Isolates Of Fusarium Avenaceum Research Articles

Aggressiveness and mycotoxin profile of Fusarium avenaceum isolates causing Fusarium seedling blight and Fusarium head blight in UK malting barley.

Fusarium avenaceum causing Fusarium seedling blight (FSB) and Fusarium head blight (FHB) on barley is associated with economic losses of crop yield and quality, and the accumulation of mycotoxins including the enniatins (ENNs) A, A1, B and B1. Although F. avenaceum is the main producer of ENNs, studies on the ability of isolates to cause severe Fusarium diseases or produce mycotoxins in barley are limited. In this work, we investigated the aggressiveness of nine isolates of F. avenaceum to two cultivars of malting barley, Moonshine and Quench, and defined their ENN mycotoxin profiles in in vitro and in planta experiments. We assessed and compared the severity of FSB and FHB caused by these isolates to disease severity by F. graminearum, F. tricinctum and F. poae. Quantitative real-time polymerase chain reaction and Liquid Chromatography Tandem Mass Spectrometry assays were used to quantify pathogen DNA and mycotoxin accumulation, respectively, in barley heads. Isolates of F. avenaceum were equally aggressive to barley stems and heads and caused the most severe FSB symptoms resulting in up to 55% reductions of stem and root length. Fusarium graminearum caused the most severe FHB disease, followed by the isolates of F. avenaceum with the most aggressive F. avenaceum isolates capable of causing similar bleaching of barley heads as F. avenaceum. Fusarium avenaceum isolates produced ENN B as the predominant mycotoxin, followed by ENN B1 and A1 in vitro. However, only the most aggressive isolates produced ENN A1 in planta and none produced ENN A or beauvericin (BEA) either in planta or in vitro. The capacity of F. avenaceum isolates to produce ENNs was related to the accumulation of pathogen DNA in barley heads, whilst FHB severity was related to the synthesis and accumulation of ENN A1 in planta. Cv. Moonshine was significantly more resistant than Quench to FSB or FHB, caused by any Fusarium isolate, and to the accumulation of pathogen DNA, ENNs or BEA. In conclusion, aggressive F. avenaceum isolates are potent ENN producers causing severe FSB and FHB with ENN A1 requiring further investigation as potential virulence factor for F. avenaceum in cereals.

PRODUCTION OF AGENTS FOR BIOCONTROL OF APPLE FUSARIUM ROT BY SOILBORNE STREPTOMYCETES

Within this paper, the potential of Streptomyces hygroscopicus in biocontrol of two isolates of Fusarium avenaceum isolated from apple fruits in the storage was tested. Production of S. hygroscopicus biocontrol agent was performed in 3 l stirred tank bioreactor at an aeration rate of 1.5 vvm and mixing speed of 150 rpm. Bioprocess was realized at 26 ±1°C for 168 hours. The activity of bioagents production was tested using in vitro diffusion method with wells. Also, residual glycerol, residual nitrogen content, and cell biomass were determined to analyze bioprocess parameters. The results showed that the highest production of bioagents was observed in 96h of cultivation when the largest zone diameters were formed against F. avenaceum KA12 and KA13 of 40.67±1.15 and 43.33±0.58 mm, respectively. The activity of the produced bioagents was confirmed in in planta research, where the difference between necrosis diameter of treated and control samples were 2.79 (for KA12) and 2.17 (for KA13) times smaller.

Production of plant protection agents in medium containing waste glycerol by Streptomyces hygroscopicus: Bioprocess analysis

The surplus of waste glycerol, by-product of the biodiesel production process, is available at the global market. Some species of the genera Streptomyces have the ability to assimilate glycerol and convert it into valuable metabolic products. In the present study, the ability of Streptomyces hygroscopicus to assimilate waste glycerol and convert it into metabolic compounds with antifungal activity against four phytopathogenic fungi obtained from apple fruit samples expressing rot symptoms, was investigated. Production of antifungal metabolites by S. hygroscopicus was carried out in 3 l stirred tank bioreactor through 7 days. Fermentation was carried out at 27 °C with aeration rate of 1.5 vvm and agitation rate of 100 r.p.m. The aim of this work was to analyse bioprocess parameters and to determine at which stage of bioprocess the production of antifungal metabolites occurs. Activity of the cultivation liquid on two isolates of Alternaria alternata and two isolates of Fusarium avenaceum were determined every 12 h using in vitro well diffusion method. It was found that the maximum production of antifungal metabolites occurred at 108 hour of cultivation. Formed inhibition zones have shown that the produced antifungal metabolites have high efficacy on tested phytopathogenic fungi (inhibition zone diameter higher than 35 mm for all test organisms).

