Pseudocercosporella Herpotrichoides Research Articles

Fungicidal spectrum and biological properties of a new fungicide, pyriofenone.

Pyriofenone is a new fungicide developed by Ishihara Sangyo Kaisha, Ltd. To determine the fungicidal spectrum of pyriofenone, in vivo pot tests and in vitro mycelial growth-inhibition tests were conducted. Pyriofenone showed excellent activity against wheat and cucumber powdery mildew and moderate efficacy against rice blast in the pot tests. In the mycelial growth-inhibition tests, most fungi were not affected by pyriofenone except for Botrytis cinerea, Helminthosporium sacchari, Pseudocercosporella herpotrichoides, Pyricularia oryzae, Rosellinia necatrix, and Verticillium dahliae. The fungicidal properties of pyriofenone on powdery mildew in cucumber and wheat were evaluated precisely. Pyriofenone exhibited excellent preventive and residual activities. It had high rainfastness in the cucumber leaves against powdery mildew. Pyriofenone also showed inhibitory activity on lesion development upon application until 2 days after inoculation, and the lesion expansion and sporulation of the cucumber powdery mildew fungus were effectively controlled. Furthermore, pyriofenone showed translaminar and vapor activities.

Constitutional and Induced Accumulation of Callose and Phenol Compounds as Elements of Systemic Resistance in Winter Wheat Sprouts

The amounts of accumulated callose and phenol compounds in sprouts of two winter wheat cultivars under inoculation with pathogenic fungus Pseudocercosporella herpotrichoides, the causing agent of wheat eyespot, were determined. Considerable differences were demonstrated in the constitutional and induced accumulation of phytoimmunity substances by the sprouts of the Myronivska 808 and Renan cultivars, which cause specific features of their resistance to pathogenic microorganisms.

Sources of eyespot resistance in winter wheat

Purpose. The study of collection samples of winter wheat for resistance to the causative agent of eyespot on artificial infectious background and the identification of effective sources of resistance among them for use in breeding. Methods. Field (creation of artificial infectious background, accounting expression of the disease) and laboratory (isolation of the pathogen Pseudocercosporellaherpotrichoides in pure culture, inoculum production. During 2016–2018 on the fields at the plant protection department of the V. M. Remeslo Myronivka Institute of Wheat of NAAS 173 collection samples of various ecological and geographical origin on artificial infectious background of Pseudocercosporella herpotrichoides (Fron.) created by spraying winter wheat plants in early spring (tillering stage) with mycelium homogenate developed from strains of the local population of the pathogen. Accounting expression of the disease was carried out in the phase of milk and wax ripeness of winter wheat according to the N. I. Vavilov All-Union Institute of Plant Production method (1976). Results. During period of the research, no winter wheat variety samples immune against eyespot pathogen was detected. The average eyespot progress on plants during the years of the research varied from 12.2 % (2017) to 31.3 % (2018). Among the material studied, 28 samples of winter wheat samples had relative resistance against eyespot, 13 collection samples were the best Mukhrau (GEO), Ignis (SVK), Lukillus (AUT), Rada (SVK), Famulus (DEU), Beres (HUN), SG-RU8096 (CZE), LIMAN (ROU), Bluskawice (POL), Patriarkh (RUS), Reia (UKR), Zysk (UKR) и Gerek (TUR) which for three years of the research in the field on artificial infectious background showed stable relative resistance to this pathogen. 116 winter wheat varieties showed relative susceptibility, the rest showed susceptibility and high susceptibility to eyespot pathogen in the late stages of organogenesis. Conclusions. Thirteen sources of relative resistance to eyespot pathogen have been identified, which are valuable source material for breeding varieties resistant to the pathogen Рseudocercosporella herpotrichoides (Fron.).

Genome-wide association mapping of resistance to eyespot disease (Pseudocercosporella herpotrichoides) in European winter wheat (Triticum aestivum L.) and fine-mapping of Pch1.

