cultivation. Differences in soil bacterial diversity and compositions among years were much lower than variation between fields, suggesting that bacterial communities are field-specific and more conserved over time. In contrast, soil fungal diversity and compositions were more influenced by sampling time. Maize residues, left after harvest, led to a soil enrichment with several fungal genera, including Epicoccum, Fusarium, Vishniacozyma, Papiliotrema, Sarocladium, Xenobotryosphaeria, Ramularia, Cladosporium, Cryptococcus, and Bullera, but not with bacterial genera. Likewise, under mesocosm conditions, the addition of maize residues had a stronger influence on fungal communities than on bacterial communities. In particular, addition of maize significantly increased soil fungal richness, while bacteria were much less prone to changes. Based on co-occurrence networks, OTUs negatively correlated to Fusarium spp. were identified, such as those assigned to Epicoccum and Vishniacozyma. Altogether, our results allowed to gain a deeper insight into the complex microbiota interactions in soils, with bacteria and fungi responding differently to environmental disturbances.

Influence of H2O2-Induced Oxidative Stress on In Vitro Growth and Moniliformin and Fumonisins Accumulation by Fusarium proliferatum and Fusarium subglutinans

Fusarium proliferatum and Fusarium subglutinans are common pathogens of maize which are known to produce mycotoxins, including moniliformin (MON) and fumonisins (FBs). Fungal secondary metabolism and response to oxidative stress are interlaced, where hydrogen peroxide (H₂O₂) plays a pivotal role in the modulation of mycotoxin production. The objective of this study is to examine the effect of H₂O₂-induced oxidative stress on fungal growth, as well as MON and FBs production, in different isolates of these fungi. When these isolates were cultured in the presence of 1, 2, 5, and 10 mM H₂O₂, the fungal biomass of F. subglutinans isolates showed a strong sensitivity to increasing oxidative conditions (27–58% reduction), whereas F. proliferatum isolates were not affected or even slightly improved (45% increase). H₂O₂ treatment at the lower concentration of 1 mM caused an almost total disappearance of MON and a strong reduction of FBs content in the two fungal species and isolates tested. The catalase activity, surveyed due to its crucial role as an H₂O₂ scavenger, showed no significant changes at 1 mM H₂O₂ treatment, thus indicating a lack of correlation with MON and FB changes. H₂O₂ treatment was also able to reduce MON and FB content in certified maize material, and the same behavior was observed in the presence and absence of these fungi, highlighting a direct effect of H₂O₂ on the stability of these mycotoxins. Taken together, these data provide insights into the role of H₂O₂ which, when increased under stress conditions, could affect the vegetative response and mycotoxin production (and degradation) of these fungi.

Interaction Between Amorolfine and Voriconazole Against Fusarium species

Fusarium species represent a range of fungal pathogens capable of causing diverse mycotic diseases. Relative to antibacterial drugs, few effective antifungal agents have been developed to date, and all are subject to significant limitations. As such, there is an urgent need to design novel antifungal treatments for infections caused by Fusarium spp. Herein, 15 clinical isolates, including 5 Fusarium oxysporum and 10 Fusarium solani strains, were analyzed to explore the relative inhibitory effects of different combinations of amorolfine (AMO) and voriconazole (VOR) on the growth of these fungal pathogens. These analyses were conducted by measuring minimal inhibitory concentration (MIC) values for these antifungal agents in a broth microdilution assay and by using an in vivo model of Fusarium-infected Galleria mellonella. These experiments revealed that in isolation, AMO and VOR exhibited MIC values ranging from 4 to 16 μg/mL and 2 to 8 μg/mL, respectively. However, these effective MIC values fell to 1-2 μg/mL and 0.5-2 μg/mL, respectively, when AMO and VOR were administered in combination with one another, exhibiting synergistic activity against 73.3% of analyzed Fusarium strains. Subsequent in vivo analyses conducted using the G. mellonella model further confirmed that combination VOR + AMO treatment was associated with significantly improved larval survival following Fusarium spp. infection. Together, these results serve as the first published evidence demonstrating that VOR and AMO exhibit synergistic activity against infections caused by Fusarium spp., indicating that they may represent an effective approach to antifungal disease treatment.

Fusarium Species in Mangrove Soil in Northern Peninsular Malaysia and the Soil Physico-Chemical Properties

Fusarium genus comprises important saprophytic and phytopathogenic fungi and is widespread in nature. The present study reports the occurrence of Fusarium spp. in soils from two mangrove forests in northern Peninsular Malaysia and analyzed physico-chemical properties of the mangrove soil. Based on TEF-1α sequences, nine Fusarium species were identified: Fusarium solani species complex (FSSC) (n = 77), Fusarium verticillioides (n = 20), Fusarium incarnatum (n = 10), Fusarium proliferatum (n = 7), Fusarium lateritium (n = 4), Fusarium oxysporum (n = 3), Fusarium rigidiuscula (n = 2), Fusarium chlamydosporum (n = 1), and Fusarium camptoceras (n = 1); FSSC isolates were the most prevalent. Phylogenetic analysis of the combined TEF-1α and ITS sequences revealed diverse phylogenetic affinities among the FSSC isolates and potentially new phylogenetic clades of FSSC. Soil analysis showed varied carbon content, pH, soil moisture, and salinity, but not nitrogen content, between sampling locations. Regardless of the physico-chemical properties, various Fusarium species were recovered from the mangrove soils. These were likely saprophytes; however, some were well-known plant pathogens and opportunistic human pathogens. Thus, mangrove soils might serve as inoculum sources for plant and human pathogenic Fusarium species. The present study demonstrates the occurrence of various Fusarium species in the extreme environment of mangrove soil, thereby contributing to the knowledge on species diversity in Fusarium.

