Plant Protection Science, 2002 (vol. 38), SI 1 - 6th Conf EFPP
Comparative study of proteases of pathogenic and saprophytic filamentous fungiOriginal Paper
Y.E. Dunaevsky, T.N. Gruban, G.A. Beliakova, M.A. Belozersky
Plant Protect. Sci., 2002, 38(10):S99-S101 | DOI: 10.17221/10328-PPS 
The presence of protein in the culture medium induced secretion of proteases in the studied filamentous fungi species. Comparative analysis of extracellular proteases expressed in vivo by saprotrophic (Trichoderma harzianum, Penicillium terlikowskii) and pathogenic (Alternaria alternata, Botrytis cinerea, Ulocladium botrytis) filamentous fungi species has been carried out. All isolated enzymes were classified as serine proteases on the basis of inhibitor analysis data. According to substrate specificity and the effect of some inhibitors it is proposed that enzymes from T. harzianum and P. terlikowskii are...
Improved diagnostic tools for the certification of strawberry propagation material - the use of PCR and NASBA for detection of Strawberry vein banding virus (SVBV)Original Paper
D. Vašková, J. Špak
Plant Protect. Sci., 2002, 38(10):S24-S27 | DOI: 10.17221/10313-PPS
Control of SVBV relies completely on the use of virus-free planting material, that can be tested either by biological indexing or by molecular methods. A NASBA-based amplification was developed for the detection of SVBV. NASBA is a method based on the primer-dependent, specific amplification of RNA by concurrent activity of a special enzyme mix (AMV-reverse transcriptase, RNaseH, T7 RNA polymerase) at a single temperature (41°C). Specific and sensitive detection of the amplified sequence can be performed in the same tube using molecular beacons. Sensitivity of SVBV-NASBA was 102 molecules of in vitro RNA detected per reaction. Results of the NASBA-based...
Molecular identification of a phytoplasma naturally infecting Populus nigra L. cv. Italica trees in CroatiaOriginal Paper
M. Šeruga, D. Škorić, S. Botti, S. Paltrinieri, N. Juretić, A. Bertaccini
Plant Protect. Sci., 2002, 38(10):S28-S30 | DOI: 10.17221/10314-PPS
Leaf and branch samples of 10 Populus nigra L. cv. Italica trees were collected from the urban Zagreb area in late summer/autumn 2001. One of the trees exhibited leaf yellowing, overall sparse foliage, stunting and decline. Phytoplasma 16S rDNA was amplified in direct and nested PCR assays using universal and specific phytoplasma primer pairs, from nucleic acids extracted by two different procedures. Strong amplification signals were observed in samples from symptomatic Lombardy poplar as well as in samples from 4 of the asymptomatic trees. RFLP analyses of amplicons showed patterns characteristic of the phytoplasmas belonging to the Aster yellows...
Discrimination of Czech Armillaria species based on PCR method and high performance liquid chromatographyOriginal Paper
J. Lochman, O. Šerý, L. Jankovský, V. Mikes
Plant Protect. Sci., 2002, 38(10):S31-S34 | DOI: 10.17221/10316-PPS
The genus Armillaria belongs to basidiomycetes and has been known to induce root rot disease and to cause extensive economic losses to a forest crop. We analysed about 40 isolates of Armillaria collected in Czech Republic by PCR and restriction analysis using gel electrophoresis and ion-exchange HPLC. Restrictase Hinf I was able to discriminate all investigated Armillaria species. The sensitivity and resolution of HPLC method was better than that performed by gel electrophoresis. HPLC was able to detect some heterozygous. The results prove the similarity of the species A. borealis, A. cepistipes, A....
Development of microsatellite markers for the characterisation of Phaeoisariopsis griseola (bean angular leaf spot agent) populations in Central AmericaOriginal Paper
J.P. Busogoro, O. Duterme, P. Lepoivre
Plant Protect. Sci., 2002, 38(10):S35-S37 | DOI: 10.17221/10315-PPS
Although several researches revealed an important diversity within Phaeoisariopsis griseola, the bean angular leaf spot (ALS) agent, no sexual recombination was already detected for this fungus. That apparent contradiction gave rise to the interest to develop codominant markers in order of a more precise analysis of the pathogen populations. Microsatellites were expected to allow characterising P. griseola populations in terms of allele frequencies. A genomic library was constructed by ligating DNA fragments, previously prepared by enzymatic restriction of total DNA of two pathogen strains, into a pZERO plasmid. After transformation...
New methods for detecting and enumerating fungal spores of plant pathogensOriginal Paper
R. Kennedy, A.J. Wakeham
Plant Protect. Sci., 2002, 38(10):S38-S42 | DOI: 10.17221/10317-PPS
Information on the presence or absence of airborne spores or other particles would be useful in an increasing number of areas including agriculture. Traditional methods used for detecting and enumerating of airborne spores of fungal plant pathogens are time consuming and require specialist knowledge. Some spore types (e.g. ascospores) are difficult to differentiate using these methods. To facilitate this, new methods, which can be used to accurately differentiate fungal spore types, are required. A Burkard 7-day volumetric spore trap used in combination with an immunofluorescence test has been developed to detect and quantify field-trapped ascosporic...
Investigation of differences between wheat and barley forms of Wheat dwarf virus and their distribution in host plantsOriginal Paper
J. Schubert, A. HABEKUß, F. Rabenstein
Plant Protect. Sci., 2002, 38(10):S43-S48 | DOI: 10.17221/10318-PPS
Wheat dwarf virus, a monogemini virus, infects several cereal species. Until now complete sequence data have been published only for wheat isolates. We cloned the complete DNA of 21 isolates from wheat, barley and Lolium spec. and compared the sequences with published data. Two types of the virus were found as previously described. Degree of entire nucleic acid homology between both isolates was in the range of 84%. The Large Intergenic Region showed most pronounced differences while the RepA gene was most conserved. No intermediate forms were found, though both isolates co-existed in the same hosts. Sequence data lead to the suggestion that...
