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The objective of this study was to evaluate the potential intra-species variability of 3 Fusarium langsethiae strains in response to extreme climate change (CC) conditions on an oat-based matrix. The impact of elevated temperature (25 vs 30-34 °C) coupled with increasing drought stress (0.98 vs 0.95 aw) and elevated CO2 (400 vs 1000 ppm) were examined on lag phases prior to growth, growth rate, and production of the mycotoxins T-2 and HT-2 and their ratio. In comparison to the control conditions (25 °C; 0.98; 400 ppm), exposure to increased temperature (30-34 °C), showed similar reductions in the lag phase and fungal growth rates of all 3 strains. However, with elevated CO2 a reduction in both lag phases prior to growth and growth rate occurred regardless of the aw examined. For T-2 and HT-2 mycotoxin production, T-2 showed the most intra-species variability in response to the interacting abiotic stress factors, with the 3 strains having different environmental conditions for triggering increases in T-2 production: Strain 1 produced higher T-2 toxin at 25 °C, while Strain 2 and the type strain (Fl201059) produced most at 0.98 aw/30 °C. Only Strain 2 showed a reduction in toxin production when exposed to elevated CO2. HT-2 production was higher at 25 °C for the type strain and higher at 30-34 °C for the other two strains, regardless of the aw or CO2 level examined. The HT-2/T-2 ratio showed no significant differences due to the imposed interacting CC abiotic conditions.

Mycotoxigenic fungi and pests are responsible for quality losses during medium to long-term storage of grain. Since gas composition is considered one of the most important abiotic conditions that influence fungal and pest growth, the use of a controlled atmosphere with a very high N2 concentration is a valid tool to control grain quality in post-harvest. Aim of the present work is to evaluate the use of a highly purified N2 controlled atmosphere – generated in situ by a Membrane Nitrogen Separator (Eurosider s.a.s) – for safely storage of corn and wheat grains. Two different parallel lab-scale experiments were performed in order to assess the effect of N2 atmosphere on: (1) the growth of Fusarium graminearum, Fusarium langsethiae, Aspergillus flavus and Fusarium verticillioides on agar and the production of aflatoxins on corn grains; (2) the populations of the most important post-harvest pests such as Sitophilus oryzae and Tribolium confusum on wheat grains and flour, respectively. When exposed to highly purified N2 controlled atmosphere (98.5%±0.5), growth and sporulation of all the four pathogens and aflatoxins production by Aspergillus were significantly reduced. In addition, atmosphere containing 98.5%±0.5 N2 caused the complete mortality of adults of S. oryzae after 3 days on wheat and of T. confusum after 7 days on flour. Results herewith reported suggest that N2 controlled atmosphere represents an eco-friendly tool that could be transferred to a large-scale system for grain storage in order to avoid or reduce chemical treatments.

The objectives of this study were to investigate the impact that interactions between key climate change (CC) related environmental factors of temperature (20, 25, 30°C), water activity (aw; 0.995, 0.98) and CO2 exposure (400, 1000 ppm) may have on (a) growth, (b) gene expression of biosynthetic toxin genes (Tri5, Tri6, Tri16), and (c) phenotypic T-2/HT-2 production by Fusarium langsethiae on oat-based agar medium and in stored oats. Fungal growth was optimum at 25°C and 0.995 aw and reduced significantly at 30°C and intermediate stress (0.98 aw, elevated CO2 (1000 ppm) exposure by approx. 4-fold. Lag phases prior to growth paralleled these results with the longest lag phase in this treatment (24 hrs). On oat-based medium, the relative Tri5 gene expression was increased in elevated CO2 conditions. The expression of both the Tri6 and Tri16 genes was reduced when compared to control (20°C, 0.995 aw, 400 ppm), especially in elevated CO2 conditions. In stored oats, the Tri5 gene expression was reduced in all conditions except at 30°C, 0.98 aw, elevated CO2 where there was a significant (5.3-fold) increase. The expression of the Tri6 was slightly over-expressed in elevated CO2 and the Tri16 gene was upregulated, especially in elevated CO2 conditions. For mycotoxin production, both on oat-based medium and in stored oats the production was higher at 25°C when compared to 30°C. In stored oats, at 0.98 aw, elevated CO2 led to higher T2/HT-2 toxin production at both 25 and 30°C with a significant increase (73-fold higher) at 30°C. In elevated CO2 conditions, Tri16 (Spearman test; 0.68; p-value=0.0019) and Tri5 gene expression (Spearman test; 0.56; p-value=0.0151) were correlated with T-2+HT-2 production. Nine T-2 and HT-2 metabolites were detected by LC-MS/MS including a new dehydro T-2 toxin and the conjugate, HT-2 toxin glucuronide (in plantae). The new dehydro T-2 toxin was the most abundant metabolites and showed correlation (R2=0.8176) with T-2 production. This is the first study to examine the impact of CC factors on growth and mycotoxin production by a strain of F. langsethiae. The influence of such scenarios on relative risk of oats contamination with these toxins in relation to the food security agenda is discussed.

Analysis of survey data from 804 spring-oat fields divided into five climatic regions suggested that low inoculum level of Fusarium langsethiae was a major limiter of T-2 + HT-2. A 30-year climate with a cool and rainy 10-day period preceding estimated mid-anthesis and a warm 3-week period following anthesis were positively associated with T-2 + HT-2 contamination. In 12 survey years, warm weather from 4 weeks before GS65 until harvesting increased T-2 + HT-2, except in the 1–2 weeks preceding mid-anthesis, when the requirement for high humidity dominated. F. langsethiae and F. sporotrichioides were consistently promoted by high temperature from mid-anthesis onwards. A positive response of T-2 + HT-2 to high humidity peaked 5–10 days earlier and was shorter and weaker than the responses of DON and F. graminearum. The probability of high concentration and regional mean concentration of T-2 + HT-2 tended to be lower under ploughing than under non-ploughing, and they tended to increase with increasing cereal intensity. T-2 + HT-2 was positively associated with zero tillage when compared with minimum tillage. The responses of F. langsethiae and F. sporotrichioides to ploughing and cereal intensity varied by region. In contrast to T-2 + HT-2, DON was the same or higher under ploughing than under non-ploughing, not consistently affected by cereal intensity and not associated with zero tillage. F. graminearum was consistently more common under ploughing than under non-ploughing, and decreased with increasing cereal intensity in four regions. Also, F. culmorum and F. poae tended to be more common under ploughing. F. culmorum increased with cereal intensity in three regions.

MotivationFusarium langsethiaeis a T-2 and HT-2 mycotoxins producingFusariumspecies firstly characterised in 2004. It is commonly isolated from oats in Northern Europe. T-2 and HT-2 mycotoxins exhibit immunological and haemotological effects in animal health mainly through inhibition of protein, RNA and DNA synthesis. The development of a high-quality and comprehensively annotated assembly for this species is therefore essential in providing the molecular understanding and the mechanism of T-2 and HT-2 biosynthesis inF. langsethiaeto help develop effective control strategies.ResultsTheF. langsethiaeassembly was produced using PacBio long reads, which were then assembled independently using Canu, SMARTdenovo and Flye; producing a genome assembly total length of 59Mb and N50 of 3.51Mb. A total of 19,336 coding genes were identified using RNA-Seq informedab-initiogene prediction. Finally, predicting genes were annotated using the basic local alignment search tool (BLAST) against the NCBI non-redundant (NR) genome database and protein hits were annotated using InterProScan. Genes with blast hits were functionally annotated with Gene Ontology.Contactf.mohareb@cranfield.ac.ukData availabilityRaw sequence reads and assembled genome can be downloaded from: GenBank under the accession JAFFKB000000000

Fusarium langsethiae is a symptomless pathogen of oat panicles that produces T‐2 and HT‐2 mycotoxins, two of the most potent trichothecenes produced by Fusarium fungi in cereals. In the last few years, the levels of these mycotoxin in oat grain has increased and the European commission have already recommended a maximum level for of 1000 μg kg−1 for unprocessed oat for human consumption. The optimal and most sustainable way of combating infection and mycotoxin contamination is by releasing resistant oat varieties. Here the objective was to determine if we could identify any genomic loci associated with either the accumulation of F. langsethiae DNA or mycotoxins in the grain. In each of two years, field trials were conducted wherein 190 spring oat varieties were inoculated with a mixture of three isolate of the pathogen. Mycotoxins were quantified using liquid chromatography–tandem mass spectrometry. Varieties were genotyped using 16,863 genotyping by sequencing markers. Genome‐wide association studies associated 5 SNPs in the linkage group Mr06 with T‐2 + HT‐2 mycotoxin accumulation. Markers were highly correlated, and a single QTL was identified. The marker avgbs_6K_95238.1 mapped within genes showing similarity to lipase, lipase‐like or lipase precursor mRNA sequences and zinc‐finger proteins. These regions have previously been shown to confer a significant increase in resistance to Fusarium species.

