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1.
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2.
Determination of the Fusarium protein equivalent (FPE) levels in kernels for better characterisation of genotypes showing Fusarium head blight (FHB) resistance, and better detection of susceptibility to kernel infection among genotypes with slight symptom expression was carried out. Twelve wheat cultivars and eight hexaploid winter wheat lines derived from a cross of Triticum aestivum with related species T. macha, T. polonicum, and T. dicoccoides were evaluated for levels of spike and kernel infection, the content of the mycotoxin deoxynivalenol (DON) and FPE in kernels after artificial inoculation with the fungus Fusarium culmorum in the field in 2006–2007. The ELISA immunochemical method was employed for the quantitative analyses of DON and FPE. Three wheat lines had a significantly low infection of spikes and kernels compared to cvs Sumai 3 and Nobeoka Bozu, indicating the presence of specific resistance mechanisms to FHB. The significantly low AUDPC (area under the disease progress curve) and the high level of FPE and DON content in kernels indicated a lack of resistance in one wheat line (crossed with T. polonicum). The results showed highly significant correlations (P < 0.01) between FPE and DON content and between FPE and AUDPC. In addition, correlations between FPE and reductions in yield components were also highly significant. Quantification of Fusarium spp. in wheat kernels can be helpful for evaluating wheat genotypes for their levels of resistance to FHB.  相似文献   

3.
Fusarium head blight (FHB), caused by fungi belonging to the Fusarium genus, is a widespread disease of wheat (Triticum aestivum) and other small-grain cereal crops. The main causal agent of FHB, Fusarium graminearum, produces mycotoxins mainly belonging to type B trichothecenes, such as deoxynivalenol (DON), that can negatively affect humans, animals and plants. DON detoxification, mainly through glucosylation into DON-3-O-glucose, has been correlated with resistance to FHB. A UDP-glucosyltransferase from the model cereal species Brachypodium distachyon has been shown to confer resistance both to initial infection and to spike colonization (type I and type II resistances, respectively). Here, the functional characterization of transgenic wheat lines expressing the Bradi5g03300 UGT gene are described. The results show that, following inoculation with the fungal pathogen, these lines exhibit a high level of type II resistance and a strong reduction of mycotoxin content. In contrast, type I resistance was only weakly observed, although previously seen in B. distachyon, suggesting the involvement of additional host-specific characteristics in type I resistance. This study contributes to the understanding of the functional relationship between DON glucosylation and FHB resistance in wheat.  相似文献   

4.
A series of experiments was conducted to determine whether type I resistance (resistance to initial infection) to fusarium head blight (FHB) in wheat could be assessed using fungal species/isolates that do not produce deoxynivalenol (DON), a mycotoxin critical to the spread of Fusarium graminearum in the wheat spike. It was shown that, while the non-toxin-producing species Microdochium nivale and M. majus could infect following spray inoculation of wheat spikes, they were unable to spread within the spike following point inoculation. However, although these species might reveal type I resistance, they are not highly pathogenic towards wheat. A nivalenol (NIV)-producing isolate of F. graminearum caused high levels of disease following spray inoculation, but spread only very slowly within the spike and rarely induced bleaching above the point of inoculation. It is proposed that spray inoculation with an appropriate, aggressive, non-DON-producing FHB pathogen may be used to characterize type I resistance to complement point inoculation with a DON-producing isolate to assess type II resistance (resistance to spread within the spike).  相似文献   

