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1.
Several Fusarium species occurring worldwide on maize as causal agents of ear rot, are capable of producing mycotoxins in infected kernels, some of which have a notable impact on human and animal health. The main groups of Fusarium toxins commonly found are: trichothecenes, zearalenones, fumonisins, and moniliformin. In addition, beauvericin and fusaproliferin have been found in Fusarium-infected maize ears. Zearalenone and deoxynivalenol are commonly found in maize red ear rot, which is essentially caused by species of the Discolour section, particularly F. graminearum. Moreover, nivalenol and fusarenone-X were often found associated with the occasional occurrence of F. cerealis, and diacetoxyscirpenol and T-2 toxin with the occurrence of F. poae and F. sporotrichioides, respectively. In addition, the occurrence of F. avenaceum and F. subglutinans usually led to the accumulation of moniliformin. In maize pink ear rot, which is mainly caused by F. verticillioides, there is increasing evidence of the wide occurrence of fumonisin B1. This carcinogenic toxin is usually found in association with moniliformin, beauvericin, and fusaproliferin, both in central Europe due to the co-occurrence of F. subglutinans, and in southern Europe where the spread of F. verticillioides is reinforced by the widespread presence of F. proliferatum capable of producing fumonisin B1, moniliformin, beauvericin, and fusaproliferin.  相似文献   

2.
Fusarium head blight (FHB) is an important fungal disease of wheat. The aim of this research was to determine the diversity of Fusarium species infecting winter wheat ears in East Croatia. In 2008 wheat kernels were obtained from three locations in the eastern part of Croatia (Tovarnik, Osijek, Pozega), and in 2009 from two additional locations (Slavonski Brod, Nova Gradiska). In total, 498 visually diseased kernels were selected for morphological identification of Fusarium spp. The identity of 226 selected isolates was further investigated by molecular techniques. The predominant species on wheat kernels in East Croatia in 2008 were F. graminearum, isolated and confirmed from more than 80% of sampled wheat kernels, followed by F. avenaceum (8%) and F. culmorum (7%). Incidence of F. poae was less than 2%. The most common species identified in 2009 were F. graminearum (50%), F. culmorum (13%), F. avenaceum (12%) and F. poae (7%). This is the first report on the identification of Fusarium species isolated from naturally infected wheat ears in Croatia.  相似文献   

3.
Different sets of wheat genotypes were tested under field conditions by spraying inocula of isolates of seven Fusarium spp. and Microdochium nivale (formerly F. nivale) in the period 1998–2002. The severity of Fusarium head blight (FHB), Fusarium-damaged kernels (FDK), the yield reduction and the deoxynivalenol (DON) contamination were also measured to describe the nature of the resistance. The degrees of FHB severity of genotypes to F. graminearum, F. culmorum, F. avenaceum, F. sporotrichioides, F. poae, F.␣verticillioides, F. sambucinum and M. nivale were very similar, indicating that the resistance to F.␣graminearum was similar to that for other Fusarium spp. listed. This is an important message to breeders as the resistance relates not only to any particular isolate of F. graminearum, but similarly to isolates of other Fusarium spp. This holds true for all the parameters measured. The DON contamination refers only to DON-producers F. graminearum and F. culmorum. Highly significant correlations were found between FHB, FDK, yield loss and DON contamination. Resistance components such as resistance to kernel infection, resistance to DON and tolerance were identified in the more susceptible genotypes. As compared with western European genotypes which produced up to 700 mg kg−1 DON, the Hungarian genotypes produced only 100 mg kg−1 at a similar FDK level. This research demonstrates the importance of measuring both FDK and DON in the breeding and selection of resistant germplasm and cultivars.  相似文献   

4.
Fusarium head blight (FHB) of cereals is a disease complex. Fusarium graminearum is the major pathogen worldwide, while F. culmorum, F. avenaceum and F. poae are also associated with this disease. In addition to the true Fusarium species, Microdochium nivale may also cause head blight and is particularly prevalent where cooler, wetter conditions prevail. Other species such as F. sporotrichioides, F. equiseti and even F. verticillioides may also be of significance in particular situations. FHB is of particular concern because of the ability of the Fusarium species to produce mycotoxins in the grain that are harmful to human and animal consumers. The predominant mycotoxins within cereals are the trichothecenes, chiefly deoxynivalenol, nivalenol and their acetylated derivatives, along with T-2, HT-2, diacetoxyscirpenol and neosolaniol. This paper reviews the use of molecular techniques to identify the individual causal agents and to quantify their relative amounts within plant tissue. Diagnostic and quantitative polymerase chain reaction assays have been developed to detect and quantify individual fungal species within the disease complex and, where relevant, to differentiate between chemotypes within a single species. Assays to determine the type of toxin produced, or monitor the regulation of toxin production also provide valuable tools for understanding this disease. These techniques are being used to dissect the disease complex into its component parts in order to study interactions between the pathogens and their host and between the pathogens themselves as well as to determine the influence of environmental factors on the disease and the toxins produced by these fungi.  相似文献   