Fusarium langsethiae is one of the common Fusarium species infecting small grain cereals in the Nordic region and the UK. It is usually described as a weak pathogen, and with a strong preference for oats, although no studies have yet addressed the explanations for this at the microscopic level. Using microscope techniques we have studied the early steps of colonization of oat and wheat grain by F. langsethiae particularly addressing the role of pollen in the infection process and the fungal ability to penetrate plant cell wall. The aim was to better understand its non-aggressive colonization picture and why oat is preferred over wheat as a host. Spray inoculated oat and wheat plants were scored for fungal progression at 3, 6, 10 and 14 days post inoculation (dpi) using light microscopy and scanning electron microscopy (SEM). Fungal hyphae entered the grain at the apex, or along the sides in the overlapping zone between palea wings and lemma, then spread basipetally and laterally, with a clear directional growth towards the caryopsis. Hyphal growth was clearly aided by the presence of pollen. On oat proliferating hyphae developed a variety of penetration structures on all internal surfaces. F. langsethiae infection on wheat progressed along the same routes, however slower and overall with less hyphal mass. Interestingly, hyphae closely associated to the wheat caryopsis seemed to undergo degradation, and profuse conidiation was observed at 14 dpi. Explanations for the differences in F. langsethiae colonization of oat versus wheat are suggested in light of the results.

To assess the in vitro activity of three phenolic acids (ferulic acid, p-hydroxybenzoic acid, vanillic acid) and two flavonols (quercetin, rutin) on mycelial growth and mycotoxin accumulation of Fusarium graminearum (FG), F. langsethiae (FL) and F. poae (FP), two different approaches were chosen. First, grains from oat varieties were inoculated with a suspension of three FL isolates to determine the influence of phenolic compounds on the accumulation of mycotoxins. The oat variety Zorro showed a tendency for lower accumulation of T-2/HT-2, diacetoxyscirpenol and neosolaniol. Second, a mycelium growth assay was conducted to follow FG, FL and FP growth on cereal based media supplemented with phenolic compounds. Increasing concentrations of ferulic acid substantially inhibited growth of FG and FL, while FP growth was reduced to 57%. In contrast, p-hydroxybenzoic acid, vanillic acid, quercetin, and rutin slightly stimulated mycelium growth. Results about mycotoxin production in cereal based media were less conclusive.

Experiments were conducted to determine the extent of Fusarium langsethiae infection in wheat, barley and oats grown under identical experimental conditions. In total, four experiments were conducted with both winter and spring sown experiments at two locations. The amount of F. langsethiae infection was determined by quantifying F. langsethiae DNA and quantifying the combined concentration of the trichothecene mycotoxins HT-2 and T-2 (HT-2 + T-2) in cereal head fractions (grain and rest of the head) after threshing at harvest. Results of the study showed that under identical experimental conditions, oats had the highest F. langsethiae DNA and HT-2 + T-2 concentrations compared to wheat and barley. This indicates that the high levels detected on UK oats compared to wheat and barley from surveys of commercial crops is a consequence of genetic differences rather than differences in agronomy applied to the cereal species. The concentration of HT-2 and T-2 per unit of F. langsethiae DNA in oats compared to wheat and barley was also significantly higher indicating host differences in either the stimulation of HT-2 and T-2 production or in the metabolism of HT-2 and T-2. The study also showed that the proportion of F. langsethiae DNA in threshed grains was significantly lower than that in the rest of the cereal head.

Fusarium langsethiae, a toxigenic fungus known to contaminate small-grain cereals with type A trichothecene mycotoxins, HT-2 and T-2 was described as a new species in 2004. HT-2 and T-2 are some of the most potent Fusarium toxins in eukaryotes, capable of inhibiting protein synthesis. The epidemiology of F. langsethiae is not well understood and with the intent of the European Commission to set maximum levels of contamination of cereals with these toxins, importance is currently placed in trying to understand the fungal infection process and its favorable growth conditions. A field study was carried out to investigate the effect of artificially inoculated oats straw, ploughing and minimum tillage with and without incorporated crop debris (straw) on infection and mycotoxin production by F. langsethiae on oats cultivar Gerald. The results indicated that cultural field practices had effects on the infection of oats by F. langsethiae. Fusarium langsethiae DNA was quantified in significantly larger amounts (p 0.05) on oat infection by F. langsethiae as quantified by DNA concentration. HT-2+T-2 quantification and analysis, gave no good evidence that either inoculation or cultural practice had any significant influence on the concentration of mycotoxins in the samples (p>0.05), but samples from minimum tillage with incorporated straw plots resulted in 2.5 times more HT-2+T-2 toxins than samples from ploughed with removed straw. These findings indicate the importance of tillage and crop debris management in the mitigation in an effort to prevent F. langsethiae infection, colonization and possible contamination of oats with HT-2 and T-2 toxins.

Numerous Fusarium species have been associated with Fusarium head blight of wheat. In Poland, Fusarium poae was reported as the dominant species isolated from wheat grain during seasons with low amounts of rainfall during anthesis (1). F. langsethiae was described as a new toxigenic Fusarium species (3) and causal agent of Fusarium head blight (2), which has been isolated from infected oats, wheat, and barley in northern and central Europe (Norway, Austria, Germany, Czech Republic, Denmark, and England) (2). On the basis of morphological similarities, F. langsethiae has long been identified as a “powdery” form of F. poae. However, F. langsethiae produces type A trichothecene toxins such as T-2, whereas F. poae produces nivalenol and other 8-keto trichothecenes, scirpentriol, and 15-acetoxyscirpenol. In 2006, we obtained several isolates of F. langsethiae from kernels collected from winter wheat ears with head blight symptoms. Isolates were collected in the central (Sobiejuchy 52°54′N, 17°43′E; Minikowo 53°29′N, 17°56′E) and northern (Radostowo 53°59′N, 18°45′E) regions of Poland. Strains were isolated on potato dextrose agar (PDA) medium (pH 5.5). Further analyses were conducted on single-spore isolates. Initial species identification of all isolates was conducted on the basis of morphological features. The strains were grown in darkness at 25°C on PDA in plastic petri dishes to diagnose colony color, odor, and growth rate. The cultures also were incubated on saltwater nutrient agar (SNA) at 25°C for 7 days in near-UV light (Philips TLD 36W/08) and darkness in a 12/12-h cycle to promote conidia formation. The calculated average mycelial growth rate per day was based on the difference in millimeters between the colony diameters after 4 and 7 days of incubation. Growth rates ranged from 5.4 to 10.3 mm/day for nine strains. Mycelium was whitish or pinkish white, sparse, and 1 to 3 mm high with no odor. All colonies showed a powdery mycelium surface. Microconidia was napiform or globose, nonseptate, sporadically 1-septate, with an average length of 6.4 μm (range 3.9 to 13.7 μm) and width of 5.6 μm (range 2.9 to 8.8 μm). Microconidia were formed in heads, borne on unbranched or branched monophialides that were 8.5 to 16.3 μm long. All strains had slim, bent monophialides, typical for F. langsethiae, and always a few, short, thick, and squat ones resembling F. poae. In young cultures, monophialides may be formed directly on hyphae. Formation of macroconidia, sclerotia, and chlamydospores were not observed after 3 weeks of incubation. Species identification was confirmed by PCR assay with the use of SCAR (sequence characterized amplified region) primers producing a 310-bp DNA fragment (4), which was deposited in GenBank (Accession No. EU088404). To our knowledge, this is the first report of F. langsethiae in Poland. References: (1) C. Sadowski et al. J. Appl. Genet. 43A:69, 2002. (2) M. Torp and A. Adler. Int. J. Food Microbiol. 95:241, 2004. (3) M. Torp and H. I. Nirenberg. Int. J. Food Microbiol. 95:247, 2004. (4) A. Wilson et al. FEMS Microbiol. Lett. 233:69, 2004.

