Effects of two pathogens on the performance of Cirsium arvense in a successional fallow     

S KLUTH  A KRUESS  & T TSCHARNTKE 《Weed Research》2005,45(4):261-269

Biological control of weeds by natural antagonists is of increasing interest. To reduce densities of the weed Cirsium arvense (creeping thistle) in a successional fallow, we applied spores of two pathogens, the biotrophic rust Puccinia punctiformis and the perthotrophic Phoma destructiva, for three consecutive years individually at different dates and combined. The proportion of systemically Puccinia punctiformis-infected C. arvense was not influenced by the treatments, but local rust infection was a good predictor of systemic infection in the following season. Artificial inoculations with P. destructiva increased the incidence of this pathogen in the third year as a result of synergistic effects, when co-inoculated with P. punctiformis. Inoculations with either pathogen had little effect on C. arvense shoot density, although there were transient reductions after combined inoculations with both fungi compared with the fungicide treatment. Cirsium arvense decreased from 60% to 5% cover within 3 years, while the cover of the co-occurring fallow vegetation increased. Under field conditions, with an already high degree of natural P. punctiformis infection, the effects of inoculations of the single pathogens were minor, but reductions in shoot density after combined inoculations indicate that this inoculation may have the potential to cause a decline of this weed.  相似文献   

Formation of pseudosclerotia and bacteria-induced chlamydospores in Phoma foveata     

Sardar Camyon  Berndt Gerhardson 《European journal of plant pathology / European Foundation for Plant Pathology》1997,103(5):467-470

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Biotic factors affecting the expression of partial resistance in pea to ascochyta blight in a detached stipule assay     

Caroline Onfroy  Alain Baranger  Bernard Tivoli 《European journal of plant pathology / European Foundation for Plant Pathology》2007,119(1):13-27

The expression of partial resistance in pea to ascochyta blight (caused by Mycosphaerella pinodes) was studied in a detached stipule assay by quantifying two resistance components (fleck coalescence and lesion expansion) using the method of point inoculation of stipules. Factors determining optimal conditions for the observation of partial resistance are spore concentration, the age of the fungal culture prior to spore harvest and the pathogenicity of the isolate used for testing. Partial resistance was not expressed when spore concentration was high or when the selected isolate was aggressive. Furthermore, assessments of components of partial resistance were highly correlated with disease severity in a seedling test. A screening protocol was developed based on inoculations of detached stipules to study partial resistance in pea. To simplify the rating process, a more comprehensive disease rating scale which took into account fleck coalescence and lesion expansion was tested by screening a large number of genotypes.  相似文献   

Genotype-isolate interaction for resistance to black stem in sunflower (Helianthus annuus)     

R. Darvishzadeh  G. Dechamp-Guillaume  T. Hewezi  A. Sarrafi 《Plant pathology》2007,56(4):654-660

Two experiments were undertaken to determine the partial resistance of sunflower genotypes to seven isolates of Phoma macdonaldii . In the first experiment, 28 genotypes, including recombinant inbred lines and their parents, M6 mutant lines developed by gamma irradiation, and some genotypes from different geographical origins, were used. The experiment consisted of a split-plot design with three replications, each with 12 seedlings per genotype per isolate, in controlled conditions. Seven days after inoculation, plantlets were scored on a 1–9 scale for percentage necrotic area. Highly significant differences were observed among genotypes, isolates and their interactions. The presence of a differential interaction between genotypes and P. macdonaldii isolates was confirmed in a second experiment using 12 genotypes representing large variability for partial resistance to P. macdonaldii isolates, as identified in the first experiment. Inbred lines B454/03, ENSAT-B5 and LC1064C were the most susceptible sunflower genotypes, whereas two American lines SDR19 and SDR18 presented high partial resistance to all P. macdonaldii isolates studied. The least and most aggressive isolates were MA6 and MP3, respectively. Isolates interacted differentially with sunflower genotypes. This study identified two genotypes (AS613 and PAC2) presenting specific resistance to isolate MP8. The results also showed a wide range of isolate-nonspecific partial resistances among the lines tested. The information presented here could assist sunflower breeders to choose parents of crosses for breeding of durable resistance to phoma black stem disease.  相似文献   

Frequency of Avirulence Alleles in Field Populations of Leptosphaeria maculans in Europe     

Anna Stachowiak  Julia Olechnowicz  Malgorzata Jedryczka  Thierry Rouxel  Marie-Hélène Balesdent  Ingrid Happstadius  Peter Gladders  Akinwunmi Latunde-Dada  Neal Evans 《European journal of plant pathology / European Foundation for Plant Pathology》2006,114(1):67-75

This paper describes the first large-scale Europe-wide survey of avirulence alleles and races of Leptosphaeria maculans. Isolates were collected from the spring rape cultivar Drakkar, with no known genes for resistance against L. maculans, at six experimental sites across the main oilseed rape growing regions of Europe, including the UK, Germany, Sweden and Poland. Additionally in Poland isolates were collected from cv. Darmor, which has resistance gene, Rlm9. In total, 603 isolates were collected during autumn in 2002 (287 isolates from Germany and the UK) and 2003 (316 isolates from Poland and Sweden). The identity of alleles at eight avirulence loci was determined for these isolates. No isolates had the virulence allele avrLm6 and three virulence alleles (avrLm2, avrLm3 and avrLm9) were present in all isolates. The isolates were polymorphic for AvrLm1, AvrLm4, AvrLm5 and AvrLm7 alleles, with virulence alleles at AvrLm1 and AvrLm4 loci and avirulence alleles at AvrLm7 and AvrLm5 loci predominant in populations. Virulent avrLm7 isolates were found at only one site in Sweden. Approximately 90% of all isolates belonged to one of two races (combinations of avirulence alleles), Av5-6-7 (77% of isolates) or Av6-7 (12%). Eight races were identified, with four races at frequencies less than 1%. The study suggested that Rlm6 and Rlm7 are still effective sources of resistance against L. maculans in oilseed rape in Europe. The results are comparable to those of a similar survey done in France in autumn 2000 and 2001.  相似文献   