5.
Identifying the Fusarium species cause Fusarium head blight (FHB) and produces mycotoxins in wheat and other cereal is difficult and time consuming because of confusing phenotypic classification systems. In Japan, the F. graminearum complex, F. culmorum, F. avenaceum, and Microdochium nivale predominantly cause FHB. The internal transcribed spacer (ITS) and 5.8S of rDNA, a partial sequence of β-tubulin and mitochondrial cytochrome b (cytb) genes of the four species were PCR-amplified and analyzed. On the basis of the ITS, β-tubulin and cytb sequences, F. avenaceum and M. nivale are distinct from the F. graminearum complex and F. culmorum, whereas the F. graminearum complex is closely related to F. culmorum. Moreover, thiophanate–methyl-resistant isolates of the F. graminearum complex and F. culmorum did not have an amino acid substitution at amino acid codon 198 or 200 of β-tubulin. In contrast, very highly or highly thiophanate–methyl-resistant isolates of M. nivale had Glu (GAG) substituted with Ala (GCG) or Lys (AAG) at codon 198, respectively. The allele-specific PCR assay was used to identify the F. graminearum complex and F. culmorum, and these Fusarium species could be distinguished rapidly.  相似文献   

6.
Foot rot and crown rot are fungal diseases of wheat caused by a complex of Fusarium species. They have a huge economic impact mainly due to yield reduction. A survey was conducted to identify four Fusarium species, occurring on wheat stem bases, using species-specific PCR assays in samples collected during spring of 2012. The dominant species was F. graminearum, which was identified in above 64 % of samples. F. culmorum was detected in 15.71 %, F. poae in 15.71 % and F. sporotrichioides in 5.71 % wheat fields. Most of the wheat fields in the eastern Poland were infected with at least one or two of Fusarium species, while in central Poland no Fusarium species were identified in most of the fields. The presence of F. graminearum tends to favor the presence of F. culmorum and this effect was visible also for F. poae and F. sporotrichioides. The frequency of F. graminearum and F. culmorum detections were highest where wheat crops were preceded by maize and in the samples from late sown fields. The opposite observation was made for F. poae and F. sporotrichioides, where the number of detections of these species was higher in samples from early sown fields. The number of detected Fusarium species was significantly lower in samples collected from fields protected with autumn herbicide in comparison to unprotected fields. The rate of autumn N fertilization did not affect the number of Fusarium detections.  相似文献   

7.
The presence of Fusarium spp. causing Fusarium head blight (FHB) of wheat was studied in Flanders (Belgium) in 2007 and 2008. Symptoms, deoxynivalenol content (DON), Fusarium spp. and trichothecene chemotypes were determined at seven locations on different commercial wheat varieties. Overall, significant differences in disease pressure between locations and varieties were observed within 1 year. In addition, we were able to detect consistent and significant resistance differences among the common varieties both under high disease pressure (2007) and low disease pressure (2008). The accumulation of DON was not related to the presence of F. graminearum but showed a clear correlation with rainfall during and after the period of anthesis. During the two-year survey, characterisation of 756 Fusarium samples by species-specific PCR designated F. poae and F. graminearum as the predominant species in Flanders. Furthermore, most of the ears were colonised by multiple FHB pathogens in 2007 whereas the Fusarium population was less complex in 2008. Log-linear analysis of these multiple (two- and three-way) species interactions revealed a clear correlation between F. poae and several pathogens of the FHB disease complex. Finally, chemotype analysis showed that F. culmorum and F. graminearum were respectively of the NIV chemotype and DON chemotype. 3-ADON and 15-ADON chemotypes occurred in more or less equal amounts within the F. graminearum population both in 2007 and 2008. The congruence of these results with observations throughout Europe are discussed.  相似文献   