High occurrence of Fusarium poae (FP) and Fusarium langsethiae (FL) and their mycotoxins nivalenol (NIV) and T‐2/HT‐2 have been observed in Swiss oats. Early prediction of mycotoxin levels is important for farmers and the cereal industry to minimize the risk of contaminated food and feed. Therefore, climate chamber experiments were conducted to investigate the influence of different temperatures (10, 15, 20 °C) and durations (4, 8, 12 h) at 99% relative humidity (RH) on the infection of oats with FP and FL. In addition, to discover the most susceptible period of oats, artificial FL inoculations were conducted at different growth stages. Field experiments were performed to observe the dispersal of these fungal species within the field and to investigate the weather conditions that influence the dispersal. The climate chamber experiments revealed higher contamination with NIV and T‐2/HT‐2 in the 10 °C treatments and with a prolonged humidity duration of 12 h 99% RH. Inoculations of oat plants at early (DC 61) and mid (DC 65) anthesis, led to higher FL infection and T‐2/HT‐2 accumulation in the grains compared with treatments at earlier growth stages, which might be due to an increased susceptibility during anthesis. No indication for spore dispersal was observed in the field experiments. The results obtained, together with the cropping factors that influence infection and mycotoxin production, could be used as a first step in developing forecasting models to predict the contamination of oats with the mycotoxins NIV and T‐2/HT‐2.

Fusarium langsethiae is amongst the most recently discovered pathogens of small grains cereals. F. langsethiae is the main producer, in Europe, of T2 and HT-toxins in small grain cereals, albeit often asymptomatic, this makes its control challenging. The European Union (EU) is pushing hard on the use of biocontrol agents to minimize the use of fungicides and pesticides, which are detrimental to the environment and responsible for serious pollution of the soil and superficial water. In line with EU directives (e.g., 128/2009), here we report the use of protein fractions, purified from the culture filtrate of the basidiomycete Trametes versicolor, for controlling F. langsethiae. T. versicolor, a so-called medicinal mushroom which is applied as a co-adjuvant in oncology and other pathologies as a producer of biological response modifiers. In this study, the exo-proteome of T. versicolor proved highly efficient in inhibiting the growth of F. langsethiae and the biosynthesis of the T2 toxin. Results are promising for its future use as a sustainable product to control F. langsethiae infection in cereals under field conditions.

In the UK and Northern Europe, ripening oats can become contaminated with T-2 and HT-2 mycotoxins, produced mainly by Fusarium langsethiae. There are indicative levels related to the maximum limits for oat grain for these toxins. The objectives of this study were to examine the effect of interacting conditions of temperature (10–30 °C) and water activity (aw, 0.995–0.90) on (a) lag times prior to growth, (b) growth and (c) T-2 and HT-2 toxins by two strains of F. langsethiae isolated from oats in the UK and compare this with the type strain (Fl201059) which has been genomically sequenced, and (d) develop (and validated with published data) a probabilistic models for impacts of temperature × aw on growth and toxin production. All three strains had an optimum aw range and temperature of 0.995–0.98 and 25 °C for growth. For T-2 + HT-2 production these were 0.995 aw and 20 °C. Overall, the type strain produced higher amounts of T-2 + HT-2 with a HT-2/T-2 ratio of up to 76. Using this study data sets and those from the literature, probabilistic models were developed and validated for growth and T-2 + HT-2 toxin production in relation to temperature × aw conditions. These models, when applied in stored oats, will be beneficial in determining the conditions on the relative level of risk of contamination with these two toxins in the context of the EU indicative maximum levels.

Fusarium langsethiae is a fungus that has recently been implicated in the contamination of small-grain cereal crops such as oats, wheat and barley with high levels of HT-2 and T-2 toxins in many European countries. The epidemiology of this fungus is not well known and may therefore be a bigger problem than currently thought to be. A study was carried out investigating the in vitro growth characteristics of F. langsethiae isolates from contaminated oats and wheat at various temperatures; 15, 20, 25 and 30 °C. Results indicated similar growth trends of oats and wheat isolates of F. langsethiae. Wheat isolates grew significantly (p

Fusarium langsethiae is a fungal pathogen of cereal crops that is an increasing problem in northern Europe, but much of its epidemiology is poorly understood. The species produces the mycotoxins T-2 and HT-2, which are highly toxic. It was hypothesized that grain aphids, Sitobion avenae , may transmit F. langsethiae inoculum between wheat plants, and a series of transmission experiments and volatile chemical analyses was performed to test this. Manual translocation of aphids from inoculated to uninfected hosts resulted in pathogen DNA accumulation in hosts. However, the free movement of wingless aphids from infected to healthy plants did not. The addition of winged aphids reared on F. langsethiae -inoculated wheat seedlings to wheat plants also did not achieve successful pathogen transfer. While our data suggested that aphid transmission of the pathogen was not very efficient, we observed an increase in disease when aphids were present. After seedling inoculation, an increase in pathogen DNA accumulation in seedling leaves was observed upon treatment with aphids. Furthermore, the presence of aphids on wheat plants with F. langsethiae- inoculated ears not only led to a rise in the amount of F. langsethiae DNA in infected grain but also to an increase in the concentrations of T-2 and HT-2 toxins, with more than 3-fold higher toxin levels than diseased plants without aphids. This work highlights that aphids increase the susceptibility of wheat host plants to F. langsethiae and that aphid infestation is a risk factor for accumulating increased levels of T-2 and HT-2 in wheat products. IMPORTANCE Fusarium langsethiae is shown here to cause increased contamination levels of grain with toxins produced by fungus when aphids share the host plant. This effect has also recently been demonstrated with Fusarium graminearum , yet the two fungal species show stark differences in their effect on aphid populations. In both cases, aphids improve the ability of the pathogens to cause and initiate Fusarium head blight (FHB) disease in wheat, but F. langsethiae may be able to act as a dispersal agent. F. langsethiae contributes harmful toxins to wheat grain that need to be controlled, but as yet, its epidemiology is unresolved. This work reveals insights into the role aphids play in promoting the successful colonization of this species in wheat and the benefit of controlling aphid populations on crops that are at high risk of FHB.

Fusarium head blight (FHB) is a significant fungal disease of barley implicated in various brewing-related disorders and could further influence the expression of genes related to malting quality. The aim of our research was to improve understanding of barley gene regulation in FHB-infected grain over time, starting from the onset of infection on flowering spikes, right up to preparation of finished malt. Two two-rowed spring barley varieties (Grace and Scarlett) were infected with species-specific spore suspensions of Fusarium culmorum , Fusarium avenaceum , Fusarium langsethiae , or Fusarium sporotrichioides under greenhouse conditions. We selected a subset of barley gene candidates related to plant defense and to malting quality traits for our gene expression analyses. We further complemented this by measuring the Fusarium DNA content in the same samples. Our work demonstrates that gene expression is indeed altered by Fusarium infection both before harvest and during malting. This includes increased expression of plant defense genes and differential expression of malting-related genes, in particular the two β -amylase genes, α-amylase and α-amylase/trypsin inhibitor. This research increases the understanding of transcriptional changes in barley grain in response to different Fusarium species and emphasizes the importance of Fusarium control before harvest for securing high quality malt.

