Dominant Fusarium Research Articles

Impact of Harvest Delay and Barley Variety on Grain Nutritional Composition and Mycotoxin Contamination.

This study investigated the effects of delayed harvesting, varying meteorological conditions, and barley variety on Fusarium spp. infection rates, nutritional composition, and mycotoxin contamination in barley grains. Field experiments were conducted from 2020 to 2022 and involved two barley varieties: 'Laureate' for malting and 'Luokė' for feed. The results indicated that the dominant Fusarium species isolated were F. avenaceum, F. culmorum, F. poae, F. sporotrichioides, F. tricinctum, and F. equiseti. These tended to increase in number with delayed harvest times and were more prevalent during harvest periods of higher precipitation (p < 0.05). Malting barley had higher starch and lower protein content compared to feed barley (p < 0.05). Delayed harvesting generally increased dry matter, crude fat, and crude ash contents while decreasing crude protein, zinc, and iron contents (p < 0.05). Mycotoxin analysis revealed significant differences under specific weather conditions. HT-2 toxin levels were higher under slightly warmer and wetter conditions during flowering, with harvest conditions similar to the long-term average. Zearalenone levels increased with dry, warm growing seasons followed by rainy harvests. Nivalenol and enniatin levels increased with rainy growing seasons and dry, warm harvests. Deoxynivalenol concentrations did not reach the limit of quantification throughout the study. No consistent trend was observed for higher contamination in any specific barley variety (p > 0.05). The strongest correlations between mycotoxins and nutritional value indicators were observed with less-studied mycotoxins, such as nivalenol and enniatins, which exhibited negative correlations with crude protein (p < 0.01), crude fat (p < 0.05), and zinc (p < 0.01), and positive correlations with crude ash (p < 0.05) and phosphorus (p < 0.01).

Evaluation of Maize Hybrids for Resistance to Ear Rot Caused by Dominant Fusarium Species in Northeast China

Evaluation of Maize Hybrids for Resistance to Ear Rot Caused by Dominant Fusarium Species in Northeast China

Prevalence, genetic diversity and antifungal susceptibility profiles of F.fujikuroi, F.solani and Fusarium incarnatum-equiseti species complexes from onychomycosis in north of Iran.

Onychomycosis, a nail fungal infection, is normally caused by dermatophytes. However, yeasts and non-dermatophyte moulds (NDM) are among pathogens that cause nail disease. Regarding, this study aimed to describe the molecular epidemiology of Fusarium onychomycosis in the North of Iran. Two hundred and fifty seven nail samples collected from the patients clinically suspected of onychomycosis were subjected to direct microscopy, calcofluor white staining and culture. Fusarium isolates were identified at a species level through determination of multi-locus sequences for internal transcribed spacer and translation elongation factor 1 alpha. Based on the findings, Fusarium species were isolated from onychomycosis patients (n=27). According to a previous partial genes analysis, the species in the recent study belonged to the members of F.fujikuroi species complex (n=14), Fusarium incarnatum-equiseti species complex (n=1) and F.solani species complex (n=12). In this study, F.proliferatum was the dominant Fusarium species collected from the samples. The correct identification of Fusarium species is essential regarding the increased prevalence of Fusarium onychomycosis and the inherent resistance of these agents to a wide spectrum of antifungals. The obtained results indicated variation in the epidemiology of Fusarium species isolated from onychomycosis. Moreover, the minimum inhibitory concentration (MIC) of luliconazole and lanoconazole was in the range of 0.001-1μg/ml, with the geometric mean of MICs obtained at 0.0103 and 0.0343 μg/ml against Fusarium species, respectively. These findings can increase researchers' knowledge regarding diversity of species, distribution of onychomycosis and the choice of a proper treatment.

Analysis of Apoptosis-Related Genes Reveals that Apoptosis Functions in Conidiation and Pathogenesis of Fusarium pseudograminearum.