Genotypes with recombination events in the Triticum ventricosum introgression on chromosome 7D allowed to fine-map resistance gene Pch1, the main source of eyespot resistance in European winter wheat cultivars. Eyespot (also called Strawbreaker) is a common and serious fungal disease of winter wheat caused by the necrotrophic fungi Oculimacula yallundae and Oculimacula acuformis (former name Pseudocercosporella herpotrichoides). A genome-wide association study (GWAS) for eyespot was performed with 732 microsatellite markers (SSR) and 7761 mapped SNP markers derived from the 90K iSELECT wheat array using a panel of 168 European winter wheat varieties as well as three spring wheat varieties and phenotypic evaluation of eyespot in field tests in three environments. Best linear unbiased estimations (BLUEs) were calculated across all trials and ranged from 1.20(most resistant) to 5.73 (most susceptible) with an average value of 4.24 and a heritability of H 2=0.91. A total of 108 SSR and 235SNP marker-trait associations (MTAs) were identified by considering associations with a -log10 (P value)≥3.0. Significant MTAs for eyespot-score BLUEs were found on chromosomes 1D, 2A, 2D, 3D, 5A, 5D, 6A, 7A and 7D for the SSR markers and chromosomes 1B, 2A, 2B, 2D, 3B and 7D for the SNP markers. For 18 varieties (10.5%), a highly resistant phenotype was detected that was linked to the presence of the resistance gene Pch1 on chromosome 7D. The identification of genotypes with recombination events in the introgressed genomic segment from Triticum ventricosum harboring the Pch1 resistance gene on chromosome 7DL allowed the fine-mapping of this gene using additional SNP markers and a potential candidate gene Traes_7DL_973A33763 coding for a CC-NBS-LRR class protein was identified.

The Effect of Pre-sowing Seed Treatment with Metal Nanoparticles on the Formation of the Defensive Reaction of Wheat Seedlings Infected with the Eyespot Causal Agent.

The paper presents research data of lipid peroxidation and lectin activity in wheat seedlings at seed treatment with solution of metal nanoparticles (Zn, Ag, Fe, Mn, Cu) and sole solution of copper nanoparticles under the high pathogen infection background of Pseudocercosporella herpotrichoides (Fron) Deighton (synonym: Oculimacula yallundae (Wallwork & Sponer) Crous & W. Gams). It was shown that investigated nonionic colloidal solutions of biogenic metals have the antioxidant effect through the inhibition of the synthesis of lipid peroxidation products. The increase of lectin activity levels during the early plants ontogenesis stages was observed in wheat seedlings infected with pathogen pre-treated with the mixture of metal nanoparticles.

VLIV APLIKACE FUNGICIDŮ NA FUSARIÓZY OZIMÉ PŠENICE A DALŠÍ PŮVODCE STÉBLOLAMU

From 1999 to 2004 the occurence of fungi: Pseudocercosporella herpotrichoides (Fron.) and Fusarium spp. was evaluated in small plot field trials on seven varieties of winter wheat. The efficacy of fungicide protection against stem base diseases and influence on yields was monitored in field conditions in Velká Bystřice near Olomouc.For diagnostic of casual fungi two methods were used: 1. Method of coloring mycelium in stems, 2. Method of cultivation of mycelim on agar.Results from detection of casual fungi are following: Pseudocercosporella herpotrichoides (Fron.), Fusarium culmorum (W. G. Sm.) Sacc. and Fusarium graminearum Schwabe.For high efficacy of protection against roots and stem base disease the following fungicide variants should be applied: Sportak Alpha 1.5 l . ha−1 (BBCH 30)/Cerelux Plus 0.7 l . ha−1 (BBCH 51), Sportak HF 1 l . ha−1 (BBCH 30)/Cerelux Plus 0.7 l . ha−1, Alert S 1.0 l . ha−1 (BBCH 30/Cerelux Plus 0.7 l . ha−1 (BBCH 51). The application of fungicides positively influenced yields. Yield increased at average by10–20 % after the aplication but the rise in yields was not in total correlation with the efficacy. These results can be possibly used in the system of integral control of winter wheat against stem base disease in wheat.

Interactions between fungi colonizing the stem base of winter wheat

<em>In vitro</em> conditions, the interactions betecen the fungi most frequently isolated from the stem base of winter wheat were determined. These were the species from genus <em>Fusarium (F. culmorum, F. avenaceum</em> and<em> F. poae</em>) and <em>Rhizoctonia cerealis, Pseudocercosporella herpotrichoides, Alternaria alternata</em> and <em>Aureobasidium bolleyi</em>. Some saprotrophes showed stimulating effect on <em>R. cerealis, P. herpotrichoides</em> and F. poae. Certain species in combined cultures showed exceptionally favourable relationships.

