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In order to identify chromosomes involved in resistance to Fusarium head blight, a set of 21 substitution lines of Triticum macha (resistant) chromosomes into ‘Hobbit’'sib’(susceptible) were evaluated in trials over 2 years. For the first year's trial, all plants were inoculated on the same day with a conidial suspension of F. culmorum. For the second trial, individual plants were inoculated precisely at mid anthesis of each plant over a period of 2 weeks. The disease level was assessed by visual scoring, relative ear weight and F. culmorumn‐specfic quantitative polymerase chain reaction. The results showed that T. macha chromosomes 1B, 4A and 7A conferred good overall resistance, suggesting that they carry important genes for resistance. In two additional trials, T. macha and ‘Hobbit’'sib’ were evaluated for resistance to brown foot rot. The results showed that T. macha was more susceptible than ‘Hobbit’‘sib’, indicating that stem base disease response is not correlated with head blight resistance in these cultivars. 相似文献
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Existing PCR-based assays for the detection of the cereal pathogen Fusarium avenaceum were found to cross-react with F. tricinctum . An investigation into the phenetic relationship between these two species using two different marker systems revealed a close relationship between them despite their being from separate taxonomic sections. Whilst RFLP differences in the ITS regions surrounding the nuclear 5.8 S rDNA were insufficient to discriminate between isolates of the two species, they were clearly differentiated by RAPD profiling. RAPD fragments from F. avenaceum isolates were screened for hybridization to F. tricinctum DNA on Southern blots. One of 12 selected RAPD fragments showed no hybridization to genomic DNA from F. tricinctum . This fragment was cloned and sequenced, and the sequence obtained was used to design PCR primers. The primers were found to be specific for F. avenaceum, with no cross-reactions obtained with F. tricinctum or any other wheat pathogen assayed. The primers were able to differentiate between the two species in infected plant material, in contrast to the earlier assays. 相似文献
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Stem base disease (eyespot, sharp eyespot and brown foot rot) was assessed visually and by the polymerase chain reaction (PCR) technique on single plants sampled at four-week intervals in two crops of winter wheat grown in the UK in 1992–3. PCR assays were conducted for Fusarium avenaceum , F. culmorum , both varieties of Microdochium nivale , both eyespot-causing species of Tapesia and Rhizoctonia cerealis . PCR diagnoses were compared with visual diagnoses at each time point. Eyespot was caused principally by T. acuformis (R-type) and developed rapidly late in the season. Visual diagnoses of eyespot were largely confirmed by PCR but T. acuformis was detected in many plants lacking eyespot symptoms. R. cerealis was detected at relatively low incidences on both sites, and sharp eyespot visual diagnoses did not correlate with the incidence of any of the pathogens assayed by PCR. Brown foot rot, caused principally by Microdochium nivale var . majus , accumulated earlier in the season than eyespot. Overall, visual diagnoses of stem base disease coincided poorly with PCR data until after growth stage (GS) 30. 相似文献
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Variation in Pathogenicity Associated with the Genetic Diversity of Fusarium graminearum 总被引：2，自引：0，他引：2
J.P. Carter H.N. Rezanoor D. Holden A.E. Desjardins R.D. Plattner P. Nicholson 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(6):573-583
We screened 188 isolates of Fusarium graminearum, which originated from northwest Europe, the USA and Nepal, for genetic diversity using a sequence-characterised amplified region polymorphism (SCAR). On the basis of this analysis, 42 of the 118 isolates were selected for random amplified polymorphic DNA (RAPD) analysis. Three groups were identified, two of which, A and B, contained the isolates from Nepal, and a third, group C, contained the isolates from Europe and the USA. In pathogenicity tests on wheat and maize seedlings, group C isolates were more pathogenic than the group A and B isolates. The isolates were assigned chemotypes based on their ability to produce the trichothecene mycotoxins nivalenol (NIV) and deoxynivalenol (DON). Isolates from group A were equally likely to produce NIV or DON while group B isolates produced predominantly NIV, and group C isolates produced predominantly DON. Within group A, isolates of the two chemotypes were equally pathogenic to wheat but isolates with the NIV chemotype were significantly more pathogenic to maize. The results confirm that distinct genetic groups exist within F. graminearum and demonstrate that these groups have different biological properties, especially with respect to their pathogenicity to two of the most economically important hosts of this pathogen. 相似文献
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The pathogenicity of Microdochium nivale var. majus and var. nivale was tested on wheat, rye and oat seedlings using both visual disease scoring and quantitative PCR measurements. In an individual inoculation trial at 10°C var. majus and var. nivale were strongly pathogenic towards wheat and rye, with var. nivale causing slightly greater disease in rye. At this temperature only var. nivale caused significant disease of oats. In a further experiment M. nivale was inoculated as a series of mixtures of the two varieties and incubated at 15°C. The ratio of the varieties present in the inoculum and present at harvest was analysed by quantitative PCR and this enabled a coefficient of selection to be calculated for the varieties on each host. M. nivale var. majus showed a weak selective advantage over var. nivale on wheat (0.33 ± 0.08) and oat seedlings (0.35 ± 0.016) and M. nivale var. nivale showed a strong selective advantage over var. majus on rye seedlings (0.92 ± 0.26). The isolates were also compared for sensitivity to benzoxazolinone (BOA), a hydroxamic acid compound derived from rye leaves. M. nivale var majus was found to be significantly more sensitive to BOA than M. nivale var. nivale , indicating a possible mechanism for the selective advantage of var. nivale growing on rye. This is the first substantiated indication of a significant difference in host preference between Microdochium nivale var. majus and var. nivale . 相似文献
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