8.
The spatial pattern of Fusarium‐infected kernels and their mycotoxin contamination was studied in four wheat fields in Germany using geo‐referenced sampling grids (12–15 × 20–30 m, 28–30 samples per field) at harvest. For each sample, frequency of Fusarium‐infected kernels and spectrum of species were assessed microbiologically; mycotoxin contents were determined by HPLC‐MS/MS analysis. Spatial variability of pathogens and mycotoxins was analysed using various parameters including Spatial Analysis by Distance IndicEs (sadie® ). Microdochium majus, the most frequent head blight pathogen in 1998, was less frequent in 1999 and could not be detected in kernels from two fields in 2004. Fusarium avenaceum, F. graminearum and F. poae were the most frequent Fusarium species, with 7–8 species per field. The frequency of Fusarium‐infected kernels was 3–15% and the incidence of species showed considerable within‐field variability. Spatial patterns varied among Fusarium species as well as from field to field. Although pathogens and mycotoxin were often distributed randomly in the field, F. avenaceum, F. graminearum, F. poae, F. sporotrichioides, F. tricinctum and the mycotoxin moniliformin had an aggregated pattern in at least one field. Patterns are discussed in relation to spread of Fusarium species depending on inoculum sources, spore type, kind of dispersal, availability of susceptible host tissue and micro‐climate. Sampling of wheat fields for representative assessment of mycotoxins is complicated by random patterns of Fusarium‐infected kernels, especially where the frequency of infection is small.  相似文献   

9.
Recent data on the epidemiology of the common mycotoxigenic species of Fusarium, Alternaria, Aspergillus and Penicillium in infected or colonized plants, and in stored or processed plant products from the Mediterranean area are reviewed. Emphasis is placed on the toxigenicity of the causal fungal species and the natural occurrence of well known mycotoxins (aflatoxins, ochratoxins, fumonisins, trichothecenes, zearalenone, patulin, Alternaria-toxins and moniliformin), as well as some more recently described compounds (fusaproliferin, beauvericin) whose toxigenic potential is not yet well understood. Several Fusarium species reported from throughout the Mediterranean area are responsible of the formation of mycotoxins in infected plants and in plant products, including: Fusarium graminearum, F. culmorum, F. cerealis, F. avenaceum, F. sporotrichioides and F. poae, which produce deoxynivalenol, nivalenol, fusarenone, zearalenone, moniliformin, and T-2 toxin derivatives in wheat and other small grains affected by head blight or scab, and in maize affected by red ear rot. Moreover, strains of F. verticillioides, F. proliferatum, and F. subglutinans, that form fumonisins, beauvericin, fusaproliferin, and moniliformin, are commonly associated with maize affected by ear rot. Fumonisins, were also associated with Fusarium crown and root rot of asparagus and Fusarium endosepsis of figs, caused primarily by F. proliferatum. Toxigenic A. alternata strains and associated tenuazonic acid and alternariols were commonly found in black mould of tomato, black rot of olive and citrus, black point of small cereals, and black mould of several vegetables. Toxigenic strains of A. carbonarius and ochratoxin A were often found associated with black rot of grapes, whereas toxigenic strains of A. flavus and/or P. verrucosum, forming aflatoxins and ochratoxin A, respectively, were found in moulded plant products from small cereals, peanuts, figs, pea, oilseed rape, sunflower seeds, sesame seeds, pistachios, and almonds. Finally, toxigenic strains of P. expansum and patulin were frequently found in apple, pear and other fresh fruits affected by blue mould rot, as well as in derived juices and jams.  相似文献   

10.
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.  相似文献   

11.
Fusarium graminearum, Fusarium culmorum and Fusarium cerealis are major causal agents of Fusarium Head Blight (scab) which is a disease of global significance in all cereal growing areas. These fungi produce trichothecene mycotoxins, principally nivalenol (NIV) and deoxynivalenol (DON). Genes Tri13 and Tri7 from the trichothecene biosynthetic gene cluster convert DON to NIV (Tri13) and NIV to 4-acetyl-NIV (Tri7). We have developed positive–negative PCR assays based on these two genes, which accurately indicate a DON or NIV chemotype in F. graminearum, F. culmorum and F. cerealis. These assays are useful in assessing the risk of trichothecene contamination, and can be informative in epidemiological studies. All NIV chemotype isolates studied have functional copies of both Tri13 and Tri7, and all DON-producing isolates have both genes disrupted or deleted. We have identified several mutations in these genes, which are conserved across F. graminearum lineage, RAPD and SCAR groupings and between the three species. There appears to be evidence of inter-species hybridisation within the trichothecene biosynthetic gene cluster.  相似文献   