The effect of treating wheat with Ethrel in conjunction with some fungicides on the susceptibility to fungal diseases and on the root zone mycoflora of this plant

Wheat cv. Grana grown under field conditions, in the early phase of the first node formation, was sprayed with Ethrel (0.35 ml/m<sup>2</sup>) and with the fungicides: Sportak 45 EC (0.1 ml/m<sup>2</sup>) and Bayleton Triple (0.2 g/m<sup>2</sup>) - separately and in conjunction with Ethrel. It was found that Ethrel reduced the plant's susceptibility to infection by <i>Cercosporella herpotrichoides</i> and by species of the genus <i>Fusarium</i>. The fungicides were more active and also reduced the susceptibility to infection by <i>Erysiphe graminis</i> and <i>Puccinia triticina</i>. The fungistatic effect of Ethrel and Sportak was synergistic only in the case of <i>Cercosporella herpotrichoides</i>. Other interactions between Ethrel and fungicides were not found. Ethrel and fungicides only slightly affected the mycoflora of the root but they completely eliminated the fungi of the genus <i>Mucor</i> from the rhizosphere and reduced the participation of isolates of the genus <i>Alternaria</i> and <i>Cladosporium</i> in the rhizosphere and rhizoplane of wheat. The fungicides were more active than Ethrel. An interaction between Ethrel and fungicides in the reduction of fungi of the genus <i>Fusarium</i> in the rhizosphere was shown.

Use of polimerase chain reaction (PCR) for detection of Pseudocercosporella herpotrichoides in winter wheat cultivated in different production systems

<i>Pseudocercosporella herpotrichoides</i> was detected by PCR in winter wheat cultivated in different production systems in 2000 and 2001. In all tested systems only pathotype R of pathogen was detected. Detection of fungus depended on production system and weather conditions. Pathogen was not detected in both tested cultivars only in ecological system but only in season with less favourable conditions for disease development

Effect of Ethrel treatment of wheat on the susceptibility to fungal diseases and on the root zone mycoflora of this plant

Wheat cv. 'Grana' grown under field conditions was sprayed with solutions of Ethrel (500, 1000 and 3000 ppm) in three phases of plant development: tillering, appearance of the first node of a culm and coming into ear. The plant analysis was done seven days after the last spray. It has been found that Ethrel treatment decreased the length of a straw, reduced plant susceptibility to <i>Cercosporella herpotrichoides</i>nfection and that with species of the <i>Fusarium</i> genus. On the other hand it increased wheat susceptibility to <i>Erysiphe graminis</i> infection, and particularly to that with <i>Puccinia triticina</i>. Ethrel slightly affected the mycoflora of the root zone - it significantly increased only the percentage of species of the genus <i>Penicillium</i> and reduced that of <i>Mucor hiemalis</i>. The Ethrel effect on the specific composition of rhizoplane mycoflora proved to be insignificant.

Effect of Ethrel treatment of wheat on the effectiveness of some fungicides used as seed dressing

The grain of winter wheat cv. Grana was treated with the following seed dressings: Baytan 17.5 WS, Oxalin K and Vincit WP and sown in experimental plots. In spring after the appearance of the first node the plants were sprayed with Ethrel solution at a concentration of 1000 mg/dm<sup>3</sup>. It was stated that Ethrel enhanced the fungistatic effect of the seed dressings with regard to <i>Cercosporella herpotrichoides, Erysiphe graminis</i> and species of the genus <i>Fusarium</i>, while it increased plant infection by <i>Puccinia triticina</i>.

Immunodiagnosis of eyespot disease in winter wheat cultivated in different production systems

The aim of the study carried out in the years 2001-2003 was to determine the occurrence of <i>Pseudocercosporella herpotrichoides</i> in winter wheat cultivated in different production systems using traditional visible disease assessment and ELISA technique. Pathogen was detected by ELISA test in all years of the study and attained highest level in 2003. The greatest quantities of <i>Pseudocercosporella herpotrichoides</i> were observed in integrated system and monoculture and significantly lower in conventional production system.