Spread of fire blight in Austria and Hungary - variability of Erwinia amylovora strainsOriginal Paper
M. Keck, M. Hevesi, W. Ruppitsch, A. Stöger, S. Richter
Plant Protect. Sci., 2002, 38(10):S49-S55 | DOI: 10.17221/10319-PPS
First outbreaks of fire blight were detected in Austria in 1993 and in Hungary in 1995. 137 Erwinia amylovora isolates were compared by PCR-RFLP, sequencing of the repeat region of the PstI fragment of plasmid pEA29, RAPD and AFLP analysis. Differences of repeat numbers in first isolates were observed. Six isolates showed different RAPD profiles. In AFLP analysis, so far, no differences in fragment pattern were determined. Pathogenicity tests with micropropagated apple cultivars revealed differences in plant susceptibility and in virulence of isolates. Responses of Malus tissue were visualized by the use of epifluorescence microscopy through...
Rice seedborne infection in southern SpainOriginal Paper
M. Aguilar, M. Castejón, M. García
Plant Protect. Sci., 2002, 38(10):S56-S59 | DOI: 10.17221/10320-PPS
Rice (Oryza sativa) seeds were analysed to determine their potential transmission of pathogenic and saprophytic micro-organisms. In four and three hundred lots (stocks) of seeds, in 1998 and 1999 respectively, proceeding from mechanical drying sheds, none presence of Pyricularia oryzae was detected. It did not happen that way for Drechslera spp., whose presence was detected in 8.3% and 28% of the lots, in 1998 and 1999; within these ones the affected seed average was 1.3% in both years. Fusarium sp. appeared in 41% and 48% of the lots, in 1998 and 1999, respectively; the affected seed percentage, within these lots,...
Airborne nomadic pathogens: does virulence accumulate along the way from Paris to Beijing?Original Paper
E. Limpert, P. Bartoš, H. Buchenauer, W.-K. Graber, K. Müller, J. Šebesta, J.G. Fuchs
Plant Protect. Sci., 2002, 38(10):S60-S64 | DOI: 10.17221/10321-PPS
It is well established that race-specific resistance selects for the specifically matching genes effecting virulence in the pathogen. As well, the use of different R-genes in time makes virulence complexity, VC (the number of virulences per pathogen genotype), to increase. Moreover, it becomes obvious here that the wind-dispersed cereal rusts and mildews are obligate nomads and highly mobile. As a consequence of these points and as a result of modelling, VC was expected to increase in the direction of predominant winds, e.g. from west to east across Europe, and it did by approximately one or more virulences per 1000 km. Starting from the barley mildew...
Initial events in the establishment of cereal powdery mildew infectionOriginal Paper
T.L.W. Carver, A.J. Wright, Thomas B.J.
Plant Protect. Sci., 2002, 38(10):S65-S68 | DOI: 10.17221/10322-PPS
Like spores of many fungi, conidia of Blumeria graminis, the powdery mildew fungus of cereals, release extracellular material. It is released within seconds where conidial surface projections touch a leaf. This ECM is probably adhesive since centrifugation showed that forces greater than those due to normal wind speeds are needed to displace conidia. Also, ECM release is probably involved in rapid sensing of substratum contact, leading to germ tube emergence close to the contact site. Thus, ECM release apparently confers at least two benefits to pathogen survival.
Plasmodiophora brassicae, the causal agent of clubroot disease, may penetrate plant cell walls via cellulaseOriginal Paper
I. Mühlenberg, A. Schuller, J. Siemens, P. Kobelt, J. Ludwig-Müller
Plant Protect. Sci., 2002, 38(10):S69-S72 | DOI: 10.17221/10323-PPS
Plasmodiophora brassicae causes the clubroot disease of Brassicaceae by its obligate biotrophic lifestyle within host roots. The pathogen enters the root cortex, but is soon found near the vascular tissue. There are basically two possibilities for the distribution of Plasmodiophora within the root tissue: 1. distribution by simultaneous division with the host cell or 2. by active migration from cell to cell. It has been shown that plasmodia of the pathogen are indeed able to penetrate plant cell walls. We have therefore begun to isolate a cellulase gene from the pathogen by using degenerated primers to different fungal cellulases....
Mutations in wheat leading to enhanced resistance to the fungal pathogen of yellow rustOriginal Paper
L.A. Boyd, J.A. Howie, T. Worland, R. Stratford, P.H. Smith
Plant Protect. Sci., 2002, 38(10):S73-S75 | DOI: 10.17221/10324-PPS
The isolation and study of plant resistance genes is revealing a story more complicated than the gene-for-gene hypothesis originally implied. The story of resistance is complicated even further by the discovery of genes that appear to have a negative effect on resistance. Early studies in the wheat line Hobbit 'sib' identified a number of chromosomes that reduced the level of field resistance to the fungal pathogen Puccinia striiformis f.sp. tritici, the causal agent of yellow rust on wheat. From a series of deletion mutants generated in Hobbit 'sib' a number of mutant lines were selected that gave enhanced resistance to yellow rust....
Biochemical mechanisms of plant defense a central role for reactive oxygen speciesOriginal Paper
I. Heiser, E.F. Elstner
Plant Protect. Sci., 2002, 38(10):S76-S86 | DOI: 10.17221/10325-PPS
In general mechanics stress is clearly defined as the point or degree of bending of an elastic system at the very point of just symptomless reversibility and irreversible deformation or break. In medicine and botany, stress is supposed to indicate all situations beyond normal, defined by the observer. All organs of higher plants (with some exceptions) perform aerobic metabolism and are thus subject to activated oxygen species. Oxygen oversaturation and thus oxygen stress may occur under various different conditions. Since most abiotic and biotic stress situations in plants result in the accelerated production of ROS oxidative stress is a common signaling...
Interactions of soil nutrient environment, pathogenesis and host resistanceOriginal Paper
G.R. Dixon
Plant Protect. Sci., 2002, 38(10):S87-S94 | DOI: 10.17221/10326-PPS
Host plants and soil borne pathogens that attack them exist within an ecological matrix populated by numerous microbial species that may influence the access of pathogenesis. These events are moderated by physical and chemical components of the soil. The impact of inorganic and organic nutrients on pathogenesis and the development of host resistance are discussed in this review using two host - pathogen combinations as examples. Calcium, boron, nitrogen and pH have been demonstrated to affect the processes of resting spore germination, host invasion and colonisation in the Plasmodiophora brassicae-Brassica combination that results in clubroot...
