Fusarium crookwellense,a newly isolated fungus from wheat in Japan: Its mycotoxin production and pathogenicity to wheat and barley

Fusarium crookwellense was isolated for the first time in Japan from scabby wheat harvested in Hokkaido in 1991. Four isolates were obtained and examined for their mycological features on culture media, mycotoxin production, and pathogenicity to wheat and barley. The texture of fungal colonies and the morphology of macroconidia on a potato dextrose agar medium were similar to those ofFusarium graminearum. AllF. crookwellense isolates examined produced nivalenol, 4-acetylnivalenol, and zearalenone on rice media at levels ranging from 0.9 to 22.5 µg/g, 0.5 to 25.0 µg/g, and 1.4 to 162.5 µg/g, respectively. All were pathogenic toward the wheat and barley strains tested, and scab symptoms were found on the heads and leaves of plants. This is the first report on domestic isolates ofF. crookwellense from the crop field in Japan.     

Mycotoxin formation by different geographic isolates of Fusarium crookwellense

Eighteen Fusarium crookwellense isolates from the continents of Australia, Europe, and North America were compared for their ability to produce mycotoxins on corn at 25 °C after 2 weeks. Extracts from corn fermented with each Fusarium isolate were analyzed by thin-layer chromatography (TLC) and gas chromatography/mass spectroscopy (GS/MS) for mycotoxins. Toxins detected were zearalenone (13 isolates), fusarin C (11 isolates), nivalenol (4 isolates), and diacetoxyscirpenol (2 isolates). Zearalenone and fusarin C were produced by isolates from each continent, while nivalenol was detected in the Fusarium isolates originating from Australia and one isolate from the United States.The mention of firm names or trade products does not imply that they are endorsed or recommended by the U.S. Department of Agriculture over other firms or similar products not mentioned     

Effect of incubation temperature on zearalenone production by strains of Fusarium crookwellense.

After 6 weeks incubation on rice 2 strains of Fusarium crookwellense produced more zearalenone (6060-5010 mg/kg dry wt of culture) at ambient temperature (16-29 degrees C) in daylight than at ambient temperature (18-23 degrees C) in darkness or at controlled temperatures of 11 degrees C, 20 degrees C or 25 degrees C in darkness. Yields at 25 degrees C were low. Incubation at 11 degrees C during the second 3 weeks incubation increased yields only when preliminary incubation had been at 25 degrees C. After 6 weeks incubation at controlled temperatures in darkness, 4 strains produced most zearalenone at 20 degrees C (2460-21 360 mg/kg), 1 strain at 11 degrees C (6570 mg/kg). Yields at a temperature oscillating daily from 10-20 degrees C were less than at 15 degrees C. One of the 5 strains produced appreciable amounts of a-zearlaenol (1645 mg/kg at 20 degrees C) and 2 of nivalenol (340 and 499 mg/kg at 20 degrees C).     

Patterns of mycotoxin production by Fusarium gmminearum isolated from Argentine wheat

Fusarium graminearum was isolated from several wheat samples of the 1985/86 Argentine crop, taken from lots that had suffered extensive invasion by this fungus. Previous chemical analysis of the cereal, had revealed contamination with deoxynivalenol (DON), but the presence of the other mycotoxins could not be excluded with certainty, due to the low sensitivity of the analytical methodology employed.Twenty four F. graminearum isolates were grown on white corn with 50% water, for 21 days at 28 °C, or in liquid medium (Sucrose 3%, Peptone 0,1% and Yeast Extract 0,1%) for 7 days at 28 °C without shaking, and tested for the production of mycotoxins. Eight isolates (33% of the total) were found to produce toxins in one or both media. Toxins detected were: DON (6 isolates), 15-AcetylDON (5), 3-AcetylDON (2) and Zearalenone (3). No traces of Nivalenol, Fusarenon-X or other trichothecenes were found.These results suggest that strains of F. graminearum, prevailing in Argentine wheat-growing regions, might belong to the DON/AcetylDON chemotype, since no organisms of the Nivalenol/Fusarenon-X chemotype were detected in this study.     

A case of sporotrichosis caused by two genetically differentSporothrix schenckii strains

A survey for the natural occurrence of Fusarium mycotoxins, deoxynivalenol (DON), nivalenol (NIV) and zearalenone (ZEN), in Dutch cereals (totaling 29 samples) harvested in 1984/1985, showed that 90%, 79% and 62% of samples were contaminated with DON, NIV and ZEN, respectively. Average contents (ng/g) in the total of positive samples were 221 (DON), 123 (NIV) and 61 (ZEN). Among the cereals examined, the highest concentrations (ng/g) was 3198 (DON), 1875 (NIV) and 677 (ZEN) in a yellow corn sample for animal feed. The results of this survey show that Dutch cereals were relatively significantly contaminated with Fusarium mycotoxins.     