5.
Pathogen development and host responses in wheat spikes of resistant and susceptible cultivars infected by Fusarium culmorum causing Fusarium head blight (FHB), were investigated by means of electron microscopy as well as immunogold labelling techniques. The studies revealed similarities in the infection process and the initial spreading of the pathogen in wheat spikes between resistant and susceptible cultivars. However, the pathogen’s development was obviously more slow in the resistant cultivars as in comparison to a susceptible one. The structural defence reactions such as the formation of thick layered appositions and large papillae were essentially more pronounced in the infected host tissues of the resistant cultivars, than in the susceptible one. β -1,3-glucan was detected in the appositions and papillae. Furthermore, immunogold labelling of lignin demonstrated that there were no differences in the lignin contents of the wheat spikes between susceptible and resistant cultivars regarding the uninoculated healthy tissue, but densities of lignin in host cell walls of the infected wheat spikes differed distinctly between resistant and susceptible cultivars. The lignin content in the cell walls of the infected tissues of the susceptible wheat cultivar increased slightly, while the lignin accumulated intensely in the host cell walls of the infected wheat spikes of the resistant cultivars. These findings indicate that lignin accumulation in the infected wheat spikes may play an important role in resistance to the spreading of the pathogen in the host tissues. Immunogold labelling of the Fusarium toxin DON in the infected lemma showed the same labelling patterns in the host tissues of resistant and susceptible cultivars. However, there were distinct differences in the toxin concentration between the tissues of the susceptible and resistant cultivars. At the early stage of infection, the labelling densities for DON in resistant cultivars were significantly lower than those in the susceptible one. The present study indicates that the FHB resistant cultivars are able to develop active defence reactions during infection and spreading of the pathogen in the host tissues. The lower accumulation of the toxin DON in the tissues of the infected spikes of resistant cultivars which results from the host’s defence mechanisms may allow more intensive defence responses to the pathogen by the host.  相似文献   

6.
Fusarium head blight and mycotoxin contamination of wheat,a review   总被引：9，自引：0，他引：9  
Summary An infection of bread wheat by fusarium head blight contaminates the crop with mycotoxins, particularly deoxynivalenol (DON) and nivalenol (NIV). The toxicity and natural occurrence of these mycotoxins in wheat are reviewed. Based on 8 years data of fusarium head blight epidemics of wheat in the Netherlands, DON contamination of the grain was estimated. Fusarium head blight ratings averaged an infection of 1.7% of all spikelets; estimates for DON contamination averaged 0.9 mg kg–1. Taking a guideline level for DON in uncleaned bread wheat of 2 mg kg–1, in 1979 and 1982 a wheat crop was produced with estimated DON concentrations above the limit of tolerance. Human and animal exposure to mycotoxins in the Netherlands appears to be small but chronic. The information presented in this paper illustrates the need for an annual evaluation of the crop for fusarium head blight incidence and mycotoxin content, and the necessity of fusarium head blight resistant wheat cultivars.Samenvatting Aaraantasting van tarwe doorFusarium culmorum enFusarium graminearum leidt tot vorming van mycotoxinen in het graan, waarvan deoxynivalenol (DON) en nivalenol (NIV) de belangrijkste toxinen zijn. In dit artikel wordt een overzicht gegeven van de toxicologische aspecten, en het voorkomen van deze toxinen in tarwe. Informatie over DON en NIV in tarwe in West-Europa is schaars. Gebaseerd op gegevens vanFusarium epidemieën in de jaren 1979–1986 wordt een schatting gegeven van de concentratie DON in Nederlandse tarwe. Rekening houdend met de herkomst en verwerking van tarwe, blijken zowel in dierlijk als menselijk voedsel lage concentraties DON chronisch voor te komen. Op basis van een maximaal toelaatbare dagelijkse dosis DON van 3 g kg–1 lichaamsgewicht is de schatting van de dagelijkse opname van DON in het jaar volgend op de oogst van 1982 net op de grens. Zowel een jaarlijkse inventarisatie vanFusarium aantasting en DON besmetting van het graan, als de ontwikkeling vanFusarium-resistente rassen zijn noodzakelijk.  相似文献   

7.
Twenty four isolates of Fusarium graminearum, half of which were 3-acetyldeoxynivalenol (3-ADON) and half 15-acetyldeoxynivalenol (15-ADON) chemotypes, were tested for their ability to produce deoxynivalenol and to cause Fusarium head blight (FHB) in spring wheat cultivars. The objectives of this study were to determine (1) whether 3-ADON isolates differ in aggressiveness, as measured by the FHB index, and DON production from 15-ADON isolates under field conditions, and (2) whether the performance of resistant host cultivars was stable across isolates. Field tests of all isolates were conducted with three replicates at each of two locations in Canada and Germany in 2008 with three host genotypes differing in FHB resistance level. The resistant host genotype showed resistance regardless of the chemotype or location. The differences between mean FHB indices of 3-ADON and 15-ADON isolates were not significant for any wheat genotype. In contrast, average DON production by the 3-ADON isolates (10.44 mg kg−1) was significantly (P < 0.05) higher than for the 15-ADON isolates (6.95 mg kg−1) at three of the four locations where moderately resistant lines were tested, and at both locations where susceptible lines were evaluated. These results indicate that 3-ADON isolates could pose a greater risk to food safety. However, as the mean aggressiveness and DON production of 3-ADON and 15-ADON chemotypes was similar on highly resistant lines, breeding and use of highly resistant lines is still the most effective measure of reducing the risks associated with DON in wheat.  相似文献   