Apoptosis, a type of programmed cell death, plays crucial roles in various physiological processes, from development to adaptive responses. Key features of apoptosis have been verified in various fungal microbes but not yet in Fusarium species. Here, we identified 19 apoptosis-related genes in Fusarium pseudograminearum using a genome-wide survey. Expression profile analysis revealed that several apoptosis-related genes were significantly increased during conidiation and infection stages. Among these is FpBIR1, with two BIR (baculovirus inhibitor-of-apoptosis protein repeat) domains at the N-terminal end of the protein, a homolog of Saccharomyces cerevisiae BIR1, which is a unique apoptosis inhibitor. FpNUC1 is the ortholog of S. cerevisiae NUC1, which triggers AIF1- or YCA1-independent apoptosis. The functions of these two proteins were assessed by creating Δfpbir1 and Δfpnuc1 mutants via targeted gene deletion. The Δfpbir1 mutant had more cells with nuclear fragmentation and exhibited reduced conidiation, conidial formation, and infectivity. Correspondingly, the Δfpnuc1 mutant contained multiple nuclei, produced thicker and more branched hyphae, was reduced in conidiation, and exhibited faster conidial formation and higher infection rates. Taken together, our results indicate that the apoptosis-related genes FpBIR1 and FpNUC1 function in conidiation, conidial germination, and infection by F. pseudograminearumIMPORTANCE The plant-pathogenic fungus F. pseudograminearum is the causal agent of Fusarium crown rot (FCR) in wheat and barley, resulting in substantial yield losses worldwide. Particularly, in the Huanghuai wheat-growing region of China, F. pseudograminearum was reported as the dominant Fusarium species in FCR infections. Apoptosis is an evolutionarily conserved mechanism in eukaryotes, playing crucial roles in development and cell responses to biotic and abiotic stresses. However, few reports on apoptosis in plant fungal pathogens have been published. In this study, we identified 19 conserved apoptosis-related genes in F. pseudograminearum, several of which were significantly increased during conidiation and infection stages. Potential apoptosis functions were assessed by deletion of the putative apoptosis inhibitor gene FpBIR1 and apoptosis trigger gene FpNUC1 in F. pseudograminearum The FpBIR1 deletion mutant exhibited defects in conidial germination and pathogenicity, whereas the FpNUC1 deletion mutant experienced faster conidial formation and higher infection rates. Apoptosis appears to negatively regulate the conidial germination and pathogenicity of F. pseudograminearum To our knowledge, this study is the first report of apoptosis contributing to infection-related morphogenesis and pathogenesis in F. pseudograminearum.

Проблема фузариоза зерна в Зауралье: ретроспектива исследований и современная ситуация

Abstract. The aim of study was to detect the fungal and mycotoxins contamination of grain samples of oat, wheat and barley grown in four regions of Ural region (Kurgan, Sverdlovsk, Tyumen, Chelyabinsk) in 2017–2018. Methods. The infection of grain with fungi was analyzed using traditional mycological methods; the content of fungal DNA was determined by quantitative PCR; the presence and amounts of toxic secondary metabolites of fungi in the grain was detected by high performance liquid chromatography with mass spectrometry. Results. In the analyzed grain samples at least 10 species of Fusarium fungi were identified, among which F. sporotrichioides, F. avenaceum sensu lato and F. poae were found to be prevailing. The areas of Fusarium species that are atypical for the territory of Ural region were specified. F. graminearum was found in 14 % of the analyzed grain samples, and F. langsethiae was detected in three grain samples from the Sverdlovsk region. The DNA of F. poae was found in 48 % of grain samples, F. avenaceum DNA – in 39 %, F. sporotrichioides DNA – in 30 %, and F. graminearum DNA – in 29 % of analyzed grain samples. The content of mycotoxins in the grain samples ranged significantly depending on the crop and the geographical origin of the samples. One to seven mycotoxins were present in each contaminated grain sample. T-2 and HT-2 toxins were most common and were detected in 59 % of samples. Following to them beauvericin and deoxynivalenol were found in 34 % and 25 % of the grain samples, respectively. The excess of the maximum permissible level of T-2 toxin in 26 times was detected in grain of barley from the Chelyabinsk region Scientific novelty. For the first time, the information about the occurrence and the amounts of moniliformin and beauvericin, which are rarely analyzed in the grain, is provided. The significant connection between the content of DNA of dominant Fusarium species and the amount of the main mycotoxins produced by them in the grain were revealed.

