Moniliformin Accumulation in Kernels of Triticale Accessions Inoculated with Fusarium avenaceum, in Poland

Twelve Polish winter triticale cultivars and 14 doubled haploid lines (DH) (derived from the cv. Lasko × line SZD 366 hybrids) were inoculated with Fusarium avenaceum isolate ATCC 64451, mycotoxin moniliformin (MON) producer to evaluate their susceptibility to Fusarium head blight (FHB). Chemical analysis revealed MON accumulation in kernels of all inoculated cultivars in three consecutive years with the following averages and ranges: 1.50 mg/kg (0.47–2.67 mg/kg) in 1996, 2.63 mg/kg (0.11–8.14 mg/kg) in 1997 and 0.25 mg/kg (0.07–0.47 mg/kg) in 1998. Cultivar Malno kernels accumulated a low level of MON in all 3 years of the experiment. In most of the genotypes examined the reaction to the pathogen and MON content changed significantly from season to season. DH lines accumulated on average 2.62 and 0.85 mg/kg of MON in 1997 and 1998, respectively. Yield parameter reductions (1000 kernel weight, kernel number per head and kernel weight per head) were higher in 1997 than in 1998. The correlation coefficient for MON content/ Fusarium damaged kernels percentage was 0.539 in cultivars and 0.548 in the DH lines. This is the first report of FHB of a segregating population in triticale.     

Cytopathological Responses of Picea abies Seedling Roots Challenged in vitro by a Necrotrophic Fusarium avenaceum (Fr.) Sacc.

Interaction of the necrotroph Fusarium avenaceum with seedling roots of Norway spruce was studied. The results showed that Norway spruce seedlings were susceptible to the pathogen but disease progression and severity was dependent on inoculum potential. Host recognition of the pathogen marked by hypersensitive browning reactions occurred late, thus making successful resistance to cellular damage impossible. Such host resistance responses were mostly in the form of lignification, accumulation of electron dense materials and papillae formation.     

Fusarium Head Blight of Common Polish Winter Wheat Cultivars – Comparison of Effects of Fusarium avenaceum and Fusarium culmorum on Yield Components

The effects of Fusarium avenaceum and Fusarium culmorum on the reduction in yield components, after independent inoculation of 14 winter wheat cultivars, were investigated. Single isolates of F. avenaceum and F. culmorum were independently used in inoculations of winter wheat heads. Reductions in the following yield traits: 1000‐kernel weight (TKW), the weight (WKH) and number (NKH) of kernels per head after inoculation were analysed statistically. The results indicate differences between both pathogens in their effects on yield traits. The statistical calculations were performed using analysis of variance (a three‐factor experiment) for particular yield trait reductions and multivariate analysis of variance for the yield trait reductions jointly. Almost all of the univariate and multivariate hypotheses concerning no differences between pathogens (F. culmorum, F. avenaceum), climatic conditions (years) and cultivars as well as hypotheses concerning no interactions between factors (pathogens, years, cultivars) were rejected at least at P= 0.05 significance level. The reduction of yield traits indicated individual reactions of the tested winter wheat cultivars to different pathogens. Among the tested traits the highest influence on the rejection of the hypothesis concerning the equivalence of F. avenaceum and F. culmorum was observed for TKW and WKH. The effect of the pathogen on yield reduction was greater for F. avenaceum than for F. culmorum during 1996 and 1997. A comparison of the cultivars indicated that the Begra cultivar showed the highest tolerance to inoculation with both Fusarium pathogens. Moreover, this genotype as well as several others showed lower tolerance to F. avenaceum rather than to F. culmorum, whereas Elena was the only cultivar with the opposite tendency.     

Evaluation of Spring and Winter Wheat Reaction to Fusarium culmorum and Fusarium avenaceum

Winter (37), spring (8) wheat accessions and additionally, 7 double haploid (DH) lines were examined for susceptibility to Fusarium seedling blight after inoculation with F. culmorum and F. avenaceum. Winter accessions exhibited lower susceptibility of about 30% to both pathogens than spring cultivars. Susceptibility of winter cultivars varied from low (22%) to high (97%). Evaluation of the root was found to be more reliable than evaluation of coleoptile necrosis.
F. avenaceum infected mostly root and, to a lesser extent, coleoptile and leaves, with about a three times lower disease score of coleoptile against root. F. culmorum caused a 1.5 higher disease score on root than on coleoptile. Susceptibility of DH lines was different from susceptibility of parental forms. Reaction of individual accessions to F. culmorum and F. avenaceum was different.     