12.
The effect of temperature on the in vitro growth rates and pathogenicity of a European Fusarium collection consisting of isolates of Fusarium graminearum, F. culmorum, F. avenaceum, F. poae and Microdochium nivale was examined. Irrespective of geographic origin, the optimum temperature for the growth of F. graminearum, F. culmorum and F. poae was 25 °C, while that for F. avenaceum and M. nivale was 20 °C. In general, the growth rates of F. graminearum, F. culmorum and F. poae increased between 10 and 25 °C and those of F. avenaceum and M. nivale increased between 10 and 20 °C. Pathogenicity tests were carried out by examining the effect of the five species on the in vitro coleoptile growth rate of wheat seedlings (cv. Falstaff). Irrespective of geographic origin, the temperature at which F. avenaceum, F. culmorum and F. graminearum caused the greatest retardation in coleoptile growth ranges 20–25 °C (>89.3% reduction), whilst for F. poae and M. nivale it was 10–15 °C (>45.6% retardation), relative to uninoculated control seedlings. In general, F. culmorum and F. graminearum were the most pathogenic of the five species, causing at least a 69% reduction in coleoptile growth at 10, 15, 20 and 25 °C. General linear model analysis (GLIM) showed that species accounted for 51.3–63.4% of the variation in isolate growth and from 19.5% to 44.3% of the variation in in vitro pathogenicity. Country of origin contributed from 22.6% to 51.9% to growth rate variation and from 0.73% to 7.61% to pathogenicity variation. The only significant correlation between in vitro growth and pathogenicity was that observed for M. nivale at 15 °C (r = -0.803, P < 0.05).  相似文献   

13.
Fusarium head blight (FHB) in small grain cereals is primarily caused by the members of the Fusarium graminearum species complex. These produce mycotoxins in infected grains, primarily deoxynivalenol (DON); acetylated derivatives of DON, 3‐acetyl‐DON (3‐ADON) and 15‐acetyl‐DON (15‐ADON); and nivalenol (NIV). This study reports the isolation of Fusarium cerealis in infected winter wheat heads for the first time in Canada. A phylogenetic analysis based on the TRI101 gene and F. graminearum species‐specific primers revealed two species of Fusarium: F. graminearum sensu stricto (127 isolates) and F. cerealis (five isolates). Chemotype determination based on the TRI3 gene revealed that 65% of the isolates were 3‐ADON, 31% were 15‐ADON and 4% were NIV producers. All the F. cerealis isolates were of NIV chemotype. Fusarium cerealis isolates can often be misidentified as F. graminearum as the morphological characteristics are similar. Although the cultural and macroconidial characteristics of F. graminearum and F. cerealis isolates were similar, the aggressiveness of these isolates on susceptible wheat cultivar Roblin and moderately resistant cultivar Carberry differed significantly. The F. graminearum 3‐ADON isolates were most aggressive, followed by F. graminearum 15‐ADON and F. cerealis NIV isolates. The findings from this study confirm the continuous shift of chemotypes from 15‐ADON to 3‐ADON in North America. In Canada, the presence of NIV is limited to barley samples and the discovery of NIV‐producing F. cerealis species in Canadian wheat fields may pose a serious concern to the Canadian wheat industry in the future.  相似文献   

14.
J. Uoti 《EPPO Bulletin》1975,5(4):419-424
Several Fusarium species occurred abundantly in spring cereal seed samples studied in 1966, 1968 and 1972 in Finland. A total of 17 species of Fusarium were isolated and identified. The most frequently isolated species were F. avenaceum (Fr.) Sacc., F. culmorum (W. G. Sm.) Sacc., F. poae (Peck) Wr. and F. tricinctum (Cda) Sacc. These species were found in more than 40% of the seed samples from 1972. The same 4 Fusarium species in addition to F. graminearum Schwabe were used in the pathogenicity test. Artificially inoculated spring wheat and barley seeds were grown in the field during the growing season of 1973. Of these 5 species F. culmorum was clearly the most pathogenic. This species significantly lowered the shooting percentage and the yield of both cereals. Foot rot assessment also revealed F. culmorum as the most damaging species. Natural soil-borne infection obviously increased the foot and root rot, and thus the soil-borne F. culmorum strongly affected all treatments. In the harvested seed F. poae dominated in all treatments, but F. culmorum still occurred most abundantly in the seed lot harvested from plots originally inoculated with this species.  相似文献   

15.
During the years 2003 and 2004 grains of wheat and rye were examined for the occurrence of different Fusarium species in Bavaria. The data obtained indicate that rye is infected with Fusarium spp. on a lower level than wheat. Overall F. graminearum was the most important Desoxynivalenol (DON) producing species with infected kernels per sample up to 18,5% whereas F. culmorum recedes more in the background. In addition F. poae was detected in high amounts: up to 28,5% kernels per sample were infected. Also the incidence of F. avenaceum was high. In contrast F. equiseti, F. tricinctum, F. sporotrichioides, F. oxysporum and Microdochium nivale were detected to a much lower extent.  相似文献   

