nivalenol and beauvericin

In recent years, due to the negative impact of toxigenic mycobiota and of the accumulation of their secondary metabolites in malting barley grains, monitoring the evolution of fungal communities in a certain cultivation area as well as detecting the different mycotoxins present in the raw material prior to malting and brewing processes have become increasingly important. In this study, a survey was carried out on malting barley samples collected after their harvest in the Umbria region (central Italy). Samples were analyzed to determine the composition of the fungal community, to identify the isolated Fusarium species, to quantify fungal secondary metabolites in the grains and to characterize the in vitro mycotoxigenic profile of a subset of the isolated Fusarium strains. The fungal community of barley grains was mainly composed of microorganisms belonging to the genus Alternaria (77%), followed by those belonging to the genus Fusarium (27%). The Fusarium head blight (FHB) complex was represented by nine species with the predominance of Fusarium poae (37%), followed by Fusarium avenaceum (23%), Fusarium graminearum (22%) and Fusarium tricinctum (7%). Secondary metabolites biosynthesized by Alternaria and Fusarium species were present in the analyzed grains. Among those biosynthesized by Fusarium species, nivalenol and enniatins were the most prevalent ones. Type A trichothecenes (T-2 and HT-2 toxins) as well as beauvericin were also present with a high incidence. Conversely, the number of samples contaminated with deoxynivalenol was low. Conjugated forms, such as deoxynivalenol-3-glucoside and HT-2-glucoside, were detected for the first time in malting barley grains cultivated in the surveyed area. In addition, strains of F. avenaceum and F. tricinctum showed the ability to biosynthesize in vitro high concentrations of enniatins. The analysis of fungal secondary metabolites, both in the grains and in vitro, revealed also the presence of other compounds, for which further investigations will be required. The combination of microbiological analyses, of molecular biology assays and of multi-mycotoxin screening shed light on the complexity of the fungal community and its secondary metabolites released in malting barley.

Topics: Alternaria; Depsipeptides; Edible Grain; Food Contamination; Fusarium; Glucosides; Hordeum; Italy; Mycotoxins; Seedlings; T-2 Toxin; Trichothecenes

Over a 4-year period (2010-13), a survey aiming at determining the occurrence of Fusarium spp. and their relations to mycotoxins in mature grains took place in southern Belgium. The most prevalent species were F. graminearum, F. avenaceum, F. poae and F. culmorum, with large variations between years and locations. An even proportion of mating type found for F. avenaceum, F. culmorum, F. cerealis and F. tricinctum is usually a sign of ongoing sexual recombination. In contrast, an unbalanced proportion of mating type was found for F. poae and no MAT1-2 allele was present in the F. langsethiae population. Genetic chemotyping indicates a majority of deoxynivalenol (DON)-producing strains in F. culmorum (78%, all 3-ADON producers) and F. graminearum (95%, mostly 15-ADON producers), while all F. cerealis strains belong to the nivalenol (NIV) chemotype. Between 2011 and 2013, DON, NIV, enniatins (ENNs) and moniliformin (MON) were found in each field in various concentrations. By comparison, beauvericin (BEA) was scarcely detected and T-2 toxin, zearalenone and α- and β-zearalenols were never detected. Principal component analysis revealed correlations of DON with F. graminearum, ENNs and MON with F. avenaceum and NIV with F. culmorum, F. cerealis and F. poae. BEA was associated with the presence of F. tricinctum and, to a lesser extent, with the presence of F. poae. The use of genetic chemotype data revealed that DON concentrations were mostly influenced by DON-producing strains of F. graminearum and F. culmorum, whereas the concentrations of NIV were influenced by the number of NIV-producing strains of both species added to the number of F. cerealis and F. poae strains. This study emphasises the need to pay attention to less-studied Fusarium spp. for future Fusarium head blight management strategies, as they commonly co-occur in the field and are associated with a broad spectrum of mycotoxins.

