In this study, the antifungal activity of cumin seed oil (CSO) was tested on Fusarium graminearum. (i) Minimum inhibitory concentrations (MICs) and related concentrations (IC75, IC50, and IC25) were detected; (ii) toxicity was evaluated by a water-soluble tetrazolium salt-1 (WST-1) assay; (iii) genomic/epigenomic alterations were evaluated by the coupled restriction enzyme digestion-random amplification (CRED-RA) method; (iv) oxidative stress was investigated by CAT expression, catalase activity, and DCF-DA staining; (v) deoxynivalenol biosynthesis was evaluated by tri6 expression; (vi) and potential effects of CSO on wheat were tested by a water loss rate (WLR) assay. MIC, IC75, IC50 and IC25 values were detected at 0.5, 0.375, 0.25, and 0.125 mg mL−1. In WST-1 assays, significant decreases (p < 0.001) were detected. Genomic template stability (GTS) related to methylation differences ranged from 94.60% to 96.30%. Percentage polymorphism for HapII/MspI values were as 9.1%/15.8%. CAT (oxidative stress-related catalase) and tri6 (zinc finger motif transcription factor) gene expressions were recorded between 5.29 ± 0.74 and 0.46 ± 0.10 (p < 0.05). Increased catalase activity was detected (p < 0.05) by spectrophotometric assays. DCF-DA-stained (oxidative stressed) cells were increased in response to increased concentrations, and there were no significant changes in WLR values. It was concluded that CSO showed strong antifungal activity on F. graminearum via different physiological levels.
The Fusarium graminearum species complex (FGSC) is a worldwide phytopathogenic fungus of small grain cereals. Genetics and bioinformatics tools have been providing an efficient strategy for identifying FGSC. However, the potential reliability of tef1−α sequencing in FGSC members has not been well investigated. In this study, the tef1−α sequencing data of 246 FGSC members, one F. culmorum, and one F. solani isolate were subjected to distance-, character-, and PCA-based phylogenetic analysis. Linux terminals and the R programming language were used in phylogenetic analysis. The Unweighted Pair Group Method with Arithmetic Mean (UPGMA) and maximum likelihood methods produced relatively more homogenous F. graminearum sensu stricto (Fgss) and F. asiaticum isolates. Fgss and F. asiaticum isolates co-clustered in two separate sub-divisions in the ML and UPGMA methods, with significant differences in the Chi2 test (p < 0.05). PCA profiling revealed a low level of variation in FGSC members, with 99–99.5% percentages in axis 1. An increased number of taxa and isolates would be tested for tef1−α in future studies. To our knowledge, this is also the first study to combine phylogenetic methods with PCA tests for comprehensive characterization of FGSC members.
The goal of this study was to find effective bacterial isolates possessing antagonistic effects against Botrytis cinerea in strawberry in field conditions and to evaluate the antifungal properties of the extracellular metabolites produced by these isolates. Four bacterial isolates with considerable antifungal activity against B. cinerea were isolated from strawberries collected from local markets in Giza, Egypt. The molecular identification of bacterial isolates indicated that two of the isolates belong to the Bacillus subtilis, while the other two isolates belong to Pseudomonas stutzeri. The supernatants of the isolates were extracted and subjected to GC/MS analysis, which revealed that the supernatants of the isolates contained different types of fatty acids with expected antifungal activity. The most potent B. subtilis strain was further applied as a foliar spray over heavily infected strawberry fields, which led to significant reduction of B. cinerea. Therefore, this strain should be investigated further.
Genetic variation at variable number tandem repeat (VNTR) markers was used to assess population structure and diversity among 296 Fusarium graminearum isolates from northern Europe (Finland, northwestern Russia, and Norway), southern Europe (southwestern and western Russia), and Asia (Siberia and the Russian Far East). We identified at least two highly differentiated and geographically structured genetic populations (E1 and E2) in Eurasia (ΦPT = 0.35). Isolates from northern Europe were almost exclusively from the E1 population (95.6%) and had the 3ADON (3-acetyldeoxynivalenol) trichothecene genotype (97.3%). In contrast, all isolates from southern Europe were from the E2 population and 94.4% had the 15ADON (15-acetyldeoxynivalenol) genotype. The E2 population also predominated in the Asian sampling locations (92.7%) where 3ADON and 15ADON genotypes occurred at nearly equal frequencies. Southern European isolates were more closely related to those from Asia (ΦPT = 0.06) than to geographically closer populations from northern Europe (ΦPT ≥ 0.31). Northern European populations also harbored substantially less genetic diversity (Ne ≤ 2.1) than populations in southern Europe or Asia (Ne ≥ 3.4), indicative of a selective sweep or recent introduction and subsequent range expansion in northern Europe. Bayesian analyses incorporating previously described genetic populations from North America (NA1 and NA2) surprisingly identified NA2 and E2 as a single genetic population, consistent with hypotheses of a recent Eurasian origin for NA2. Additionally, more than 10% of the isolates from Asia and southern Europe were assigned to the NA1 population, indicating recent introductions of NA1 into parts of Eurasia. Collectively, these results demonstrate that there are at least three genetic populations of F. graminearum in the Northern Hemisphere and indicate that population-level diversity in Eurasia and North America has been shaped by recent transcontinental introductions.