8.
 为明确不同小麦品种(系)对赤霉病的抗性和麦穗组织中DON毒素积累水平,培育和利用抗赤霉病和DON毒素积累的品种提供资源和依据,本研究采用单小花滴注接种法对河南省的106个小麦品种(系)抗赤霉病性进行鉴定分析,并用ELISA测定了病穗组织中DON毒素水平。结果表明不同小麦品种(系)对赤霉病的抗性有显著差异,106个小麦品种(系)中未发现抗病和中抗材料,中感品种(系)有华育198、郑麦103和春丰0021等14个,占13.2%;感病的有曌式2010-06、百农898和中麦63等92个,占86.8%。不同小麦品种(系)籽粒、颖壳和穗轴中DON毒素积累水平有显著差异,籽粒中DON毒素水平在(0.70~287.63)mg/kg之间,其中郑03876、豫保1号和中麦63 的DON毒素水平在2 mg/kg 以下,为抗毒素材料;其他的103个品种DON毒素水平大于2 mg/kg;颖壳和穗轴中的DON毒素水平在(51.03~392.87)mg/kg之间,普遍比籽粒中DON毒素含量高。籽粒中DON毒素水平与小麦品种(系)的平均病害严重度间呈极显著正相关。  相似文献   

9.
Fusarium head blight (FHB) and deoxynivalenol (DON) mycotoxin produced by Fusarium graminearum reduce barley yield and quality worldwide. Hundreds of quantitative trait loci (QTLs) have been identified in wheat and barley but their functions are largely unknown. Metabolic profiling was applied to better understand the mechanisms of resistance and to identify potential FHB resistance biomarker metabolites in barley. Four FHB resistant (H15-2, H148-3, H203-2 and H379-2) and one susceptible (H97-2), two-row, purple, doubled-haploid (DH) lines of barley were inoculated with either the pathogen or mock-solution. The disease severity quantified as the area under the disease progress curve (AUDPC) significantly varied between the resistant and susceptible genotypes, but not among the resistant genotypes. Neither the amount of DON nor the detoxified product, proportion of total DON, was significant among lines. The resistance related (RR, higher in abundance in resistant than in susceptible) metabolites varied in numbers and fold changes among the DH resistant lines. A total of 144 RR constitutive (RRC) and 167 RR induced (RRI) metabolites were selected, of which 39 and 37, respectively, were putatively identified. These RR metabolites mainly belonged to six chemical groups: phenylpropanoids, hydroxycinnamic acid amides, flavonoids, fatty acids, terpenoids, and alkaloids. The specific RR metabolites identified in each DH line, the possible mechanisms of resistance in each and their use as potential biomarkers are discussed.  相似文献   

10.
Fusarium head blight (FHB) is a complex cereal disease associated with trichothecene production; these mycotoxins are factors of aggressiveness in wheat. Six species (bread and durum wheat, triticale, rye, barley and oats) were submitted to point inoculations with two isogenic strains of Fusarium graminearum; a wild strain (Tri5 +) produced trichothecenes and the mutated strain (Tri5 –) did not. The trichothecene-producing strain was generally more aggressive than the non-producing strain, but this varied according to crop species. The difference in aggressiveness was less pronounced in rye, a very resistant species. High resistance levels were observed in oats due to the large spacing between florets. In six-row barley, despite the existence of a moderate Type II resistance, the fungus was often observed to move externally from one floret to another within the dense spike, without penetrating the rachis. Bread wheat had low resistance to the trichothecene-producing strain and good resistance to the non-producing strain. Triticale responded to the strains in a similar way but was somewhat more resistant to both: symptoms on the spikelets and rachis of the triticales were restricted to below the point of inoculation. Durum wheat was susceptible to the trichothecene-producing strain and only moderately resistant to the non-producing strain, which was able to cause serious damage only to this species. Our study confirmed that the role of trichothecenes in FHB pathogenesis differs among species. The failure of the trichothecene non-producing F. graminearum strain to spread within the inflorescence of wheat, triticale, rye and barley, and the significant reduction of spread in the durum wheat spike strongly suggested that trichothecenes are a major determinant of fungal spread and disease development in Triticeae.  相似文献   

