Reaction of winter wheat (Triticum aestivum L.) cultivars to infection with Fusarium spp.: mycotoxin contamination in grain and chaff.

This study compares the susceptibility of winter wheat (Triticum aestivum L.) cultivars to Fusarium head blight (FHB) and accumulation of mycotoxins in kernels and chaff under different climatic conditions in two locations-Cerekwica near Poznan (Central West Poland) and Sitaniec, near Zamosc, Lublin region (South East Poland). Very high variations were found in the concentrations of mycotoxins (zearalenone, ZEA; nivalenol, NIV; deoxynivalenol, DON; moniliformin, MON) in examined fractions: Fusarium-damaged kernels (FDK) and healthy looking kernels (HLK) and in chaff for individual cultivars in both locations. In most cases, significantly higher concentrations of investigated toxins were recorded in wheat from the area of Lublin than from Poznan (p < 0.05). The highest Fusarium infection rates and mycotoxin biosynthesis levels were observed in the Lublin location, with the percentage of the FDK fraction ranging 8.1-81.6. In this region, ZEA concentration (microg g(-1)) after inoculation with F. culmorum and F. graminearum ranged from 0.02-0.48 and 0.32-1.04, respectively. In the Poznan area, the toxin concentrations were considerably lower, ranging 0.01-0.10 and 0.03-0.13 microg g(-1) for both isolates, respectively. The concentration of DON was significantly higher than ZEA or NIV levels. The levels of MON accumulation (microg g(-1)) in the FDK fraction were between 0.14 and 1.73 (Poznan area) and ND (not detected) to 2.51 (Lublin area). F. avenaceum infection rate ranged 7-35% in samples where the toxin was detected.

Natural occurrence of scirpentriol in cereals infected by Fusarium species.

Wheat, barley and oat grain samples naturally contaminated with Fusarium spp. were analysed for the presence of scirpentriol (STO). This toxin was detected in 1, 37 and 8% of 248 wheat, 32 barley and 99 oat grain samples, respectively, and the maximum concentration was 83 microg x kg(-1). Samples of wheat and oat grain with visible scab symptoms were also analysed, and STO (mean level 255 microg x kg(-1)) was detected only in oat samples infected with F. sporotrichioides and F. poae as the dominant species. We analysed 15 barley samples that were subdivided based on seed size into fractions of <2.5 and > 2.5 mm in diameter. The smaller kernels contained an average 94% of the STO in the samples (in kernel fraction > 2.5 mm 28 microg x kg(-1), <2.5 mm 297 microg x kg(-1)). In oats, STO levels were highest in the chaff, lower in the stalk's apical internode and lowest in the grain.

Moniliformin accumulation in kernels of oats used for food and feed purposes.

Inoculation experiments with 12 genotypes of oats (9 lines: CHD 894, CHD 1095, CHD 1296, CHD 1607, CHD 1653, CHD 1692, STH 2293, STH 2393, STH 2494, STH 2694 and 2 cultivars: Farys, Slawko) were performed during the vegetation seasons of 1999 - 2000 in Zamosc region in the South - Eastern part of Poland.Panicles of oats were inoculated with a conidial suspension ofFusarium avenaceum, which caused the following average reductions of traits: yield by 37.8 % and weight of 1000 kernels by 40.2 % respectively.The highest susceptibility to scab development caused by theF. avenaceum inoculation was found particularly for two lines (CHD 894, and CHD 1296) while cultivar Farys and line CHD 1607 exhibited the highest resistance to the disease in terms of TKW and yield reductions after inoculation. During 2 consecutive years (1999 and 2000 respectively) the average level of moniliformin accumulation (mg/kg) in positive samples was respectively 0.51 and 0.12 the highest being 1.11 and 0.26, while the lowest was 0.30 and 0.01.

Levels of fungi and mycotoxins in samples of grain and grain dust collected on farms in Eastern Poland.