In Vivo Antifungal Activity of South African Medicinal Plant Extracts against Fusarium pathogens and Their Phytotoxicity Evaluation

Smallholder farmers play a major role in crop production towards household food security, particularly in resource-poor communities. Maize is a common crop produced in smallholder farming and it is cultivated from seeds that has been stored and re-used for years. Spoilage of stored grains is a major challenge, which leads to yield loss and poor seed quality. The objectives of this study were to evaluate in vivo antifungal activity of selected plant extracts against Fusarium pathogens on maize seeds, and to evaluate their phytotoxicity on seed germination and seedling growth. Fresh leaves collected from eight medicinal plants were dried and selectively extracted with water, ethyl acetate or acetone. The dried extracts were evaluated for antifungal activity against Fusarium pathogens (F. proliferatum, F. oxysporum, F. subglutinans, F. verticilloides, F. semitectum, F. chlamydosporum, F. solani, F. equisite and F. graminearum) inoculated on maize seeds. Melia azedarach acetone extract showed strong antifungal activity (97% inhibition) against F. proliferatum while combined acetone extracts from Combretum erythrophyllum and Quercus acutissima exhibited 96%, 67% and 56% inhibition against F. verticilloides, F. proliferatum and F. solani, respectively. With the exception of Quercus acutissima ethyl acetate, none of the extracts significantly inhibited seed germination when compared to untreated seeds. This study showed that plant extracts could control Fusarium diseases without any adverse effects on maize seed germination or plant growth.

Non-dermatophyte Mould Onychomycosis in Japan

The incidence of non-dermatophyte mould onychomycosis has been increasing worldwide for the past several decades, but it is not well recognized in Japan. Recent molecular techniques and phylogenetic analyses contributed to the identification of uncommon and emerging species. We came across 13 (0.5%) cases of non-dermatophyte onychomycosis among a total of 2,591 onychomycosis cases in 106,703 outpatients during the past 5 years (January 2015-December 2019). The cases included 5 patients with Aspergillus species, 4 patients with Fusarium species, and one patient each with Scopulariopsis brevicaulis and Botryosphaeria dothidea, respectively. Botryosphaeria dothidea is closely related phylogenetically to Neoscytalidium dimidiatum. In Japan, at the time of writing this report, there are 26 reported cases of ungual aspergillosis and 18 cases of hyalohyphomycosis caused by Fusarium species. We summarize these cases and report the symptoms and mycological features.

Diversity of the Seedborne Fungi and Pathogenicity of Fusarium Species Associated with Intercropped Soybean

Maize/soybean relay strip intercropping has been widely practiced in Southwest China due to its high productivity and effective application of agricultural resources; however, several seedborne diseases such as seedling blight, pod and seed decay are frequently observed causing severe yield loss and low seed quality. So far, the population and pathogenicity of the seedborne fungi associated with intercropped soybean remain unexplored. In this study, seeds of 12 soybean cultivars screened for intercropping were collected from three growing regions in Sichuan Province of Southwest China, and the seedborne fungi were isolated from the surface-sterilized seeds. Based on sequence analysis of ribosomal DNA internal transcribed spacer (rDNA ITS), 148 isolates were identified into 13 fungal genera, among which Fusarium covered 55.0% as the biggest population followed by Colletotrichum. Furthermore, Fusarium isolates were classified into five distinct species comprising F. fujikuroi, F. proliferatum, F. verticillioides, F. asiaticum and F. incarnatum through sequence analysis of translation elongation factor 1 alpha (EF-1α) and DNA-directed RNA ploymerase II second largest subunit (RPB2). Among them, F. fujikuroi accounted for 51.22% (42/82) and was isolated from 91.7% (11/12) soybean varieties. Pathogenicity assay showed that five Fusarium species were able to infect the seeds of soybean cultivar “Nandou12” and caused water-soaked or rot symptoms, while F. fujikuroi and F. asiaticum had much higher aggressiveness than other species with significant reductions of seed fresh weight and germination percentage. Accordingly, this study indicates that Fusarium species are the dominant seedborne fungi in the intercropped soybean in Sichuan, China, and this provides some useful references for the effective management of seedborne fungal diseases as well as soybean resistance breeding in maize/soybean relay strip intercropping.