The evaluation of winter wheat roots and leaf sheath diseases diagnostic methods

The maltose and mineral media for isolation of <i>Gaeumannomyces graminis</i> from roots were assessed. The differences in numbers of obtained isolates were found depending on the medium used and sampling date. Easier identification of pathogen was possible employing maltose medium. The fungi from genus <i>Fusarium</i> occurring on winter wheat leaf sheaths were identified by mycological analysis and PCR, while the fungus <i>Pseudocercosporella herpotrichoides</i> was detected by PCR and ELISA methods. PCR and ELISA methods enabled to detect pathogens also in periods before the disease symptoms on plants occurred.

我が国におけるムギ類眼紋病菌のfast-evenタイプとslow-featheryタイプの発生

我が国におけるムギ類眼紋病菌のfast-evenタイプとslow-featheryタイプの発生

Diagnostic value of molecular markers linked to the eyespot resistance gene Pch1 in wheat

Eyespot is a major disease of common wheat (Triticum aestivum L.) in temperate climates and causes yield losses of up to 40%. The causal agents of eyespot are Oculimacula acuformis (syn. Tapesia acuformis; anamorph: Helgardia acuformis syn. Pseudocercosporella herpotrichoides var. acuformis) and O. yallundae (syn. T. yallundae; anamorph: H. yallundae syn. P. h. var. herpotrichoides). Pch1 located on chromosome 7DL is the most important and most effective resistance gene, but its use in practical breeding is limited because of difficulties in phenotyping and the fact that markers like XustSSR2001-7DL are often population-specific in German wheat cultivars. Therefore, based on results obtained for endopeptidase Ep-D1a, which is very closely linked to Pch1, molecular markers located in the terminal region of chromosome 7DL were analysed in three DH (double haploid) populations. In a next step these molecular markers were validated on a set of German winter wheat cultivars to obtain information on their usefulness for marker assisted selection (MAS). Based on the analysis of 127 DH-lines, linkage to Pch1 (Ep-D1) was obtained for Xorw1, Xorw5, Xorw6, Xcfd175, Xbarc76, Xwmc14, and Xcfa2040. Analyses of 104 German winter wheat cultivars showed that Xorw1, Xorw6 and the SSR Xcfd175 of these markers are well suited for MAS in German wheat breeding.

Экспрессия генов лектина и дефенсина у сортов пшеницы Мироновская 808 и Roazon при инфицировании Pseudocercosporella herpotrichoides

Экспрессия генов лектина и дефенсина у сортов пшеницы Мироновская 808 и Roazon при инфицировании Pseudocercosporella herpotrichoides

Sensitivity of fungi to urea, ammonium nitrate and their quimolar solution UAN

The sensitivity of oomycota, saprophytic and pathogenic fungi to urea, ammonium nitrate and UAN (urea plus ammonium nitrate in equimolar solution) was studied in laboratory trials. The compounds were applied in agar in concentrations of 0.06, 0.19 and 0.6M. The most toxic was urea. Ammonium nitrate inhibited the growth of fungi only in higher concentrations. In contrast, the growth of <I>Gaeumannomyces graminis</I> was stimulated by even the highest concentration of 0.6M ammonium nitrate. The fungi most sensitive to urea and UAN were <I>Alternaria tenuissima, Botrytis cinerea, Cladosporium cladosporioides and Pseudocercosporella herpotrichoides</I>. No synergistic effect between the two compounds in UAN was found. Urea was toxic also to <I>Colletotrichum acutatum</I> which does not produce urease. Likewise, the urease inhibitor NBPT did not decrease the toxicity of urea to fungi; the urea degradation product ammonia should, therefore, not be assumed to be the only toxic agent. Application of urea in agricultural practice can decrease the population of a pathogen not only by the stimulation of antagonists, but also by the direct toxic effect. The tested concentrations of 0.06–0.6M correspond to 0.36–3.6% (w/w) solution of urea and to 0.64–6.4% UAN used in agricultural practice as a 75% water solution. If the dilution and metabolisation under natural conditions is taken into account, the concentration of urea 0.06M (0.36%) was too low to have an effect of practical importance on fungi. While after application of urea on plants or on plant debris its concentration is increasing due to water evaporation, the concentration of the extremely hygroscopic UAN is decreasing. Therefore, the control effect will depend more on the applied rate than on the concentration.

