The sensitivity of a modified agglutination test for the detection of Erwinia amylovora and Pseud... more The sensitivity of a modified agglutination test for the detection of Erwinia amylovora and Pseudomonas syringae pv. pisi antisera was examined. The bacterial polyclonal antisera were sensitized by Staphylococcus aureus bacteria. These antisera enhanced the sensitivity of the agglutination test by two or three times. The modification of the agglutination test described is recommended for the detection of E. amylovora in plant sap and in bacterial slime of hawthorns (Crataegus sp.) attacked by E. amylovora.
Theoretical approaches, methodology and experimental results of plant physiology, biochemistry an... more Theoretical approaches, methodology and experimental results of plant physiology, biochemistry and molecular biology have substantially influenced the development of plant pathology during the last 20 years. The nature of plant-microbe interactions, the initial signalling, signal transduction and defense response could be explained primarily at these levels. The rapid expansion of knowledge in this area is demonstrated by the increasing number of journals and papers dealing with this topic. The book "The Biochemistry and Physiology of Plant Disease" written by R. N.GOODMAN, Z. KIRÁLY and K.R. WOOD (1986) could without any doubt be considered as a bible in this field of plant pathology. However, we have been missing an updated, more general and comprehensive treatment of this topic. The book reviewed here can thus be taken as a welcome sequel of that by GOODMAN et al. The book is divided into four sections and ten chapters. Section I (Infection process) summarizes in one chapter the present knowledge on penetration of cuticles by plant pathogens. Section II (Plant pathogenesis) is divided into five chapters and deals with degradation of cell walls by plant pathogens, bioenergetics of plant-pathogen interactions, Rhizobium-legume symbiosis and the effect of diseases on nodulation, growth regulators and plant tumorogenesis, phytotoxins and plant pathogenesis. Section III (Signal transduction) focuses on host-pathogen specificity with emphasis on the role of signal molecules, their perception and transduction, host responses to signals, gene expression and regulation. Section IV (Dynamics of plant defense) presents an up-to-date overview of fortification of plant cell walls and accumulation of phytoalexins as a resistance mechanism, pathogenesis-related proteins and disease resistance. Throughout the book, individual chapters are divided into numerous subchapters and parts with easily understood numerical codes. The text is augmented by many tables and highly instructive figures. Each chapter is followed by a large number of references, mostly recent. Easy orientation is possible by a combined (subject, host, pathogen) index. Because of its high scientific level, the book should be useful for researchers, teachers and advanced undergraduate and graduate students of biology, plant sciences, plant pathology, physiology, biochemistry, molecular biology and related branches of life sciences. It could be considered as an exciting textbook of plant pathological physiology and biochemistry, but also as an excellent reference manual of recent literature in this area. Both author and publisher are to be commended for an extraordinary good work! ALEŠ LEBEDA (Olomouc)
Journal of Phytopathology and Pest Management, Nov 12, 2016
To maintain Clavibacter michiganensis subsp. sepedonicus-free (Cms-free) potato genetic resources... more To maintain Clavibacter michiganensis subsp. sepedonicus-free (Cms-free) potato genetic resources, a three-stage process of checking limited lots of initial and new breeding potato materials was designed for small breeders in terms of costs, personnel and facilities. For an intensified evaluation of the presence of Cms in different vegetative stages within one growing season a mixture of 10 randomly selected artificially infected and healthy tubers of individual cultivars and breeding materials were prepared. In the first stage, a visual assessment of the vascular vessels of mother tubers was performed and at least 20% of each material was deemed positive, indicating that it should be discarded. In the second stage, one half of mother tubers were grown in the greenhouse and the other in a netting house. Plants in bloom and daughter tubers were evaluated. Within the second stage 1.4%-28% of each individual potato material could be excluded based on double-antibody sandwich enzyme-linked immunosorbent assays and SYBR Green real-time PCR assays, including a melting point analysis using PSA 1/R and CelA F/R primer sets and biological tests on aubergines. In the third stage, in vitro plants transferred from potato resources that tested negative in the previous stages were evaluated using the methods used in the second stage. The specificity of the antibodies and the two primer sets, PSA1/R and CelA F/R, were evaluated with 100% success.
Clavibacter michiganensis subsp. sepedonicus (Spieckermann & Kotthoff 1914) according to Davis et... more Clavibacter michiganensis subsp. sepedonicus (Spieckermann & Kotthoff 1914) according to Davis et al. (1984) (Cms), the causal agent of bacterial ring rot of potato, is a quarantine organism which constitutes a worldwide threat to potato growers and the potato industry. Cms can cause damage of different types-by direct crop loss during growth and storage, by rejection of infected seed lots and the cost of control measures, by loss of export markets or by difficulties experienced in opening new markets. In Europe, Cms annually causes an estimated 15 million Euro in economic damage (van der Wolf et al. 2005). According to Straňák (1917), a disease named bacterial ring rot (BRR) occurred in potato crops around the Czech Lands at the beginning of the 20 th century. Among the Czech Lands, South Bohemia was supposed to be most severely threatened by BRR. Towards the end of the 20 th century in the CR, a relatively high percentage of potato tuber samples proved to be infected by Cms, namely 1.14% in seed potatoes in 1998 and 4.13% in com-Supported by the Ministry of Agriculture of the Czech Republic, Project No. QF 4105.