Fungi produce wide range of secondary metabolites including mycotoxins. Mycotoxins, predominantly synthesized by Alternaria spp., Aspergillus spp., Claviceps spp. and Fusarium spp. are molecules with low molecular mass and hazardous effects on humans, animals and plants. Humans take up these hazardous molecules via food chain in particular plants contaminated with mycotoxigenic fungi. Aflatoxins, fumonisins, zearalenone and trichothecenes are major mycotoxins produced by Aspergillus and Fusarium genera. Detailed analyses such as identification, characterization and quantification related to these mycotoxins and their producers are important in terms of mycotoxin inhibition at indoor and outdoor places and of disease management strategies. For these purposes, identification of mycotoxin presence, chemotype and sub-chemotype characterization, quantification of the specific mycotoxin(s), inhibition and elimination the potential presence and adverse effects of mycotoxins are needed in investigations related to mycotoxigenic fungi and their mycotoxins. Here, we describe the comprehensive knowledge on structures, presence, identification and characterization of four major mycotoxins which are present throughout the world.
Fusarium avenaceum (Fr.) Sacc. is an important phytopathogen. Fight against F. avenaceum includes primarily fungicide usage. However, novel strategies are needed in a struggle with F. avenaceum. In this study, terpinolene was used against F. avenaceum as an antimicrobial agent, and the harmlessness of terpinolene was tested on two contrast barley genotypes, Hordeum vulgare L. cv. Cervoise and H. vulgare L. cv. Premium. Firstly, minimum inhibitory concentration (MIC) and half inhibitory concentration (IC50) were detected as 6 and 3 µg µL-1. Quantitative real-time polymerase chain reaction (qRT-PCR) assay was informative about the effects of terpinolene on enniatin and zearalenone biosynthesis in F. avenaceum. Terpinolene leads to the potential decreased enniatin and zearalenone biosynthesis in F. avenaceum. However, no significant differences were recorded for gene expression of aurofusariun biosynthesis. In barley, electroconductivity (EC), catalase (CAT) activity, coupled restriction enzyme digestion-random amplification (CRED-RA), and qRT-PCR assays were tested. No significant ion leakage differences (p>0.05) were detected. Similarly, CAT activity and water loss rate (WLR) values in barley sets were not affected (p>0.05) by terpinolene treatment in majority of experiment sets. Relatively low levels of genomic template instability (75-85%) and epigenetics changes (11-20.6%) were recorded in barley due to terpinolene treatment. WRKY6, WRKY24, and WRKY41 expressions were not significantly changed. The findings showed that terpinolene could be accepted as a potential plant protective agent against phytopathogenic fungi.
Crop diseases caused by Fusarium graminearum threaten crop production in both commercial and smallholder farming. F. graminearum produces deoxynivalenol mycotoxin, which is stable during food and feed processing. Therefore, the best way to prevent the sporulation of pathogens is to develop new prevention strategies. Plant-based pesticides, i.e., natural fungicides, have recently gained interest in crop protection as alternatives to synthetic fungicides. Herein we show that treatment with the methanolic extract of medicinal plant Zanthoxylum bungeanum (M20 extract), decreased F. graminearum growth and abrogated DON production. The F. graminearum DNA levels were monitored by a quantitative TaqMan real-time PCR, while DON accumulation was assessed by HPLC quantification. This M20 extract was mainly composed of four flavonoids: quercetin, epicatechin, kaempferol-3-O-rhamnoside, and hyperoside. The in vitro bioassay, which measured the percent inhibition of fungal growth, showed that co-inoculation of four F. graminearum strains with the M20 extract inhibited the fungal growth up to 48.5%. After biocontrol treatments, F. graminearum DNA level was reduced up to 85.5% compared to that of wheat heads, which received F. graminearum mixture only. Moreover, DON production was decreased in wheat heads by 73% after biocontrol treatment; meanwhile in wheat heads inoculated with F. graminearum conidia, an average of 2.263 ± 0.8 mg/kg DON was detected. Overall, this study is a successful case from in vitro research to in planta, giving useful information for wheat protection against F. graminearum responsible for Fusarium Head Blight and DON accumulation in grains. Further studies are needed to study the mechanism by which M20 extract inhibited the DON production and what changes happened to the DON biosynthetic pathway genes.