Pathogenicity of Fusarium avenaceum isolates to tulip leaves assessed on leaf disks

The purpose of this study was to investigate the pathogenicity of 14 Fusarium avenaceum (Giberella avenacea) isolates, obtained from tulip plantations located in Puławy region, to leaves of tulip cv. Apeldoorn. Mycelial plugs 3 mm in diameter from the margins of the colonies growing on PDA and SNA were placed on 20 mm disks cut from tulip leaves. The disks were placed abaxial surface up, in Petri dishes on top of filter paper soaked with 100 mg/l gibberellic acid to retard leaf senescence. There were 5 replications for each isolate. Leaves in each Petń dish were inoculated with one isolate. Plates were incubated at 20°C and lesion diameters were measured after 4 days. The pathogenicity of investigated isolates was compared by measuring lesion development on tulip leaves. All of isolates colonized leaves disks succesfull - causing after 4 days necrotic lesions and sporulating after 14 days what indicated that an infection had occurred. There were significant differences in lesions size among isolates. Isolates: 27, 1, 2, 48 and 3 caused largest lesions at mean size from 150 mm<sup>2</sup> to 163 mm<sup>2</sup> what indicates their high pathogenicity. Less pathogenic were isolates: 28, 42, 7 and 72 caused lesions at mean size from 46 mm<sup>2</sup> to 97 mm~<sup>2</sup>. On average, mycelial plugs taken from PDA medium colonized leaf disks more efficient in comparison to them taken from SNA, that caused smaller lesions.

Characterization of virulence and PCR-DGGE profiles of Fusarium avenaceum from western Canadian Prairie Ecozone of Saskatchewan

Fusarium avenaceum isolates causing fusarium head blight (FHB) in wheat were collected from the Canadian Prairies and Mixed Wood Plains Ecozones. A total of 91 isolates were grouped into 15 phenotypes and 10 VCGs which formed seven ITS rDNA phylogenetic clades and three EF-1α PCR-DGGE groups. Variation in virulence within F. avenaceum isolates ranged from high to avirulent on wheat. In general, virulent isolates demonstrated greater host range and geographic distribution, while avirulent isolates had a limited spread. Virulent isolates demonstrated greater heat tolerance, colour plasticity and growth rate compared with avirulent isolates. Overall, data indicate that pathogen dynamics and outbreaks might be influenced by the abundance ratio of virulent/avirulent isolates related to climate characteristics of each agro-region. The characterization of F. avenaceum ‘sensu lato’ isolates, obtained from western and eastern ecozones, provided baseline information on the variation that exists for this FHB-causing species. Combined with environmental or ecological information, this knowledge could establish a consistent, long-term management of the pathogen.

Sphaerodes mycoparasitica sp. nov., a new biotrophic mycoparasite on Fusarium avenaceum, F. graminearum and F. oxysporum

A new species, Sphaerodes mycoparasitica (Ascomycetes, Melanosporales), was isolated from isolates of Fusarium avenaceum and Fusarium graminearum originating from wheat fields in Saskatchewan, and from Fusarium oxysporum originating from asparagus fields in Quebec, Canada. The species is characterized by a unique combination of ascospore size, shape (fusiform and triangular) and wall ornamentation (reticulate and smooth). Also, conidia are produced from simple phialides on the surface of ascoma peridial wall, on ascoma surrounding hyphae, and on irregularly branched conidiophores arising from hyphae. The closest relation of S. mycoparasitica is Sphaerodes quadrangularis, which has no detected anamorphic stage. The description of S. mycoparasitica, its phylogenetic position—based on DNA sequences of large subunit ribosomal RNA gene (LSU)—as well as a key for all known Sphaerodes species are provided.

Whole-cell protein and ITS rDNA profiles as diagnostic tools to discriminateFusarium avenaceumintraspecific variability and associated virulence

A total of 91 isolates of Fusarium avenaceum were regrouped into 15 phenotypes and 10 vegetative compatibility groups showing specific one-dimensional sodium dodecyl sulphate polyacrylamide gel electrophoresis (1-D SDS-PAGE) protein profiles and less-specific internal transcribed spacer rDNA profiles. Each isolate possessed reproducible signature protein bands. Indeed, the unweighted pair group method with arithmetic averages clustering revealed that the protein profile of each group of isolates correlated with fungus virulence. The use of SDS-PAGE offers a simple and sensitive technique for routine differentiation between pathogenic and nonpathogenic isolates within unknown F. avenaceum populations. The discovery has significant implications for risk assessment of cereal yield to ensure food and feed safety. This low-cost approach has the potential to be optimized and extended to a broad spectrum of Fusarium head blight pathogens.