Plant resistance and strategies for breeding resistant varietiesReview
D.A.C. Pink, P. Hand
Plant Protect. Sci., 2002, 38(10):S9-S14 | DOI: 10.17221/10310-PPS
An explanation of the 'boom-bust' cycle of resistance breeding was provided by the gene-for-gene relationship between a pathogen and its host. Despite this understanding, most R genes continued to be deployed singly and resistance has been ephemeral. The reasons for breeding 'single R gene' varieties are discussed. Alternative strategies for the deployment of R genes and the use of quantitative race non-specific resistance have been advocated in order to obtain durable resistance. The feasibility of both of these approaches is discussed taking into account the impact of technologies such as plant transformation and marker-assisted...
The influence of jasmonic acid on the amount and the distribution of cysteine proteinase PLCP-2 in healthy and PVYNTN infected potato plants (Solanum tuberosum L.)Original Paper
M. Pompe-Novak, M. Tušek-Žnidarič, B. Štrukelj, M. Ravnikar
Plant Protect. Sci., 2002, 38(10):S95-S98 | DOI: 10.17221/10327-PPS
The localization of cysteine proteinase PLCP-2 was investigated in potato plants (Solanum tuberosum L.) cultivar Désirée by electron microscopy. Healthy and PVYNTN infected potato plants were grown in vitro on media with or without a supplement of jasmonic acid. We had already shown that PLCP-2 is present in leaves, stems, tips of shoots and tips of roots of healthy and PVYNTN infected plants. It was detected in various cell types in protein bodies in vacuoles, in cytoplasm and in cell walls. There were significantly larger amounts of PLCP-2 in plants grown on medium with a supplement of jasmonic acid in both healthy...
Development of RT-PCR tests for the routine detection of latent and ILAR viruses in fruit treesOriginal Paper
S. Marbot, J. Kummert, M. Salmon, M. Vendrame, A. Huwaert, O. Dutrecq, P. Lepoivre
Plant Protect. Sci., 2002, 38(10):S21-S23 | DOI: 10.17221/10312-PPS
The detection throughout the year of latent and ILAR viruses in fruit trees by classical serological tests appears to be unreliable. Recently, these problems have smoothed themselves out by the use of molecular methods. We have developed RT-PCR protocols which are simple and reliable for routine detection of these viruses throughout the year.
Turnip mosaic virus determinants of virulence for Brassica napus resistance genesOriginal Paper
C.E. Jenner, F. Sánchez, K. Tomimura, K. Ohshima, F. Ponz, J.A. Walsh
Plant Protect. Sci., 2002, 38(10):S155-S157 | DOI: 10.17221/10343-PPS
Dominant resistance genes identified in Brassica napus lines are effective against some, but not all, Turnip mosaic virus(TuMV) isolates. An infectious clone of an isolate (UK 1) was used as the basis of chimeric virus constructions usingresistance-breaking mutants and other isolates to identify the virulence determinants for three dominant resistance genes.For the resistance gene TuRB01, the presence of either of two mutations affecting the cylindrical inclusion (CI) proteinconverted the avirulent UK 1 to a virulent isolate. Acquisition of such mutations had a slight cost to viral fitness inplants lacking the resistance...
Special Issue - DISEASE RESISTANCE IN PLANT PATHOLOGY, 6th Conference of European Foundation for Plant Pathology, Prague, Czech Republic, 8-14 September 2002Fist part
editors
Plant Protect. Sci., 2002, 38(10):S0 | DOI: 10.17221/10620-PPS
Plant pathology in the Czech RepublicReview
V. Kůdela
Plant Protect. Sci., 2002, 38(10):S1-S8 | DOI: 10.17221/10309-PPS
An outline of past achievements in plant pathology in the CR and main recent problems of Czech plant pathologists are given. A description of the present state in plant pathology in the CR is preceded by data on the structure of CR, on its agriculture, research and development. The outstanding feature of the Czech agriculture is large-scale production. However, the CR still lags behind the EU in yields per hectare. Compared with the EU member states, the CR devotes less money (less then 0.7% of GDP) to research and development (R&D). The trend of state subsidies to R&D in the agriculture sector in current prices is stagnant. It represents an...
Serine proteases in the extracellular preparations of Phytophthora infestans: does their presence relate to the aggressiveness of the pathogen?Original Paper
J. Hamill, C. Selby, L.R. Cooke
Plant Protect. Sci., 2002, 38(10):S102-S103 | DOI: 10.17221/10329-PPS
In this study the aggressiveness of nine isolates of P. infestans was determined using detached leaflets from cultivars Bintje and Stirling. The growth of the isolates on the leaflets was recorded on a daily basis, for seven days, and an assessment of their aggressiveness could then be made. Extracellular preparations (ECPs) from the zoospore suspension of each isolate were used as a source of proteolytic activity. The ECPs were found to contain a level of serine protease activity using BTEE (N-Benzoyl-L-Tyrosine Ethyl Ester) as a substrate and recording the absorbance at 256 nm. The possible relationship between the serine protease activity...
Ultrastructural localization and epitope mapping of Beet yellows closterovirus replicative proteinsOriginal Paper
T.N. Erokhina, R.A. Zinovkin, D.-E. Lesemann, W. Jelkmann, A.A. Agranovsky
Plant Protect. Sci., 2002, 38(10):S104-S107 | DOI: 10.17221/10330-PPS
A total of 19 Iranian native barley cultivars were in artificial infection experiments tested for resistance against isolate19 of the leaf stripe fungs, Pyrenophora graminea. The cultivar Eram was immune against isolate 19 and the cultivarsJonob, Makoy, C2, showed high resistance with less than 6% plant infected, the cultivars Zarjo, Valfajr, Reyhan, Karun,Karun × Kavir were the most susceptible cultivars.