Ten samples of stored wheat grain and 10 samples of settled grain dust released during machine threshing of wheat grain were collected on 10 farms located in Lublin province (eastern Poland). The samples were examined for the concentration of total microfungi, Fusarium species, fusariotoxins (moniliformin, deoxynivalenol, nivalenol), and ochratoxin. Microfungi able to grow on malt agar were present in 30% of grain samples (median for all examined samples = 0, range 0-227.5 x 10(3) cfu/g) and in all samples of grain dust (median = 977.5 x 10(3) cfu/g, range 115.0-16,700.0 x 10(3) cfu/g). Fusarium species (F. avenaceum) were found only in 10% of grain samples (median = 0, range 0-800.0 x 10(3) cfu/g), but in 90% of grain dust samples (median = 1,150 x 10(3) cfu/g, range 5.5-10,060.0 x 10(3) cfu/g). The species F. avenaceum, F. culmorum, F. graminearum, F. poae and F. sporotrichioides were isolated respectively from 50%, 10%, 20%, 40% and 20% of examined grain dust samples. The presence of the mycotoxins produced by Fusarium (moniliformin, deoxynivalenol, and nivalenol) was found altogether in 70% of wheat grain samples (median = 0.1275 microg/g, range 0-1.480 microg/g) and in 90% of grain dust samples (median = 0.350 microg/g, range 0-1.090 microg/g). Moniliformin (MON), deoxynivalenol (DON), and nivalenol (NIV) were each detected in 40% of grain samples, and respectively in 80%, 40%, and 40% of grain dust samples. Ochratoxin A (OTA) was detected in 60% of grain samples and in 60% of grain dust samples (median in both cases was 0.0005 microg/g). The concentrations of F. poae (p<0.05) and of total Fusarium species (p<0.01) in grain samples, and the concentrations of F. culmorum and F. graminearum (p<0.05) in grain dust samples were significantly correlated with the concentration of deoxynivalenol. The concentrations of F. poae (p<0.05) and of total Fusarium species (p<0.01) in grain dust samples were significantly correlated with the concentration of total fusariotoxins. Moreover, the concentration of total Fusarium species in grain dust samples was significantly correlated with the concentration of nivalenol (p<0.05). In conclusion, the majority of samples of wheat grain and grain threshing dust collected on farms in eastern Poland contained notable quantities of fusaria and/or fusariotoxins. This fact poses a potential risk of mycotoxicoses to agricultural workers exposed to grain dust when handling wheat during threshing, unloading, shuffling, and other farm occupations.

Fusariotoxins in kernels of winter wheat cultivars field samples collected during 1993 in Poland.

In South-Eastern region of Poland (near Lublin), where frequency of scab (fusariosis) is much higher than in other parts of the country, during harvest of 1993 kernels of 25 winter wheat cultivars were collected. On the basis of morphological studies Fusarium graminearum was found in 42% of investigated samples while other fungi appeared less frequently: F. nivale and F. poae (35%), F. avenaceum (31%) and F. culmorum (12%). Chemical analysis (by HPLC) revealed that the tested cultivars were contaminated with deoxynivalenol (96% of investigated samples), its acetyl derivatives (48%), nivalenol (76%) and moniliformin (28%). The average levels of the metabolite concentrations were as follows: 104; 16; 97; and 63 micrograms/kg, respectively. Co-occurrence of 2 toxic metabolites was found in the following percentage of the positive samples: deoxynivalenol and nivalenol (72%), deoxynivalenol and moniliformin, as well as nivalenol and moniliformin (24%). Usually (71-83% of contaminated samples) mycotoxins were accumulated in the concentration range > or = 10, < 100 micrograms/kg.

Natural contamination of spring barley with group A trichothecene mycotoxins in south-eastern Poland.