11.
Fusarium head blight (FHB) of wheat is a destructive fungal disease worldwide and has become more severe over the last two decades. Development of FHB resistant wheat varieties is the most effective way to manage FHB. The middle and lower reaches of the Yangtze River are the traditional FHB epidemic areas in China. The landraces and germplasms with resistance to FHB originating from this region were used to identity FHB resistance quantitative trait loci (QTLs). Yangmai 158 and Ningmai 9 are the most popular varieties for commercial wheat production in this region and both have moderate FHB resistance. A high-density genetic map was constructed using 282 recombinant inbred lines (RILs) from a cross between Ningmai 9 and Yangmai 158. Ten QTLs related to Type II FHB resistance were identified, and QFhb-3B.1 and QFhb-5A were stably detected across all environments. Based on position alignment, QFhb-3B.1 from Ningmai 9 is likely to be Fhb1 and QFhb-5A from Yangmai 158 is a novel QTL not previously described. A competitive allele-specific PCR (KASP) marker closely linked to QFhb-5A was developed and could be used for marker-assisted selection. Distribution of QFhb-5A was tested with numerous accessions from a widespread core collection. The results suggest that QFhb-5A has undergone both natural and artificial selection. Some RILs with both Fhb1 and QFhb-5A presented better FHB resistance than the parents and could be used in FHB resistance breeding.  相似文献   

12.
为研究小麦UDP-葡萄糖基转移酶7(UDP-glycosyltransferase 7,TaUGT7)的抗赤霉病功能,利用DNAMAN 6.0软件对Ta UGT7及其同源蛋白进行序列比对,应用实时荧光定量PCR(quantitative real-time PCR,qRT-PCR)技术分析经赤霉菌Fusarium graminearum和脱氧雪腐镰刀菌烯醇（deoxynivalenol,DON）处理后的苏麦3号小穗中TaUGT7基因的表达特征,利用基因枪在洋葱表皮细胞瞬时表达TaUGT7-eGFP进行亚细胞定位,采用农杆菌介导法在小麦品种Fielder中过量表达TaUGT7基因并进行赤霉病抗性鉴定。结果表明,TaUGT7在氨基酸序列上与已知赤霉病抗性相关UGT相似性较低;TaUGT7在赤霉菌接种24 h后开始被诱导表达,在DON处理2 h后逐步被诱导表达;Ta UGT7蛋白亚细胞定位于细胞膜和细胞核中;qRT-PCR检测发现,TaUGT7在8株独立的过表达转基因株系中均有不同程度的上调表达;与野生型对照相比,过表达株系TaUGT7-395和TaUGT7-457中的平均病小穗率显著下降。...  相似文献   

13.
Fusarium head blight (FHB) is a major threat to wheat production globally, causing not only yield losses but also food and feed contamination. FHB research began at the International Maize and Wheat Improvement Center (CIMMYT) in the early 1980’s, and since then, large-scale FHB screening has been conducted to identify and incorporate new resistance genes into elite CIMMYT germplasm. Promising lines with good FHB resistance were regularly compiled as a Fusarium Head Blight Screening Nursery (FHBSN) and distributed worldwide. The first FHBSN was assembled in 1985, and the most recent two were the 13th and 14th FHBSN that were released in 2011 and 2012, respectively. Candidate lines for a FHBSN came mainly from different CIMMYT wheat breeding programs and were tested for three consecutive years before being included in an FHBSN. FHBSN screening was conducted under strictly standardized field conditions at El Batán, where CIMMYT headquarters is located, using artificial inoculation of F. graminearum strains, whose aggressiveness and DON chemotypes had been previously identified. FHB index was scored at 31 days after inoculation for all lines and DON concentration was measured only for elite lines in their 2nd and 3rd year of evaluation. Haplotyping is a new tool for genetic characterization of FHBSN entries and helps to identify new resistance sources with novel resistance genes and to better target crosses toward diversifying and/or pyramiding resistance. The 13th FHBSN was taken as an example in this paper to show the procedure and strategy for the development of new FHB resistant lines.  相似文献   