Fusarium species intramedullary spinal cord fungus ball: case report

The Fusarium species are one of the most common opportunistic fungal infections occurring in immunocompromised patients and are associated with high morbidity and mortality. Common sites of infection include blood, skin, nasal passages, lungs, bone, and other visceral organs. There is a paucity of literature on Fusarium infections in the brain, and the true nature and extent of central nervous system involvement is not well described. To the authors' knowledge, there have been no reported cases of Fusarium infection of the spine. The authors report the case of a man with acute myeloblastic leukemia and resultant pancytopenia who presented with fungal sinusitis, upper- and lower-extremity weakness, and cardiopulmonary arrest. Imaging studies revealed a spinal cervical intramedullary ring-enhancing lesion. Because of the progressive nature of his symptoms, neurosurgical intervention involving a C2-3 laminectomy and drainage of the lesion was performed. Intraoperative cultures and histopathology results were positive for Fusarium species and, along with intraoperative findings, were consistent with a fungus ball. The patient was placed on a regimen of intravenous and intrathecal antifungal therapy. Unfortunately, his clinical condition declined postoperatively, and he ultimately died of disseminated infection.

Maize/Soybean Relay Strip Intercropping Reduces the Occurrence of Fusarium Root Rot and Changes the Diversity of the Pathogenic Fusarium Species

Fusarium species are the most detrimental pathogens of soybean root rot worldwide, causing large loss in soybean production. Maize/soybean relay strip intercropping has significant advantages on the increase of crop yields and efficient use of agricultural resources, but its effects on the occurrence and pathogen population of soybean root rot are rarely known. In this study, root rot was investigated in the fields of the continuous maize/soybean strip relay intercropping and soybean monoculture. Fusarium species were isolated from diseased soybean roots and identified based on sequence analysis of translation elongation factor 1α (EF-1α) and RNA polymerase II second largest subunit (RPB2), and the diversity and pathogenicity of these species were also analyzed. Our results showed that intercropping significantly decreased soybean root rot over monoculture. A more diverse Fusarium population including Fusarium solani species complex (FSSC), F. incarnatum-equiseti species complex (FIESC), F. oxysporum, F. fujikuroi, F. proliferatum and F. verticillioides, F. graminearum and F. asiaticum was identified from intercropping while FSSC, FIESC, F. oxysporum, F. commune, F. asiaticum and F. meridionale were found from monoculture. All Fusarium species caused soybean root infection but exhibited distinct aggressiveness. The most aggressive F. oxysporum was more frequently isolated in monoculture than intercropping. FSSC and FIESC were the dominant species complex and differed in their aggressiveness. Additionally, F. fujikuroi, F. proliferatum and F. verticillioides were specifically identified from intercropping with weak or middle aggressiveness. Except for F. graminearum, F. meridionale and F. asiaticum were firstly reported to cause soybean root rot in China. This study indicates maize/soybean relay strip intercropping can reduce soybean root rot, change the diversity and aggressiveness of Fusarium species, which provides an important reference for effective management of this disease.

First Comprehensive Report of Clinical Fusarium Strains Isolated in the State of Sao Paulo (Brazil) and Identified by MALDI-TOF MS and Molecular Biology

The aim of this study was to compare the performance of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), phenotypic and molecular methods for the identification of Fusarium species complexes isolated from clinical cases in the State of Sao Paulo (Brazil) between the years 2001 and 2017. Sequencing of ITS region of ribosomal DNA and elongation factor 1 alpha gene (ET1α) were used as reference method in the analysis of a total of 108 Fusarium spp. clinical strains isolated from human hosts with superficial and systemic infections. Agreement between MALDI-TOF-MS and molecular data was observed for 97 out of 108 clinical isolates (89.8%), whereas five (4.6%) and six (5.5%) clinical isolates were misidentified and were not identified by MALDI-TOF MS, respectively. ITS region sequences and MALDI-TOF MS mass spectra identified and grouped correctly most of Fusarium clinical isolates at species complex level. This investigation highlights the potential of MALDI-TOF MS technique as a fast and cost-efficient alternative for clinical Fusarium identification. However, MALDI-TOF MS requires a more accurate and larger database. This work is the first comprehensive report for Fusarium population, based on phenotypic analyses, proteomic profile by MALDI-TOF and phylogenetic analyses of Fusarium species complexes isolated from clinical cases in the State of Sao Paulo, Brazil.

Species Composition and Toxigenic Potential of Fusarium Isolates Causing Fruit Rot of Sweet Pepper in China

Apart from causing serious yield losses, various kinds of mycotoxins may be accumulated in plant tissues infected by Fusarium strains. Fusarium mycotoxin contamination is one of the most important concerns in the food safety field nowadays. However, limited information on the causal agents, etiology, and mycotoxin production of this disease is available on pepper in China. This research was conducted to identify the Fusarium species causing pepper fruit rot and analyze their toxigenic potential in China. Forty-two Fusarium strains obtained from diseased pepper from six provinces were identified as F. equiseti (27 strains), F. solani (10 strains), F. fujikuroi (five strains). This is the first report of F. equiseti, F. solani and F. fujikuroi associated with pepper fruit rot in China, which revealed that the population structure of Fusarium species in this study was quite different from those surveyed in other countries, such as Canada and Belgium. The mycotoxin production capabilities were assessed using a well-established liquid chromatography mass spectrometry method. Out of the thirty-six target mycotoxins, fumonisins B₁ and B₂, fusaric acid, beauvericin, moniliformin, and nivalenol were detected in pepper tissues. Furthermore, some mycotoxins were found in non-colonized parts of sweet pepper fruit, implying migration from colonized to non-colonized parts of pepper tissues, which implied the risk of mycotoxin contamination in non-infected parts of food products.