Aflatoxin B1 (AFB1) is a food-borne toxin produced by Aspergillus flavus and a few similar fungi. Natural anti-aflatoxigenic compounds are used as alternatives to chemical fungicides to prevent AFB1 accumulation. We found that a methanolic extract of the food additive Zanthoxylum bungeanum shuts down AFB1 production in A. flavus . A methanol sub-fraction (M20) showed the highest total phenolic/flavonoid content and the most potent antioxidant activity. Mass spectrometry analyses identified four flavonoids in M20: quercetin, epicatechin, kaempferol-3-O-rhamnoside, and hyperoside. The anti-aflatoxigenic potency of M20 (IC 50 : 2–4 µg/mL) was significantly higher than its anti-proliferation potency (IC 50 : 1800–1900 µg/mL). RNA-seq data indicated that M20 triggers significant transcriptional changes in 18 of 56 secondary metabolite pathways in A. flavus , including repression of the AFB1 biosynthesis pathway. Expression of aflR , the specific activator of the AFB1 pathway, was not changed by M20 treatment, suggesting that repression of the pathway is mediated by global regulators. Consistent with this, the Velvet complex, a prominent regulator of secondary metabolism and fungal development, was downregulated. Decreased expression of the conidial development regulators brlA and Medusa, genes that orchestrate redox responses, and GPCR/oxylipin-based signal transduction further suggests a broad cellular response to M20. Z. bungeanum extracts may facilitate the development of safe AFB1 control strategies.
Maize and other cereals are the commodities most contaminated with fumonisins. The maize acreage is increasing in Africa, and the maize harvest provides important foods for humans and feeds for domestic animals throughout the continent. In North Africa, high levels of fumonisins have been reported from Algeria and Morocco, while low levels have been detected in the rather few fumonisin analyses reported from Tunisia and Egypt. The West African countries Burkina Faso, Cameroon, Ghana, and Nigeria all report high levels of fumonisin contamination of maize, while the few maize samples analysed in Togo contain low levels. In Eastern Africa, high levels of fumonisin contamination have been reported from the Democratic Republic of Congo, Ethiopia, Kenya, Tanzania, and Uganda. The samples analysed from Rwanda contained low levels of fumonisins. Analysis of maize from the Southern African countries Malawi, Namibia, South Africa, Zambia, and Zimbabwe revealed high fumonisin levels, while low levels of fumonisins were detected in the few analyses of maize from Botswana and Mozambique.
The 3ADON chemotype of Fusarium graminearum predominates in northern Europe, whereas the 15ADON chemotype is predominant in central and southern Europe. Therefore, it has been suggested that there are two F. graminearum populations in Europe, which may have been specialized to different host plants. The aim of the present work was to test this hypothesis by comparing southern European isolates (15ADON chemotype) from southern Russia and northern European isolates (3ADON chemotype) from Finland in the infection of grains in wheat cultivar Wellamo and oat cultivar Venla. F. graminearum biomass levels were measured by TaqMan (2018) and SYBR Green (2019) qPCR, while DON levels were measured by chromatographic methods. Most of the qPCR and DON results are supporting the hypothesis that in F. graminearum the 15ADON isolates from southern Russia are more specialized to wheat than the 3ADON isolates from Finland. In oat, there were not as clear differences between the 15ADON and 3ADON isolates, but in 2018 higher F. graminearum DNA levels and in 2019 higher DON and F. graminearum DNA levels were found in oat samples inoculated with 3ADON isolates. Our results are in line with literature according to which F. graminearum DNA and DON levels are also highest in oat in northern Europe, while in southern Europe they are highest in wheat and maize.