Identification and characterization of host proteins interacting with NSm, the Tomato spotted wilt virus movement proteinOriginal Paper
M. Paape, S. Nell, S. Von Bargen, J.-W. Kellmann
Plant Protect. Sci., 2002, 38(10):S108-S111 | DOI: 10.17221/10331-PPS
To search for host proteins involved in systemic spreading of Tomato spotted wilt virus (TSWV), the virus-encoded NSm movement protein has been utilized as a bait in yeast two-hybrid interaction trap assays. J-domain chaperones from different host species and a protein denominated At-4/1 from Arabidopsis thaliana showing homologies to myosins and kinesins were identified as NSm-interacting partners. In this communication we illustrate that following TSWV infection, J-domain proteins accumulated in systemically infected leaves of A. thaliana, whereas At-4/1 was constitutively detected in leaves of A. thaliana and...
Transcript imaging and candidate gene strategy for the characterisation of Prunus/PPV interactionsOriginal Paper
V. Decroocq, V. Schurdi-Levraud, D. Wawrzyńczak, J.P. Eyquard, M. Lansac
Plant Protect. Sci., 2002, 38(10):S112-S116 | DOI: 10.17221/10332-PPS
Plum pox virus (PPV), the causing agent of the sharka disease, belongs to the genus Potyvirus that contains the largest number of virus species infecting plants. The virus genome has been extensively characterised and sequenced. However, few data are available on its interactions with the host plant, Prunus. In this study, we are focusing on the cloning and characterisation of any candidate genes involved in the expression of the resistance/susceptibility trait and any polymorphic genes putatively involved in the trait variation. In order to clone candidate genes, two main approaches are currently developed: the homology...
Origin of resistance to Plum pox virus in apricot: microsatellite (Ssr) data analysisOriginal Paper
T.N. Zhebentyayeva, G.L. Reighard, B. Krška, V.M. Gorina, A.G. Abbott
Plant Protect. Sci., 2002, 38(10):S117-S121 | DOI: 10.17221/10333-PPS
The objective of this study was to establish the genetic relationship among cultivars commonly used as donors for resistance to Plum pox virus (PPV) in order to identify the putative sources of resistance to PPV. The plant material tested represented the European, Central Asian and Chinese ecogeographical groups of cultivated apricots as well as the wild Dzhungar-Zailij population of Prunus armeniaca L. Forty-eight native accessions as well as the resistant (or tolerant) cultivars Harlayne, Stark Early Orange (SEO), Goldrich, Vestar and two hybrid forms Vestar × SEO (LE 3276) and Velkopavlovická × SEO (LE 2904) were screened by means...
Systemic induced resistanceOriginal Paper
Y. Cohen
Plant Protect. Sci., 2002, 38(10):S122-S125 | DOI: 10.17221/10334-PPS
Biotic and abiotic agents may induce resistance in plants against pathogens. Abiotic agents may be synthetic or natural. The natural, non-protein amino acid BABA (DL-β-aminobutyric acid) induces systemic resistance in crop plants against pathogens. Dry, killed mycelia of Penicillium chrysogenum (DM) induces local resistance in plants against soil-borne pathogens. The activity of BABA and DM are described here in detail. Both products were shown to effectively control plant disease in nature.
Induction of resistance to fire blight in apple (Erwinia amylovora)Original Paper
J.P. Paulin, R. Chartier, M. Tharaud, C. Heintz, V. Karniewicz, M.N. Brisset
Plant Protect. Sci., 2002, 38(10):S126-S127 | DOI: 10.17221/10335-PPS
Apple genotypes show different levels of resistance to fire blight caused by the bacterium E. amylovora. This resistance is considered to be polygenic, thus relying on a number of defense mechanisms. On the assumption that in susceptible genotypes these defenses may be present but not activated during the infection process, we attempted their induction by various abiotic and biotic elicitors. Two kinds of experiments were performed in the greenhouse and in the orchard: i) evaluation after controlled inoculation of the level of protection conferred to the plant by each elicitor and ii) investigation of various defense responses potentially...
Oxalic-acid elicited resistance to Fusarium wilt in Lycopersicon esculentum Mill.Original Paper
I.H. Attitalla, S. Brishammar
Plant Protect. Sci., 2002, 38(10):S128-S131 | DOI: 10.17221/10336-PPS
Systemic induced resistance (SIR) in a plant enhances disease resistance to a broad spectrum of pathogens. Under climate chamber conditions, oxalic acid's ability to elicit SIR in tomato (Lycopersicon esculentum Mill.) against wilt caused by Fusarium oxysporum f.sp. lycopersici (Fol) was tested with a susceptible cultivar (Danish Export). Oxalic acid (OA) was sprayed onto the green part of the tomato plants, at concentrations 2.5, 5, 10, and 20 mM. Two days later, each plant was challenged with 10 ml of Fol suspension (106 conidia/ml) inoculated into the soil around the root system. After inoculation, disease incidence...
Genetics of disease resistance in Arabidopsis to crop pathogensOriginal Paper
E.B. Holub, M. Tör, A. Cooper, P. Gordon, N. Gunn
Plant Protect. Sci., 2002, 38(10):S151-S154 | DOI: 10.17221/10341-PPS
Arabidopsis is universally resistant as a species to many crop pathogens, including examples from other crucifers suchas Albugo candida and Hyaloperonospora parasitica from Brassica oleracea. This species level trait could potentiallyprovide a source of durable disease resistance in crops if examples can be found which are amenable to molecular geneticcharacterization. Our research has developed from the observation that null mutation in Arabidopsis of a defense regulatorygene EDS1 (enhanced disease susceptibility) is susceptible to isolates of A. candida and H. parasitica from brassica.EDS1...
