Predicting ash dieback severity and environmental suitability for the disease in forest stands     

Eva Chumanová  Dušan Romportl  Ludmila Havrdová  Daniel Zahradník  Vítězslava Pešková  Karel Černý 《Scandinavian Journal of Forest Research》2019,34(4):254-266

Ash dieback, caused by the ascomycete fungus Hymenoscyphus fraxineus, has been rapidly expanding across Europe during the last two decades, posing a considerable threat to native ash populations. In this study, we applied regression-based models trained by field data, in conjunction with geographic information systems, to produce spatial predictions of ash dieback severity and environmental suitability for the disease in Czech forests. A model of actual ash dieback severity relates disease extent to silvicultural and environmental characteristics of forest stands and their neighbourhood, while a model of environmental suitability for the disease quantifies the relative susceptibility of sites to the disease, independent of the current silvicultural characteristics. The final predictive maps suggested that fertile lowlands and humid areas bordering Poland and Slovakia were the most endangered regions. Areas at the lowest risk of damage were concentrated in dry areas and in highland and mountain areas in the western part of the country, usually with poor soils on acid bedrock. Predictions of actual disease severity are an effective tool for guiding the current management of infested stands whereas predicting environmental suitability is useful for making long-term strategic decisions, e.g. identifying areas where future ash regeneration and cultivation may be unsuccessful.  相似文献   

Pre-symptomatic detection of <Emphasis Type="Italic">Plasmopara viticola</Emphasis> infection in grapevine leaves using chlorophyll fluorescence imaging     

Ladislav Cséfalvay  Gabriele Di Gaspero  Karel Matouš  Diana Bellin  Benedetto Ruperti  Julie Olejníčková 《European journal of plant pathology / European Foundation for Plant Pathology》2009,125(2):291-302

Plasmopara viticola is an economically important pathogen of grapevine. Early detection of P. viticola infection can lead to improved fungicide treatment. Our study aimed to determine whether chlorophyll fluorescence (Chl-F) imaging can be used to reveal early stages of P. viticola infection under conditions similar to those occurring in commercial vineyards. Maximum (F_V/F_M) and effective quantum yield of photosystem II (Φ_PSII) were identified as the most sensitive reporters of the infection. Heterogeneous distribution of F_V/F_M and Φ_PSII in artificially inoculated leaves was associated with the presence of the developing mycelium 3 days before the occurrence of visible symptoms and 5 days before the release of spores. Significant changes of F_V/F_M and Φ_PSII were spatially coincident with localised spots of inoculation across the leaf lamina. Reduction of F_V/F_M was restricted to the leaf area that later yielded sporulation, while the area with significantly lower Φ_PSII was larger and probably reflected the leaf parts in which photosynthesis was impaired. Our results indicate that Chl-F can be used for the early detection of P. viticola infection. Because P. viticola does not expand systemically in the host tissues and the effects of infection are localised, Chl-F imaging at high resolution is necessary to reveal the disease in the field.  相似文献   

The first detection of ‘<Emphasis Type="Italic">Candidatus</Emphasis> Phytoplasma trifolii’ in <Emphasis Type="Italic">Rhododendron</Emphasis> hybridum     

Jaroslava Přibylová  Karel Petrzik  Josef Špak 《European journal of plant pathology / European Foundation for Plant Pathology》2009,124(1):181-185

Four Rhododendron hybridum plants (from cvs Moravanka and Don Juan), all exhibited symptoms of shortened axillary shoots, reduced leaves with vein clearing and yellowing, undeveloped flowers, and general stunting in a rhododendron nursery garden in southern Bohemia in 2007. Electron microscopy examination of ultra-thin sections revealed the presence of numerous polymorphic phytoplasma-like bodies in the phloem tissue of leaf midribs and petioles. The phytoplasma etiology of this disease was further confirmed by polymerase chain reaction (PCR) using universal phytoplasma primers. Restriction fragment length polymorphism (RFLP) analysis of amplification products obtained with a R16F2/R16R2 primer pair from all symptomatic plants indicated the presence of phytoplasma from the 16SrVI-A subgroup. A detailed comparison of the amplified sequences and phylogenetic analysis confirmed that the phytoplasma belonged to the subgroup 16SrVI-A (clover proliferation phytoplasma group). This is the first report of the natural occurrence of ‘Candidatus Phytoplasma trifolii’ in plants of Rhododendron hybridum.  相似文献   

Purple coneflower with reddening and phyllody: a new host of clover phyllody phytoplasma   总被引：1，自引：0，他引：1  

Jana?FránováEmail author  Jaroslava?P?ibylová  Karel?Petrzik 《European journal of plant pathology / European Foundation for Plant Pathology》2009,123(1):85-90

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<Emphasis Type="Italic">Turnip ringspot virus</Emphasis> recognised on Chinese cabbage in Russia     

Igor Koloniuk  Josef Špak  Karel Petrzik 《European journal of plant pathology / European Foundation for Plant Pathology》2008,122(3):447-450