Owing to the high carcinogenicity of aflatoxins, these toxic secondary metabolites pose a severe risk to human and animal health and can have major economic implications. Herein, we report the development of a noncompetitive immunoassay for aflatoxins based on a monoclonal capture antibody and a unique antiimmunocomplex (anti-IC) antibody fragment (scFv) isolated from a synthetic antibody repertoire. The anti-IC scFv recognizes the immunocomplex and enables the development of noncompetitive sandwich-type assays despite the small size of the analyte. The single-step assay developed in this work, with a detection limit of 70 pg mL(-1), could detect aflatoxins within 15 min. The assay was applied to the analysis of spiked food samples, and the results showed that the method could provide a rapid and simple tool for aflatoxin detection. Moreover, the work demonstrates the potential of anti-IC antibodies and non-competitive immunoassays for the analysis of small molecule contaminants.
Many recent articles feature research on the Fusarium tricinctum species complex (FTSC), and their authors present different ideas on how the isolates of this species complex can be identified at the species level. In previous studies, our aim was to investigate the phylogeny of FTSC strains, which researchers have morphologically identified as Fusarium avenaceum, Fusarium arthrosporioides, and Fusarium anguioides. In the current study, our phylogenetic maximum parsimony and likelihood analyses of the DNA sequences of the translation elongation factor 1-alpha (TEF1) and combined sequences of TEF1 and beta-tubulin (TUB2) supported the existence of at least four main groups among these strains. Main Group I mainly contains F. avenaceum strains, while Main Group II contains two subgroups, one of which primarily includes F. arthrosporioides strains, and the other mainly includes European F. anguioides strains. Main Group III contains strains from different plants that originated from Asia, including two F. anguioides strains. F. avenaceum strains, which are mostly isolated from different trees, form Main Group IV. A fifth group (Main Group V) was only supported by TEF1 sequences. The main groups previously found by us based on TUB2 sequences could be connected to the new species of the FTSC, which were identified based on TEF1 sequences. In addition, we found strains that significantly differ from Main Groups I-V, and we grouped some of them as single, intermediate, or sister groups. All of the main groups of the present work, and some single and intermediate strains, may represent different species of the FTSC, while the two subgroups of Main Group II constitute intraspecific variation. Regardless of whether they belonged to the main groups, all the analysed strains were able to form different enniatins and 2-amino-14,16-dimethyloctadecan-3-ol, but did not produce beauvericin.
Scientific communication is facilitated by a data-driven, scientifically sound taxonomy that considers the end-user's needs and established successful practice. In 2013, the Fusarium community voiced near unanimous support for a concept of Fusarium that represented a clade comprising all agriculturally and clinically important Fusarium species, including the F. solani species complex (FSSC). Subsequently, this concept was challenged in 2015 by one research group who proposed dividing the genus Fusarium into seven genera, including the FSSC described as members of the genus Neocosmospora, with subsequent justification in 2018 based on claims that the 2013 concept of Fusarium is polyphyletic. Here, we test this claim and provide a phylogeny based on exonic nucleotide sequences of 19 orthologous protein-coding genes that strongly support the monophyly of Fusarium including the FSSC. We reassert the practical and scientific argument in support of a genus Fusarium that includes the FSSC and several other basal lineages, consistent with the longstanding use of this name among plant pathologists, medical mycologists, quarantine officials, regulatory agencies, students, and researchers with a stake in its taxonomy. In recognition of this monophyly, 40 species described as genus Neocosmospora were recombined in genus Fusarium, and nine others were renamed Fusarium. Here the global Fusarium community voices strong support for the inclusion of the FSSC in Fusarium, as it remains the best scientific, nomenclatural, and practical taxonomic option available.
In summer 2019, perithecia superficial on the leaf sheath near the base of the stem were visually observed on stalks of winter wheat cultivar Ceylon in Southwest Finland. Mycological examination and translation elongation factor 1-alpha gene sequence of single ascospore isolates determined that they wereFusarium verticillioides(Sacc.) Nirenberg (teleomorph:Gibberella moniliformisWineland). According to the published information, neither the anamorph nor the teleomorph stages of this pathogen have been previously detected in cereals in Finland and Scandinavian countries. The emergence of this fungus is probably caused by the influence of climate change, which may favour the distribution, development and adaptation of introduced mycotoxigenic fungi. Detection of a fumonisin-producingF. verticillioidesallows the prediction of changes in the pattern of grain mycotoxin contamination in northern European countries. A mutation in sexual reproduction was also detected. The mature perithecia contained three types of spores: straight one- or three-septate and abnormal rounded ascospores.
This erratum is published due to incorrect name placement in original article.