A critical appraisal of non conventional resistance to plant virusesReview
G.P. Martelli
Plant Protect. Sci., 2002, 38(10):S15-S20 | DOI: 10.17221/10311-PPS
Among natural resistance mechanisms to plant pathogens, cultivar resistance has been extensively used in plant breeding to introduce what can be defined as "conventional" resistance to a number of them, including viruses. The necessity of overcoming the constraints of genetic incompatibility, so as to widen the range of possibile use of genetic control of infectious agents, has propitiated the utilization of biotechnological procedures, whereby "non conventional" or transgenic resistance was developed. Transgenic resistance to plant viruses encompasses the identification, cloning and tranferring into the recipient host of single viral genes, which...
Resistance variation in natural plant populationsOriginal Paper
J.J. Burdon, P.H. Thrall
Plant Protect. Sci., 2002, 38(10):S145-S150 | DOI: 10.17221/10342-PPS
The general outcomes of long-term trajectories of coevolutionary interactions between specific hosts and pathogens areset by the interaction of their life histories. However, within those outcomes the speed of co-evolutionary responses andthe extent of their expression in the resistance/virulence structure of wild plant and pathogen populations respectively,are highly variable characters changing from place-to-place and time-to-time as a result of the interaction of host andpathogen with the physical environment. As a consequence, understanding of the role of diseases in the evolution of theirhosts requires approaches that simultaneously deal with...
Resistance mechanisms in Lycopersicon spp. to tomato powdery mildew (Oidium neolycopersici)Original Paper
A. Lebeda, B. Mieslerová, L. Luhová, K. Mlíčková
Plant Protect. Sci., 2002, 38(10):S141-S144 | DOI: 10.17221/10340-PPS
Limited information on the resistance mechanisms in Lycopersicon spp. to Oidium neolycopersici is still available. Macroscopically the resistance is characterized by a very low amount of mycelium development and a lack of sporulation. The leaf surface did not effectively inhibite conidium germination, however significant differences in germ tube and appressorium development were recorded. A large variation was observed in host tissue response. The prevailing resistance mechanism was hypersensitivity (HR). Considerable changes of peroxidase and catalase activities during pathogenesis were detected among tested wild Lycopersicon spp....
Molecular defense responses of apple genotypes in compatible and incompatible interactions with Erwinia amylovoraOriginal Paper
M.N. Brisset, J.S. Venisse, J.P. Paulin
Plant Protect. Sci., 2002, 38(10):S139-S140 | DOI: 10.17221/10339-PPS
Erwinia amylovora is the causal agent of fire blight, a bacterial disease of apple and pear. Pathogenicity determinants of the bacteria are identified (hrp-dsp cluster, capsule, siderophore) but molecular mechanisms leading to susceptibility or resistance of the plant are not yet understood. To address this question, we challenged two genotypes of apple, known for their contrasting susceptibility to fire blight, with a wild-type strain of E. amylovora (Ea wt), an avirulent hrp mutant of this bacteria (Ea hrp) or a wild-type strain of the incompatible pathogen Pseudomonas syringae pv. tabaci...
Lack of active defence responses revealed in a soil-free Arabidopsis/Peronospora sterile co-cultivation systemOriginal Paper
M. Hermanns, A.J. Slusarenko, L.N.L. Schlaich
Plant Protect. Sci., 2002, 38(10):S136-S138 | DOI: 10.17221/10338-PPS
The molecular basis of organ specificity in plant diseases is little characterised. Downy mildew of Arabidopsis caused by the oomycete Peronospora parasitica is characteristically a leaf disease. Resistant host genotypes recognise the pathogen in a gene-for-gene dependent manner and respond with the production of H2O2 and the execution of a genetically programmed hypersensitive cell death (HR). We inoculated the roots of Arabidopsis genotypes Col-0, Ws-0 and Wei-0 with the NOCO and WELA races of the pathogen and compared the responses with those observed in infected leaves. Combinations of incompatible genotypes...
Mechanisms of resistance to virusesOriginal Paper
J.P.T. Valkonen
Plant Protect. Sci., 2002, 38(10):S132-S135 | DOI: 10.17221/10337-PPS
Resistance associated with a hypersensitive response (HR) and subsequent development of necrotic lesions (cell death) at the sites of virus infection can restrict virus movement in plants. Genes for HR are dominant and act on a gene-for-gene basis. Many viral proteins triggering HR have been identified. Also, several genes for HR-based virus resistance, or virus-induced cell death without resistance, have been isolated and characterized in plants, which provides novel insights to the mechanisms of virus resistance. Another international, major research frontier has formed more recently around RNA silencing, a universal RNA surveillance system and inducible...
Stochastic variation and probabilistic model - estimating frequency of fungicide resistant phenotype in plant pathogen populationOriginal Paper
E. Kosman
Plant Protect. Sci., 2002, 38(10):158-160 | DOI: 10.17221/10344-PPS
Methodological aspects of stochastic variation were considered on example of bioassay for estimation of fungicide resistance(KADISH & COHEN 1988). The corresponding probabilistic model for measuring frequency of fungicide resistantphenotype in a plant pathogen population was developed. Unpredictable relationships between estimates from the modeland the experimental results were observed.
Selection of AFLP markers linked with crown rust resistance in Lolium: efficiency of bulk segregant analysis in an Allogamous speciesOriginal Paper
H. Muylle, E. Van Bockstaele, I. Roldan-Ruiz
Plant Protect. Sci., 2002, 38(10):161-164 | DOI: 10.17221/10345-PPS
Ryegrasses are important forage species. An important foliar disease in Lolium is crown rust, caused by the fungus Pucciniacoronata. This cosmopolitan biotrophic fungus causes forage and seed losses, and decoloration of amenity grasslands.In breeding towards resistant cultivars, it is important to know the mode of inheritance of crown rust resistance. A paircross between a susceptible and a resistant plant resulted in a F1 population segregating for rust resistance. According tothe segregation data, major genes were assumed to encode for crown rust resistance. In a bulk segregant analysis (BSA)187 primer combinations revealed AFLP...