Strains (10705) of microscopic fungi were isolated from spring barley heads in the region of Lublin (south-eastern Poland). Fusarium sporotrichioides Sherb was found in 418 (3.9%) of isolated strains. Group A trichothecene mycotoxins were detected in the collected barley kernels colonized by F. sporotrichioides, with Fusarium head blight symptoms. Among 24 samples analysed, 12 were T-2 toxin positive in a range of contamination from 0.02 to 2.40 micrograms/g (average 0.45), while in five samples HT-2 toxin ranged from 0.01 to 0.37 micrograms/g (average 0.23) and T-2 tetraol was detected in two samples in a range of 0.01-0.21 micrograms/g (average 0.11). Twelve samples were free of detectable amounts of the toxic metabolites analysed.

Toxicity, of extracts of barley kernels inoculated withFusarium spp. toArtemia salina.

Toxicity toA. salina, of the Fusarium metabolites: deoxynivalenol (DON), its acetylated derivatives (3- and 15-AcDON), zearalenone (ZON), neosolaniol (NEO), nivalenol (NIV), T-2, HT-2 toxins, has been examined and compared with toxicity of extracts of barley kernels (8 cultivars and 4 lines) inoculated withFusarium culmorum, F. graminearum andF. sporotrichioides respectively. Estimated LC50 values were expressed as relative toxicity (RT) in mg DON/kg for samples inoculated withF. culmorum, F. graminearum or in mg T-2/kg forF. sporotrichioides inoculations.Toxicity of extracts of the same genotype/line kernels was compared among different pathogens used for inoculation and differences in Fusarium head blight susceptibility of different genotypes/lines inoculated with the sameFusarium strain were found. Significant correlation between toxicity of extracts (LC50, RT) and toxic metabolites concentration was found ([Formula: see text]; P = 0.01).Bioassays withA. Salina offer a fast, easy and inexpensive method to examine cereal genotypes susceptibility to Fusarium head blight and mycotoxins accumulation in kernels.

Fusariosis of spring barley cultivated in Lublin region.

Diseases of spring barley in 1986-1988 seasons have been examined on barley plantations in Lublin region. Observations in eight weeks after sowing each year spring showed the occurrence of root rot and sheath rot in seedlings. As a result of mycological examination of infected seedlings 34 species of fungi were isolated:Fusarium spp. amounted up to 23% of all isolates. Each year,Fusarium culmorum andF.avenaceum were isolated, butF graminearum only in 1987. On all inspected fields there occurred plants with eye - spots or necrotic stripes on lower internodes. As a result of fungi isolation the colonies belonging to 30 species were identified from stems and roots of examined plants. There was about 35% of fusaria between isolates each year.Fusarium culmorum was most frequently isolated. This fungus both from stems with two mentioned kinds of symptoms and from roots was isolated.Fusarium avenaceum each year andFusarium graminearum in 1986 and 1988 were isolated. Mentioned there species were also isolated from kernels.

Trichothecene mycotoxins in kernels and head fusariosis susceptibility in winter triticale.

A single isolates ofFusarium graminearum Schwabe KF 366 andFusarium culmorum (W.G.Sm.) Sacc. KF 365 were used to infect 10 genotypes (9 lines and one cultivar) of winter triticale, 1 rye cultivar and 1 wheat cultivar, and amounts of mycotoxins in kernels were analysed at the same stage of development. One genotype of triticale CHD 353/79 and rye "Chodan" were found to be most resistant towards both species infection with lowest amount of mycotoxins (deoxynivalenol) content in kernels and also the lowest yield reduction. The most susceptible line CZR 142 cumulated in kernels about ten times higher amount of mycotoxins (up 53 mg DON/kg and 16 mg 3AcDON/kg, and 5 mg zearalenone/kg). GenerallyF, culmorum formed higher level of mycotoxins in kernels of infected heads thanF. graminearum. In kernels of more susceptible genotypes except deoxynivalenol, 3 acetyldeoxynivalenol and zearalenone also were present.