Antifungal activity of essential oil of Tinospora cordifolia against storage fungi of wheat

Sixteen fungal species belonging to Alternaria, Aspergillus, Fusarium, Penicillium, Rhizopus, Trichoderma and Trichothecium genera were found to be associated in stored wheat (Triticum aestivum L.) grains and Fusarium oxysporum, Aspergillus niger, A. ochraceus and A. terreus were identified to be associated with wheat storage. The essential oil isolated from leaf of Tinospora cordifolia showed absolute inhibitory activity (MIC) of 100 per cent against all the test fungi at 400 ppm concentration except Aspergillus candidus and Fusraium moniliform where MIC was reported at 800 and 600 ppm, respectively. The detailed investigation of the Tinospora oil was made with the major dominant fungi, Fusarium oxysporum and Aspergillus niger, where MIC was recorded as 400 ppm. No adverse effect in the antifungal activity of the oil was recorded against the two test fungi after autoclaving. No adverse effect was also observed for a storage period of 120 days on fungal inhibitory activity of the oil (400 ppm). The comparative study showed that Tinospora oil was more effective than standard commercial pesticides such as copper oxychloride and carbendazim. The results of our study suggests that Tinospora leaf oil can be exploited effectively in the management of seed-borne pathogenic fungi and prevent bio-deterioration of wheat grains during storage.

Interactions among Fungal Community, Fusarium Mycotoxins, and Components of Harvested Wheat under Simulated Storage Conditions.

Economic loss of postharvest wheat under poor storage conditions due to fungal spoilage and mycotoxin contamination is severe. In order to study the influencing factors of the aggravation of mildew in natural wheat during storage, we assessed changes in Fusarium mycotoxins by high performance liquid chromatography, changes in fungal communities by high-throughput sequencing, and changes in biochemical components in wheat stored under artificial simulation conditions. Deoxynivalenol was the dominant Fusarium mycotoxin, reaching 1103 μg/kg at 25 °C with 75% relative humidity after 30 weeks. Under these conditions, Fusarium dominated the fungal communities, and Fusarium graminearum was significantly negatively correlated with glutenin (p < 0.05). Low storage temperatures and low humidity result in lower levels of Fusarium mycotoxins. Different fungi tended to consume different wheat components, and the interaction between environmental and biological factors eventually leads to the deterioration of wheat quality. These findings might provide valuable information for control strategies of mildew occurrence during grain storage.

Diversity of trichothecene genotypes of Fusarium graminearum sensu stricto from winter wheat in Serbia

Data related to genetic diversity of F. graminearum chemotypes in Serbia are limited, thus the main objective of this study was to analyze the divergence of genes associated with the trichothecene cluster. F. graminearum was shown to be the dominant Fusarium species in Serbia occurring with frequency of 65.6% in 2016/2017 growing season. Isolates of F. graminearum dominantly belonged to SCAR type 1 (104/105) producing PCR product of 420 bp, but one isolate was proven to be SCAR type 6 producing PCR product of 400 bp. This is the first report of the presence of SCAR type 6 in Southeastern Europe. Results from this study reveal that F. graminearum populations were shown to be DON-DON chemotype with respect to Tri7 and Tri13 genes. All but one of these isolates were 15-AcDON chemotypes based on Tri3 gene. One isolate carried a deletion of Tri7 and was found to be 3-AcDON by using Tri303F/R primer pair. This is the first record on the presence of a 3-AcDON isolate with the Tri7 deletion in Serbia. The Tri7F/Tri7DON primer pair was not effective if isolates carried more than four 11-bp repeats in the Tri7 gene. Primer pair GzTri7f1/r1 was proven to be more effective in comparison with Tri7F/Tri7DON. Genetic variation ranged from 57 to 80% with no significant association of Tri7 alleles with localities. Results of this study have brought new insights into the distribution and population structure of F. graminearum in Serbia.

Performance and microbial community evolution of toluene degradation using a fungi-based bio-trickling filter

Fungi have their unique advantages in capturing and degrading hydrophobic VOCs. To study the performance of fungi-based bio-trickling filters (BTFs) with respect to the degradation of toluene, and the succession process of the fungal colony under different operating conditions, a three-layer BTF packed by dominant Fusarium oxysporum immobilized with ceramic particles were set up. The fungal BTF started quickly within 7 days and restarted less than 7 days after starvation; its average RE was higher than 92.5% when the toluene inlet loading rate (ILR) ranging from 7.0 to 100.9 g m-3 h-1 at steady state. Moreover, the maximum elimination capacity (EC) of 98.1 g m-3 h-1 was obtained at a toluene ILR of 100.3 g m-3 h-1. The microorganism analysis of time and space revealed that the dominant fungi Fusarium were replaced by Paramicrosporidium saccamoebae after a certain evolutionary period. The intermediate layer had more microbes and a more complex community than the other two layers, and was more suitable for the survival of the varieties of microbes.