Fusarium langsethiae is a widespread pathogen of small grain cereals, causing problems with T-2 and HT-2 toxin contamination in grains every year. In an effort to better understand the biology of this fungus, we present a draft genome sequence of F. langsethiae Fl201059 isolated from oats in Norway. The assembly was fragmented, but reveals a genome of approximately 37.5 Mb, with a GC content around 48%, and 12,232 predicted protein-coding genes. Focusing on secondary metabolism we identified candidate genes for 12 polyketide synthases, 13 non-ribosomal peptide synthetases, and 22 genes for terpene/isoprenoid biosynthesis. Some of these were found to be unique compared to sequence databases. The identified putative Tri5 cluster was highly syntenic to the cluster reported in F. sporotrichioides. Fusarium langsethiae Fl201059 produces a high number of secondary metabolites on Yeast Extract Sucrose (YES) agar medium, dominated by type A trichothecenes. Interestingly we found production of glucosylated HT-2 toxin (Glu-HT-2), previously suggested to be formed by the host plant and not by the fungus itself. In greenhouse inoculations of F. langsethiae Fl201059 on barley and oats, we detected the type A trichothecenes: neosolaniol, HT-2 toxin, T-2 toxin, Glu-HT-2 and numerous derivatives of these.

High concentrations of the mycotoxins HT-2 and T-2 (HT2 + T2), primarily produced by Fusarium langsethiae, have occasionally been detected in Norwegian oat grains. In this study, we identified weather variables influencing accumulation of HT2 + T2 in Norwegian oat grains. Oat grain samples from farmers’ fields were collected together with weather data (2004–2013). Spearman rank correlation coefficients were calculated between the HT2 + T2 contamination in oats at harvest and a range of weather summarisations within estimated phenological windows of growth stages in oats (tillering, flowering etc.). Furthermore, we developed a mathematical model to predict the risk of HT2 + T2 in oat grains. Our data show that adequate predictions of the risk of HT2 + T2 in oat grains at harvest can be achieved, based upon weather data observed during the growing season. Humid and cool conditions, in addition to moderate temperatures during booting, were associated with increased HT2 + T2 accumulation in harvested oat grains, whereas warm and humid weather during stem elongation and inflorescence emergence, or cool weather and absence of rain during booting reduced the risk of HT2 + T2 accumulation. Warm and humid weather immediately after flowering increased the risk, while moderate to warm temperatures and absence of rain during dough development, reduced the risk of HT2 + T2 accumulation in oat grains. Our data indicated that HT2 + T2 contamination in oats is influenced by weather conditions both pre- and post-flowering. These findings are in contrast with a previous study examining the risk of deoxynivalenol contamination in oat reporting that toxin accumulation was mostly influenced by weather conditions from flowering onwards.

Between 2013 and 2015, 325 samples of commercially grown oats were collected in Switzerland along with data on respective cropping factors. The incidence of different Fusarium species was determined using a seed health test and quantitative PCR was used to measure the amount of F. poae and F. langsethiae DNA. Mycotoxins were quantified by LC–MS/MS. Among all Fusarium species, F. poae was found to be dominant whereas T-2/HT-2 toxins were the major mycotoxins. Samples from fields with the previous crop cereal showed the highest concentrations of T-2/HT-2. Higher amounts of nivalenol (NIV) and T-2/HT-2 were detected in samples from fields with reduced tillage compared with samples from ploughed fields. Furthermore, we observed a higher contamination with NIV and T-2/HT-2 in winter sown varieties compared with spring sown varieties. Results from the current study are highly valuable to develop recommendations for optimised cropping systems that reduce the risk of mycotoxin contamination of oat grains.

We report a case of keratitis due to Fusarium langsethiae in a 56-year-old man. The patient presented with pain and tearing of 10 days duration in the right eye, which had sustained a paddy stalk injury. On examination, a hypopyon corneal ulcer was noted in the right eye. Multiple scrapings were obtained from the affected part of the cornea. A lactophenol cotton blue wet mount and a Gram-stained smear of scrapings were made. Scrapings were also inoculated on various culture media, including Sabouraud dextrose agar (SDA). A fungal etiology was sought by conventional microbiological techniques and polymerase chain reaction. In vitro susceptibility testing was performed by an agar dilution method. Direct microscopy of corneal scrapings revealed septate hyphae, leading to initiation of intensive topical therapy with natamycin (5 %). However, the keratitis progressed, necessitating therapeutic penetrating keratoplasty. White, powdery-like colonies, with abundant aerial mycelium, were recovered on SDA from corneal scrape material. Based on macroscopic and microscopic morphological features, the isolated fungus was initially identified as a Fusarium species. Sequence analysis of the 28S rRNA region of the fungal genome led to a specific identification of F. langsethiae. Antifungal susceptibility testing results suggested that the strain isolated was susceptible to voriconazole, ketoconazole, and itraconazole. To our knowledge, this is the first reported case of keratitis due to F. langsethiae; attention is drawn to the unique characteristics of the fungal isolate, difficulties in identification and non-responsiveness to medical therapy.

Phytopathogenic fungi can lead to significant cereal yield losses, also producing mycotoxins dangerous for human and animal health. The fungal control based on the use of synthetic fungicides can be complemented by "green" methods for crop protection, based on the use of natural products. In this frame, the antifungal activities of bergamot and lemon essential oils and of five natural compounds recurrent in essential oils (citronellal, citral, cinnamaldehyde, cuminaldehyde and limonene) have been evaluated against three species of mycotoxigenic fungi (Fusarium sporotrichioides, F. graminearum and F. langsethiae) responsible for Fusarium Head Blight in small-grain cereals. The natural products concentrations effective for reducing or inhibiting the in vitro fungal growth were determined for each fungal species and the following scale of potency was found: cinnamaldehyde > cuminaldehyde > citral > citronellal > bergamot oil > limonene > lemon oil. Moreover, the in vitro mycotoxin productions of the three Fusaria strains exposed to sub-lethal concentrations of the seven products was evaluated. The three fungal species showed variability in response to the treatments, both in terms of inhibition of mycelial growth and in terms of modulation of mycotoxin production that can be enhanced by sub-lethal concentrations of some natural products. This last finding must be taken into account in the frame of an open field application of some plant-derived fungicides.

Analysis of 49 strains of Fusarium langsethiae originating from northern Europe (Russia, Finland, Sweden, UK, Norway, and Latvia) revealed the presence of spontaneous auxotrophic mutants that reflect natural intraspecific diversity. Our investigations detected that 49.0% of F. langsethiae strains were auxotrophic mutants for biotin, and 8.2% of the strains required thiamine as a growth factor. They failed to grow on vitamin-free media. For both prototrophic and auxotrophic strains, no growth defect was observed in rich organic media. Without essential vitamins, a significant reduction in the growth of the auxotrophic strains results in a decrease of the formation of T-2 toxin and diacetoxyscirpenol. In addition, all analysed F. langsethiae strains were distinguished into two subgroups based on PCR product sizes. According to our results, 26 and 23 strains of F. langsethiae belong to subgroups I and II respectively. We determined that the deletion in the intergenic spacer (IGS) region of the rDNA of F. langsethiae belonging to subgroup II is linked with temperature sensitivity and causes a decrease in strain growth at 30 °C. Four thiamine auxotrophic strains were found in subgroup I, while 21 biotin auxotrophic strains were detected in subgroups II. To the best of our knowledge, the spontaneous mutations in F. langsethiae observed in the present work have not been previously reported.

We describe a novel positive single-stranded RNA virus, termed Fusarium langsethiae hypovirus 1 (FlHV1), from the isolate AH32 of the phytopathogenic fungus Fusarium langsethiae . The properties of FlHV1 permit assignment to the genus Alphahypovirus in the family Hypoviridae . This is the first report of a mycovirus identified in F. langsethiae .