Major changes in Fusarium spp. in wheat in the Netherlands

The re-emergence of fusarium head blight throughout the world and especially in Western Europe prompted a survey of the situation in the Netherlands. To allow for a high throughput screening of large numbers of samples, a diagnostic PCR method was developed to detect the most common species of Fusarium occurring on wheat. Seven primer pairs were tested for their ability to identify isolates of Fusarium avenaceum, F. culmorum, F. graminearum, F. poae, F. proliferatum and Microdochium nivale var. majus and M. nivale var. nivale. Each primer pair only generated a PCR product with the corresponding Fusarium species and all PCR fragments had different molecular sizes. This allowed the generation of these amplicons using a mixture of all seven primer pairs. The robustness of this multiplex PCR encouraged us to screen a large series of isolates collected in 2000 and 2001. In both years 40 fields were sampled leading to a collection of 209 isolates from 2000 and 145 isolates from 2001. The results of the multiplex PCR demonstrated that F. graminearum was the most abundant species in the Fusarium complex on wheat in both years. This is in sharp contrast to reports from the 1980s and early 1990s, which found F. culmorum as the predominant species. Primers derived from the tri7 and tri13 genes, which are implicated in the acetylation and oxygenation of the C-4 atom of the backbone of the trichothecene molecule, were used to discriminate between deoxynivalenol and nivalenol (NIV) producers. The populations of F. culmorum and F. graminearum both showed a slight increase in NIV-producers in 2001.

Moniliformin in barley inoculated with Fusarium avenaceum

To assess production of the mycotoxin moniliformin, inoculation trials with four barley cultivars and local isolates of Fusarium avenaceum were performed at two different experimental farms in southern Manitoba, Canada, during 1997–99. In the 1997 study, moniliformin was detected in 11 of 16 barley rows at levels between 0.19 and 1.62 mg g-1, and F. avenaceum infection ranged from 10 to 57% in rows where the toxin was detected. In the 1998 study, moniliformin was detected in only three of 16 barley rows, with levels between 0.06 and 0.43 μg g-1, and F. avenaceum infection between 16 and 39%. In the 1999 study, moniliformin was detected in 11 of 16 barley rows with levels between 0.09 and 0.42 μg g-1, and F. avenaceum infection between 37 and 76%. In the 1997 trial, moniliformin was found in a single water-inoculated control row at 0.15 μg g-1. The data suggest that in years of high rainfall and F. avenaceum infection, moniliformin is likely to be found in Manitoba barley.

Mycotoxin production by Fusarium avenaceum strains isolated from Norwegian grain and the cytotoxicity of rice culture extracts to porcine kidney epithelial cells.

The secondary metabolites of 24 isolates of Fusarium avenaceum from Norwegian cereals and grown on rice have been characterized. Moniliformin (MON), enniatins (ENNs), and beauvericin (BEA) were analyzed by high-performance liquid chromatography. Porcine kidney epithelial cells (PK15, American Type Culture Collection) were used to study the cytotoxicity of MON in the extracts. The following metabolites were produced by all isolates, ranked by concentration in rice cultures: ENN-B, MON, ENN-B1, and ENN-A. BEA was produced by eight isolates. The productions of BEA and ENN-A were significantly correlated, as was the case with ENN-B and ENN-B1. MON production was correlated neither to any of the other toxins nor to toxicity.