Interaction Of Barley Yellow Dwarf Virus and Fusarium culmorum (W. G. Sm.) Sacc. in Winter Wheat

The barley yellow dwarf virus (BYDV) epidemics, which occurred predominantly in northern Germany in 1988–90 and caused unusual yield losses of wheat, prompted our study on interactions of BYDV and Fusarium culmorum. At the late stages of plant development (EC 55/65) infections with BYDV resulted in a lower yield reduction of wheat plants than infections with F. culmorum. Combined infections at flowering resulted in severer yield reduction, indicating additive effects of the two pathogens. However, if wheat infected by BYDV at stage EC 25/35 was secondarily inoculated with the fungus at EC 55/65 the yield was less reduced than in combined infections at EC 55/65. Our results proved that the susceptibility of wheat plants to F. culmorum is increased when infection by BYDV takes place during the late stages of growth. These results correspond to observations during 3 years of the epidemic in Germany. In these years BYDV was spread mainly during the late spring, resulting in a severe secondary infection by the fungus. From the results of these investigations it may be concluded that during the years of BYDV epidemic the yield of wheat was reduced to an economically important extent because of the fungal infection, which was favoured by the virus infection.     

Susceptibility of Barley Cultivars and Lines to Fusarium Infection and Mycotoxin Accumulation in Kernels

Heads of 12 barley genotypes (8 cultivars and 4 lines) were inoculated with conidial suspension of the following single isolates: F. culmorum no. 3, F. graminearum no. 122 and F. sporotrichioides no. ATCC 62 360. The number of kernels per head. 1000 Kernel weight and yield have been calculated for each genotype. Seed samples collected at harvest were analysed for each genotype. Seed samples collected at harvest were analysed for several trichothecene mycotoxins and zearalenone.The mycotoxin concentrations (mg/kg) in barley kernels inoculated with F. graminearum were as follows. deoxynivalenol (DON) 0.1 to 5.4 (av. 2.3). 3-acetyldeoxy-nivalenol (3-AcDON) 0.0–0.2 (av. 0.1), 15-acetyldeoxynivalenol (15-AcDON) 0.0–0.7 (av.0.2), nivalenol (NIV) 0.0–0.8 (av. 0.3). zearalenone (ZEA) 0.0–0.1 (av. 0.0); F. culmorum: DON 0.6 to 12.0 (av. 5.3), 3-AcDON 0.1 to 1.0 (av. 0.6). 15-AcDON nd. NIV 0.1–0.7 (av. 0.3). ZEA 0.1–0.5 (av. 0.2). F. sporotrichioides T-2 toxin 2.4–13.9 (av. 6.0), HT-2-toxin 0.1–0.8 (av.0.3) and neosolaniol 0.2–1.5 (av.0.7).     

Cellulolytic Activity of Three Fusarium culmorum (W. G. Sm.) Sacc. Isolates Pathogenic towards Wheat Seedlings

Fusarium culmorum isolates pathogenic to wheat (severely, medium and weakly pathogenic) proved to be producers of endo-1,4-β-glucanase and exo-1,4-β-glucanase. The activity of the latter enzyme was low. There was no correlation between the activities in vitro of the two enzymes and pathogenicity of the isolates.     

Metabolic activities of the sugarbeet pathogens Fusarium solani (Mart.) Sacc. and Sclerotium rolfsii Sacc. under pyramin stress

Effects of different concentrations of active ingredient of the herbicide pyramin on metabolic activities of Fusarium solani and Sclerotium rolfsii were examined. High concentrations of this herbicide (1000 and 2000 g mL^-1 for F. solani and 100 and 200 g mL^-1 for S. rolfsii) had inhibitory effects on the metabolic activities of both fungi. These were demonstrated by significant decreases in growth, and increases in rates of CO₂ evolved, O₂ consumed and keto acids produced. These were accompanied by increased rates of sugar, nitrate and inorganic phosphorus absorption as well as lowered rates of synthesis of carbohydrates and insoluble nitrogenous (including protein) and phosphorus (including RNA-P and DNA-P) compounds. In addition, rates of excretion of both nitrogen and phosphorus fractions by the mycelial mats were increased.A concentration of 25 g mL^-1 exerted little or no effect on the metabolic activities of these fungi, although S. rolfsii was somewhat sensitive to this concentration.     