Characterization of a phytotoxic glycoprotein produced byPhoma eupyrena — A pathogen on water lettuce     

Babu  R. Mohan  Sajeena  A.  Vidhyasekaran  P.  Seetharaman  K.  Reddy  M. S. 《Phytoparasitica》2003,31(3):265-274

Phoma eupyrena, the causal agent of leaf blight disease of water lettuce, when purified by affinity and ion exchange chromatography produced an extracellular glycoprotein (Pe 65) in concentrations of ∼ 8 μg ml⁻¹ in the stationary culture. Coomassie-blue stained SDS-PAGE analysis of culture filtrates and purified Pe 65 showed its molecular mass to be 65 kDa. The blighting and necrosis of leaf tissues were observed within 4–6 days when 1–5 μg of Pe 65 was injected into the mesophyll of water lettuce. These symptoms closely resembled those caused by foliar inoculation with the pathogen. Recognition of Pe 65 by N-glycosidase F treatment and by polyclonal antibodies raised in rabbit against the whole glycoprotein, indicated that the protein is a highly glycosylated protein (50% carbohydrate) and that it is strongly enclosed by the antigenic glycosidic moiety. http://www.phytoparasitica.org posting May 6, 2003.  相似文献   

枣铁皮病病原鉴定   总被引：23，自引：0，他引：23  

康绍兰 《植物病理学报》1998,28(2):165-171

 枣铁皮病主要为害大枣果实,可导致果实腐烂和提早落果,据症状特点可分为铁皮型和缩果型2种类型。1993~1995年对河北和河南2省6个不同枣区大枣铁皮病病果进行分离、接种和再分离,证实枣铁皮病病原为:链格孢Alternaria alternata(Fr.) Keissler;实腐茎点霉Phoma destructiva Plowr,壳梭孢属一种真菌Fusicoccum sp.3种病原真菌可以单独或混合侵染。  相似文献   

向日葵黑茎病菌主要生物学特性及致病性研究   总被引：1，自引：0，他引：1  

轩娅萍  郭庆元  吴喜莲  陈为民 《新疆农业大学学报》2011,(6):494-500

采用传统生物学方法,对向日葵黑茎病菌(Phoma macdonaldii Boerema)主要生物学特性及致病特性进行了系统研究.生物学特性研究表明,向日葵黑茎病菌在PSA等多种常用培养基上均能生长,以PSA培养基最适;病菌生长温度范围为5～35℃,最适生长温度为25℃,致死温度为50℃;较适宜的酸碱范围为pH5.0～...  相似文献   

不同营养和培养条件对向日葵黑茎病菌生长特性的影响     

刘彬  张祥林  王翀  罗明  乾义柯  陈燕 《新疆农业科学》2011,48(2):271-277

[目的]对向日葵黑茎病菌Phoma helianthi Taberosi生态适应性中的营养和培养条件进行研究,以期建立常规生物学检测方法,以便采取有效检疫处理措施.[方法]不同营养和培养条件下(包括培养基、碳源、氮源、温度、酸碱度、光照),对该菌培养7 d,测量其菌落直径大小和观察其生长状况.并用SPSS 12.0软件进行相应的计算处理、统计分析.[结果]向日葵黑茎病菌在PDA、HLA培养基上生长较好,在WA培养基上生长较慢.该病菌能充分利用可溶性淀粉和硝酸钾.在温度4-32℃均能生长,最适生长温度为24-28℃,适宜生长的PH4.0-8.0,最适PH5.0-7.0;在全光照培养条件下有助于菌丝的生长.[结论]通过不同营养和培养条件下的生长情况,可知该病菌的最适生长条件,有助于对该病菌进行有效的检疫处理.  相似文献   

Differences in resistance in onion cultivars to pink root rot disease in Iran     

M. Nasr Esfahani  B. Ansari Pour 《Journal of General Plant Pathology》2008,74(1):46-52

Forty-five onion (Allium cepa) cultivars were evaluated for disease resistance to the fungal pathogen Pyrenochaeta terrestris (pink root disease). Forty-three Iranian cultivars and two commercially exotic resistant cultivars (Texas Early Grano and Yellow Sweet Spanish) were grown in a glasshouse for two successive years (2003 and 2004) in Isfahan, Iran. Susceptibility of the cultivars was determined using a scale of 0–3. Six cultivars had significantly lower susceptibility of pink root compared to the exotic ones. High susceptibility tended to be associated with high mean scores (2–3), and the highly resistant cultivars had the lowest scores (0–1). In addition, the 45 examined cultivars were ranked from 1 to 45 according to their markedly differing reactions to P. terrestris, which differed markedly. Of 32 cultivars that were less resistant, 30 with an intermediate status or tolerance (1–2) differed considerably in their rank order. No pink root symptoms were seen in the early stages, but on blotter paper or wheat-straw agar some roots turned pink with no pycnidia formation, whereas on potato dextrose agar medium (PDA) with a few fresh healthy and sterile onion roots on the surface, mycelia and pycnidia were recovered. Variance and cluster analysis showed similar results among the cultivars with various levels of resistance, tolerance and susceptibility as determined by scoring scales.  相似文献