Analysis of 49 strains of Fusarium langsethiae originating from northern Europe (Russia, Finland, Sweden, UK, Norway, and Latvia) revealed the presence of spontaneous auxotrophic mutants that reflect natural intraspecific diversity. Our investigations detected that 49.0% of F. langsethiae strains were auxotrophic mutants for biotin, and 8.2% of the strains required thiamine as a growth factor. They failed to grow on vitamin-free media. For both prototrophic and auxotrophic strains, no growth defect was observed in rich organic media. Without essential vitamins, a significant reduction in the growth of the auxotrophic strains results in a decrease of the formation of T-2 toxin and diacetoxyscirpenol. In addition, all analysed F. langsethiae strains were distinguished into two subgroups based on PCR product sizes. According to our results, 26 and 23 strains of F. langsethiae belong to subgroups I and II respectively. We determined that the deletion in the intergenic spacer (IGS) region of the rDNA of F. langsethiae belonging to subgroup II is linked with temperature sensitivity and causes a decrease in strain growth at 30 °C. Four thiamine auxotrophic strains were found in subgroup I, while 21 biotin auxotrophic strains were detected in subgroups II. To the best of our knowledge, the spontaneous mutations in F. langsethiae observed in the present work have not been previously reported.

Surveys on the occurrence of type A trichothecenes in wheat, and particularly for the T-2 and HT-2 toxins, and information on the biology and epidemiology of the causative Fusarium species (i.e. F. langsethiae, F. sporotrichioides) are scarce in Italy, as compared to the more common type B trichothecene, deoxynivalenol and its producers. This 4-year monitoring of phytopathogenic Fusarium species on 183 seed lots of durum wheat shows wide distribution of F. langsethiae in Italy and the potential of several isolates of this fungus to produce high amounts of T-2 and HT-2 in wheat. Fusarium langsethiae was observed for approximately 48% of the analysed samples, with a maximum incidence for a single lot of 10.5%. Fusarium sporotrichioides was observed only in 2011, with an average incidence of 2% (range, 0-3%). A collection of F. langsethiae isolates representative of the main cultivation areas in Italy was established. These isolates showed great variability for their toxin production in vitro. Of 28 strains, all except one isolate can produce the T-2 and HT-2 toxins. HT-2 was generally in greater amounts than T-2, with an average concentration ratio for HT-2 to T-2 of 2.1 (range, 0.7-5.4). The artificial inoculation of wheat with three isolates of F. langsethiae produced no Fusarium head blight symptoms under field conditions. However, significantly higher incidence of F. langsethiae was seen on the kernels of inoculated plants, compared to the uninoculated controls.

Fusarium head blight (FHB) of wheat and barley has been extensively researched worldwide; in contrast, there is limited information on the effects of environmental conditions on Fusarium toxin accumulation in oat grains. More than 300 samples of oat grain from various regions of the United Kingdom from 2006 to 2008 were analyzed for mycotoxin contamination due to infection by Fusarium spp. HT2 and T2 toxins were the two most commonly detected, and their concentrations in individual samples were highly correlated. Hourly weather data were obtained from meteorological recording stations near most of the sampling sites. Statistical modeling was applied to both the original toxin (HT2 plus T2) data and the toxin data adjusted for oat cultivars and number of cereal crops in the previous four seasons. Accumulation of HT2 and T2 toxin was positively correlated with warm and wet conditions during early May and dry conditions thereafter. Using a collection of 51 environmental variables summarized over three lengths (10, 15, and 20 days) of time periods encompassing early May, late May, and early July, all-subsets regression showed that many models, consisting of three to six predictor variables, could be identified with similar explanatory strength for the effect of environmental conditions on toxin accumulation. Most important predictor variables were related to wet conditions during the early-May period, which was before anthesis. These results suggest that the predominant period for Fusarium langsethiae infection of oat is likely to be before rather than during anthesis, as for other head blight pathogens. These empirical models may be further improved by using quantified pathogen biomass within the grains and weather predictor variables summarized in relation to plant growth stages (instead of calendar times).

The health-beneficial properties of oats have led to an increase in the consumption of oats and oat-based food products in recent years. Fusarium langsethiae grows on small grain cereals, especially oats and can result in contamination with type A trichothecenes (T-2 toxin (T-2) and HT-2 toxin (HT-2)) in crops pre- and post-harvest. The aim of this work was to assess the efficacy of three fungicides (fenpropimorph, prochloraz and tebuconazole) on temporal growth of two F. langsethiae strains and the accumulation of T-2 and HT-2 in oat grains, under different water activities (aw; 0.95 and 0.98) and temperatures (15 and 25 °C). All the antifungal agents reduced growth rates when compared to controls, and this increased with increasing fungicide dose. The ranges of ED50 values (mg/kg) were 65–270 for fenpropimorph, 0.25–4.2 for prochloraz, and 0.3–14 for tebuconazole. The ED90 values (mg/kg) ranged from 170 to > 800, 0.5 to > 10 and 0.5 to > 15 for these three fungicides respectively. The ED50 values were not statistically significantly affected by the factors aw, temperature or strain. However, there were significant differences among the fungicides. Fenpropimorph proved less efficient that the two azoles, which do not differ significantly. In general, levels of HT-2 were higher than T-2 in all cultures regardless of environmental conditions. Overall, HT-2 concentration was always higher at 25 than 15 °C and increased from day 14 to day 21. Levels of both toxins generally decreased with increasing fungicide dose regardless of fungicide type, strain and incubation time. No toxins were detected in cultures at 0.95 aw in the presence of any of the three fungicides. Also under wetter conditions at 0.98 aw neither mycotoxin was found in cultures treated with prochloraz at doses >1 mg/kg (15 °C) or >3 mg/kg (25 °C) or tebuconazole at doses >6 mg/kg (15 or 25 °C). ANOVA showed that in treatments with each fungicide the factors dose, time and temperature significantly affected toxin production while there was no difference between the strains.

Fusarium langsethiae, formally described as a new species over a decade ago, has been identified as the main producer of HT-2 (HT2) and T-2 (T2) toxins in Europe in small cereal grains. Mycotoxin contamination caused by this Fusarium species can represent a food safety hazard that deserves further attention. In the present work, the mycotoxin profile in wheat cultures of F. langsethiae is presented with particular reference to the production of major type-A trichothecenes and their glucosyl derivatives. F. langsethiae isolates, representative of the major Italian wheat cultivation areas, were tested for the production of T2, HT2, diacetoxyscirpenol (DAS) and neosolaniol (NEO), and relevant glucosyl derivatives. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used for the identification and chemical characterization of these metabolites. F. langsethiae isolates under investigation resulted to be potent producers of T2, HT2 and NEO. Furthermore, a well-defined set of isolates, all originating from Central Italy, produced also DAS. All isolates were found to be able to produce HT2 glucosyl derivatives, whereas only traces of T2 glucoside were detected in one sample. Furthermore, two mono-glucosyl derivatives of NEO and one mono-glucoside derivative of DAS were identified and characterized. The screening for the presence/absence of glucosylated trichothecenes in analyzed fungal extracts revealed a general co-occurrence of these derivatives with the parent toxin at levels that could be roughly estimated to account up to 37% of the relevant unconjugated toxin. This is the first report of the production of glucosylated trichothecenes by F. langsethiae cultured on small grains.