Characterization and Pathogenicity of Fusarium Species Associated with Soybean Pods in Maize/Soybean Strip Intercropping

Intercropping has been considered as a kind of a sustainable agricultural cropping system. In southwest China, maize/soybean strip intercropping has commonly been practised under local limited agricultural land resources. However, heavy rainfall in combination with high humidity and low temperatures cause severe pod and seed deterioration in the maturity and pre-harvesting stages of intercropped soybean. Numerous Fusarium species have been reported as the dominant pathogens of soybean root rot, seedling blight, as well as pod field mold in this area. However, the diversity and pathogenicity of Fusarium species on soybean pods remain unclear. In the current study, diseased soybean pods were collected during the cropping season of 2018 from five different intercropped soybean producing areas. A total of 83 Fusarium isolates were isolated and identified as F. fujikuroi, F. graminearum, F. proliferatum, and F. incarnatum-equiseti species complex based on morphological characteristics and phylogenetic analysis of the nucleotide sequence of EF1-α and RPB2 genes. Pathogenicity tests demonstrated that all Fusarium species were pathogenic to seeds of the intercropped soybean cultivar Nandou12. Fusarium fujikuroi had the maximum disease severity, with a significant reduction of seed germination rate, root length, and seed weight, followed by F. equiseti, F. graminearum, F. proliferatum, and F. incarnatum. Additionally, the diversity of Fusarium species on soybean pods was also considerably distinct according to the geographical origin and soybean varieties. Thus, the findings of the current study will be helpful for the management and resistance breeding of soybean pod decay in the maize/soybean intercropping system.

Performance of Winter Wheat Cultivars Grown Organically and Conventionally with Focus on Fusarium Head Blight and Fusarium Trichothecene Toxins

Growing acreage and changing consumer preferences cause increasing interest in the cereal products originating from organic farming. Lack of results of objective test, however, does not allow drawing conclusions about the effects of cultivation in the organic system and comparison to currently preferred conventional system. Field experiment was conducted in organic and conventional fields. Thirty modern cultivars of winter wheat were sown. They were characterized for disease infection including Fusarium head blight, seed sowing value, the amount of DNA of the six species of Fusarium fungi as well as concentration of ergosterol and trichothecenes in grain. The intensity Fusarium head blight was at a similar level in both systems. However, Fusarium colonization of kernels expressed as ergosterol level or DNA concentration was higher for the organic system. It did not reflect in an increased accumulation of trichothecenes in grain, which was similar in both systems, but sowing value of organically produced seeds was lower. Significant differences between analyzed cropping systems and experimental variants were found. The selection of the individual cultivars for organic growing in terms of resistance to diseases and contamination of grain with Fusarium toxins was possible. Effects of organic growing differ significantly from the conventional and grain obtained such way can be recommended to consumers. There are indications for use of particular cultivars bred for conventional agriculture in the case of organic farming, and the growing organic decreases plant stress resulting from intense fertilization and chemical plant protection.

Fusarium onychomycoses in Switzerland-A mycological and histopathological study

Onychomycoses in temperate climates are most commonly due to dermatophytes, particularly Trichophyton rubrum. Non-dermatophyte nail infections are much less frequent, and their diagnosis requires a careful and repeated search for a potential dermatophyte that may have been overgrown in culture. A series of histological slides of suspected onychomycoses with uncommon fungal morphology prompted us to search for non-dermatophytic moulds causing dermatophytosis-like nail infections. Thirty cases were identified by culture as F solani, F oxysporum, F dimerum or F spp, and two more were only diagnosed histopathologically. None of these patients was immunocompromised. Treatment was mostly unsuccessful with terbinafine whereas itraconazole showed a moderately better treatment result; in all cases, a topical ciclopirox nail varnish in a hydroxychitosan base was added.

Bioprospecting endophytic fungi from Fusarium genus as sources of bioactive metabolites

Endophytic fungi became an attractive source for the discovery of new leads, because of the complexity and the structural diversity of their secondary metabolites. The genus Fusarium comprising about 70 species is extremely variable in terms of genetics, biology, ecology, and consequently, secondary metabolism and have been isolated from countless plants genera from diverse habitats. These endophytic microbes may provide protection and survival strategies in their host plants with production of a repertoire of chemically diverse and structurally unprecedented secondary metabolites reported to exhibit an incredible array of biological activities including antimicrobial, anticancer, antiviral, antioxidants, antiparasitics, immunosuppressants, immunomodulatory, antithrombotic, and biocontrol ability against plants pathogens and nematodes. This review comprehensively highlights over the period 1981-2019, the bioactive potential of metabolites produced by endophytes from Fusarium genus. Abbreviations: AIDS: Acquired immune deficiency syndrome; BAPT: C-13 phenylpropanoid side chain-CoA acyltransferase; CaBr2: Calcium bromide; DBAT: 10-deacetylbaccatin III-10-O-acetyl transferase; DNA: Deoxyribonucleic acid; EI-MS: Electron ionization mass spectrometer; EN: Enniatin; ERK: Extracellular regulated protein kinase; EtOAc: Ethyl acetate; FDA: Food and Drug Administration; GAE/g: Gallic acid equivalent per gram; GC-MS: Gas chromatography-mass spectrometry; HA: Hyperactivation; HCV: Hepatitis C Virus; HCVPR: Hepatitis C Virus protease; HeLa: Human cervical cancer cell line; HIV: Human immunodeficiency viruses; HPLC: High Performance Liquid Chromatography; IAA: Indole-3-acetic acid; IARC: International Agency for Research on Cancer; IC50: Half maximal inhibitory concentration; LC50: Concentration of the compound that is lethal for 50% of exposed population; LC-MS: Liquid chromatography-mass spectrometry; MCF-7: Human breast cancer cell line; MDR: Multidrug-resistant; MDRSA: Multidrug-resistant S. aureus; MFC: Minimum fungicidal concentration; MIC: Minimum inhibitory concentration; MRSA: Multidrug-resistant S. aureus; MTCC: Microbial type culture collection; PBMCs: Peripheral blood mononuclear cells; PCR: Polymerase chain reaction; TB: Tuberculosis; TLC: Thin layer chromatography; TNF: Tumor necrosis factor; WHO: World Health Organization http://www.zoobank.org/urn:lsid:zoobank.org:pub:D0A7B2D8-5952-436D-85C8-C79EAAD1013C.