Understanding field resistance mechanisms for improved control of Septoria triticiOriginal Paper
D.J. Lovell, S.R. Parker, N.D. Paveley, A.J. Worland
Plant Protect. Sci., 2002, 38(10):165-169 | DOI: 10.17221/10346-PPS
Field resistance can contribute to reductions in epidemic progress of Septoria tritici in winter wheat. Crop growth andcanopy architecture are identified as key mechanisms of field resistance. Near isogenic lines differing for dwarfing (Rht)and photoperiod sensitivity (Ppd) genes, enabled the study of target traits in a constant background of genetic resistance.Epidemics were consistently earlier in shorter crops across a range of environments. The mechanism for this effect wasidentified as an increase in spore arrival due to a reduction in the required dispersal distance between infective tissueand emerging upper culm leaves.
Evaluation of barley cultivars for resistance to leaf stripeOriginal Paper
H.R. Etebarian
Plant Protect. Sci., 2002, 38(10):170-173 | DOI: 10.17221/10347-PPS
A total of 19 Iranian native barley cultivars were in artificial infection experiments tested for resistance against isolate19 of the leaf stripe fungs, Pyrenophora graminea. The cultivar Eram was immune against isolate 19 and the cultivarsJonob, Makoy, C2, showed high resistance with less than 6% plant infected, the cultivars Zarjo, Valfajr, Reyhan, Karun,Karun × Kavir were the most susceptible cultivars.
Viroids: sequence variability and evolution of pathogenic RNAOriginal Paper
J. Matoušek
Plant Protect. Sci., 2002, 38(10):173-176 | DOI: 10.17221/10348-PPS
Viroids as the smallest pathogenic circular single-stranded pathogenic RNAs form populations of quasi-species, whichhas been recently identified by thermodynamic methods like TGGE pre-selection and heteroduplex analysis. It was foundthat replication under thermal stress led to enormously high level of viroid mutagenesis. Mostly multiple mutants havingnon-random distribution of base changes were found. A specific "hot spots" were identified in the regions, wherea characteristic "pathogenicity domains" are localised in different viroids of the pospiviroidae family. Specific viroidmicroevolution was observed upon artificial inoculation of non-host plant...
Gene-for-gene interactions are required for disease resistance mediated by virus transgeneOriginal Paper
M. Ravelonandro
Plant Protect. Sci., 2002, 38(10):177-179 | DOI: 10.17221/10349-PPS
Plant viruses cause severe damage and significant economic losses to agriculture. Control of virus usually consist ofthe elimination of virus vectors (insects, nematodes, fungi, etc), improvement of the sanitary status of the propagationmaterial, the use of resistance sources in breeding programs. The application of the pathogen-derived resistance strategyhas opened new avenues to protect plants against viruses. Two molecular mechanisms seem to underlie the engineeredprotection, the virus transgene-derived protein and the transgene-RNA interference. A few examples that support theefficiencies of these two molecular mechanisms are reviewed here and...
Genetics of resistance to Plum pox virus in apricotOriginal Paper
B. Krška, J. Salava, J. Polák, P. Komínek
Plant Protect. Sci., 2002, 38(10):180-182 | DOI: 10.17221/10350-PPS
Plum pox virus (PPV) causes serious damage in apricots grown in the Czech Republic and other countries where it ispresent. The virus spreads in orchards from infected trees by aphids to healthy trees of susceptible cultivars. Chemicalcontrol is ineffective from epidemiological point of view. For this reason growing of resistant apricot cultivars is the onlyway how to solve one of the most significant phytopathological problem. To study PPV resistance in apricot, three crossesbetween an apricot cultivars or a selection resistant to PPV and an apricot cultivars or a selection susceptible to PPV(LE-3218 × Stark Early Orange, LE-3241 × Vestar...
Molecular studies of Potato mop-top virus (PMTV) in transgenic N. benthamiana and S. tuberosumOriginal Paper
A. Germundsson, M. Sandgren, H. Barker, E.I. Savenkov, J.P.T. Valkonen
Plant Protect. Sci., 2002, 38(10):183-185 | DOI: 10.17221/10351-PPS
Resistance to Potato mop-top virus (PMTV) was studied in Nicotiana benthamiana and potato (Solanum tuberosum cv.Saturna) transformed with the coat protein (CP) gene of PMTV. In N. benthamiana plants mechanically inoculated withPMTV, RNA2 was detected in leaves and roots in several plants in the absence of RNA3. When N. benthamiana wasgrown in infested soil, viral RNA was detected in roots, but no systemic movement of PMTV to above-ground parts wasobserved. The incidence of PMTV infections was reduced in the CP-transgenic potato plants grown in an infested fieldin Sweden. However, in infected tubers, all...
Genetics of wheat somaclones resistance to Bipolaris sorokiniana Shoem.Original Paper
L.G. Tyryshkin, N.A. Tyryshkina-Shishelova
Plant Protect. Sci., 2002, 38(10):186-188 | DOI: 10.17221/10352-PPS
Genetics of resistance to common root rot and dark brown leaf spot blotch (both caused by Bipolaris sorokiniana Shoem.)was studied in wheat somaclonal lines, obtained in calluses culture of samples 181-5 and Vera. Four different approacheswere used: linear analysis of resistance in generations of segregating somaclonal lines, hybridological analysis, studyof resistance components, study of possible durability of resistance. Results showed, that resistance to both diseases islikely controlled by polygenic systems with additive actions of minor genes. Different lines possess non-identical geneticsystems for resistance. Several lines kept their...
Resistance and tolerance to potato cyst nematodes among Ukrainian potato cultivars and breeding materialsOriginal Paper
L.A. Pylypenko
Plant Protect. Sci., 2002, 38(10):189-194 | DOI: 10.17221/10353-PPS
Potato is the fourth important cultivated crop in Ukraine; the potato cyst nematode Globodera rostochiensis, Ro1 consistsone of the most serious threats to its industry. A total of 3769 cultivars and hybrids were assessed for resistanceto G. rostochiensis from 1992 to 2002. On the base of the two-stages assay, resistance was identified at 419 and partialresistance at 90 genotypes, which had inherited resistance from 39 resistant cultivars and 23 hybrids. Resistance of the74 genotypes was confirmed in both greenhouse and field plots; their effectiveness in reduction of population densitiesof G. rostochiensis varied from 51...