Fusarium head blight incidence and detection of Fusarium toxins in wheat in relation to agronomic factors

We investigated incidences of Fusarium head blight (FHB) and concentrations of six mycotoxins (deoxynivalenol, nivalenol, 3-acetyldeoxynivalenol, T-2 toxin, HT-2 toxin and zearalenone) in wheat from 2010 to 2013. Field trials were conducted at the Experimental Station of Cultivar Testing in Chrząstowo, Poland (53o11’N, 17o35’E). We examined the effects of four agronomic factors, including pre-crop type (corn, sugar beets and wheat), date of sowing (late autumn: November 8–December 9 or spring: March 29–April 19), fungicidal application (untreated or treated with two applications) and cultivar (Monsun, Cytra), on FHB index (FHBi) and mycotoxin levels in order to minimize the risk of wheat grain contamination by mycotoxins via integrated pest management methods. The dominant Fusarium species observed on wheat heads were F. culmorum, F. avenaceum (Gibberella avenacea) and F. graminearum (Gibberella zeae), at 21.1%, 17.2% and 7.1%, respectively. A monthly rainfall sum of 113.9 mm and a relatively low air temperature (monthly average 15.5 °C) resulted in the highest FHBi in untreated wheat (25.1%). Agronomic factors crucial for the FHB incidence were the pre-crop, fungicidal treatments and cultivar selection. In wheat planted after wheat or corn, the FHBi was higher compared with a pre-crop of sugar beet. A double application of fungicides at BBCH 30–32 with prothioconazole and spiroxamine and at a BBCH 65 with fluoxastrobin and prothioconazole effectively reduced the FHBi and mycotoxin concentrations, respectively, in grain. The cultivar ‘Cytra’ had a greater FHBi (10.4%) than ‘Monsun’ (4.6%), and grain infestations by Fusarium species were also greater in ‘Cytra’, at 16.5%, than in ‘Monsun’, at 11.2%. Untreated cv. Cytra grown after corn in spring produced grains with the highest amounts of the mycotoxins, deoxynivalenol, 3-acetyldeoxynivalenol, zearalenone and HT-2 (605, 103, 17.5 and 5.53 μg/kg, respectively). Total mycotoxin levels in wheat were correlated with five determinants: duration of the period between the end of flowering and the beginning of kernel abscission, FHBi, F. culmorum isolation, G. zeae isolation and Fusarium ratio (FR) as a % of total mould isolations. Although, the mean concentration of mycotoxins in grain did not exceed the maximum permissible values for unprocessed wheat our study suggests necessity to monitor and mitigate FHB risk for susceptible cultivars, when wheat spring sowing follows corn or wheat.

Molecular phylogeny and diversity of Fusarium endophytes isolated from tomato stems.

Plant tissues are a known habitat for two types of Fusarium species: plant pathogens and endophytes. Here, we investigated the molecular phylogeny and diversity of endophytic fusaria, because endophytes are not as well studied as pathogens. A total of 543 Fusarium isolates were obtained from the inside of tomato stems cultivated in soils mainly obtained from agricultural fields. We then determined partial nucleotide sequences of the translation elongation factor-1 alpha (EF-1α) genes of the isolates. Among the isolates from tomato, 24 EF-1α gene sequence types (EFST) were found: nine were classified as being from the Fusarium oxysporum species complex and its sister taxa (FOSC, 332 isolates), seven from the F. fujikuroi species complex (FFSC, 75 isolates) and eight from the F. solani species complex (FSSC, 136 isolates). To determine more characteristic details of the tomato isolates, we isolated 180 fusaria directly from soils and found 95% of them were nested within the FOSC (82 isolates; five EFSTs), FFSC (21 isolates; six FESTs) and FSSC (68 isolates; 11 EFSTs). These results suggested that the dominant Fusarium endophytes within tomato stems were members of the same three species complexes, which were also the dominant fusaria in the soils.