The Relationship Analysis on Corn Stalk Rot and Ear Rot According to Fusarium Species and Fumonisin Contamination in Kernels

Fusarium diseases, including corn root rot, sheath rot, stalk rot, and ear rot are frequently occurring in maize producing areas of China. Fusarium stalk rot and ear rot are the most serious diseases and often occur at the same time, but it is unclear whether there is a correlation between Fusarium composition and disease occurrence. This study was conducted to clarify the relationship between the two diseases. A total of 49 corn stalk rot samples were collected from 15 regions of eight provinces in China from 2016 to 2018. The pathogens were isolated and identified separately from stalks, ear stems, and kernels. The contents of the fumonisins (FB₁ and FB₂) were detected in kernels. The results showed that the main Fusarium species were found in corn kernels, ear stems and stalks at the same time. The results showed that 1201 strains of Fusarium verticillioides, 668 strains of Fusarium oxysporum, 574 strains of Fusarium graminearum species complex (FGSC), 318 strains of Fusarium equiseti, 95 strains of Fusarium proliferatum, and 40 strains of Fusarium subglutinans were isolated from 1470 corn kernels, 245 ear stems, and 1225 stalks randomly selected from 49 samples. The contamination rate of fumonisins in the 49 samples was 57.1% with an average content of 1.9 μg/g, of which four samples exhibited higher levels as set by the European Commission (4.0 μg/g). These results provide a certain association between stalk rot and ear rot and lay a foundation to study the relationships among Fusarium maize diseases.

Fusarium Toxins in Chinese Wheat since the 1980s

Wheat Fusarium head blight (FHB), caused by Fusarium species, is a widespread and destructive fungal disease. In addition to the substantial yield and revenue losses, diseased grains are often contaminated with Fusarium mycotoxins, making them unsuitable for human consumption or use as animal feed. As a vital food and feed ingredient in China, the quality and safety of wheat and its products have gained growing attention from consumers, producers, scientists, and policymakers. This review supplies detailed data about the occurrence of Fusarium toxins and related intoxications from the 1980s to the present. Despite the serious situation of toxin contamination in wheat, the concentration of toxins in flour is usually lower than that in raw materials, and food-poisoning incidents have been considerably reduced. Much work has been conducted on every phase of toxin production and wheat circulation by scientific researchers. Regulations for maximum contamination limits have been established in recent years and play a substantial role in ensuring the stability of the national economy and people's livelihoods.

Occurrence of Mycotoxigenic Fusarium Species and Competitive Fungi on Preharvest Maize Ear Rot in Poland

Maize has become one of the most important crops for food and feed production-both as a silage and crop residue worldwide. The present study aimed to identify the co-occurrence of Fusarium subglutinans, Fusarium verticillioides, Trichoderma atroviride, Sarocladium zeae, and Lecanicillium lecanii on maize ear rot. Further, the accumulation of mycotoxins as secondary metabolites of Fusarium spp. in maize ear samples was also analyzed. Maize ear samples were collected between 2014 and 2017 from two main maize growing areas in Poland (Greater Poland and Silesia region). A significant difference was found in the frequency of two main Fusarium spp. that infect maize ears, namely F. subglutinans and F. verticillioides. In addition to Fusarium spp. T. atroviride, S. zeae, and L. lecanii were also identified. T. atroviride species was found in 14% of maize samples examined between 2014 and 2017, particularly with a high percentage of Trichoderma spp. recorded in 2014, i.e., in 31% of samples. However, mycotoxin content (beauvericin and fumonisins) varied, depending on both the location and year of sampling. The interaction of fungi and insects inhabiting maize ear and kernel is very complex and not yet elucidated. Therefore, further research is required in this area.