Modes of action of non-pathogenic strains of Fusarium oxysporum in controlling Fusarium wiltsOriginal Paper
C. Alabouvette, Ch. Olivain
Plant Protect. Sci., 2002, 38(10):195-199 | DOI: 10.17221/10354-PPS
Many studies have demonstrated the capacity of non-pathogenic strains of F. oxysporum to control Fusarium diseases.These non-pathogenic strains show several modes of action contributing to their biocontrol capacity. They are able tocompete for nutrients in the soil, affecting the rate of chlamydospore germination and the saprophytic growth of thepathogen, diminishing the probability for the pathogen to reach the root surface. They are competing with the pathogenat the root surface for colonization of infection sites, and inside the root where they induce plant defence reactions. Bytriggering the defence reactions, they induce systemic resistance...
Plant extracts as the source of physiologically active compounds suppressing the development of pathogenic fungiOriginal Paper
V.A. Karavaev, M.K. Solntsev, A.M. Kuznetsov, I.B. Polyakova, V.V. Frantsev, E.V. Yurina, T.P. Yurina
Plant Protect. Sci., 2002, 38(10):200-204 | DOI: 10.17221/10355-PPS
It is shown that aqueous extracts from bird cherry tree Padus avium L., aspen Populus tremula L., and celandine Chelidoniummajus L., effectivily suppress the germination of Puccinia triticina Eriks uredospores. Fungitoxic activity ofthe extracts is supposed to be determined by high content of phenolic compounds and high peroxidase activity in theleaves of these plants. Fungitoxic activity of the extracts from the leaves, inflorescences, roots, and stems of siberiancowparsnip Heracleum sibiricum L., was also correlated with the content of phenolic compounds in these organs. Treatmentof healthy wheat...
Antibiotic production of the biocontrol agents Epicoccum nigrum and Candida sakeOriginal Paper
I. Larena, M. LIÑÁN, P. Melgarejo
Plant Protect. Sci., 2002, 38(10):205-208 | DOI: 10.17221/10356-PPS
In the framework of the study of the mode of action of biocontrol agents (BCAs) it is important to know if BCAs areantibiotic-producers. Epicoccum nigrum 282 and Candida sake CPA-1 are BCAs effective against post-harvest pathogensof stone and pome fruits. The antibiotics produced by these BCAs and the relationship to biocontrol were studied.Production of antibiotics by E. nigrum in in vitro cultures began at 5 days of incubation being maximal at different timesdepending on media used. However, no antibiotic was detected when E. nigrum was grown in a solid state-fermentationsystem or in peaches. In the case...
Influence of Pythium oligandrum on population of Fusarium oxysporum f.sp. dianthi and development of Fusarium wilt of carnationOriginal Paper
L.B. Orlikowski, A. Jaworska-Marosz
Plant Protect. Sci., 2002, 38(10):209-211 | DOI: 10.17221/10357-PPS
Relationship between initial oospore number of Pythium oligandrum, mode of the mycoparasite application and populationdynamics of Fusarium oxysporum f.sp. dianthi and development of Fusarium wilt of carnation was studied. Mixing ofoospores with peat 10 days before carnation planting resulted in strong inhibition of the pathogen development. Numberof colony forming units of the pathogen decreased at least 3 times. Application of P. oligandrum resulted in suppressionof Fusarium wilt development, especially when the mycoparasite was applied at dose 100 oospore/g of peat.
Practical application of integrated disease managementOriginal Paper
V. Zinkernagel, H. Hausladen, H. Habermeyer
Plant Protect. Sci., 2002, 38(10):212-220 | DOI: 10.17221/10358-PPS
A decision support system for cereal diseases and late blight of potatoes has been developed at the Chair of Phytopathology,Technische Universität München. The Wheat and Barley Prognosis System has been in use for many years by theBavarian official advisory service. It is based on an exact diagnosis and established biological thresholds influenced byweather. Certain fungicides are recommended also covering diseases which have not reached the threshold. Diseases underconsideration are eye spot disease, powdery mildew, Septoria leaf blotch, Septoria leaf and glume blotch, tan spot, brownand yellow rusts.The PhytophthoraModel Weihenstephan consists of...
Winter wheat protection against diseases and pests in conventional programme of crop protection and in integrated pest managementOriginal Paper
C. Jańczak, S. Pruszyński, P. Bubniewicz
Plant Protect. Sci., 2002, 38(10):221-226 | DOI: 10.17221/10359-PPS
Results of researches carried out in 2000 and 2001 have demonstrated, that main factors determining yield of winterwheat are: agrotechnical measures, mainly proper choice of field, optimal nitrogen fertilization as well as choice ofcultivar well adapted to local climatic conditions. Chemical protection of winter wheat affects first of all stability ofyield. Regular inspections of fields with special account to present phytosanitary situation, thresholds of noxiousness andexpected development of disease and pest populations should decide on the need of chemical treatments.
Effect of barley-legume intercrop on disease frequency in an organic farming systemOriginal Paper
J. Kinane, M.F. Lyngkjaer
Plant Protect. Sci., 2002, 38(10):227-231 | DOI: 10.17221/10360-PPS
The effect of barley-legume intercrop in an organic farming system on disease incidence was investigated. The legumeswere lupin, faba bean and pea. Diseases were detected on pea and barley. On pea, only ascochyta blight (Ascochyta pisi)was observed. When either pea variety was intercropped with barley, the level of ascochyta blight was reduced. Netblotch (Pyrenophora teres), brown rust (Puccinia recondita) and powdery mildew (Blumeria graminis f.sp. hordei) (inorder of incidence) were monitored on barley between flag leaf emergence and heading. The levels of all three diseaseswere reduced in every intercrop...
Developing Verticillium resistant rootstock for Norway mapleOriginal Paper
J.A. Hiemstra
Plant Protect. Sci., 2002, 38(10):232-234 | DOI: 10.17221/10361-PPS
Verticillium wilt causes serious losses in the cultivation of shade trees, especially Norway maple (Acer platanoides L.).In 1993 research was started aiming at the development of Verticillium resistant rootstocks for Norway maple. Efficientmethods to select and screen for resistance in maple were developed, leading to several large-scale selection experimentscarried out in the period 1994-1996. This resulted in a first selection of about 300 plants out of a total of nearly 20 000 seedlingplants. An attempt was made to propagate these plants vegetatively in order to develop small clones for resistancetesting. During this stage of the research...