Aflatoxins (AF) are highly toxic compounds produced by Aspergillus section Flavi. They spoil food crops and present a serious global health hazard to humans and livestock. The aim of this study was to examine the phylogenetic relationships among aflatoxigenic and non-aflatoxigenic Aspergillus isolates. A polyphasic approach combining phylogenetic, sequence, and toxin analyses was applied to 40 Aspergillus section Flavi isolates collected from eight countries around the world (USA, Philippines, Egypt, India, Australia, Indonesia, China, and Uganda). This allows one to pinpoint the key genomic features that distinguish AF producing and non-producing isolates. Based on molecular identification, 32 (80%) were identified as A. flavus, three (7.5%) as A. parasiticus, three (7.5%) as A. nomius and one (2.5%) as A. tamarii. Toxin analysis showed that 22 (55%) Aspergillus isolates were aflatoxigenic. The majority of the toxic isolates (62.5%) originated from Egypt. The highest aflatoxin production potential was observed in an A. nomius isolate which is originally isolated from the Philippines. DNA-based molecular markers such as random amplified polymorphic DNA (RAPD) and inter-simple sequence repeats (ISSR) were used to evaluate the genetic diversity and phylogenetic relationships among these 40 Aspergillus isolates, which were originally selected from 80 isolates. The percentage of polymorphic bands in three RAPD and three ISSR primers was 81.9% and 79.37%, respectively. Analysis of molecular variance showed significant diversity within the populations, 92% for RAPD and 85% for ISSR primers. The average of Polymorphism Information Content (PIC), Marker Index (MI), Nei’s gene diversity (H) and Shannon’s diversity index (I) in ISSR markers are higher than those in RAPD markers. Based on banding patterns and gene diversities values, we observed that the ISSR-PCR provides clearer data and is more successful in genetic diversity analyses than RAPD-PCR. Dendrograms generated from UPGMA (Unweighted Pair Group Method with Arithmetic Mean) cluster analyses for RAPD and ISSR markers were related to the geographic origin.
This erratum is published due to incorrect name placement in original article.
Fusarium graminearum and F. culmorum are phytopathogenic species that cause head blight and crown rot diseases in cereals worldwide. These two phytopathogenic fungi show great variation in terms of phenotypic, biochemical and genetic characteristics. In this study, linear growth rate, thiophanate methyl (TPM) resistance, survival and toxin production- associated gene expressions, and beta-tubulin nucleotide sequence knowledge of F. graminearum from Turkey and Iran and F. culmorum isolates from Turkey were investigated. The mean linear growth rate values of isolates ranged from 7.58 to 15.16 mm/day. In TPM resistance analysis, each isolate was characterized as highly sensitive to TPM, with IC50 values between 2 and 4 μg/ml TPM. TPM-subjected isolates showed decreased tri5 gene expression and increased Mgv and StuA expression. Amino acid conservations at codons 198 and 200 in the beta tubulin gene were also investigated in order to confirm TPM resistance and reveal genetic diversity in Fusarium species. Each isolate showed conserved amino acids at 198 and 200 codons, resulting in sensitive genotypes. The bootstrap support value for genetic similarity was more than 70%. Findings obtained from this study showed that Fusarium isolates that cause head blight and crown rot in Turkey have a low level of variation in terms of phenotype and genetic characteristics. Moreover, this is the first report to show that TPM led to a potential decrease in toxin production-associated genes and increased potential of sexual/asexual reproduction genes. Results could provide improved and comprehensive data for the struggle against Fusarium pathogens.
Fusarium avenaceum and closely related species are common fungi on various plants, cultivated in different climatic regions. The aim of this study was to determine the taxonomic affiliations of the F. avenaceum, Fusarium arthrosporioides, and Fusarium anguioides strains by using morphological, physiological and molecular-genetic approaches. Twenty-six single-spored morphologically identified strains, which were mainly from cereals, were investigated in order to find out, if they belong to a separate species. Pathogenicity of strains to wheat seedlings and ISSR (Inter Simple Sequence Repeats) fingerprint and beta-tubulin DNA sequence patterns were analyzed. According to phylogenetic analyses, the strains could be divided into two big groups consisting of mostly F. avenaceum or F. anguioides strains. F. arthrosporioides was not detected as a separate species by the sum of the characters. F. anguioides was characterized as a separate species, which could be identified by morphological and molecular data. High genetic diversity of the F. avenaceum and related species was revealed. One F. anguioides strain (rudbeckia, Vladivostok, Russia), had an identical beta-tubulin sequence with two previously sequenced strains of Fusarium tricinctum species complex, which were isolated from dicotyledonous plants in Asia.