Fusarium vascular graft infection

A 37-year-old African American male with a past medical history significant for end stage renal disease on hemodialysis via a femoral arteriovenous graft, systemic lupus erythematous, with a recent hospitalization for cavitary Candida pneumonia treated with micafungin, presented with a fever of 102° F for 3 days and worsening left groin pain. He also complained of chills, nausea, and malaise. On physical examination, the patient was hemodynamically stable with swelling and tenderness at the site of the graft. He was started on vancomycin, piperacillin/tazobactam and micafungin. Computed tomography scan and duplex scan of the left lower extremity showed diffuse swelling and attenuation of the graft material consistent with thrombosis of the graft. Excision of the graft and thrombectomy was performed and the graft thrombus was sent for culture. Examination of the sample showed fungal hyphae (Figure). Micafungin was switched to voriconazole; however, the patient did not show any improvement of his groin pain. On day 5 of hospitalization, culture showed Fusarium, and hence amphotericin B was added resulting in subsequent clinical improvement. We are presenting an unusual site of Fusarium infection which responded to combination therapy, a case which has not been reported.

Diversity and mycotoxin production by Fusarium temperatum and Fusarium subglutinans as causal agents of pre-harvest Fusarium maize ear rot in Poland

Maize ear rot is a common disease found worldwide, caused by several toxigenic Fusarium species. Maize ears and kernels infected by Fusarium subglutinans contained significant amounts of beauvericin, fusaproliferin, moniliformin, and enniatins. In 2011, F. subglutinans sensu lato has been divided into two species: Fusarium temperatum sp. nov. and F. subglutinans sensu stricto, showing different phylogeny and beauvericin production within the populations of maize pathogens in Belgium. Isolates of the new species—F. temperatum—were also identified and characterized in Spain, Argentina, Poland, France, and China as one of the most important pathogens of maize. Moreover, F. temperatum was proved to be pathogenic to maize seedlings and stalks. We identified Fusarium isolates obtained from diseased maize ears collected between 2013 and 2016 in Poland (321 isolates). Based on morphological analyses, six Fusarium species were identified. Molecular identification performed on the set of selected isolates (42 isolates) revealed 34 isolates to be F. temperatum and only five to be F. subglutinans. Interestingly, the phylogenetic analysis showed that the population of F. temperatum infecting maize in Poland remained quite uniform for over 30 years with only a few exceptions. For the first time, a single isolate of Fusarium ramigenum was detected from the area of Poland. Significant amounts of BEA were found in Fusarium-damaged kernels. The same kernel samples contained also enniatins A1, A, B1, and B. The results clearly demonstrate the occurrence of F. temperatum as maize pathogen in Poland for over the last three decades.

Potent Activities of Luliconazole, Lanoconazole, and Eight Comparators against Molecularly Characterized Fusarium Species

A collection of clinical (n = 47) and environmental (n = 79) Fusarium isolates were tested against 10 antifungal drugs, including 2 novel imidazoles. Luliconazole and lanoconazole demonstrated very low geometric mean MIC values of 0.005 and 0.013 μg/ml, respectively, compared with 0.51 μg/ml for micafungin, 0.85 μg/ml for efinaconazole, 1.12 μg/ml for natamycin, 1.18 μg/ml for anidulafungin, 1.31 μg/ml for voriconazole, 1.35 μg/ml for caspofungin, 1.9 μg/ml for amphotericin B, and 4.08 μg/ml for itraconazole. Results show that these drugs are potential candidates for (topical) treatment of skin and nail infections due to Fusarium species.

The Major Fusarium Species Causing Maize Ear and Kernel Rot and Their Toxigenicity in Chongqing, China

Fusarium verticillioides, F. proliferatum, and F. meridionale were identified as the predominant fungi among 116 Fusarium isolates causing maize ear and kernel rot, a destructive disease in Chongqing areas, China. The toxigenic capability and genotype were determined by molecular amplification and toxin assay. The results showed that the key toxigenic gene FUM1 was detected in 47 F. verticillioides and 19 F. proliferatum isolates. Among these, F. verticillioides and F. proliferatum isolates mainly produced fumonisin B₁, ranging from 3.17 to 1566.44, and 97.74 to 11,100.99 µg/g for each gram of dry hyphal weight, with the averages of 263.94 and 3632.88 µg/g, respectively, indicating the F. proliferatum isolates on average produced about an order of magnitude more fumonisins than F. verticillioides did in these areas, in vitro. Only NIV genotype was detected among 16 F. meridionale and three F. asiaticum isolates. Among these, 11 F. meridionale isolates produced NIV, varying from 17.40 to 2597.34 µg/g. ZEA and DON toxins were detected in 11 and 4 F. meridionale isolates, with the toxin production range of 8.35-78.57 and 3.38-33.41 µg/g, respectively. Three F. asiaticum isolates produced almost no mycotoxins, except that one isolate produced a small amount of DON. The findings provide us with insight into the risk of the main pathogenic Fusarium species and a guide for resistance breeding in these areas.