Variation in 8-ketotrichothecenes and zearalenone production by Fusarium graminearum isolates from corn and barley in Korea

A total of 214 Fusarium graminearum isolates were obtained from corn and barley which were collected from Kangwon province and the southern part of Korea, respectively, and were tested for 8-ketotrichothecenes and zearalenone (ZEA) production on rice grains. The incidences of trichothecene production by 105 isolates of F. graminearum from corn were 59.0% for deoxynivalenol (DON), 37.1% for 15-acetyldeoxynivalenol(15-ADON), 13.3% for 3-acetyldeoxynivalenol (3-ADON), 7.6% for 3,15-diacetyldeoxynivalenol (3,15-DADON), 20.0% for nivalenol (NIV), 6.7% for 4-acetylnivalenol (4-ANIV), and 1.0% for 4,15-diacetylnivalenol (4,15-DANIV). DON chemotypes frequently produced 15-ADON as the major isomer rather than 3-ADON and 9 of the 61 DON chemotypes produced low levels of NIV. On the other hand, the incidences of trichothecene production of 109 isolates by F. graminearum from barley were 24.8% for DON, 72.5% for NIV, 62.4% for 4-ANIV, and 10.1% for 4,15-DANIV. Of these isolates, 78 were NIV chemotypes and only one isolate produced DON and 3-ADON as major toxins. In addition, 26 of the 78 NIV chemotypes produced low levels of DON. ZEA was frequently produced by the trichothecene-producing isolates and the incidences of ZEA were 51.4% and 31.2% for the isolates from corn and barley, respectively. There was a great regional difference in trichothecene production by F. graminearum isolates between corn- and barley-producing areas in Korea.     

Influence of the interactions among ecological variables in the characterization of zearalenone producing isolates of Fusarium spp

To carry out the physiological characterization of Fusarium graminearum and F. culmorum isolates with regard to its zearalenone producing ability, an in-depth experiment with a full factorial design was conducted. The effects and mutual interactions of temperature, moisture, substrate and isolate on the production of the toxin were studied. The study was done with twelve isolates of Fusarium (7 of F. graminearum and 5 of F. culmorum). The analysis of variance shows that there is a complex interaction of all of these factors, which can influence the relative concentrations of the mycotoxin produced, and hence, the correct physiological characterization of the strain. All the tested cultures were susceptible to invasion by Fusarium. The moisture content of grains (water activity values 0.960, 0.970 and 0.980) did not constitute a limiting factor for fungal growth or ZEA production, but incubation temperature (15 degrees C, 20 degrees C, 28 degrees C, and 32 degrees C) affected the rate of zearalenone synthesis. Very low or undetectable ZEA production was observed at 32 degrees C. All tested isolates showed a characteristic behavior concerning the optimum temperature for ZEA production, which was usually 20 degrees C maintained during the whole incubation period. This finding, which does not agree with other reports obtained with strains from different origins, suggests that there are genetic differences that would explain the particular physiological behavior of each isolate related to the optimal production conditions for ZEA. The existence of significant differences regarding the susceptibility of the assayed cereal grains (wheat, corn and rice) used for ZEA production by the different Fusarium species (F. graminearum and F. culmorum) is described for the first time in this paper.     

Mycotoxin production by Fusarium species isolated from New Zealand maize fields

Forty Fusarium isolates obtained from maize fields were screened for moniliformin production on maize kernels. Twelve isolates, including seven of F. subglutinans, were found to produce moniliformin at levels ranging from 0.4 to 64 ppm. Twenty six isolates were also screened for production of deoxynivalenol, diacetoxyscirpenol, T-2 toxin and zearalenone. Of these, 22, including all 11 isolates of F. graminearum, produced zearalenone at levels ranging from 0.1 to 96.0 ppm, while 13 produced T-2 toxin at low levels, (<1.1 ppm). Deoxynivalenol and diacetoxyscirpenol were each produced by six isolates, also at low levels (<1.0 ppm). Three isolates of F. graminearum and one of F. sambucinum produced four toxins simultaneously.     