14.
A. Serfling  F. Ordon 《Plant pathology》2014,63(6):1230-1240
Fusarium culmorum causes head blight, produces toxins and reduces yield and quality of cereals. To prevent damage caused by fusarium head blight (FHB), azole fungicides are mainly applied. The occurrence of insensitivity to azoles is a major problem in agriculture. The present study shows that a tebuconazole insensitive strain of F. culmorum can be readily produced in the laboratory, but that the resulting strain of the fungus is of lower fitness in vitro. Insensitivity was confirmed microscopically and by cell viability and metabolic activity. The tebuconazole insensitive strain shows cross insensitivity to nine important azoles. In addition, plants inoculated with the insensitive F. culmorum strain showed no reduction of FHB symptoms and deoxynivalenol (DON) content after tebuconazole treatment, compared to an inoculation with the sensitive strain. Use of wheat cultivars carrying a high resistance level (i.e. cv. Toras) was the most effective method for reducing symptoms and decreasing DON content, independent from the level of fungicide insensitivity of the F. culmorum strain. In conclusion, resistant cultivars and a fungicide mixture which combines different mechanisms of action in fungal metabolism should be applied to avoid fungicide insensitivity of Fusarium spp. in future.  相似文献   

15.
赤霉病是我国小麦上的重要病害,品种抗病性利用是控制病害发生的重要措施,明确小麦抗赤霉病资源的抗性类型,有利于小麦抗赤霉病育种。2003年和2004年对9个常用抗源在穗期进行单花滴注和喷雾接种,研究其抗侵染和抗扩展性,并对病穗中的脱氧雪腐镰刀菌烯醇(DON)的含量进行分析。结果表明,望水白和苏麦3号具较好的抗侵染和抗扩展能力,其中望水白的抗扩展性最好;感染赤霉病后,DON在5个抗源穗组织中的含量差异显著,DON在望水白和繁60096穗组织中积累量明显比在苏麦3号、延岗坊主和翻山小麦低。通过对望水白/安农8455遗传群体两年的病小穗率和病穗中DON毒素含量的比较,发现二者具有一定的相关性,且受环境影响比较大。  相似文献   

16.
Fusarium head blight (FHB) symptom development, relative spikelet weight (RSW), fungal DNA (FDNA) and deoxynivalenol (DON) content of grain was assessed in the FHB resistant winter wheat cv. WEK0609 and the FHB susceptible cv. Hobbit sib, and among doubled haploid progeny lines (DHLs) developed from a cross between these cultivars. In addition, the relationship between FHB resistance traits and germination on DON-containing medium (in vitro DON tolerance (IVDT)) was also investigated to assess the possibility of using this test as in vitro method of screening for FHB resistance in this cultivar. Analysis indicated that WEK0609 resistance significantly reduced symptom development, yield loss and the FDNA and DON content of grain relative to Hobbit sib. Although both the DON and FDNA content were greater in susceptible than in resistant progeny lines, the ratio of DON to FDNA decreased with increasing susceptibility. The resistance derived from WEK0609 appears to have a greater effect on colonisation of the grain by the fungus than on the accumulation of DON within the grain. In vitro tolerance to DON does not appear to relate to FHB resistance in WEK0609 and thus does not provide a means of selecting for FHB resistance derived from this cultivar.  相似文献   