Saskatchewan Regional Meeting, 2001, The Canadian Phytopathological Society / Réunion régionale de la Saskatchewan, 2001, La Société Canadienne de Phytopathologie

Genetic studies on resistance to blotch caused by Stagonospora nodorum in hexaploid wheat. J. Feng and G.R. Hughes. Department of Plant Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada. Pathogenicity of Fusarium avenaceum isolates from cereal and noncereal crops on durum wheat. M.R. Fernandez. Semiarid Prairie Agricultural Research Centre, Agriculture and Agri-Food Canada, P.O. Box 1030, Swift Current, SK S9H 3X2, Canada. Biotransformation of the phytoalexin brassinin by Sclerotinia sclerotiorum. M.S.C. Pedras and P.W.K. Ahiahonu. Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada. Phytotoxins from new black-leg fungal isolates. M.S.C. Pedras and P.B. Chumala. Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada. Biotransformation of analogs of the phytoalexin camalexin by the phytopathogen Rhizoctonia solani. M.S.C. Pedras and J. Liu. Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada. HPLC analyses of cultures of black-leg isolates from the Canadian prairies. M.S.C. Pedras, V. Uppala, and V. Cekic. Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon, SK S7N 5C9, Canada. Identification of two loci in Brassica napus for resistance to Leptosphaeria maculans. F. Yu, S.R. Rimmer, D.J. Lydiate, and G. Buzza. Saskatoon Research Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK S7N 0X2, Canada; and (G.B.) Advanta Seeds Canada Inc., Unit 3-75 Scurfield Boulevard, Winnipeg, MB R3Y 1P6, Canada.

Lisianthus Crown and Stem Rot Caused by Fusarium avenaceum in Central Italy.

Lisianthus (Eustoma russelianum, syn. E. grandiflorum), a member of the Gentian family, is grown in the greenhouse in Italy as a commercial cut-flower crop. Its cultivation is a relatively new industry with high economic potential. However, disease problems have been observed on various greenhouse-planted lisianthus in Central Italy (Tuscany): symptoms of wilting, tan leaf flecks, tan stem discoloration, crown and stem rot, and death. White mycelia and orange sporodochia were also commonly observed on diseased crowns and stems. Fusarium avenaceum isolates were recovered from diseased tissues. Four single-spore isolates were selected for artificial inoculation. Pathogenicity tests were conducted in the greenhouse on 16- to 17-week-old E. russelianum plants, cvs. Mariacki, Echo, and Heidi, by placing a colonized agar plug, or drops of a conidial suspension, at the crown previously wounded with a sterile scalpel. Moist cotton was fastened to the wound site. Control plants were inoculated with sterile agar plugs or drops of sterile, distilled water. Five plants per cultivar and per treatment were used for each isolate. All plants developed typical disease symptoms within 1 or 2 weeks when inoculated with mycelial plugs or conidial suspensions, respectively. Control plants developed no symptoms. Koch's postulates were completed by consistently reisolating the pathogen from inoculated plants. This is the first report of F. avenaceum on lisianthus in Italy and is similar to reports of the disease in California and Florida (1,2).

Variation in pathogenicity on potato tubers and sensitivity to thiabendazole of the dry rot fungusFusarium avenaceum

The majority of isolates ofFusarium avenaceum caused dry rot on potato tubers; many were as pathogenic asF. coeruleum. Pathogenicity ofF. avenaceum was not related to the plant species from which the isolates originated. Tubers of potato cv. Cara were more susceptible than those of cvs Romano or Maris Piper. Temperature (5–15° C) had no effect on lesion depth but lesions tended to be slightly wider at the lowest temperature. Two isolates (of 61) from wheat and white lupin had a moderate level of resistance to thiabendazole. The results are discussed in relation to the control of dry rot in stored potato tubers.

Variation Among Isolates of Fusarium Avenaceum from Different Hosts Determined by DNA Analyses and Vegetative Compatibility Groupings

Fusarium avenaccum is pathogenic on a wide range of hosts. Isolates of F. avenaceum were obtained from root samples of different crops including lupins, beans, wheat and brassicas from fields at Rothamsted with different cropping histories. Nuclear ribosomal DNA (rDNA) from 80 isolates was amplified by PCR using ITS4 and ITS5 primers. RFLP analysis revealed two definite pattern of bands suggesting two distinct groups among the isolates. Analysis using RAPDs revealed great variation among isolates, including those from the same host and from the same field. Vegetative compatibility was studied in 20 isolates by using nit-mutants and high VCG diversity was observed with 16 VCGs. Our results suggest a high degree of variation among the isolates of F. avenaceum.