Fumonisins production by Fusarium proliferatum strains isolated from asparagus crown

The present work deals with the capability for producing fumonisin by Fusarium proliferatum strains isolated from asparagus in China. Fifty of F. proliferatum strains were randomly selected and incubated on cultures of maize grain and asparagus spear, respectively. Fumonisin levels (FB₁ and FB₂) were determined by high-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The results showed that all 50 strains produced fumonisins in maize culture within a wide range of concentrations, 10–11,499 μg/g and 2–6,598 μg/g for FB₁ and FB₂, respectively. On culture of asparagus spear,48 strains (96%) produced fumonisins in the range 0.2–781.6 μg/g and no detected to 40.3 μg/g for FB₁ and FB₂, respectively. All of F. proliferatum strains produced much higher levels of FB₁, FB₂ and total fumonisins (FB₁ + FB₂) in maize grain culture than in asparagus spear culture. Meanwhile, fumonisin B₃ (FB₃) was identified in all maize culture extracts and most of asparagus spear culture extracts. This is the first study carried out the fumonisin-producing ability of F. proliferatum strains isolated from asparagus in China. The information obtained is useful for assessing the risk of fumonisins contamination in asparagus spear. Electronic supplementary material The online version of this article (doi: ) contains supplementary material, which is available to authorized users.     

Impact of essential oils on growth rate, zearalenone and deoxynivalenol production by Fusarium graminearum under different temperature and water activity conditions in maize grain

AIMS: The effect of five essential oils (oregano, cinnamon, lemongrass, clove and palmarose) on growth rate, zearalenone (ZEA) and deoxynivalenol (DON) production by Fusarium graminearum strains was assessed. METHODS AND RESULTS: The influence of the essential oils was tested on irradiated maize at two concentrations (500 and 1000 mg kg-1), at different water activity (aw) (0.95 and 0.995) and temperature (20 and 30 degrees C) levels. At 0.995 aw all essential oils tested had an inhibitory effect on growth rate of F. graminearum at both temperatures studied. At this aw level, DON production in general was inhibited by all essential oils at 30 degrees C and, although palmarose and clove were the only essential oils with statistically significant inhibitory effect on ZEA production, an inhibitory trend was observed when cinnamon and oregano oils were added to maize grain. CONCLUSIONS: Antifungal and antimycotoxigenic activity of the essential oils assayed was shown to depend on environmental conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: It is apparent that essential oils should be considered as alternative preharvest natural fungicides. Further investigation on natural maize grain might be useful to study the effectiveness of these essential oils in the presence of natural mycoflora of maize grain.     

Two-dimensional environmental profiles of growth,deoxynivalenol and nivalenol production by Fusarium culmorum on a wheat-based substrate

AIMS: To determine the effect of interacting conditions of water activity (aw, 0.99-0.85), temperature (15, 25 degrees C) and time (40 days) on growth and production of the mycotoxins deoxynivalenol (DON) and nivalenol (NIV) by Fusarium culmorum on a wheat-based agar medium. METHODS AND RESULTS: Fusarium culmorum grew optimally at 0.995aw and minimally at 0.90 at both 15 and 25 degrees C. No growth was observed at <0.90aw. Overall, temperature, aw and their interaction had a statistically significant effect on the growth rate of F. culmorum. Production of both DON and NIV were over a much narrower range (0.995-0.95aw) than that for growth. The highest concentrations of DON and NIV levels were produced at 0.995aw and 0.981aw at 25 degrees C, respectively, after 40 days of incubation. Statistically, aw, temperature and incubation time, and aw x temperature and temperature x incubation time had a statistically significant effect on DON/NIV production. CONCLUSIONS: This is the first detailed report on the two-dimensional environmental profiles for DON/NIV production by F. culmorum in the UK. SIGNIFICANCE AND IMPACT OF THE STUDY: As part of a hazard analysis critical control point (HACCP) approach, this type of information is critical in monitoring critical control points for prevention of DON/NIV entering the wheat production chain.     

温度对茄病镰刀菌生长情况及产孢量的影响

目的 探讨不同孵育温度对茄病镰刀菌生长状态的影响,为获得大量饱子寻找较好方案.方法 茄病镰刀菌按孵育温度不同分为6组,A组、B组、C组、D组、E组分别于20℃,25℃,30℃,35℃,37℃温箱黑暗孵育7d,F组于35℃温箱黑暗孵育3d再于25℃温箱黑暗孵育至7d,各组在培养24h,3d,5d,7d时分别用游标卡尺测量...     