Fusarium langsethiae is a toxigenic fungal species that has been reported in European small-grain cereal crops such as oats, wheat and barley. Although its relative contribution to fusarium head blight (FHB) symptoms is not well understood, it is reported to contaminate these cereals with high levels of HT-2 and T-2 trichothecenes mycotoxins that are currently under consideration for legislation by the European Commission. Ten commercial oat fields in Shropshire and Staffordshire (two adjacent counties in the Midlands) in the UK were surveyed in the 2006/2007 growing season. Samples were taken from predetermined field locations at Zadoks growth stages 32/33, 69, 77-85 and 90-92 for F. langsethiae biomass and HT-2 and T-2 toxins quantification. The results from this study showed that oats can be heavily infected with F. langsethiae and have high concentrations of HT-2 and T-2 toxins with no apparent FHB symptoms. The regression of HT-2 + T-2 toxins on F. langsethiae DNA concentration was highly significant (P < 0.001, r2 = 0.55). The results indicated that although F. langsethiae had no direct effect on crop yield, it may result in indirect economic losses where the grain can be rejected or downgraded as a result of intolerable levels of HT-2 and T-2 toxins, which are of human food and animal feed safety concern. The influence of cultural field practices on the infection and HT-2 and T-2 toxins accumulation in oats was not clear and warrants further studies to identify the sources of F. langsethiae inoculum and conditions favourable for infection and mycotoxin production

A field survey was performed to study the infection and development of Fusarium langsethiae in the growing season of wheat, barley, oats and triticale under commercial (2009 – 2011) production. Sampling was completed over three years from fields within the counties of Shropshire and Staffordshire in the UK. Plants sampled (from tillering to harvest) were divided into roots, leaves, lower stem, upper stem and inflorescence/head sub-samples depending on the growth stage of the cereal. DNA was extracted and F. langsethiae DNA quantified using real-time PCR. Fusarium mycotoxins HT-2 and T-2 were quantified from head samples at harvest. Three years of data showed oat to contain the highest levels of both F. langsethiae biomass and HT-2 + T-2 mycotoxins in harvested heads of the cereals studied. The development of F. langsethiae in all three cereals appeared to be similar. Fusarium langsethiae DNA was not detected in the roots and seedlings of all three cereals suggesting F. langsethiae is not a seedling pathogen of cereals. Head infection if it occurs, is at head emergence but before flowering. Seemingly symptomless heads had high levels of F. langsethiae DNA and HT-2 + T-2, confirming previous suggestions that F. langsethiae is a symptomless pathogen of oats.

International audience; The effect of natural phenolic acids was tested on the growth and production of T‐2 and HT‐2 toxins by Fusarium langsethiae and F. sporotrichioides, on Mycotoxin Synthetic medium. Plates treated with 0.5 mM of each phenolic acid (caffeic, chlorogenic, ferulic and p‐coumaric) and controls without phenolic acid were incubated for 14 days at 25 °C. Fungal biomass of F. langsethiae and F. sporotrichioides was not reduced by the phenolic acids. However, biosynthesis of T‐2 toxin by F. langsethiae was significantly reduced by chlorogenic (23.1%) and ferulic (26.5%) acids. Production of T‐2 by F. sporotrichioides also decreased with ferulic acid by 23% (p < 0.05). In contrast, p‐coumaric acid significantly stimulated the production of T‐2 and HT‐2 toxins for both strains. A kinetic study of F. langsethiae with 1 mM ferulic acid showed a significant decrease in fungal biomass, whereas T‐2 production increased after 10 days of incubation. The study of gene expression in ferulic supplemented cultures of F. langsethiae revealed a significant inhibition for Tri5, Tri6 and Tri12 genes, while for Tri16 the decrease in gene expression was not statistically significant. Overall, results indicated that phenolic acids had a variable effect on fungal growth and mycotoxin production, depending on the strain and the concentration and type of phenolic acid assayed.

During the last ten years, Norwegian cereal grain industry has experienced large challenges due to Fusarium spp. and Fusarium mycotoxin contamination of small-grained cereals. To prevent severely contaminated grain lots from entering the grain supply chain, it is important to establish surveys for the most prevalent Fusarium spp. and mycotoxins. The objective of our study was to quantify and calculate the associations between Fusarium spp. and mycotoxins prevalent in oats and spring wheat. In a 6-year period from 2004-2009, 178 grain samples of spring wheat and 289 samples of oats were collected from farmers’ fields in South East Norway. The grains were analysed for 18 different Fusarium-mycotoxins by liquid chromatography – mass spectrometry. Generally, the median mycotoxin levels were higher than reported in Norwegian studies covering previous years. The DNA content of Fusarium graminearum, Fusarium culmorum, Fusarium langsethiae, Fusarium poae and Fusarium avenaceum were determined by quantitative PCR. We identified F. graminearum as the main deoxynivalenol (DON) producer in oats and spring wheat, and F. langsethiae as the main HT-2 and T-2-toxins producer in oats. No association was observed between quantity of F. graminearum DNA and quantity of F. langsethiae DNA nor for their respective mycotoxins, in oats. F. avenaceum was one of the most prevalent Fusarium species in both oats and spring wheat. The following ranking of Fusarium species was made based on the DNA concentrations of the Fusarium spp. analysed in this survey (from high to low): F. graminearum = F. langsethiae = F. avenaceum > F. poae > F. culmorum (oats); F. graminearum = F. avenaceum > F. culmorum > F. poae = F. langsethiae (spring wheat). Our results are in agreement with recently published data indicating a shift in the relative prevalence of Fusarium species towards more F. graminearum versus F. culmorum in Norwegian oats and spring wheat.

Due to contamination of barley grains by Fusarium langsethiae, T-2 toxin can be present in the brewing process. It has been observed that the presence of the yeast Geotrichum candidum during malting can reduce the final concentration of this mycotoxin in beer. In this work, a co-culture method was carried out for both microorganisms in order to evaluate the effect on T-2 mycotoxin concentration in comparison with the pure culture of F. langsethiae in the same conditions. The microbial growth of both microorganisms was assessed using three different methods: dry weight, DOPE-FISH, and DNA quantification. In coculture, both microorganisms globally developed less than in pure cultures but G. candidum showed a better growth than F. langsethiae. The concentration of T-2 was reduced by 93 % compared to the pure culture. Hence, the interaction between G. candidum and F. langsethiae led to a drastic mycotoxin reduction despite the only partial inhibition of fungal growth

This study has compared the effect of water activity (aw, 0.995-0.93) and two temperatures (15, 25 °C) on the growth and HT-2 and T-2 toxin production by three strains of Fusarium sporotrichioides and Fusarium langsethiae in an oat-based medium. There were very little intra-strain differences for each of the species in relation to growth at 0.995-0.93 aw and 15 and 25 °C. Inter-species comparisons showed that at 0.995 and 0.98 aw growth was similar at both temperatures. However, under water stress at 0.95 and 0.93 awF. sporotrichioides strains were more tolerant than those of F. langsethiae. Statistical analyses showed that aw and temperature were significant factors for both species, while strain differences were not (P=0.05). In contrast, the patterns of production of T-2 and HT-2 toxins were very different from that for growth. For F. sporotrichioides, a generally higher amount of toxin was produced at 15 than at 25 °C, with a maximum produced at 0.995 aw, while the production decreased with water stress. Interestingly, maximum production of T-2+HT-2 toxin was achieved by F. langsethiae at 0.98 aw and 25 °C, with very little produced at 0.93 aw. Statistically, aw was the most significant (P=0.05) factor for the mean of the three strains of both species with a significant inter-species difference in terms of toxin production. This was confirmed by the changes in the ratio of HT-2:T-2 toxin in relation to the aw × temperature conditions studied. These results are discussed in the context of the effect of environment on the relative importance of these two species in contaminating oats with these toxins.

Fusarium langsethiae is a toxigenic fungus that was formally described as a new species in 2004. This fungus was first detailed in the 1990s but was initially referred to as ‘powdery Fusarium poae’ having a spore morphology similar to F. poae but a mycotoxin profile like that of Fusarium sporotrichioides. The species has been isolated from infected oat, wheat and barley grains but has been reported as more problematic in the former crop rather than the latter two. Whilst the epidemiology of F. langsethiae remains unclear, the fungus has been shown to produce high levels of type-A trichothecenes HT-2 and T-2 toxins in small-grain cereals. HT-2 and T-2 toxins are two of the most potent trichothecenes capable of inhibiting protein synthesis in eukaryotes. In this regard, mycotoxin contamination caused by F. langsethiae is clearly a food and feed safety hazard. With the European Commission considering legislation of HT-2 and T-2 toxins, more information is required not only on the producer and conditions favouring mycotoxin production, but also on reliable methods of pathogen detection and reduction of cereal contamination. This review describes recent research concerning the known epidemiology of F. langsethiae and suggestions of what needs to be known about the fungus in order to be able to understand and employ measures for preventing its infection and contamination of cereals with HT-2 and T-2 toxins.