Utilizing UV Mutagenesis to Breeding Strains with High Ability of Oil Shale Degradation

For the screening of degrading oil shale strains, oil shale bacteria collected from Fushun Western Open were diluted moderately, then mutated with UV mutagenesis techniques, and tested the degradation. For bacteria when the mutagenic time was 1920 seconds, the death rate was 97.92%, while the degradation rate is always at 0.66% or so. For fungi, when the mutagenic time was 1920 seconds, the death rate was 93.75%, while degradability and mutagenesis time showed a certain degree of correlation. The highest degradation rate was 1.24%, when the mutagenesis time was 240s. There were three culturable fungi strains isolated from the microbial, called CPC ZYK2, ZYK4 and ZYK7. By PCR amplification of rDNA ITS area and compareing the database, the homology of the dominant strain ZYK7 and Fusarium oxysporum (JF807394) of Genbank was 100%.

Real-time PCR detection of Fusarium species in Swedish oats and correlation to T-2 and HT-2 toxin content

Contamination of Fusarium moulds and subsequent production of mycotoxins is a common problem in cereals grown in Northern Europe. Oats is the third most important cereal crop in Sweden and is commonly contaminated by Fusarium. To date there are no published reports on the distribution of trichothecene-producing Fusaria in Swedish oats and correlation to T-2 and HT-2, the two most dominant toxins. Identification of Fusarium species by traditional methods requires specific skill and experience and quantification of specific species is not possible. Using modern molecular methods such as real-time PCR both identification and quantification of specific Fusarium species are possible directly from the food or feed samples. In this study, specific methods for Fusarium langsethiae, Fusarium sporotrichioides, Fusarium graminearum, Fusarium culmorum and Fusarium poae as well as for the total amount of DNA from trichothecene-producing species were evaluated with respect to precision, robustness and efficiency and then used in the analysis of oat samples. Sixty-two oat samples were taken from field trial harvests from 2006-2008 in the central and southern parts of Sweden and analysed for the presence of Fusarium species by using species-specific real-time PCR-based methods with TaqMan or SYBR Green biochemistry. The T-2 and HT-2 toxin content was analysed by gas chromatography with electron capture detection of the toxins' pentafluoropropyl derivatives. The results showed that F. langsethiae and F. poae were the most dominant Fusarium species among those tested in Swedish oats during this period. The DNA level of F. langsethiae correlated well with the level of T-2 and HT-2 toxin (r=0.7), indicating that this species was the most important producer of T-2 and HT-2 toxins in Swedish oats during the sampling period (2006 to 2008). It can also be concluded that real-time PCR is a powerful tool when studying Fusarium species distribution in oats.

What about the 'other' Fusarium mycotoxins?

Most Fusarium species are capable of producing mycotoxins that may cause adverse effects on human or animal health. The most commonly studied Fusarium mycotoxins include trichothecenes, zearalenone and fumonisins. However, it seems that nearly all of the most prevalent Fusarium species infecting grains are also capable of producing other toxic metabolites. The existing studies, although exiguous, have clearly demonstrated that other toxic metabolites of Fusarium spp. are also present in our foods and feeds, occasionally at very high levels. It is apparent that since mycotoxins, including these 'other' metabolites, are natural toxins, they cannot be completely eliminated from food and feed chains. However, scientific studies are needed to determine their true significance. Thus, the mechanism and level of toxicity as well as presence and concentration levels will have to be fully clarified. In this paper, we briefly review the prevalence of the dominant Fusarium species contaminating maize and small-grain cereals worldwide, and the current knowledge on the biological activity as well as the natural occurrence of their selected less-known toxic metabolites. Additionally, the significance of these 'other' Fusarium mycotoxins is discussed.