Topics: Belgium; Depsipeptides; DNA, Fungal; Edible Grain; Food Contamination; Fusarium; Genes, Mating Type, Fungal; Humans; Mycotoxins; Principal Component Analysis; Trichothecenes; Zearalenone

Wheat is often infected by Fusarium species producing mycotoxins, which may pose health risks to humans and animals. Deoxynivalenol (DON) is the most important Fusarium toxin in Swedish wheat and has previously been shown to be produced mainly by Fusarium graminearum. However, less is known about the co-occurrence of DON and F. graminearum with other toxins and Fusarium species in Sweden. This study examined the distribution of the most important toxigenic Fusarium species and their toxins in winter wheat (2009 and 2011) and spring wheat (2010 and 2011). DNA from seven species was quantified with qPCR and the toxin levels were quantified with a multitoxin analysis method based on liquid chromatography/electrospray ionisation-tandem mass spectrometry (HPLC/ESI-MS/MS). The method enabled detection of many fungal metabolites, including DON, zearalenone (ZEA), nivalenol (NIV), T-2 toxin, HT-2 toxins, moniliformin (MON), beauvericin (BEA), and enniatins (ENNs). It was found that Fusarium poae and Fusarium avenaceum were present in almost all samples. Other common Fusarium species were F. graminearum and F. culmorum, present in more than 70% of samples. Several species occurred at lower DNA levels in 2011 than in other years, but the reverse was true for F. graminearum and Fusarium langsethiae. The most prevalent toxins were ENNs, present in 100% of samples. DON was also common, especially in spring wheat, whereas ZEA and NIV were common in 2009 and in winter wheat, but less common in 2011 and in spring wheat. Only three samples of spring wheat contained T-2 or HT-2 above LOQ. Annual mean levels of several mycotoxins were significantly lower in 2011 than in other years, but the reverse applied for DON. The strongest correlations between mycotoxin and Fusarium DNA levels were found between F. avenaceum and ENNs (r(2) = 0.67) and MON (r(2) = 0.62), and F. graminearum and DON (r(2) = 0.74). These results show that several Fusarium species and toxins co-occur in wheat. The highest toxin levels were detected in spring wheat and DON and ENNs, the latter belonging to the group of so called "emerging toxins", which were the most prevalent toxins and those occurring at the highest levels.

Topics: Chromatography, High Pressure Liquid; Cyclobutanes; Depsipeptides; DNA, Fungal; Food Contamination; Fusarium; Real-Time Polymerase Chain Reaction; Sweden; T-2 Toxin; Tandem Mass Spectrometry; Trichothecenes; Triticum; Zearalenone

Fusarium moulds frequently contaminate oats and other cereals world-wide, including those grown in Northern Europe. To investigate the presence of toxigenic Fusarium species and their toxins in oats, samples were taken during 2010 and 2011 in three geographical regions of Sweden (east, west, south). The samples were analysed by real-time PCR for the specific infection level of seven Fusarium species associated with oats and other cereals (Fusarium poae, Fusarium graminearum, Fusarium langsethiae, Fusarium culmorum, Fusarium tricinctum, Fusarium sporotrichioides and Fusarium avenaceum) and with a multi-mycotoxin method based on liquid chromatography/electrospray ionisation-tandem mass spectrometry (HPLC/ESI-MS/MS) for the detection of many fungal metabolites, including deoxynivalenol (DON), zearalenone (ZEA), nivalenol (NIV), T-2 toxin, HT-2 toxins, moniliformin (MON), beauvericin (BEA) and enniatins (ENNs). Most samples contained at least four of the seven Fusarium species analysed and F. poae, F. langsethiae and F. avenaceum were present in approximately 90-100% of all samples. The most common toxins detected were DON, NIV, BEA and ENNs, which were present in more than 90% of samples. Most Fusarium species and their toxins occurred in higher concentrations in 2010 than in 2011, with the exception of DON and its main producer F. graminearum. Significant regional differences were detected for some moulds and mycotoxins, with higher levels of F. graminearum, DON and ZEA in western Sweden than in the east (P<0.05) and higher levels of F. tricinctum and MON in the south (P<0.05). Correlation analysis showed significant correlations between many Fusarium species and toxin levels. For example, F. tricinctum was significantly correlated to F. avenaceum (r = 0.72, P<0.001), DON to ZEA (r = 0.52, P<0.001), DON to F. graminearum (r = 0.77, P<0.001) and the sum of T-2 and HT-2 to F. langsethiae (r = 0.77, P<0.001). The multi-toxin approach employed allowed simultaneous detection of many Fusarium mycotoxins in each sample. In combination with real-time PCR analysis of seven toxigenic Fusarium spp., the results gave an overall picture of the presence of Fusarium and their toxins in Swedish oats and revealed significant annual and regional differences. This is the first study of the so-called emerging mycotoxins (e.g., ENNs, MON and BEA) in oats grown in Sweden.

Topics: Avena; Chromatography, High Pressure Liquid; Cyclobutanes; Depsipeptides; DNA, Fungal; Edible Grain; Food Contamination; Fusarium; Geography; Real-Time Polymerase Chain Reaction; Sweden; T-2 Toxin; Tandem Mass Spectrometry; Trichothecenes; Zearalenone