Antibiotic Y: biosynthesis by Fusarium avenaceum (Corda ex Fries) Sacc., isolation, and some physicochemical and biological properties.

A compound very similar to the mycotoxin citrinin was observed on thin-layer chromatographic plates during the screening analysis of grain extracts. This compound was produced by 22 of the tested Fusarium avenaceum (Corda ex Fries) Sacc. strains isolated from wheat, triticale, barley, corn, and potatoes. A chemical test confirmed the presence of an unknown compound, which was given the preliminary name of antibiotic Y (indicating yellow fluorescence). The following properties of the new metabolite are described: spectroscopic (UV, infrared, proton nuclear magnetic resonance, fluorescence, and mass spectrometry), phytotoxic, antibiotic (inhibitory effect of bacterial growth), and toxic (toxicity to Artemia salina, chicken embryos, and mouse fibroblasts). Elemental analysis of the compound showed that it had the general formula C15H10O8, in agreement with the mass spectrometric finding that the molecular ion had a molecular weight of 318. The structure of the compound is presently under study.     

Formation of Avenacein Y by Fusarium avenaceum Fries Sacc. isolates from Germany and pathogenicity of the isolates to cereal seedlings

Twelve isolates ofFusarium avenaceum Fries Sacc. originating from diseased corn plants from Germany produced Avenacein Y in amounts ranging from 0.001 to 1.6 g/kg of wheat grain. The isolates proved most pathogenic to triticale seedlings, less pathogenic to rye seedlings and least to wheat. Pathogenicity of the isolates was not correlated with their ability to produce Avenacein Y.     

Antibiotic Y: biosynthesis by Fusarium avenaceum (Corda ex Fries) Sacc., isolation, and some physicochemical and biological properties

A compound very similar to the mycotoxin citrinin was observed on thin-layer chromatographic plates during the screening analysis of grain extracts. This compound was produced by 22 of the tested Fusarium avenaceum (Corda ex Fries) Sacc. strains isolated from wheat, triticale, barley, corn, and potatoes. A chemical test confirmed the presence of an unknown compound, which was given the preliminary name of antibiotic Y (indicating yellow fluorescence). The following properties of the new metabolite are described: spectroscopic (UV, infrared, proton nuclear magnetic resonance, fluorescence, and mass spectrometry), phytotoxic, antibiotic (inhibitory effect of bacterial growth), and toxic (toxicity to Artemia salina, chicken embryos, and mouse fibroblasts). Elemental analysis of the compound showed that it had the general formula C15H10O8, in agreement with the mass spectrometric finding that the molecular ion had a molecular weight of 318. The structure of the compound is presently under study.     

Effects of Moniliformin on Mitosis in Maize (Zea mays L.)

Maize (Zea mays L. ‘Norfolk White’) roots were treatedwith solutions of moniliformin (a metabolite of Fusarium moniliformeSheldon) at 0.0001 M and 0.001 M for 8, 24, and 48 h. Only aslight inhibition of division was noted in root tips treatedwith the lower concentration. The higher concentration causeda disruption of the spindle apparatus and consequent C-mitosis,and metaphase accumulation. (Received February 14, 1984; Accepted May 18, 1984)     

Occurrence of Beauvericin and Enniatins in Wheat Affected by Fusarium avenaceum Head Blight

We evaluated Fusarium contamination and the levels of hexadepsipeptide mycotoxins in 13 wheat samples affected by head blight in Finland. Fusarium avenaceum was the dominant species (91%) isolated from all samples, but isolates of F. culmorum (4%), F. tricinctum (3%), and F. poae (2%) also were recovered. Beauvericin (0.64 to 3.5 μg/g) was detected in all 13 samples. Enniatin B (trace to 4.8 μg/g) was detected in 12 samples, enniatin B₁ (trace to 1.9 μg/g) was detected in 8 samples, and enniatin A₁ (trace to 6.9 μg/g) was detected in 10 samples. Ten of 13 strains of F. avenaceum and 2 strains of F. poae and F. tricinctum produced beauvericin in culture on rice (trace to 70, 9.4, and 33 μg/g, respectively). All strains also produced enniatins (trace to 2,700 μg/g). This is the first report on the natural cooccurence of beauvericin and enniatins in wheat infected predominantly by F. avenaceum.     