Mycotoxigenic Fusarium species in animal feed

Fusarium species are among the most studied plant-pathogenic fungi, with several species causing diseases on maize, wheat, barley, and other food and feed grains. Decreased yield, as well as diminished quality and value of the grain, results in significant worldwide economic losses. Additionally, Fusarium species produce a chemically diverse array of mycotoxins such as diacetoxyscirpenol, deoxynivalenol, nivalenol, T-2 toxin, zearalenone, fumonisins, fusarin C, beauvericin, moniliformin, and fusaproliferin. The dominant Fusarium species associated with feed grain that produce these mycotoxins are reviewed with emphasis on their current taxonomy, phylogenetic relationships, and general biology. Ecological and environmental factors associated with plant–fungal interactions and potential mycotoxin contamination of feed also are discussed with primary emphasis on two main diseases: head blight of small grains and ear rot of maize. The past quarter-century has provided much detail on the morphology, physiology, genetics and genomics of Fusarium species. Such data are critical for understanding these fungi and for managing their impact on the safety, value, and yield of quality grain.

Natural Occurrence of Fusarium Species, Fumonisin Production by Toxigenic Strains, and Concentrations of Fumonisins B1 and B2 in Conventional and Organic Maize Grown in Spain

Sixty samples of corn from both conventional and organic farms were tested for internal fungal contamination. Molds were identified to genus, and those belonging to the genus Fusarium were identified to species. Twenty isolates of Fusarium verticillioides were tested with a high-performance liquid chromatography–naphthalene dicarboxaldehyde–fluorescence method for their ability to produce fumonisins B1 and B2. The internal fungal infection in organic maize (63.20%) was significantly higher than that in conventional maize (40.27%) (P < 0.05). However, the distribution of fungal genera indicated a significantly higher prevalence of Fusarium in conventional (34.93%) than in organic (18.15%) maize, making Fusarium the predominant fungus in conventional maize. This difference in mold distribution between organic and conventional maize was attributed to the difference in cultivation system. The dominant Fusarium species in both conventional and organic samples was F. verticillioides. There were no significant differences in the ability of 20 selected isolates of F. verticillioides to produce fumonisins on conventional or organic corn. Up to 13.3% of the conventional corn samples contained fumonisins B1 and B2 at mean concentrations of 43 and 22 ng/g, respectively. Organic corn samples had somewhat lower levels of contamination: 35 ng/g fumonisin B1 and 19 ng/g fumonisin B2 (P > 0.05). The organic farming system, with well-balanced crop rotation, tillage, and compost fertilization, produced corn that was less likely to be contaminated with Fusarium species, although no significant difference in fumonisin concentrations was found between the two types of contaminated corn.

Changes in Communities of Fusarium and Arbuscular Mycorrhizal Fungi as Related to Different Asparagus Cultural Factors

Asparagus (Asparagus officinalis) is a high-value perennial vegetable crop that has shown a marked decline in productivity after many years of continuous harvesting. This decline is caused by an increase in both abiotic (autotoxicity, harvesting pressure) and biotic stresses [fungal infections, mainly Fusarium crown and root rot (FCRR)]. To gain insight into disease development and possible mitigation strategies, we studied the effects of harvesting, time in the growing season, and field age on FCRR development, Fusarium species composition, and arbuscular mycorrhizal fungi (AMF) communities in both a controlled field experiment and an ecological survey of commercial fields. In one experiment, a 3-year-old asparagus field was subdivided into plots that were harvested or not and sampled throughout the growing season to assess short-term dominant Fusarium species shifts. In addition, diseased and healthy asparagus plants sampled from six commercial fields in the same geographical region were used to assess Fusarium and AMF communities in relation to different parameters. Fusarium and AMF communities were described by using a polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE) approach, and results were analyzed by mainly correspondence analysis and canonical correspondence analysis. Results showed that dominant Fusarium taxa assemblages changed throughout the growing season. Harvested plots had significantly more FCRR symptomatic plants at the end of the growing season, but this effect was not related with any trend in Fusarium community structure. Sampling site and plant age significantly influenced AMF community structure, whereas only sampling site consistently influenced the Fusarium community. Diseased and healthy plants harbored similar Fusarium and AMF communities. Shifts in Fusarium community might not be responsible for different disease incidence because they are ubiquitous regardless of plant health status or harvesting regime. The different incidence noted might rather be related to plant physiology, antagonist microbial communities, or soil parameters.

