Occurrence of Didymella ascospores in western and southern Poland in 2004–2006

The concentration of airborne Didymella spores has been investigated at two monitoring sites situated along the west–south transect in Poland (Szczecin, Kraków), i.e. from a height of 100 to 219 m, respectively, above sea level. The aerobiological monitoring of fungal spores was performed by means of two Lanzoni volumetric spore traps. The high Didymella spore numbers were observed at both cities in June, July and August. Statistically significant correlations have been found mainly between the Didymella spore concentrations in the air and the minimum air temperature and relative air humidity. The spore count of Didymella is determined by the diversity of local flora and weather conditions, especially by the relative air humidity. The identification of factors that influence and shape spore concentrations may significantly improve the current methods of allergy prevention

Effect of hosts on competition among clones and evidence of differential selection between pathogenic and saprophytic phases in experimental populations of the wheat pathogen Phaeosphaeria nodorum

<p>Abstract</p> <p>Background</p> <p>Monoculture, multi-cropping and wider use of highly resistant cultivars have been proposed as mechanisms to explain the elevated rate of evolution of plant pathogens in agricultural ecosystems. We used a mark-release-recapture experiment with the wheat pathogen <it>Phaeosphaeria nodorum </it>to evaluate the impact of two of these mechanisms on the evolution of a pathogen population. Nine <it>P. nodorum </it>isolates marked with ten microsatellite markers and one minisatellite were released onto five replicated host populations to initiate epidemics of Stagonospora nodorum leaf blotch. The experiment was carried out over two consecutive host growing seasons and two pathogen collections were made during each season.</p> <p>Results</p> <p>A total of 637 pathogen isolates matching the marked inoculants were recovered from inoculated plots over two years. Genetic diversity in the host populations affected the evolution of the corresponding <it>P. nodorum </it>populations. In the cultivar mixture the relative frequencies of inoculants did not change over the course of the experiment and the pathogen exhibited a low variation in selection coefficients.</p> <p>Conclusions</p> <p>Our results support the hypothesis that increasing genetic heterogeneity in host populations may retard the rate of evolution in associated pathogen populations. Our experiment also provides indirect evidence of fitness costs associated with host specialization in <it>P. nodorum </it>as indicated by differential selection during the pathogenic and saprophytic phases.</p

The role of biomass and fossil fuel substitutes in infrastructure and technology of the sustainable agriculture

W pracy przedstawiono charakterystykę kilku rodzajów biomasy, przydatnej do przetwarzania na biopaliwa stałe, ciekłe i gazowe I, II i III generacji. Zaprezentowano korzyści i zagrożenia, wynikające z niezbędnego zwiększania udziału rolnictwa w energetycznym wykorzystaniu biomasy jako odnawialnego źródła energii (OZE).Presented are several types of biomass suitable for conversion to solid, liquid and gaseous biofuels of I, II and III generation. Considered are advantages and threats connected with indispensable increase of the share of agriculture in the use of biomass as the Renewable Energy Source (RES)

Reaction of winter triticale somaclonal lines to Fusarium spp. at the seedling stage

Response of 136 somaclonal lines obtained from 15 winter triticale genotypes (Bolero, Dagro, Grado, Lasko, Moniko, Presto, Ugo, GRH 32-1, KS-24, MAH 15668-1, MAH 15833-1/1, T/8, T/9, T/28, T/47), to Fusarium seedling blight was evaluated. Mixture of five Fusarium species was used for inoculation. Somaclonal lines varied widely in their resistance to Fusarium spp. scored by coleoptile and root infection, and reduction of length of shoot and roots, and seedling weight. Most of the somaclonal lines differed significantly from parental genotypes in at least one of the above parameters. It was found that resistant parental genotypes (e.g. Grado, KS-24) produced mainly more susceptible somaclonal lines and susceptible ones (e.g. Ugo, MAH 15833-1/1) gave rise mainly to more resistant lines. However, some resistant lines originated from resistant genotypes (e.g Presto) were found

Use of random amplified polymorphic DNA [RAPD] assay for differentiation among isolates of Stagonospora spp. and Septoria tritici

