Search Results (12)

Fusarium spp. represent a critical threat to maize production and food safety due to their mycotoxin production. This study introduces a refined molecular identification protocol integrating four genomic regions—ITS1, IGS, TEF-1α, and β-TUB—for robust species differentiation of Fusarium spp. isolates from post-harvest maize in Bulgaria. The protocol enhances species resolution, especially for closely related taxa within the Fusarium fujikuroi species complex (FFSC). A newly optimized multiplex PCR strategy was developed using three primer sets, each designed to co-amplify a specific pair of toxigenic genes: fum6/fum8, tri5/tri6, and tri5/zea2. Although all five genes were analyzed, they were detected through separate two-target reactions, not in a single multiplex tube. Among 17 identified isolates, F. proliferatum (52.9%) dominated, followed by F. verticillioides, F. oxysporum, F. fujikuroi, and F. subglutinans. All isolates harbored at least one toxin biosynthesis gene, with 18% co-harboring genes for both fumonisins and zearalenone. This dual-protocol approach enhances diagnostic precision and supports targeted mycotoxin risk management strategies. Full article

Rice spikelet rot disease (RSRD) affects the production and market price of rice, and can be harmful to humans and livestock. In this study, 51 strains of Fusarium spp. were isolated from rice spikelets in the Lin’an, Yuhang, and Fuyang regions. The isolates comprised four composite species: Fusarium incarnatum-equiseti species complex (FIESC), Fusarium asiaticum species complex (FSAMSC), Fusarium fujikuroi species complex (FFSC), Fusarium commune species complex (FNSC), and five species of Fusarium spp. (F. luffae, F. sulawesiense, F. asiaticum, F. fujikuroi, and F. commune). The separation rate of F. sulawesiense was the highest (41.2%), followed by F. asiaticum at 37.3%. The results of this study, compared with those of other studies, found that the newly discovered species of Fusarium spp. associated with RSRD were FSAMSC (F. asiaticum) and FNSC (F. commune). Temperature is one of the important factors causing RSRD; the optimal growth temperature for F. sulawesiense and F. commune was 30 °C, and the optimal growth temperature for other species was 25 °C. A high temperature of 35 °C did not inhibit the growth of Fusarium, as F. commune and F. fujikuroi could grow at this temperature. At 20–30 °C, the growth rate of F. asiaticum was higher than those of other strains. To determine whether the occurrence of RSRD is related to the correlation between Fusarium and other fungi in rice spikelets under different health conditions, the genetic diversity of fungi in rice spikelets was analyzed by amplicon Internal Transcribed Spacer (ITS) sequencing, and the correlations between strains of Fusarium spp. were measured. The results showed that the fungal diversity of diseased rice spikelets (RD) was higher than that of relatively healthy rice spikelets (RH). Curvularia spp., which was affected by the condition of the spikelets, was negatively correlated with Fusarium spp. in RH and positively correlated with Fusarium spp. in RD. Therefore, Fusarium spp. and Curvularia spp. can jointly cause the occurrence of RSRD. The results of the study are significant for understanding the occurrence of RSRD and formulating prevention and control measures. Full article

Contamination of agricultural products by Fusarium species is a significant concern and is commonly found in various agricultural products. They cause severe economic losses in the products, and contaminate and threaten human and animal health due to the toxins they produce. Therefore, determining species diversity in various agricultural products is crucial. Bozcaada is well suited for cultivating the highest quality Çavuş grape due to its unique location and climate. Therefore, in this study, the sequencing of the tef1 and tub2 genes in Fusarium isolates from table Çavuş and wine grapes Karalahna, which are specific to Bozcaada, was performed, and their phylogenetic relationships were examined. As a result, it was determined that 11 of the 17 isolates were Fusarium annulatum from the Fusarium fujikuroi species complex (FFSC), 2 were Fusarium nirenbergiae from the Fusarium oxysporum species complex (FOSC), 2 were Fusarium fabacearum from the FOSC, and the last 2 isolates were Fusarium makinsoniae and Fusarium clavus (as ‘clavum’) from the F. incarnatum-equiseti species complex (FIESC). The F. makinsoniae and F. fabacearum species obtained in the study are the first recorded for Türkiye. This research highlights the variety of Fusarium species identified in Bozcaada vineyards in Türkiye. Full article