Fusarium Head Blight Reactions and Accumulation of Deoxynivalenol (DON) and Some of its Derivatives in Kernels of Wheat, Triticale and Rye

Fifty-three commercially grown cultivars and germplasm lines of winter triticale (n = 18), wheat (n = 13), and rye (n = 5) and spring triticale (n = 8), wheat (n = 7) and rye (n = 2) were inoculated at mid anthesis with a spore suspension consisting of a mixture of Fusarium culmorum, Fusarium avenaceum and Fusarium graminearum isolates of known toxinogenic activity. Reactions to Fusarium head blight were measured as disease severity, reductions of kernel number/head, kernel weight/head and 1000 kernel weight, number of Fusarium-damaged kernels and kernel content of deoxynivalenol (DON) and its acetyl-derivatives 3-AcDON, 15-AcDON, and moniliformin. None of the cereal genotypes was completely resistant to Fusarium head blight. Wheat suffered from the largest kernel weight reductions, and accumulated the largest amounts of deoxynivalenol (up to 39.5 mg/kg) and 3AcDON (up to 6.0 mg/kg) in kernels. Deoxynivalenol was not detected in grain samples of winter rye cv. Dańkowskie Z?ote, and spring rye cv. Ludowe. 15-AcDON was only detected in genotypes of triticale, and 3AcDON only in a few genotypes of winter wheat and rye. Moniliformin was detected at low concentrations (up to 0.092 mg/kg) in kernels of some genotypes selected for the mycotoxin analysis. A moderately strong Pearson correlation was found between head blight severity parameters and the accumulation of deoxynivalenol and its derivatives in grain of the cereal genotypes studied. Fusarium head blight severity parameters were correlated with the percentage of Fusarium-damaged kernels and reductions of yield components. However, some head blight-susceptible genotypes realized their potential yields, but accumulated high levels of mycotoxins in kernels. Both Fusarium head blight resistant and susceptible genotypes of the three cereal species accumulated deoxynivalenol in kernels. This finding suggests that the system regulating deoxynivalenol accumulation may be independent of Fusarium head blight reaction.     

Effects of External Potassium (K) Supply on Drought Tolerances of Two Contrasting Winter Wheat Cultivars

Background

Drought is a common stress limiting crops growth and productivities worldwide. Water deficit may increase cellular membrane permeability, resulting in K outflow. Internal K starvation may disorder plant metabolism and limit plant growth. However, it is seldom reported about the effects of external K on drought tolerance of contrasting wheat cultivars.

Methodology/Principal Findings

A hydroponics experiment was carried out in a non-controlled greenhouse. Seedlings of drought-tolerant SN16 and intolerant JM22 were simultaneously treated by five levels of K₂CO₃ (0, 2.5, 5, 7.5, 10 mM) and two levels of PEG6000 (0, 20%) for 7 days. External K₂CO₃ significantly increased shoot K⁺ content, water potential, chlorophyll content as well as gas exchange, but decreased electrolyte leakage (EL) and MDA content in both cultivars under PEG6000 stress. Antioxidant enzymes activities were up-regulated by PEG6000 while external K₂CO₃ reduced those changes. Molecular basis was explained by measuring the expression levels of antioxidant enzymes related genes. Shoot and root biomass were also increased by K₂CO₃ supply under drought stress. Although adequate K₂CO₃ application enhanced plant growth for both cultivars under drought stress, SN16 was better than JM22 due to its high drought tolerance.

Conclusions/Significance

Adequate external K may effectively protect winter wheat from drought injuries. We conclude that drought-tolerant wheat combined with adequate external K supply may be a promising strategy for better growth in arid and semi-arid regions.     

Studies on a strain of Fusarium solani (Mart.) Sacc. Isolated from a case of mycotic keratitis

A strain of Fusarium solani (Mart.) Sacc. (IMI-216517), isolated from a patient of mycotic keratitis, produced experimental keratomycosis in albino rabbit cornea and survived in internal tissues of albino mice for varying periods. Alantolactone, isolated from the plant — Inula racemosa Hook. f. exhibited marked in vitro fungistatic activity against this strain of F. solani at 100–200 g/ml concentrations. The strain was less sensitive to amphotericin B and showed more acid than alkaline proteinase and phosphatase activities.Communication No. 2526.