The genetic similarity of three species: Septoria tritici, Stagonospora nodorum and Stagonospora avenae f. sp. triticea - important pathogens in many cereal production areas worldwide was assessed by random amplified polymorphic DNA (RAPD) assay. In preliminary research DNA of 14, 9, and 7 monopyenidios- pore isolates of S. nodorum, S. tritici, and S. a. tritícea, respectively, were amplified by PCR with four primers. Afterwards the research was focused on three mono- pyenidiospore isolates from each species studied. The isolates of each species selected for the study varied in pathogenicity and were diverse geographically. PCR with the set of 14 selected primers resulted in 99 different bands, ranged from 180 to 2500 base pairs in length. Most primers in PCR (especially RAD11, RAD31, RAD32, RAD33) revealed uniform bands for isolates of S. a. tritícea, that allow to identify this species among the others. The cluster analysis using Unweighed Pair-Group Method with Averaging (UPGMA) revealed interspecies disagreement among the isolates ranging from 32 to 53%. The intraspecies disagreement ranges were 17-20%, 38-43%, 42-44% for S. avenae f. sp. triticea, S. nodorum and S. tritici, respectively. Cluster analysis classified isolates into three homogeneous clusters. Each cluster grouped isolates of one species according to their current taxonomie ranks based on spore size, colony morphology and host ranges. In addition, two of the clusters represented by isolates of S. nodorum and S. a. tritícea were distinctly separated at a lower linkage distance from the third one comprising isolates of S. tritici. A slight inconsistency found in grouping some isolates indicates that such groupings should be done with caution. The present study indicates that the PCR- RAPD assay is of a potential use in taxonomy of Stagonospora spp. and Septoria tritici as well as in molecular identification of casual disease agents

Odporność grzyba Botryotinia fuckeliana (De Bary) Whetzel (Botrytis cinerea Pers.) – patogena malin, truskawek i innych roślin uprawnych na fungicydy benzimidazolowe [Resistance of Botryotinia fuckeliana (De Bary) Whetzel (Botrytis cinerea Pers.) to benzimidazole fungicides]

In the period 1975-1977 forms of the fungus Botrytis cinerea were found in Poland resistant to benzimidazole fungicides. The incidence of the resistant forms increases with the more intensive use of these fungicides. The resistance of Botrytis cinerea to benzimidazole compounds is a cross-resistance involving the whole group of these agents, nowithstanding wihich of them was applied. The resistance acquired by the fungus does not change its reaction to other prophylactic fungicides

Sequence diversity of beta-tubulin (tubA) gene in Phaeosphaeria nodorum and P. avenaria

Full-length coding sequences of the beta-tubulin gene (tubA) were PCR-amplified and sequenced from 42 Phaeosphaeria isolates, including, 16 P. nodorum and 23 P. avenaria species from cereals, two Polish isolates from rye (Secale cereale L.), and one isolate from dallis grass (Paspalum dilatatum Poir). A tubA gene of size 1556 bp was identified in wheat- and barley-biotype P. nodorum (PN-w and PN-b), P. avenaria f. sp. avenaria (Paa), homothallic P. avenaria f. sp. triticea (P.a.t.) (Pat1) and the P.a.t. isolate (Pat3) from the State of Washington. The tubA gene length polymorphisms were detected in two P.a.t. isolates (Pat2) from foxtail barley (Hordeum jubatum L.), one from dallis grass and two Polish isolates from rye. These size differences were due to the variation of intron lengths among these three Phaeosphaeria species. All Phaeosphaeria isolates have identical 1344 bp exons that can be translated into a 447 amino acid P-tubulin. Like glyceraldehyde-3-phosphate dehydrogenase, the P-tubulin amino acid sequence was identical in all Phaeosphaeria species used in this study, with the exception of the two Pat2 isolates. Six amino acid differences were evident in the P-tubulin of these Pat2 isolates. (c) 2005 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved

Cell wall-degrading enzymes and aggressiveness in Stagonopspora nodorum

Stagonospora nodorum produces cell wall degrading enzymes when grown in culture media containing cell wall components. The pathogen grew as well on minimal agar plates containing cellulose, xylan and pectin as glucose, except having sparser mycelia. Four cell wall-degrading enzymes, cellulase, xylanase, pectinase and b-1,3-glucanase were coordinately induced in culture filtrates growing on xyaln and cellulose as substrates. An aggressive isolate (sn26-1) secreted more cell wall-degrading enzymes than the others. Based on isoelectric focusing profiles, six to seven xylanase isozymes were induced by cellulose and xylan. No difference was found in the high (sn26-1) and low (9074) aggressive isolates. Addition of cell wall-degrading enzyme mixtures, not high xylanase alone, to a spore suspension of a low aggressive isolate (9074) caused a limited increase in tissue necrosis. We conclude that the cell wall degrading enzymes play a role in early penetration of the host by the fungus, but they are not important elicitors for disease development