Fusarium langsethiae has been isolated from infected cereals in central and northern Europe where it has been identified in the last decade as the main species involved in the occurrence of high levels of T-2 and HT-2 toxins, mainly in oats. The efficacy of three fungicides (prochloraz, tebuconazole, fenpropimorph) for controlling growth of two strains of F. langsethiae isolated from oats was examined at 0.96 and 0.98 a(w) at 15, 20 and 25 °C on oat-based media. The concentrations necessary for 50 and 90% growth inhibition (ED₅₀ and ED₉₀ values) were determined. The effect on the trichothecene type A mycotoxins T-2 and HT-2 was also determined. Without fungicides both strains grew faster at 0.98 than at 0.96 a(w) and the influence of temperature on growth rates was 25>20>15 °C. Prochloraz and tebuconazole were more effective than fenpropimorph against F. langsethiae. Strain, temperature and type of fungicide significantly influenced the ED₅₀ and ED₉₀ values for growth. The concentration ranges under different environmental conditions were: prochloraz (0.03-0.1 and 0.3-1.5), tebuconazole (0.06-0.9 and 1.3-8.2), and fenpropimorph (22-59 and 125-215 mg l⁻¹). Production of T-2 and HT-2 toxins was influenced by temperature, a(w), type of fungicide and dose. Levels of T-2 were usually higher than those of HT-2 under the same conditions. The biosynthesis of T-2 toxin increased after 10 day incubation, but was reduced with decreasing temperature and increasing fungicide dose. At 0.98 a(w) T-2 levels increased in cultures containing fenpropimorph while at 0.96 a(w) the toxin concentrations increased in response to the other two fungicides. Low doses of prochloraz or tebuconazole enhanced toxin production when compared with untreated cultures for strain 2004-59 at 0.96 a(w) and 20-25 °C. HT-2 was hardly detectable in the treatments with prochloraz or tebuconazole at 0.98 a(w). This is the first study on the effect of these anti-fungal compounds on control of growth of F. langsethiae and on production of T-2 and HT-2 toxins in oat-based media.

The aim of this study was to determine the environmental conditions over which Fusarium langsethiae species can (a) grow, (b) produce T-2 and HT-2 toxins in oats, and (c) to determine the relationship between dry matter losses (DMLs) and mycotoxin accumulation in stored oats for the first time. Oats were stored under different combinations of water activity (0.89–0.97 aw) and temperature (15–30 °C) and the amount of CO2 produced was measured on a daily basis by gas chromatography (GC). These data were used to quantify the effect of storage on dry matter losses. Results showed that the optimum conditions for colonisation of oats and T-2 and HT-2 toxin production by F. langsethiae were at 0.97 aw and 25 °C. T-2 and HT-2 contamination exceeded 4 mg/kg and 0.75 mg/kg respectively after 10 days storage at these conditions and the calculated DMLs were also higher, exceeding 2%. At intermediate (0.945) and suboptimal (0.89) aw levels for growth of F. langsethiae, DMLs were higher at 30 °C than 25 °C. Models were developed to relate quality losses and toxin production to the different storage conditions. This allows the identification of high and low risk conditions for storage of oats. A good positive correlation was obtained between combined T-2 and HT-2 toxin production and DMLs. This suggests that in situ measurements of CO2 production during storage may be useful in predicting toxin accumulation in stored oats.

Fusarium langsethiae is a recently characterized fungus within the genus Fusarium. It is found as a grain contaminant of small grain cereals such as oats and barley, and to a lesser extent wheat. Fusarium langsethiae is particularly widespread in the Nordic countries and the UK where it poses a serious problem as the main producer of T-2 and HT-2 mycotoxins. The biology of F. langsethiae and its interaction with the plant remains poorly understood, partly hampered by difficulties reproducing a natural level of infection under controlled conditions. The reported study was designed as a series of glasshouse experiments to advance our understanding of F. langsethiae biology by investigating alternative infection routes and its proliferation in oats, Avena sativa. Various methods of seed, soil, and seedling inoculation, boot injection and spray inoculation, were tested. The results clearly show a strong preference of F. langsethiae for the panicle, ruling out alternative infection routes. At relatively low temperatures spray infection, accompanied by prolonged humidity, ensured a thorough establishment of the fungus both at flowering and at early dough stage. Boot injection proved to be a reliable working tool for production of an even and predictable grain infection. Apart from in the panicle, considerable fungal proliferation was only detected in flag leaf nodes, and was a direct consequence of the boot injection method. Fungal presence in the node tissue also correlated with significant stunting of infected shoots. In light of the results the pathogenic and endophytic abilities of F. langsethiae are discussed.

Production of type A trichothecenes has been reported in the closely related species Fusarium langsethiae and F. sporotrichioides. Here, we characterized a collection of Fusarium isolates from Siberia and the Russian Far East (hereafter Asian isolates) that produce high levels of the type A trichothecene T-2 toxin and are similar in morphology to the type A trichothecene-producing F. langsethiae, and to F. poae which often produces the type B trichothecene nivalenol. The Asian isolates possess unique macroscopic and microscopic characters and have a unique TG repeat in the nuclear ribosomal intergenic spacer (IGS rDNA) region. In Asian isolates, the TRI1–TRI16 locus, which determines type A versus type B trichothecene production in other species, is more similar in organization and sequence to the TRI1–TRI16 locus in F. sporotrichioides and F. langsethiae than to that in F. poae. Phylogenetic analysis of the TRI1 and TRI16 gene coding regions indicates that the genes in the Asian isolates are more closely related to those of F. sporotrichioides than F. langsethiae. Phylogenetic analysis of the beta-tubulin, translation elongation factor, RNA polymerase II and phosphate permease gene sequences resolved the Asian isolates into a well-supported sister lineage to F. sporotrichioides, with F. langsethiae forming a sister lineage to F. sporotrichioides and the Asian isolates. The Asian isolates are conspecific with Norwegian isolate IBT 9959 based on morphological and molecular analyses. In addition, the European F. langsethiae isolates from Finland and Russia were resolved into two distinct subgroups based on analyses of translation elongation factor and IGS rDNA sequences. Nucleotide polymorphisms within the IGS rDNA were used to design PCR primers that successfully differentiated the Asian isolates from F. sporotrichioides and F. langsethiae. Based on these data, we formally propose that the Asian isolates together with Norwegian isolate IBT 9959 comprise a novel phylogenetic species, F. sibiricum, while the two subgroups of F. langsethiae only represent intraspecific groups.

Aggressiveness of Fusarium langsethiae isolates towards wheat, barley and oats in an in vitro leaf assay Fusarium langsethiae has been identified as the primary producer of HT-2 and T-2 in European cereals. HT-2 and T-2 are considered as two of the most potent trichothecenes mycotoxins and a public health concern in Europe. There is currently no legislation on HT-2 and T-2, however, there is a discussion limit of 500 μg kg-1 in unprocessed oats, 200 μg kg-1 for oat products and 50 μg kg-1 for infant food. There are limited data regarding F. langsethiae's pathogenicity and mycotoxin production, but it is evident that its behaviour deviates from traditional trichothecene-producing Fusarium species. This experiment was aimed at assessing the aggressiveness (measured by lesion length) of 20 different F. langsethiae isolates on wheat, barley and oats using an in vitro detached leaf assay. There was a significant (Plangsethiae isolates used. Isolate Fl/2004/17(a) caused the shortest lesion on all cereals and this was significantly (PP

In 2010, the populations of Fusarium sp. and Microdochium sp. were monitored in Belgium and 16 strains were identified as Fusarium langsethiae on wheat in Belgium. The other species identified from the sampling were F. poae, F. tritinctum, F. graminearum, F. avenaceum and Microdochium nivale. The pathogenicity potential of the F. langsethiae strains was assessed via an in vitro coleoptile growth rate test on wheat seedlings and compared with strains of F. poae, F. tritinctum, F. graminearum and F. avenaceum known to cause Fusarium head blight. The results showed the ability of F. langsethiae to cause retardation in the wheat coleoptile growth rate, but at a lower rate than F. graminearum, F. avenaceum, F. poae and F. tricinctum. A test for mycotoxin production in vitro showed the ability of the four strains tested to produce T-2 and HT-2 toxins at a rate of up to 290 mg kg−1. This is the first report on the potential pathogenicity of F. langsethiae on wheat in Belgium, a species known to produce T-2 and HT-2 toxins, which are highly toxic for humans and animals.