Limitations of exotic and indigenous isolates ofFusarium avenaceum for the biological control of spotted knapweed — Centaurea maculosa

Three isolates ofFusarium avenaceum are pathogenic on spotted knapweed(Centaurea maculosa), a major weed plant of pasturelands and rangelands of the Pacific Northwestern USA. One isolate (no. 1) obtained from the European centre of origin of knapweed and isolate no. 365 native to Montana, did not significantly affect knapweed seed germination. However,F. avenaceum no. 1003, another Montana native isolate, caused a 100% decrease in seed germination and hence, no seedling emergence. When formulated, isolate no. 1003, could be recovered from treated soils after 7 days and caused a significant reduction in seedling emergence or seedling dry weight. This organism had no effect on the germination ofTriticum aestivum orMedicago sativa, but did affect the germination of other plant species.F. avenaceum appears to be a candidate for the biocontrol of spotted knapweed, however, a native isolate is potentially more effective than an isolate obtained from the centre of origin ofC. maculosa.

Universally primed polymerase chain reaction analysis of Fusarium avenaceum isolated from wheat and barley in Finland

Twenty-two Fusarium avenaceum isolates from Finnish wheat and barley were analysed using the chain reaction with universal primers (UP-PCR). Each isolate could be distinguished from others by UP-PCR products on polyacrylamide gels. The isolates tested were clustered into two main groups and further into several subgroups by UP-PCR profiles and phylogenetic analyses. The phylogenetic relationships of these groups are discussed. No clear correlation was found between the groups and host plant preference or the geographic origin of F. avenaceum isolates. Pathogenicity tests showed differences between F. avenaceum isolates, but two isolates, one from wheat and the other from barley, were the most aggressive in wheat and barley. This fungus, usually known as a weak pathogen of cereals and other crops, has thus probably not evolved in respect to its ability to damage wheat or barley.

Isozyme and RAPD‐PCR analyses of Fusarium avenaceum strains from Finland

Differences in isozyme and RAPD‐PCR polymorphisms amongst 33 isolates of Fusarium avenaceum were compared using native polyacrylamide gel electrophoresis and agarose gel electrophoresis. The isolates were collected from different regions of Finland. Amongst eight enzymes analysed clear isozyme polymorphism was detected in five enzymes which could be grouped into 20 different electrophoretic phenotypes and three main groups at the similarity level of 70% in unweighted pair group method with arithmetic average (UPGMA) analysis. RAPD‐PCR analysis differentiated all F. avenaceum strains from each other. The phenotypes resulting from RAPD‐PCR analysis were grouped into five main groups by UPGMA analysis at the similarity level of 55%. These main groups had several similarities with the main groups from isozyme analysis. RAPD‐PCR patterns of 16 isolates of Fusarium graminearumF. culmorumF. equisetiF. oxysporum and F. redolens were also studied and strains from each Fusarium species formed individual groups in UPGMA and principal components analyses. Thus, the extent of isozyme and RAPD‐PCR polymorphisms found in Fusarium strains potentially provides a method for identifying the fungi both at strain and species level.

Identification of Fusarium avenaceum strains by isozymes analysis 1

Differences in isozyme polymorphisms between 33 isolates of Fusarium avenaceum were compared using the native polyacrylamide gel electrophoresis technique. The isolates were collected from different regions of Finland. Of eight enzymes analysed, five showed clear isozyme polymorphism. By using these five enzymes, the isolates could be grouped into 20 different electrophoretic phenotypes. One of them was specific for oats, five for wheat and six for barley. Two further phenotypes were isolated from each of these crop species. In addition, two phenotypes were isolated from strawberry, one from both rye and cotoneaster, while the electrophoretic phenotypes from thuja, apple and hawthorn were specific for each. The phenotypes could be classified into five main groups. The extent of isozyme polymorphisms found in F. avenaceum provides a useful method for studying the identification and evolution of F. avenaceum strains.

Resistance to thiabendazole and thiophanate-methyl in canadian isolates ofFusarium sambucinum andHelminthosporium solani

Resistance to both thiabendazole (TBZ) and thiophanate-methyl (TPM) was observed in Canadian isolates ofFusarium sambucinum andHelminthosporium solani recovered from diseased potato tubers. Resistance was not found in isolates ofFusarium avenaceum, Fusarium culmorum, Fusarium equiseti andFusarium solani. A high level of resistance to both TBZ (EC50 180 to ≫500 mg/l) and TPM (EC50 ≫500 mg/l) was observed forH. solani isolates, whereasF. sambucinum exhibited a relatively low level of resistance to TBZ (EC50 34 to 71 mg/l) and a high level of resistance to TPM (growth uninhibited by 2,500 mg/l). The incidence ofF. sambucinum resistant to the benzimidazoles was lower (60%) than that observed forH. solani (95%)

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.