This study presents the first report of a Fusarium wilt in Cymbopogon citratus in Portugal. Fusarium is one of the most prominent genera of plant pathogens due to its wide range of hosts and mycotoxin production. The Fusarium fujikuroi species complex (FFSC) encompasses several threatening known plant pathogens. Cymbopogon citratus is a broadly distributed aromatic and medicinal plant rich in bioactive volatiles, which are relevant to several industries. The primary goal of this study was to identify and characterize the Fusarium fujikuroi species putatively responsible for the observed wilt. This report displays symptomatologic, cultural, morphologic, genetic, and cytogenomic characteristics associated with this fungus and disease. The cultural features included flat, white-colored colonies with filiform margins. Additionally, these colonies displayed abundant cottony aerial mycelia at the upper surface and orange-violet color at the lower surface. On Carnation Leaf-Piece Agar, septate fusoid macroconidia were present, displaying a flattened tapering toward the basal part and a number of septa ranging from one to four. The comparison between the amplified and aligned ITS sequences revealed 100% similarity between the isolate and the FFSC. Finally, a flow cytometry assay revealed an estimated genome size of 29.9 Mbp. This finding contrasts with other known pathogens from the Fusarium fujikuroi species complex. Ultimately, novel pathogens might be uncovered by exploring the mycobiome of diseased Cymbopogon citratus plants. Full article

Sarocladium and Fusarium species are commonly identified as causal agents of rice sheath rot disease worldwide. However, limited knowledge exists about their genetic, pathogenic, and toxigenic diversity in sub-Saharan African (SSA) countries, where an increasing incidence of this disease has been observed. In this study, seventy fungal isolates were obtained from rice plants displaying disease symptoms in rice research programs and farmer fields in Mali, Nigeria, and Rwanda. Thus, an extensive comparative analysis was conducted to assess their genetic, pathogenic, and toxigenic diversity. The Fusarium spp. were characterized using the translation elongation factor (EF-1α) region, while a concatenation of Internal Transcribed Spacer (ITS) and Actin-encoding regions were used to resolve Sarocladium species. Phylogenetic analysis revealed four Fusarium species complexes. The dominant complex in Nigeria was the Fusarium incarnatum-equiseti species complex (FIESC), comprising F. hainanense, F. sulawesiense, F. pernambucatum, and F. tanahbumbuense, while F. incarnatum was found in Rwanda. The Fusarium fujikuroi species complex (FFSC) was predominant in Rwanda and Mali, with species such as F. andiyazi, F. madaense, and F. casha in Rwanda and F. annulatum and F. nygamai in Mali. F. marum was found in Nigeria. Furthermore, Fusarium oxysporum species complex (FOSC) members, F. callistephi and F. triseptatum, were found in Rwanda and Mali, respectively. Two isolates of F. acasiae-mearnsii, belonging to the Fusarium sambucinum species complex (FSAMSC), were obtained in Rwanda. Isolates of Sarocladium, which were previously classified into three phylogenetic groups, were resolved into three species, which are attenuatum, oryzae, and sparsum. S. attenuatum was dominant in Rwanda, while S. oryzae and S. sparsum were found in Nigeria. Also, the susceptibility of FARO44, a rice cultivar released by Africa Rice Centre (AfricaRice), was tested against isolates from the four Fusarium species complexes and the three Sarocladium species. All isolates evaluated could induce typical sheath rot symptoms, albeit with varying disease development levels. In addition, liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to determine variation in the in vitro mycotoxins of the Fusarium species. Regional differences were observed in the in vitro mycotoxins profiling. Out of the forty-six isolates tested, nineteen were able to produce one to four mycotoxins. Notably, very high zearalenone (ZEN) production was specific to the two F. hainanense isolates from Ibadan, Nigeria, while Fusarium nygamai isolates from Mali produced high amounts of fumonisins. To the best of our knowledge, it seems that this study is the first to elucidate the genetic, pathogenic, and toxigenic diversity of Fusarium species associated with the rice sheath rot disease complex in selected countries in SSA. Full article