Analyzing formation of silver nanoparticles from the filamentous fungus Fusarium oxysporum and their antimicrobial activity

In recent years much attention has been paid to the biosynthesis of silver nanoparticles (AgNPs) and their important medical applications. The current study employs Fusarium oxysporum for the formation of silver nanoparticles and examines the antimicrobial activity of the particles against some multidrug-resistant (MDR) microbes. Silver nitrate was transformed into silver oxide, forming well-dispersed nanoparticles, by the action of F. oxysporum metabolically. The size of the nanoparticles ranged from 21.3 to 37.3 nm, and UV-spectroscopy showed a peak at 408-411 nm. Moreover, SEM, TEM, and AFM results revealed spherical and oval shapes and showed no sign of aggregation. Furthermore, the FT-IR histogram detected amide I and amide II, which are responsible for the stability of AgNPs in the aqueous solution. The AgNPs halted the growth of MDR bacteria, including some members of Enterobacteriaceae and Staphylococcus species at a concentration of 50% (v/v). The AgNPs also have the ability to inhibit pathogenic yeasts Candida albicans and Candida krusei. The AgNPs displayed antigrowth activity against MDR microbes, suggesting that they might be potential alternatives to antibiotics. However, additional studies may be necessary to substantiate the fact that the benefits of using nanoparticles outweigh the potential risks.

Multiplex polymerase chain reaction assays for the detection of the zearalenone chemotype of Fusarium species in white and brown rice

Early detection of the zearalenone (ZEA) chemotype of Fusarium species could be a precautionary measure for preventing ZEA contamination in rice. In this study, a multiplex polymerase chain reaction (mPCR) assay for detecting ZEA-producing fungi in rice was established using a set of four primers targeting the ZEA biosynthesis genes PKS3, PKS13, ZEB1, and ZEB2. Two mPCR approaches were used: one that amplified the DNA obtained from Fusarium isolates (conventional method) and another that directly amplified the target DNA from rice samples without time-consuming DNA isolation (direct method). The two mPCR methods showed high sensitivity in detecting ZEA-producing species, with a detection limit of 1.25 pg/μL of genomic DNA and 10² and 10³ spores/g of white and brown rice, respectively. Both methods were specific for ZEA-producing species and gave four band patterns. The application of the two mPCR methods to 51 Fusarium isolates and 41 rice samples revealed that 31% (16 of 51) and 24% (10 of 41) of the samples were contaminated with ZEA-producing species, respectively. The mPCR results were further evaluated using high-performance liquid chromatography; in general, the two methods yielded similar results. These findings indicate that both mPCR methods are suitable for the detection of ZEA-producing Fusarium species in white and brown rice; however, the direct method yielded more rapid results.

Pathological Interrelations of Soil-Borne Diseases in Cucurbits Caused by Fusarium Species and Meloidogyne incognita

Pathological interrelations of two soil-borne diseases in cucurbits (watermelon, oriental melon, shintosa and cucumber) caused by Fusarium isolates (FI) and the root-knot nematode (RKN), Meloidogyne incognita were characterized by the fusarium disease severity index (DI), RKN gall index (GI) and eggmass index (EI) in inoculation tests using FI and RKN. Virulence of FI as determined by DI at 4 weeks after inoculation was mostly in the higher order of Fusarium proliferatum F6, F5 and Fusarium oxysporum f. sp. melonis or Fusarium oxysporum f. sp. niveum with no significant differential interactions among the cucurbits and RKN co-infection. Significant increases of DI due to RKN coinfection were noticed in watermelon and oriental melon infected with F. proliferatum isolates, suggesting the DI increase due to RKN coinfection may depend upon the virulence of FI relative to aggressiveness of RKN on the cucurbits. For the coinfection of FI and RKN, GI and EI were mostly reduced logarithmically with the increase of DI, largely more in EI than GI, in all cucurbits except for shintosa. Microscopic examination of the root tissues showed histopathological features characteristic to infection types; formation of fungal hyphae and/or spores and plant defense structures (tyloses and mucilage) in variable degrees and formation of giant cells at variable developmental stages and with variable cytoplasmic depletion or degeneration which were visualized in relations with the values of DI, GI and EI. These findings will be helpful to develop control strategies of the soil-borne disease complex based on their pathological characteristics.

Potential Reasons for Prevalence of Fusarium Wilt in Oriental Melon in Korea

This study aims to examine the potential reasons for the current prevalence of the fusarium wilt in the oriental melon. Twenty-seven Fusarium isolates obtained from oriental melon greenhouses in 2010-2011 were identified morphologically and by analysis of elongation factor-1 alpha gene (EF-1α) and internal transcribed spacer (ITS) rDNA sequences as 6 Fusarium species (8 isolates of F. oxysporum, 8 F. commune, 5 F. proliferatum, 3 F. equiseti, 2 F. delphinoides, and 1 F. andiyazi), which were classified as same into 6 EF-1α sequence-based phylogenetic clades. Pathogenicity of the Fusarium isolates on the oriental melon was highest in F. proliferatum, next in F. oxysporum and F. andiyazi, and lowest in the other Fusarium species tested, suggesting F. proliferatum and F. oxysporum were major pathogens of the oriental melon, inducing stem rots and vascular wilts, respectively. Oriental melon and watermelon were more susceptible to F. oxysporum than shintosa and cucumber; and cucumber was most, oriental melon and watermelon, medially, and shintosa was least susceptible to F. proliferatum, whose virulence varied among and within their phylogenetic subclades. Severe root-knot galls were formed on all the crops infected with Meloidogyne incognita; however, little indication of vascular wilts or stem and/or root rots was shown by the nematode infection. These results suggest the current fungal disease in the oriental melon may be rarely due to virulence changes of the fusarium wilt pathogen and the direct cause of the severe root-knot nematode infection, but may be potentially from other Fusarium pathogen infection that produces seemingly wilting caused by severe stem rotting.