The nucleotide sequence of the 3′-terminal part of the RNA1 genome segment of the M12 isolate of comovirus Turnip ringspot virus (TuRSV) was established. This isolate originated in 1989 in Moscow (Russia) from Chinese cabbage with Radish mosaic virus-like symptoms. Comparison of the M12 RNA polymerase amino acid sequence with that of Radish mosaic virus (RaMV) revealed significant differences; these proteins are of different length and are only about 75% identical. On the other hand, the amino acid sequence of the M12 RNA polymerase was more than 94% identical with that of TuRSV recently described in Toledo (USA). We conclude that TuRSV occurs in Europe as well as in America and probably represents a new species of the genus Comovirus.  相似文献   

Quail cell lines supporting replication of Marek's disease virus serotype 1 and 2 and herpesvirus of turkeys     

Li X  Schat KA 《Avian diseases》2004,48(4):803-812

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Cytotoxic T lymphocyte responses to Marek's disease herpesvirus-encoded glycoproteins     

Markowski-Grimsrud CJ  Schat KA 《Veterinary immunology and immunopathology》2002,90(3-4):133-144

Cell-mediated immune responses are important for protective immunity to Marek’s disease (MD), especially because MD herpesvirus (MDV) infection is strictly cell-associated in chickens with the exception of the feather follicle epithelium. A system previously developed using reticuloendotheliosis (REV)-transformed cell lines stably expressing individual MDV genes allows the determination of relevant MDV proteins for the induction of cytotoxic T lymphocyte (CTL) responses. To examine the importance of glycoproteins for the induction of CTL, the MDV genes coding for glycoproteins (g) C, D, E, H, I, K, L, and M were stably transfected into the REV-transformed chicken cell lines RECC-CU205 (major histocompatibility complex (MHC): B²¹B²¹) and RECC-CU91 (MHC: B¹⁹B¹⁹). All transfected cell lines were lysed by REV-sensitized, syngeneic splenocytes obtained from MD-resistant N2a (MHC: B²¹B²¹) and MD-susceptible P2a (MHC: B¹⁹B¹⁹) chickens, indicating that the expression of individual MDV glycoproteins did not interfere with antigen processing pathways. Only cell lines expressing gI were recognized by CTL from both N2a and P2a MDV-infected chickens. Cell lines expressing glycoproteins gC and gK, and to a lesser extent, gH, gL, and gM were lysed by syngeneic MDV-sensitized splenocytes from N2a birds but not P2a birds. In contrast, gE was recognized by MDV-sensitized effector cells from the P2a line and not the N2a line. Glycoprotein D was not recognized by either line, with the exception of one marginally significant P2a assay. These results indicate that late viral glycoproteins are relevant for the induction of cell-mediated immunity during MDV infection.  相似文献   

Chicken innate immune response to oral infection with Salmonella enterica serovar Enteritidis     

Marta Matulova  Karolina Varmuzova  Frantisek Sisak  Hana Havlickova  Vladimir Babak  Karel Stejskal  Zbynek Zdrahal  Ivan Rychlik 《Veterinary research》2013,44(1):37

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Biotic homogenization of Central European urban floras depends on residence time of alien species and habitat types     

Zdeňka Lososová  Milan Chytrý  Lubomír Tichý  Jiří Danihelka  Karel Fajmon  Ondřej Hájek  Kateřina Kintrová  Deana Láníková  Zdenka Otýpková  Vladimír Řehořek 《Biological conservation》2012,145(1):179-184

Spread of alien species may result in biotic homogenization, i.e. increasing similarity between biotas of different areas. We examined whether the flora of Central European cities is becoming homogenized because of the spread of alien species, whether the contribution of aliens to homogenization depends on residence time, and whether habitats under more intense human pressure are more homogenized. Using floristic composition data from a standardized sample of 1-ha plots located in seven habitat types in 32 cities in Central Europe, Belgium and the Netherlands, we compared homogenization effects of archaeophytes (pre-AD 1500 aliens) and neophytes (post-AD 1500 aliens) using rarefaction curves, Jaccard dissimilarity index, Mantel tests and homogenization index. We found that archaeophytes contributed to homogenization and neophytes to differentiation of floras among cities, but generally the spread of alien species caused differentiation. Differentiation was low in the most disturbed urban habitats, such as city squares, boulevards or early successional sites, but was strongest in moderately disturbed habitats, such as city parks and residential areas with an open building pattern. We conclude that biotic homogenization depends on alien plants’ residence time. Aliens introduced within the past five centuries are often rare, not yet having achieved their potential range; they therefore increase floristic differentiation. Conversely, species introduced more than five centuries ago have had sufficient time to disperse into most suitable habitats, and consequently contribute to homogenization. Although invasions may therefore initially increase biodiversity, they could ultimately lead to homogenization. These processes are faster and stronger in more disturbed habitats.  相似文献   

Toxicity of ggr-Benzene Hexachloride in Clothing     

Horton RG  Karel L  Chadwick LE 《Science (New York, N.Y.)》1948,107(2775):246-247

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