Grain mold and stalk rot are among the fungal diseases that cause significant losses in sorghum worldwide and are caused by different Fusarium spp. The presence of Fusarium species in sorghum grains causes yield losses and mycotoxin contamination, which represents a risk to consumers. In this study, Fusarium graminearum species complex (FGSC) had a high incidence, followed by Fusarium fujikuroi species complex (FFSC) and F. incarnatum-equiseti species complex. Within FFSC, F. proliferatum, F. andiyazi, F. fujikuroi, F. thapsinum, F. verticillioides and F. subglutinans were identified, and this was the first report of F. fujikuroi in sorghum. The most frequent toxins found in sorghum samples were deoxynivalenol (DON) and zearalenone (ZEN). The presence of fumonisins and nivalenol (NIV) was detected at low levels. This study adds new knowledge about the occurrence of Fusarium species and mycotoxins in sorghum grains. Furthermore, this is the first report in Uruguay on fungicide sensitivity for Fusarium isolates from sorghum, which constitutes an important starting point for defining management practices to minimize fungal infection and mycotoxin contamination. Full article

The pathogen causing Fusarium wilt in banana is reported to be Fusarium oxysporum f. sp. cubense (FOC). In 2019, wilt symptoms in banana plants (cultivar: Cavendish) in the Philippines were detected, i.e., the yellowing of the leaves and discoloration of the pseudostem and vascular tissue. The fungus isolated from the vascular tissue was found to be pathogenic to Cavendish bananas and was identified as a new species, F. mindanaoense, belonging to the F. fujikuroi species complex (FFSC); species classification was assessed using molecular phylogenetic analyses based on the tef1, tub2, cmdA, rpb1, and rpb2 genes and morphological analyses. A reciprocal blast search using genomic data revealed that this fungus exclusively included the Secreted in Xylem 6 (SIX6) gene among the SIX homologs related to pathogenicity; it exhibited a highly conserved amino acid sequence compared with that of species in the FFSC, but not with that of FOC. This was the first report of Fusarium wilt in Cavendish bananas caused by a species of the genus Fusarium other than those in the F. oxysporum species complex. Full article

Fusarium fujikuroi species complex (FFSC) strains are a major concern for food quantity and quality due to their strong ability to synthesize mycotoxins. The effects of interacting conditions of water activity, temperature, and incubation time on the growth rate, toxin production, and expression level of biosynthetic genes were examined. High temperature and water availability increased fungal growth. Higher water activity was in favor of toxin accumulation. The maximum amounts of fusaric acid (FA) and fumonisin B1 (FB1) were usually observed at 20–25 °C. F. andiyazi could produce a higher content of moniliformin (MON) in the cool environment than F. fujikuroi. The expression profile of biosynthetic genes under environmental conditions varied wildly; it was suggested that these genes might be expressed in a strain-dependent manner. FB1 concentration was positively related to the expression of FUM1, while a similar correlation of FUB8 and FUB12 with FA production could be observed in F. andiyazi, F. fujikuroi, and F. subglutinans. This study provides useful information in the monitoring and prevention of such toxins entering the maize production chain. Full article

The Fusarium fujikuroi species complex (FFSC) includes socioeconomically important pathogens that cause disease for numerous crops and synthesize a variety of secondary metabolites that can contaminate feedstocks and food. Here, we used comparative genomics to elucidate processes underlying the ability of pine-associated and grass-associated FFSC species to colonize tissues of their respective plant hosts. We characterized the identity, possible functions, evolutionary origins, and chromosomal positions of the host-range-associated genes encoded by the two groups of fungi. The 72 and 47 genes identified as unique to the respective genome groups were potentially involved in diverse processes, ranging from transcription, regulation, and substrate transport through to virulence/pathogenicity. Most genes arose early during the evolution of Fusarium/FFSC and were only subsequently retained in some lineages, while some had origins outside Fusarium. Although differences in the densities of these genes were especially noticeable on the conditionally dispensable chromosome of F. temperatum (representing the grass-associates) and F. circinatum (representing the pine-associates), the host-range-associated genes tended to be located towards the subtelomeric regions of chromosomes. Taken together, these results demonstrate that multiple mechanisms drive the emergence of genes in the grass- and pine-associated FFSC taxa examined. It also highlighted the diversity of the molecular processes potentially underlying niche-specificity in these and other Fusarium species. Full article