Fungal mycoflora and mycotoxins in Korean polished rice destined for humans

Rice samples collected from the Republic of Korea were analyzed for fungal mycoflora and mycotoxins: fumonisins, ochratoxin A, trichothecenes, and zearalenone. The potential of the fungi to produce each mycotoxin was also examined, so that the fungal isolates associated with mycotoxins occurring in rice could be verified. Penicillium citrinum and Aspergillus candidus were the most prevalent species infecting the samples, while Fusarium proliferatum was found as the dominant Fusarium species. Ochratoxin A was the most commonly detected mycotoxin analyzed in the present study; moreover, its level in some samples was above the EU tolerable limit (3 ng/g). According to rice culture experiments, it was revealed that in Korea, fumonisins detected in rice were due to F. proliferatum infection, whereas the occurrence of ochratoxin A was caused by Penicillium verrucosum, though there were no symptoms of disease in rice found in any sample. Furthermore, there appears to be an uneven geographical distribution of P. verrucosum as well as ochratoxin A in that most of them are found in the rice samples produced in the northern region of Korea.

Effects of temperature on fusaria and Fusarium mycotoxins during short‐term storage of maize kernels (Zea mays)

In three trials freshly harvested maize kernels (Zea mays) of different moisture contents (MC) (19%, 24%, 27%) were stored at 20°C, 25°C, 30°C, and 37°C for 3, 6, and 10 days and changes in the percentages of Fusarium‐infected kernels and in the concentrations of the mycotoxins nivalenol (NIV) and deoxynivalenol (DON) measured. The effects of storage varied with the initial Fusarium infections and moisture content as well as with time and temperature. In the grain of 19% MC, F. subglutinans was the dominant Fusarium species and initially infected 16% of kernels, while the NIV + DON concentration was below 0.2 mg/kg. Neither the percentage of Fusarium infection nor the toxin concentration changed greatly at any temperature during the storage period, although the proportion of F. subglutinans increased at 30°C and 37°C. In the harvest sample of 24% MC, F. graminearum was the dominant Fusarium species on day 0 and infected 26% of kernels. The total content of NIV plus DON was less than 0.5 mg/kg. By day 10 during storage at 20–30°C the infection rate of F. graminearum rose to 42–60% and NIV + DON concentration to over 2 mg/kg. At 37°C F. graminearum was no longer recovered by day 6 and NIV + DON concentration was unchanged from the initial level. In the harvest sample of 27% MC, F. graminearum was dominant and initially infected 80% of the kernels. The initial NIV + DON concentration was 2 mg/kg. At 20–30°C the infection rates did not materially change but toxin content rose to c. 6 mg/kg by day 10. At 37°C F. graminearum was no longer recoverable at day 10 while the NIV + DON concentration remained at the original level. Visual inspection of the incubated samples showed visible mould growth about the grains in samples incubated for 10 days at 37°C for the 24% MC sample or for 6–10 days at all temperatures in for the 27% MC sample. The incidence of Penicillium was favoured by storage, and at 37°C the predominant fungus found at day 10 was Penicillium (19% MC and 27% MC samples) or Aspergillus (24% MC sample).

Natural Occurrence and Distribution of Fusarium Toxins in Contaminated Barley Cultivars

Grain samples of 15 naturally contaminated barley cultivars, collected after harvest in southeastern Poland, were analysed for occurrence of Fusarium trichothecenes and zearalenone (ZEA). Barley kernels were contaminated with the following toxic metabolites: deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-AcDON), 15-acetyldeoxynivalenol (15-AcDON), nivalenol (NIV), HT-2 toxin (HT-2), T-2 toxin (T-2), diacetoxyscirpenol (DAS), T-2 tetraol and ZEA. Significant correlations between concentrations of individual toxins and the dominant Fusarium species were found. Moreover, significant differences in toxin concentrations between cultivars were detected. Distribution of these mycotoxins was studied in two fractions of kernels (diameter > 2.5 mm and < 2.5 mm). A two-factor analysis of variance revealed significant differences between the two fractions, and between the analysed cultivars. Most of the interactions between fractions and cultivars were also significant. The highest concentration of the analysed toxins was in the fraction of small kernels. Kernel fraction <2.5 mm, although accounting for only 12.8% of sample weight, contained high proportions of the total toxin content: 80% of DON, 94% of NIV, 85% of ZEA, 83% of T-2 tetraol, 80% of DAS, 68% of HT-2 toxin and 81% of T-2 toxin. The results indicate that the level of contamination with Fusarium trichothecenes and ZEA, can be reduced by rejection of small kernels.