Characterization of gibberellin producing strains of Fusarium moniliforme based on DNA polymorphism

The gibberellins are one of the major groups of growth promoting hormones and are secondary metabolites of the fungus Fusarium moniliforme (Perfect stage: Gibberella fujikuroi). Sixteen strains of Fusarium from different geographical regions and different hosts were analysed for their ability to produce gibberellins (GA) and for genetic relatedness by random amplified polymorphic DNA (RAPD). Range of gibberellin production varied between 28.9 to 600.0 mg g^-1 dry weight of mycelium in different strains of Fusarium. RAPD analysis showed completely different pattern between high, moderate and low producing strains. High producers formed nearly identical RAPD patterns, whereas the low and moderate producers gave heterologous amplification patterns. Since Fusarium pallidoroseum was in another group, it was possible to distinguish between different species of the genus Fusarium by RAPD. These investigations may find an application in the diagnosis of unknown Fusarium species and in distinguishing isolates of Gibberella fujikuroi within the section of Liseola. This revised version was published online in June 2006 with corrections to the Cover Date.     

Aflatoxin B1, zearalenone and deoxynivalenol production by Aspergillus parasiticus and Fusarium graminearum in interactive cultures on irradiated corn kernels

The influence of inoculum size in the production of aflatoxin B1 (AFB1), zearalenone (ZEN) and deoxynivalenol (DON) was determined when Aspergillus parasiticus NRRL 3000 and Fusarium graminearum ITEM 124 were cultured alone and in pairs on irradiated corn kernels at 28 °C and 0.97 water activity (aw). The highest levels of AFB1 produced by A. parasiticus were produced at the lowest levels of the inoculum (103 spores/ml). No significant differences were observed in ZEN and DON production at any inoculum level during the experimental period. When A. parasiticus was co-inoculated with F. graminearum both to the same inocula (106 spores/ml), AFB1 inhibition percentage were 60, 72 and 56% at 10, 20 and 35 days of incubation respectively, while at 106 spores/ml the percentages of inhibition were 34, 84 and 93% at 10, 20 and 35 days. In the mixture cultures A. parasiticus 103 × F. graminearum 106 spores/ml the percentage of inhibition of AFB1 oscillated in 99% during all the incubation. In the interaction A. parasiticus 106 spores/ml × F. graminearum 103 spores/ml the accumulation of AFB1 decreased in 80, 94 and 86% at 10, 20 and 35 days of incubation respectively. In single culture F. graminearum was inoculated with 10³ or 106 spores/ml and the highest levels of ZEN and DON were detected at 35 days of incubation. The levels oscillated in 538–622 μg/kg for ZEN and 870–834 μg/kg for DON respectively. In paired cultures there were no significant differences in the levels regardless of the spore concentrations during the incubation time. This revised version was published online in June 2006 with corrections to the Cover Date.     

First survey on the natural occurrence of Fusarium mycotoxins in Bulgarian wheat

Wheat for human consumption (140 samples) was collected after harvest from all regions of Bulgaria. The 1995 crop year was characterized by heavy rainfall in the spring and summer months. The internal mycoflora of wheat samples was dominated by Fusarium spp. and Alternaria spp., and storage fungi were rarely present. The samples were analysed for contamination with Fusarium mycotoxins deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-AcDON), 15-acetyldeoxynivalenol (15-AcDON), T-2 Toxin (T-2), diacetoxyscirpenol (DAS), and zearalenone (ZEA), using enzyme immunoassay methods. DON and ZEA were the predominant toxins, with a contamination frequency of 67% and 69%, respectively. The average levels of these toxins in positive samples were 180 g/kg (DON) and 17 g/kg (ZEA), maximum concentrations were 1800 g kg^–1 and 120 g kg^–1, respectively. Acetyl derivatives of DON, namely 3-AcDON and 15-AcDON, were found in 2.1 % and 0.7% of the samples, at at maximum level of about 100 g kg^–1. Only one sample was positive for T-2 (55 g/kg), DAS was not detected. This is the first report about the natural occurrence of a range of Fusarium mycotoxins in wheat for human consumption in Bulgaria.Abbreviations 3-AcDON 3-acetyldeoxynivalenol - 15-AcDON 15-acetyldeoxynivalenol - DAS diacetoxyscirpenol - DON deoxynivalenol - EIA enzyme immunoassay - T-2 T-2 toxin - ZEA zearalenone     

Effect of temperature shock and elevated incubation temperature on androgenic embryo yield of diploid potato

Using three diploid tuber-bearing Solanum clones as anther donors, experiments were conducted on the effect of high temperature shock and elevated incubation temperature during anther culture on androgenic embryo production. Five incubation treatments were tested on two clones and three treatments were repeated in a second experiment on one of the same clones and an additional one. In the first experiment, temperature treatment, genotype, date of culture initiation, and their interactions were all significant sources of variation. A treatment combining a high temperature shock (35 °C for 12 h) with elevated incubation temperature (30/20 °C) yielded 11 times as many embryos (44 per flask) as the control 20 °C (4 per flask). By conducting several replications per day of bud collection, the significant variation due to experimental dates was separated from experimental error to provide a more sensitive test of treatment effects. Temperature shock (35 °C 12h) during anther culture did not appear to influence the subsequent conversion rate of androgenic embryos.     