Onychomycosis is a nail fungal infection that produces nail discolouration, thickness, and separation from the nail bed. The species of the Fusarium genus that cause onychomycosis are emerging and the number of cases has increased throughout the years. Microscopic examination, as well as cultures, are required for the accurate diagnosis of onychomycosis. The goal of treatment is to eliminate the organism that causes the disease and restore the nail’s normal appearance. Here, we provide an overview of the onychomycosis cases that have been reported in literature over the last 24 years, which have been caused by the Fusarium species. We performed a review on the onychomycosis cases caused by the Fusarium species from January 1997 to January 2021. Patients aged between 40 and 49 years made up 30.23% of the cases. The most common aetiologic species was Fusarium solani species complex (FSSC), which accounted for 44.11% of the cases, followed by F. fujikuroi species complex (FFSC), which accounted for 17.64%; 14.70% of the cases were due to F. dimerum species complex (FDSC) and 14.70% of the cases were due F. oxysporum species complex (FOSC). Europe accounted for 29.06% of the cases caused by FOSC, whereas Africa accounted for 46.67% of the cases due to FSSC. The clinical presentation of onychomycosis due to Fusarium spp. is commonly the distal–lateral pattern of onychomycosis. Identification of the infectious agent in onychomycosis cases due to Fusarium is crucial in deciding the proper treatment. Although antifungal susceptibility tests have only been performed in a few cases, susceptibility testing can help with patient management. Full article

Fusarium temperatum Scaufl. & Munaut is a newly described taxon belonging to the Fusarium fujikuroi species complex (FFSC) and a frequent causative factor of maize ear rot. The aim of the present study was to determine the responses to the disease in maize populations differing in endosperm features that were classified to flint, dent, and a group of plants with intermediate kernel characteristics. In inoculation studies, substantial variation of host response to the fungus was found among the tested maize types. The dent-type kernels contained significantly less amylose (28.27%) and exhibited significantly higher rates of infection (I_FER = 2.10) and contamination by beauvericin (7.40 mg kg⁻¹) than plants of the flint maize subpopulation. The study documents a significant positive correlation between the Fusarium ear rot intensity (I_FER) and ergosterol content (the R value ranged from 0.396 in 2015 to 0.735 in 2018) and between I_FER and the presence of beauvericin (the R value ranged from 0.364 in 2015 to 0.785 in 2017). The negative correlation between (I_FER) and amylose content (ranging from R = −0.303 to R= −0.180) stresses the role of the endosperm starch composition in the kernel resistance to Fusarium ear rot. The conducted study indicated that the risk of kernel infection and contamination with fungal metabolites (beauvericin and ergosterol) was associated with the maize type kernels. Full article

The Repeat-Induced Point (RIP) mutation pathway is a fungal-specific genome defense mechanism that counteracts the deleterious effects of transposable elements. This pathway permanently mutates its target sequences by introducing cytosine to thymine transitions. We investigated the genome-wide occurrence of RIP in the pitch canker pathogen, Fusarium circinatum, and its close relatives in the Fusarium fujikuroi species complex (FFSC). Our results showed that the examined fungi all exhibited hallmarks of RIP, but that they differed in terms of the extent to which their genomes were affected by this pathway. RIP mutations constituted a large proportion of all the FFSC genomes, including both core and dispensable chromosomes, although the latter were generally more extensively affected by RIP. Large RIP-affected genomic regions were also much more gene sparse than the rest of the genome. Our data further showed that RIP-directed sequence diversification increased the variability between homologous regions of related species, and that RIP-affected regions can interfere with homologous recombination during meiosis, thereby contributing to post-mating segregation distortion. Taken together, these findings suggest that RIP can drive the independent divergence of chromosomes, alter chromosome architecture, and contribute to the divergence among F. circinatum and other members of this economically important group of fungi. Full article