16.
The biocontrol effect of Clonostachys rosea (strains 016 and 1457) on Fusarium graminearum, F. avenaceum, F. verticillioides, F. langsethiae, F. poae, F. sporotrichioides, F. culmorum and Microdochium nivale was evaluated on naturally infected wheat stalks exposed to field conditions for 180 days. Experiments were conducted at two locations in Argentina, Marcos Juarez and Río Cuarto. Antagonists were applied as conidial suspensions at two inoculum levels. Pathogens were quantified by TaqMan real‐time qPCR. During the first year at Marcos Juarez, biocontrol was observed in one antagonist treatment for F. graminearum after 90 days (73% reduction) but after 180 days, the pathogen decreased to undetectable levels. During the second year, biocontrol was observed in three antagonist treatments for F. graminearum and F. avenaceum (68·3% and 98·9% DNA reduction, respectively, after 90 days). Fusarium verticillioides was not controlled at Marcos Juarez. At Río Cuarto, biocontrol effects were observed in several treatments at different intervals, with a mean DNA reduction of 88·7% for F. graminearum and F. avenaceum, and 100% reduction for F. verticillioides in two treatments after 180 days. Populations of F. avenaceum and F. verticillioides were stable; meanwhile, F. graminearum population levels varied during the first 90 days, and low levels were observed after 180 days. The other pathogens were not detected. The study showed that wheat stalks were important reservoirs for F. avenaceum and F. verticillioides populations but less favourable for F. graminearum survival. Clonostachys rosea (strain 1457) showed potential to reduce the Fusarium spp. on wheat stalks.  相似文献   

17.
Details of our long-term research programme concerning the epidemiology of Fusarium spp. and mycotoxin production are summarized. Evaluation of the occurrence of Fusarium spp., mainly on winter wheat (Triticum aestivum), was carried out by investigating Fusarium infection and mycotoxin contamination. Two to 15% of grains were infested during 1995–1998 at three climatologically differing localities of the Rhineland, Germany. Disease progress was accelerated by rainfall during the flowering season. The species most frequently isolated were Fusarium avenaceum, F. poae, F. culmorum and F. graminearum. The mean deoxynivalenol (DON) content varied from 19gkg–1 (1995) to 310gkg–1 (1998) and was not always correlated with disease severity. Organic farming systems showed lower rates of infection with ear blight and lower mycotoxin contamination than conventional farming systems.  相似文献   

18.
In 2001 the range of the total Fusarium contamination percentage of infected seeds was between 0% and 44%, while in 2002 the contamination level was 2–25% in naturally infected Finnish samples and 5–14.5% in six samples from northwestern Russia. The most common Fusarium species in barley were F. avenaceum, F. arthrosporioides, F. sporotrichioides and F. culmorum, while in spring wheat the most common Fusarium species were F. avenaceum, F. arthrosporioides, F. culmorum, F. sporotrichioides and F. graminearum. In most cases, molecular identification with species-specific primers corresponded to the morphological analyses and allowed the identification of degenerated and otherwise morphologically difficult cultures. It was even possible to separate most of the F. arthrosporioides isolates from Finland from the closely-related F. avenaceum isolates. In the phylogenetic analysis of combined β-tubulin, IGS and ITS sequences most European F. arthrosporioides formed a separate clade from most isolates of F. avenaceum and from all isolates of F. tricinctum. Most of the species-specific primers also amplified DNA extracted from grain samples. It was, for instance, possible to detect F. avenaceum in all barley samples with contamination levels higher than 1% and in all spring wheat samples with contamination levels higher than 3%. The detection level for F. graminearum was at a contamination level of 3–5% and that for F. culmorum at a contamination level of 1–5%. In addition, the first Finnish F. langsethiae isolate was found by means of species-specific primers.  相似文献   

19.
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.  相似文献   

20.
Fifteen novel microsatellite markers were isolated from Fusarium graminearum. The level of polymorphism at these novel and 13 previously published microsatellite markers was analysed in 33 F. graminearum strains from Europe, North America, and Nepal. The number of alleles for each of the novel markers ranged from 4 to 20 and gene diversity from 0.417 to 0.962. In comparison with the previously published markers, the resolution for distinguishing among different strains was slightly increased. Twenty-seven markers were also detectable in three F. culmorum strains and one F. crookwellense strain. None of the markers was detected in three F. avenaceum and four F. poae strains, underlining the potential use of these microsatellite markers for species differentiation.  相似文献   

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