Fusarium species identification and fumonisin production in maize kernels from Shandong Province, China, from 2012 to 2014

A total of 225 maize kernel samples were collected from Shandong Province in China from 2012 to 2014 and analysed for contamination with Fusarium spp. and fumonisins (FBs) using molecular methods and high-performance liquid chromatography with fluorescence detection. The results showed that the average incidences of Fusarium spp. in 2012, 2013 and 2014 were 23.3%, 37.1% and 36.5%, respectively, Fusarium verticillioides being the predominant species. In 2012, the average contamination level of FBs was 3071 ng g(-1), which was higher than that in 2014 (2913 ng g(-1)) and 2013 (2072 ng g(-1)). Of all samples, 13% and 19% had FB contamination levels higher than 2000 and 4000 ng g(-1), which are the maximum limits as set by the Food and Drug Administration of the United States and the European Commission, respectively. Therefore, efforts should be taken to minimise the potential risk of FBs to the health of humans and animals.

Updated survey of Fusarium species and toxins in Finnish cereal grains

The aim of the project was to produce updated information during 2005-14 on the Fusarium species found in Finnish cereal grains, and the toxins produced by them, as the last comprehensive survey study of Fusarium species and their toxins in Finland was carried out at the turn of the 1960s and the 1970s. Another aim was to use the latest molecular and chemical methods to investigate the occurrence and correlation of Fusarium species and their mycotoxins in Finland. The most common Fusarium species found in Finland in the FinMyco project 2005 and 2006 were F. avenaceum, F. culmorum, F. graminearum, F. poae, F. sporotrichioides and F. langsethiae. F. avenaceum was the most dominant species in barley, spring wheat and oat samples. The occurrence of F. culmorum and F. graminearum was high in oats and barley. Infection by Fusarium fungi was the lowest in winter cereal grains. The incidence of Fusarium species in 2005 was much higher than in 2006 due to weather conditions. F. langsethiae has become much more common in Finland since 2001. F. graminearum has also risen in the order of importance. A highly significant correlation was found between Fusarium graminearum DNA and deoxynivalenol (DON) levels in Finnish oats, barley and wheat. When comparing the FinMyco data in 2005-06 with the results of the Finnish safety monitoring programme for 2005-14, spring cereals were noted as being more susceptible to infection by Fusarium fungi and the formation of toxins. The contents of T-2 and HT-2 toxins and the frequency of exceptionally high DON concentrations all increased in Finland during 2005-14. Beauvericin (BEA), enniatins (ENNs) and moniliformin (MON) were also very common contaminants of Finnish grains in 2005-06. Climate change is leading to warmer weather, and this may indicate more changes in Finnish Fusarium mycobiota and toxin contents and profiles in the near future.

A comparative analysis of distribution and conservation of microsatellites in the transcripts of sequenced Fusarium species and development of genic-SSR markers for polymorphism analysis

We used an in silico approach to survey and compare microsatellites in transcript sequences of four sequenced members of genus Fusarium. G + C content of transcripts was found to be positively correlated with the frequency of SSRs. Our analysis revealed that, in all the four transcript sequences studied, the occurrence, relative abundance and density of microsatellites varied and was not influenced by transcript sizes. No correlation between relative abundance and transcript sizes was observed. The relative abundance and density of microsatellites were highest in the transcripts of Fusarium solani when compared with F. graminearum, F. verticillioides and F. oxysporum. The maximum frequency of SSRs among all four sequence sets was of trinucleotide repeats (67.8%), whereas the dinucleotide repeat represents <1%. Among all classes of repeats, 36.5% motifs were found conserved within Fusarium species. In order to study polymorphism within Fusarium isolates, 11 polymorphic genic-SSR markers were developed. Of the 11 markers, 5 were from F. oxysporum and remaining 6 belongs to F. solani. SSR markers from F. oxysporum were found to be more polymorphic (38%) as compared to F. solani (26%). Eleven polymorphic markers obtained in this study clearly demonstrate the utility of newly developed SSR markers in establishing genetic relationships among different isolates of Fusarium.

Molecular strategies for detection and quantification of mycotoxin-producing Fusarium species: a review

Fusarium contamination is considered a major agricultural problem, which could not only significantly reduce yield and quality of agricultural products, but produce mycotoxins that are virulence factors responsible for many diseases of humans and farm animals. One strategy to identify toxigenic Fusarium species is the use of modern molecular methods, which include the analysis of DNA target regions for differentiation of the Fusarium species, particularly the mycotoxin-producing Fusarium species such as F. verticillioides and F. graminearum. Additionally, polymerase chain reaction assays are used to determine the genes involved in the biosynthesis of the toxins in order to facilitate a qualitative and quantitative detection of Fusarium-producing mycotoxins. Also, it is worth mentioning that some factors that modulate the biosynthesis of mycotoxins are not only determined by their biosynthetic gene clusters, but also by environmental conditions. Therefore, all of the aforementioned factors which may affect the molecular diagnosis of mycotoxins will be reviewed and discussed in this paper.