17.
Fusarium head blight (FHB) caused by Fusarium graminearum (FG) is a destructive disease impacting barley worldwide. The disease reduces the grain yield and contaminates grains with mycotoxins, such as the trichothecene deoxynivalenol (DON). Although the infection mainly affects the grain yield, little is known about its impact on grain structural and biochemical properties. Yet, such information is instrumental to characterize the facets of resistance in the grains. After artificial inoculation of six barley cultivars with FG in a 2 years field test, different levels of symptoms on spikes, of colonisation of grains and of DON content were observed. The infections caused a reduction in grain weight and an average decrease of 10% of the β-glucan content in grains, indicating alterations of grain filling, composition and structure. According to our results, we postulate the presence of two distinct resistance mechanisms in the grain, tolerance to grain filling despite infection as well as the inhibition of mycotoxin accumulation. Differently to wheat, in barley, type IV resistance (tolerance of the grain to infection) is directly linked with type III resistance (resistance against kernel infection). The resistance against toxin accumulation (named type V resistance in wheat) appeared to be independent to all other resistance types. Generally, the resistance was significantly influenced by the environment and by genotype x environment interactions explaining the generally weak stability of resistance in barley. Interestingly, a significant and inverse relationship between DON contamination and β-glucan content in grains suggests that high β-glucan content in grains contributes to type V resistance.  相似文献   

18.
Host resistance is the main way to control Fusarium head blight (FHB) in wheat. Despite improved levels of resistance to infection and spread in vegetative tissue, the toxin deoxynivalenol (DON) can still accumulate to unacceptable concentration levels. In this study, our objectives were to assess the genetic variation for resistance to kernel infection (RKI) and resistance to toxin accumulation (RTA) and their role in controlling DON. We collected spikes with different levels of visual symptoms from each of 32 wheat genotypes and at four environments and determined DON and fungal biomass (FB) from each sample. We assessed RKI by regressing FB on the level of visual symptoms and RTA by regressing DON on FB for each genotype. Significant genetic effects were found for RKI and RTA. Some genotypes consistently had low FB in their grain despite increasing visual symptoms suggesting RKI. Additionally, some genotypes consistently had low DON in their grain despite increasing FB levels suggesting a higher RTA in these genotypes. The variation for RKI and RTA explained a significant fraction of the variation for DON among genotypes with moderate visual symptoms using independent grain samples. Although RKI and RTA were significantly correlated (r = 0.58, P = 0.05), RTA was more predictive of DON accumulation because it modeled 32 to 44% of the genotype sum of squares for DON, while only 9 to 10% were predicted using RKI. Thus, variation for RTA was important in explaining variation for DON among genotypes with acceptable levels of resistance to fungal infection and spread. This work indicates that there is a need to develop a better understanding of RTA and rapid screening methods for this trait.  相似文献   

19.
Introduction of alien genes into wheat has been proposed as a strategy to breed cultivars with improved resistance to Fusarium seedling blight (FSB) and Fusarium head blight (FHB). In this study, we co-transformed different anti-fungal peptides (AFPs) into an elite wheat cultivar Yangmai11. We identified the genetically stable transgenic wheat lines carrying single or multiple genes by PCR, qRT-PCR and Southern blot analyses. Transgenic wheat lines 451 and 513 expressing two AFPs displayed a consistent, significantly improved overall resistance to FSB and FHB, whereas only FHB resistance was observed from other lines. Furthermore, crude proteins extracted from the lines 451 and 513 showed a clear inhibitory activity against F. graminearum in vitro. Taken together, it was essential to properly combine and express AFPs in transgenic wheat in order to obtain an improved overall resistance to Fusarium pathogens.  相似文献   

20.
Seven spring wheat, 13 barley, 14 oats and 20 winter wheat genotypes were inoculated at flowering in 1993 and 1994 with mixed conidial suspensions of 8 isolates of Fusarium culmorum. Four weeks after inoculation, head blight was recorded in the field. After harvest, seed infection was assessed by a Freezing Blotter Test in the laboratory. Seed samples were also analyzed for deoxynivalenol (DON) content. Differences were found in head blight rating, the levels of infected seeds and the DON content between wheat, barley, and oats and between cultivars. Highly significant correlations were found between the percentage of heavily infected seed and the DON content. The weighted mean value of infected seeds and DON content were also significantly correlated. No significant correlation was found between head blight rating in the field and DON content. The level of infected seeds, as determined by the Freezing Blotter Test, was a better indication of the DON content in the seeds than the head blight rating. This visual assessment of levels of infected seeds gives a reliable estimate of resistance to Fusarium.  相似文献   

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