Performance of the Biocontrol Fungus Piriformospora indica on Wheat Under Greenhouse and Field Conditions

ABSTRACT The endophyte Piriformospora indica colonizes roots of a range of host plants and increases biomass production and resistance to fungal pathogens and, thus has been considered a biocontrol fungus. However, the field performance of this fungus has not yet been tested in temperate climates. Therefore, we evaluated the performance of this fungus in different substrata under greenhouse and practical field conditions. Roots of winter wheat were colonized efficiently, and biomass was particularly increased on poor substrata. In greenhouse experiments, symptom severity of a typical leaf (Blumeria graminis f. sp. tritici), stem base (Pseudocercosporella herpotrichoides), and root (Fusarium culmorum) pathogen was reduced significantly. However, in field experiments, symptoms caused by the leaf pathogen did not differ in Piriformospora indica-colonized compared with control plants. In the field, Pseudocercosporella herpotrichoides disease severity was significantly reduced in plants colonized by the endophyte. Increased numbers of sheath layers and hydrogen peroxide concentrations after B. graminis attack were detected in Piriformospora indica-colonized plants, suggesting that root colonization causes induction of systemic resistance or priming of the host plant. Although the endophyte is not well suited for growth at Central European temperature conditions, it remains to be shown whether P. indica is more suitable for tropical or subtropical farming.

Introgression of a Strawbreaker Foot Rot Resistance Gene from Winter Wheat into Jointed Goatgrass

Strawbreaker foot rot (SFR) [Pseudocercosporella herpotrichoides(Fron) Deighton] is a disease of winter wheat (Triticum aestivumL.) in many wheat growing regions in the world. Resistance to SFR can be conferred by a single dominant gene (Pch1) fromAegilops ventricosaTausch that was transferred onto chromosome 7D of wheat. ‘Madsen’, a hexaploid winter bread wheat, carriesPch1and is highly resistant to SFR. Jointed goatgrass (Ae. cylindricaHost.) is a winter annual grass weed. Wheat and jointed goatgrass have the D genome in common and have been found to hybridize and backcross under field conditions. Since SFR resistance in winter wheat is controlled byPch1on the D genome, it is theoretically possible for resistance to be transferred to jointed goatgrass via backcrossing. A SFR resistant jointed goatgrass population would potentially have an ecological advantage in the presence of the disease. To evaluate the likelihood of gene introgression, Madsen, ‘Stephens’ (a SFR susceptible winter wheat), three jointed goatgrass accessions, and 15 artificially produced backcross progenies (BC2S2) were inoculated with SFR. The percentage of infection in Stephens, the joined goatgrass accessions, and the backcross progenies was 80% or greater except for one BC2S2progeny that had only 20% infection. Madsen had 0% infection. The presence ofPch1in the BC2S2progeny was confirmed using a biochemical marker linked to the resistance gene. These results show that a SFR resistance gene from winter wheat can be transferred to jointed goatgrass.

Analysis of wheat disease resistance data originating from screenings of Gatersleben genebank accessions during 1933 and 1992

Series of 10,348 accessions belonging to 21 species (hexaploid, tetraploid, diploid) of the genus Triticum and 489 accessions belonging to 20 species of the genus Aegilops were scored for disease resistance during a period of 60 years. Tests were performed at the seedling stage for powdery mildew (Erysiphe graminis DC. f. sp. tritici March.), leaf rust (Puccinia recondita Rob. ex Desm. f. sp. tritici Erikss.), stripe rust (Puccinia striiformis West. f. sp. tritici Erikss.) and eyespot (Pseudocercosporella herpotrichoides (Fron.) Deight.) but also at the adult plant stage considering powdery mildew, leaf rust, stripe rust, eyespot and glume blotch (Septoria nodorum Berk.). About 150,000 disease scores recorded on index cards using different scoring scales were transferred to the computer, converted into a 1–9 scale and used to summarise the results. Within the genus Triticum 20% of the material analysed was classified as heterogeneous. For the accessions without detectable segregation a large variability for resistance/susceptibility was detected. At the adult plant stage resistant accessions without visible infections were identified for all diseases. The percentages of resistant accessions at that growth stage were always higher than the ones found in the material tested at the seedling stage. The probability for finding resistant material was shown to be highest in the diploid species ( > 50%) but decreased with increasing ploidy level to about 10% in the hexaploids. For Aegilops it was shown that most of the accessions were homogeneous and highly resistant against powdery mildew (seedling and adult plant stage), leaf rust (adult plant stage) and eyespot (seedling and adult plant stage/natural infection). The data obtained for the individual accessions are available via Internet (http://www.ipk-gatersleben.de).