Trichothecene production by Fusarium species isolated from grain and pasture throughout New Zealand

Liquid cultures of 200 Fusarium isolates selected to represent the most common species found in autumn pasture (70 isolates) and in grain (130 isolates) grown in New Zealand were analysed for trichothecenes and related compounds. Production of butenolide, cyclonerodiol derivatives and culmorins was also measured. The principal trichothecenes produced were derivatives of either nivalenol (NIV), deoxynivalenol (DON) or scirpentriol (Sctol), in order of frequency. The principal trichothecene producing species were F. crookwellense, F. culmorum and F. graminearum. Isolates of the first two species were predominantly NIV-chemotypes with one or two isolates respectively as Sctol-chemotypes. F. graminearum showed equal quantities of NIV- and DON-chemotypes, with the DON-chemotypes producing primarily 15-acetyldeoxynivalenol (15-ADON).     

Effect of temperature on bacterial gellan production

The effect of temperature on the production of the polysaccharide gellan by the bacterium Sphingomonas paucimobilis ATCC 31461 was studied in relation to carbon source. When glucose served as the carbon source, gellan formation by the strain was highest after 72 h of growth at an incubation temperature of 30–31 °C. Polysaccharide production by the sphingomonad cells grown on corn syrup for 72 h was maximal at an incubation temperature of 31 °C. The highest cellular productivity in elaborating gellan was observed at 31 °C after 72 h of growth independent of the carbon source utilized.     

Factors affecting gibberellic acid production by Fusarium moniliforme in solid-state cultivation on starch

The production of gibberellic acid (GA₃) by Fusarium moniliforme M-7121 in solid-state culture was evaluated in flask cultures as well as in 3-I horizontal rotary reactors. The highest production rate of GA₃ was with 80% (w/v) maize flour mixed with wheat bran. The optimum initial moisture content was inversely dependent on the ambient relative humidity. The initial water activity range for optimal growth and GA₃ accumulation was about 0.98 to 0.99, which is unusually high for a filamentous fungus. A low O₂ concentration resulted in a much decreased GA₃ yield and the appearance of a yellow to reddish pigmentation in the mycelium. The lag phase was short and rapid growth continued for up to 2 days in the rotary reactor, with a maximum specific growth rate of 0.12 h^–1. The maximum rate of GA₃ production occurred during the subsequent 3 to 10 days of incubation and the final GA₃ concentration reached was 18.7 mg to 19.3 mg/g dry culture. The point of maximum GA₃ accumulation after 10 to 12 days of incubation was usually marked by a sharp increase in pH.The authors are with the Department of Microbiology and Biochemistry, University of the Orange Free State, P.O. Box 339, 9300 Bioemfontein, Republic of South Africa     

Comparison of in vitro cytotoxicity of Fusarium mycotoxins,deoxynivalenol, T-2 toxin and zearalenone on selected human epithelial cell lines

Three human epithelial cell lines (CaCo-2, HEp-2 and HeLa) implicated as potential targets for three Fusarium toxins were tested for the extent of survival on exposure to increasing toxin concentration and incubation periods. Cytotoxicity assay using 3(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide (MTT) was carried out with deoxynivalenol (DON), T-2 toxins and zearalenone (ZON) on CaCo-2, HEp-2 and HeLa cell lines. Of the three cell lines used, HeLa was the most sensitive, eliciting cell death after 2 days exposure at 100 ng ml^–1with T-2 toxin. HeLa was the only cell line to exhibit cytotoxicity towards ZON showing cell death at 1000 ng ml^–1after 2 days which increased to 4 days, showing substantial cell death at 200 ng ml^–1. HEp-2 was sensitive to DON showing cell death after 2 days (100 ng ml^–1) with complete cell death occurring at 200 ng ml^–1 after 4 days of exposure. Substantial cytoxicity of T-2 towards HEp-2 occurred after 2 days at 1000 ng ml^–1 and complete cell death occurred with 100 ng ml^–1 at day 4. The CaCo-2 cell line was generally resistant to the mycotoxins tested between 100 and 1000 ng ml^–1. This study shows that cytotoxicity of Fusarium toxins to epithelium cell lines is concentration- and time- dependant and results from ZON–HeLa interaction indicate possible cell type-mycotoxin specificity.