Biotic relations between Rhizoctonia solani (damping-off pathogen) and soil fungal communities from forest nurseryOriginal Paper
S. Stepniewska, M. Mańka
Plant Protect. Sci., 2002, 38(10):235-238 | DOI: 10.17221/10456-PPS
In forest nursery Wronczyn (central-west Poland) the occurrence of Scots pine (Pinus sylvestris L.) seedlings damping-offcaused by Rhizoctonia solani Kühn is connected with a strong supporting effect of soil fungi community on R. solani.Both the soil fungi community isolated in June and in October 1999 supported the pathogen growth to considerable extent.In both months the support was bigger in the case of more severe isolate of the pathogen.
Advances in the methods of detection of plant viruses and bacteria (abstract only)
M. Cambra, M.M. López, M.T. Gorris, P. Llop, E. Bertolini, A. Olmos
Plant Protect. Sci., 2002, 38(10):239 | DOI: 10.17221/10362-PPS
Serological and molecular techniques are the most appropriate for rapid and reliable detection of plant viruses and plant pathogenic bacteria when high numbers of samples need to be analysed. For viruses, the sample preparation step has been simplified trough the possibility to imprint or squash plant material or insect vectors in membranes, instead of performing extracts preparation, and trough the automatic purification of targets by robotics. Immobilised targets on membranes can be detected by tissue print-ELISA, imprint-hybridisation or print-PCR. For bacteria, the sensitivity has been improved by the selection of media and conditions for efficient...
Frequent occurrence of natural recombinant Plum pox virus isolates in Slovakia: from identification to epidemiological consequences (abstract only)
M. Glasa, V. Marie-Jeanne, Z. Šubr, O. Kúdela
Plant Protect. Sci., 2002, 38(10):240 | DOI: 10.17221/10365-PPS
Genomic approaches to natural and artificial evolution of plant disease resistance genes (abstract only)
R. Michelmore
Plant Protect. Sci., 2002, 38(10):241 | DOI: 10.17221/10367-PPS
We are interested in the evolution of specificity in plant-pathogen interactions. A significant proportion of genes in the genome potentially encode resistance related genes. A variety of genetic events have been demonstrated to occur at loci encoding disease resistance in a range of plant species. These include point mutations, insertion/deletions, intragenic and intergenic unequal crossing-over, and gene conversion. The relative frequencies and importance of each of these processes to the evolution of new resistance specificities is now beginning to be understood. We are currently refining a 'birth-and-death' model using data on the relative frequencies...
Gene transcript profiling of single barley epidermal cells attacked by powdery mildew (abstract only)
M.L. Lyngkjaer, T. Gjetting
Plant Protect. Sci., 2002, 38(10):242 | DOI: 10.17221/10368-PPS
Resistance or susceptibility in barley to powdery mildew is determined at the single cell level. The fungus attempt to penetrate the plant cell wall and the attacked barley epidermal cell tries to prevent this by reinforcing its cell wall. However, this defence is only partially efficient and a number of fungal penetration attempts will succeed, leading to a mixture of infected and uninfected epidermal cells on the leaf. This makes it impossible to relate powdery mildew induced gene expression to resistance or susceptibility. Using glass micro-capillaries and micromanipulation we extracted contents from single barley epidermal cells. Three situations...
Plant immunization - manipulating innate defence responses (abstract only)
Lucas J.A.
Plant Protect. Sci., 2002, 38(10):243 | DOI: 10.17221/10370-PPS
Mechanisms of plant resistance to bacterial pathogens (abstract only)
T. Lahaye, D. Gürlebeck, T. Jordan, E. Marois, A. Meyer, K. Peters, S. Schornack, B. Szurek, U. Bonas
Plant Protect. Sci., 2002, 38(10):244 | DOI: 10.17221/10372-PPS
Bipolaris sorokiniana on cereals: a new model for molecular work on hemibiotrophy (abstract only)
P. Schäfer, R. Hückelhoven, G. Langen, J. Kumar, K.H. Kogel
Plant Protect. Sci., 2002, 38(10):245 | DOI: 10.17221/10374-PPS
Resistance to Turnip mosaic virus in cabbage (abstract only)
R. Krämer, F. Marthe, U. Ryschka, E. Klocke, J. Schubert, F. Ehrig, J. Rabenstein, G. Schumann
Plant Protect. Sci., 2002, 38(10):246 | DOI: 10.17221/10376-PPS
In white cabbage (Brassica oleracea) Turnip mosaic virus (TuMV) infection may cause up to 25% yield loss as well as necrosis during cold storage of the heads. An effective way for plant protection is the establishment of resistance to different TuMV pathotypes in cabbage. TuMV isolates were characterized and resistance screening methods utilizable under greenhouse and field conditions were developed. The search for resistance to TuMV in more than 300 accessions of the Brassicaceae family revealed some new resistance donors. Resistance to different TuMV pathotypes was found in B. oleracea primitive forms, in Chinese...
Biocontrol agents, resistance inducers and genetic engineering for protection of apple and pear against fire blight (Erwinia amylovora) (abstract only)
P. Sobiczewski
Plant Protect. Sci., 2002, 38(10):247 | DOI: 10.17221/10378-PPS
The paper, based on data from literature and own studies, deals with non-bactericides based strategies for control of fire blight. Of many bacterial representatives some were selected and already used in commercial biocontrol products. They are among others: Pseudomonas fluorescens A506 (BlightBan), Pantoea agglomerans P10C (BlossomBless), Bacillus subtilis QST713 (Serenade). The principal mechanism of action of the above mentioned antagonistic bacteria is based on antibiosis and/or competition for nutrients and space. Moreover, products based on plant compounds, like AkseBio (Thymbra spicata), Biomit Plussz (various...