The toxin producing capacity of seven Fusarium species (F. langsethiae, F. sporotrichioides, F. poae, F. avenaceum, F. tricinctum, F. graminearum and F. culmorum) and the effect of culture conditions on the toxin production were studied. The strains were isolated from Finnish grains and cultivated on a grain mixture at three different water activity/temperature combinations (i.e. 0.994/15 degrees C; 0.994/25 degrees C; 0.960/25 degrees C). The mycotoxins produced were analyzed with a multi-toxin method based on liquid chromatography-tandem mass spectrometry enabling the simultaneous determination of 18 different Fusarium toxins. The general toxin profiles revealed F. langsethiae and F. sporotrichioides as producers of diacetoxyscirpenol, neosolaniol, HT-2 and T-2-toxins. F. sporotrichioides produced additionally beauvericin. In the F. poae cultures, only beauvericin was detected. F. avenaceum and F. tricinctum were capable of producing enniatins, moniliformin and antibiotic Y, and F. graminearum and F. culmorum produced zearalenone, deoxynivalenol and 3-acetyl deoxynivalenol. Differences existed in the quantitative toxin production between the individual strains representing the same species. Additionally, the culture conditions affected the range and amounts of toxins produced. In general, a(w) 0.994 and temperature of 15 degrees C favoured the type-A trichothecene production of F. langsethiae and F. sporotrichioides. The beauvericin production of F. sporotrichioides occurred more favourably at a(w) 0.960 and 25 degrees C. F. poae produced the highest concentrations of beauvericin under two different conditions, namely at a(w) 0.994/15 degrees C and a(w) 0.960/25 degrees C. None of the combinations particularly favoured toxin production of F. avenaceum, with all three toxins being produced extensively at all culture conditions. F. tricinctum produced enniatins most efficiently at a(w) 0.994/25 degrees C. The moniliformin production of both these two species occurred readily at a(w) 0.960/25 degrees C. F. culmorum and F. graminearum produced the highest concentrations and variety of mycotoxins at a(w) 0.960/25 degrees C. The results give valuable information on the toxigenicity of some important Fusarium species. Additionally, this is the first in-depth study to investigate the influence of environmental conditions on the toxin production by F. langsethiae, F. poae, F. avenaceum and F. tricinctum.

This study has examined the effect of water activity (a(w), 0.995-0.90) and temperature (10-37 degrees C) on the lag phases prior to growth, growth rates and used models to develop two dimensional profiles for optimum and marginal conditions for two strains of Fusarium langsethiae from four northern European countries (UK, Norway, Sweden, and Finland) on an oat-based medium. Results showed that the optimum a(w) for growth was at 0.98-0.995 and 25 degrees C. The limit for growth of the strains was at 0.92-0.93 a(w) with minima of 10 degrees C. No growth occurred at 37 degrees C. The lag phases prior to growth were lowest under optimum conditions and extended to10days at marginal conditions. Statistical analyses of intra and inter-strain differences in terms of both lag phases prior to growth and growth rates were not statistically significant. However, a(w) and temperature were statistically significant factors. Two dimensional profiles for strains from each country of origin were built to identify optimum and marginal conditions for F. langsethiae for the first time. These environmental profiles will be beneficial for improving the ecological knowledge of this species which is able to produce trichothecene mycotoxins in a range of temperate cereals.

The quality of harvested wheat grain can deteriorate markedly during the post-harvest management stages. Biotic factors, such as grain type and ripeness, coupled with the prevailing abiotic factors, such as water content and temperature, and also preservative concentration will influence the safe storage life and the level of contamination with mycotoxins. These mycotoxins include deoxynivalenol (DON) produced pre-harvest and zearalenone (ZEA) produced post-harvest by Fusarium graminearum and Fusarium poae, respectively, ochratoxin (OTA) produced by Penicillium verrucosum post-harvest in cool damp northern European climates, and perhaps T-2 and HT-2 toxins produced by Fusarium langsethiae. This review presents recent data on the relationship between dry matter losses caused by F. graminearum under different environmental regimes (water activities, temperatures) and the level of contamination with DON. This is important as poor post-harvest drying and storage management may exacerbate DON contamination already present pre-harvest. It is thus critical to relate the environmental factors in stored wheat grain during storage, especially of intergranular relative humidity (RH) and temperature, to safe storage periods without spoilage or risk from increased DON contamination. The growth/no growth and DON/no DON (F. graminearum) and OTA/no toxin production (P. verrucosum) have been used to build a model with a simple interface to link temperature and RH values to the potential risk level which may allow growth or toxin production. This paper also considers the use of modified atmospheres, preservatives and biocontrol to minimise DON and OTA in moist wheat grain. These approaches together with clear monitoring criteria and hygiene could contribute to better post-harvest management of stored temperate cereals and ensure that mycotoxin contamination is minimised during this key phase in the food/feed chain.

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.

Fusarium and Microdochium species are causal agents of seedling blight of small-grain cereal crops where they may contribute to a significant reduction in crop establishment and final yield. Two experiments were carried out to investigate the potential pathogenicity and aggressiveness of F. langsethiae, a recently identified fungus linked with the contamination of cereals with high levels of the trichothecene mycotoxins, HT-2 and T-2. An artificial seed inoculation method involving conidial suspensions was used and the experiments conducted in a growth cabinet set at either 5 or 15°C with a 12 h photoperiod. Known seedling blight pathogens of the genus Fusarium and Microdochium were used for comparison. At 15oC, F. culmorum, M. nivale and M. majus caused seedling blight of oats and wheat with F. culmorum, on average being the most aggressive than the latter two. At 5oC, only F. culmorum and M. nivale caused seedling blight of oats and wheat. Under the experimental conditions employed, F. langsethiae and F. poae failed to produce seedling blight disease indicating that these two species are not pathogenic to oat and wheat cultivars, Gerald and Claire respectively, at the seedling stage of development. They are therefore unlikely to affect crop establishment and other yield components such as tiller number, grain yield per head as well as grain weight if there is no subsequent foot-rot and/or head blight where infected seeds are sown.

HT-2 and T-2 toxins are two of the most potent trichothecenes; they have a combined (HT-2+T-2) temporary Tolerable Daily Intake (TDI) of 0.06 µg/kg body weight/day. The distribution of HT-2 and T-2 appears to be largely restricted to Europe. Of the cereal species, HT-2 and T-2 usually have higher incidences and concentrations on oats followed by barley and then wheat, however, this can vary between countries. Survey data from Nordic countries have indicated that these mycotoxins have increased in recent years, reaching concentrations of >1000 µg/kg HT-2+T-2 in some samples. HT-2 and T-2 have also been detected in malting barley in France, and in particular in spring sown varieties. A newly identified species, Fusarium langsethiae, has been implicated as a producer of HT-2 and T-2 in European cereals. There is limited data available regarding this species' pathogenicity and mycotoxin production. The impact of agronomy on the concentration of HT-2 and T-2 in cereals has not been clearly identified, but it is evident that it is different to the impact of agronomy on deoxynivalenol. Processing of cereals can have a major impact on the HT-2 and T-2 content of cereals. Oats are de-hulled during processing for human consumption; de-hulling reduces the mycotoxin content of oats by more than 90%. During the malting and brewing of barley the concentration of HT-2 and T-2 increases and decreases within various stages of the processes and the final mycotoxin load of beers will depend on the individual processes used by each maltster and brewer. Whether these mycotoxins are an issue for human health cannot be determined until a full TDI is calculated based on more long-term exposure studies, and human exposure levels are calculated from surveys of retail products using new, highly sensitive assays.