The susceptibility of 14 pear cultivars to the bacterium Erwinia amylovora, the causal agent of f... more The susceptibility of 14 pear cultivars to the bacterium Erwinia amylovora, the causal agent of fire blight disease, was evaluated using three different methods of in vivo inoculation-the leaf inoculation method on detached shoots of pear cultivars in a climate chamber, and the terminal shoot and blossom inoculation methods on potted trees of the same pear cultivars in a net house. The results of the artificial inoculations of the European and Asian pear cultivars were compared using the susceptibility score scale, as well as the ANOVA and post hoc methods. The differences among the pear cultivar susceptibility increased during the evaluation periods in the given year, but there were no significant differences between the annual evaluation in 2020 and 2021. The results of the pear cultivar susceptibility after inoculation of the detached shoots differed significantly from the results of the terminal shoot and blossom inoculation. The detached shoot susceptibility under pathogen-favourable conditions in the climate chamber was lower than the terminal shoot and blossom susceptibility in the net house for most pear cultivars. In both years, the highest values of the terminal shoot and blossom susceptibility were coincidently calculated for the Ananaska česká European old cultivar and the Nijissejkii Asian cultivar.
Polyclonal antisera to detect and determine two related pathovars, Pseudomonas syringae pv. pisi ... more Polyclonal antisera to detect and determine two related pathovars, Pseudomonas syringae pv. pisi and Pseudomonas syringae pv. syringae, were prepared Untreated bacterial cells, or fixed by formaldehyde or glutaraldehyde were used as antigens. After cross-absorption with heterologous antigens, antisera revealed a high level of specificity in slide agglutination, Ouchterlony gel double-diffusion and in DAS-ELISA and PTA-ELISA. Each of 14 P s. pisi prepared polyclonal antisera could detect and deter mine all strains of P s. pisi, regardless of race. PTA-ELISA was the most appropriate serological test to distinguish Pseudomonas syringae pathovars on peas. Most of the P s. pisi strains from foreign collections were in serological tests confirmed asP. s. pisi, while most of the Czech strains suspected as P s. pisi were determined as P s. syringae strains. The principal biochemical reaction, i.e., use of DL-homoserine as a carbon source to grow P s. pisi but not P s. syringae , was proved...
Variability in the responses of plants propagated from in vitro tissue cultures of 52 ware and in... more Variability in the responses of plants propagated from in vitro tissue cultures of 52 ware and industrial potato cultivars to different Clavibacter michiganensis subsp. sepedonicus inoculum size was tested during 2015–2017. Bacterial ring rot symptoms on plants and tubers xylem vessels were recorded for 8 weeks and the susceptibility index (SI) for individual cultivars was calculated. Based on foliage symptoms, potato cultivars were placed into three symptoms groups. The symptomless group had SIs ≤ 1, for the moderate symptom group SIs ranged from 1.01 to 2.99, and the severe symptom group had SIs ≥ 3.0. The pathogen concentrations in vascular vessels of all infected potato plants increased during the experiment regardless of the foliage symptom group.
The strict use of healthy propagating materials as the most important preventive measures against... more The strict use of healthy propagating materials as the most important preventive measures against the bacterial canker of apricot Knowledge of various reservoirs of Pseudomonas bacteria and their traits relative to the aptitude to survive and spread in apricot orchards is particularly pertinent for implementing
The methodology includes a method of artificial infection of plants and potato tubers as a prereq... more The methodology includes a method of artificial infection of plants and potato tubers as a prerequisite for the study of migration and localization of the pathogen in tubers and within the plant vascular tissues, time schedule and recommended size of samples of individual parts of plants and potato tubers during the growing season, depending on external conditions and potato genotype, how to deal with samples of the plants and potato tubers prior to treatment, method of processing samples of individual plant parts and tuber depending on the detection method and the optimization of methods for detection of the pathogen Clavibacter michiganensis subsp. sepedonicus. In compliance with the proposed methodological procedure should be interrupted vertical transmission of the pathogen in the process of breeding, the possibility of detection of the pathogen in breeding and propagation material and reduction of suspicious samples should be increased and the late positive determination of rin...
The methodology is to assessment the level of resistance of potato genotypes to soft rot bacteria... more The methodology is to assessment the level of resistance of potato genotypes to soft rot bacteria of Dickeya, Pectobacterium and Pseudomonas genera using slice test
The aim of this study was to find out whether causal agents of bacterial canker and the premature... more The aim of this study was to find out whether causal agents of bacterial canker and the premature death of apricot trees are present in the internal tissues of propagating material of various origins. In total, 33 samples of apricot (Prunus armeniaca L.) scion materials from eight and six samples of rootstocks from four European localities were analysed for the presence of the pathogenic Pseudomonas species. Significant differences were found in the diversity of the culturable bacterial population and the incidence of Pseudomonas bacteria in internal tissues of scion and rootstock buds. In most of the rootstocks, no Pseudomonas bacteria were detected. A total of 148 Pseudomonas-like strains isolated from scion samples were collected mainly from localities F1-F5 (in France) and G1-G2 (in Germany). These strains were clustered into 11 groups by means of fatty acid methyl ester (FAME) analysis; 91.9% of them were able to induce a hypersensitive reaction on tobacco leaves and 37.8% were positive in ice nucleation activity. A set of 89 Pseudomonas strains was characterised by means of Psy-PCR targeting of the Pseudomonas syringae (Ps) complex, complex phylogroup (PG), syrB-PCR targeting of the syringomycin synthesis, pathogenicity on detached apricot twigs, and the ability to survive within epiphytic microflora. Pseudomonas strains attributed to PG01, PG04, and PG07-08 were slightly pathogenic to detached apricot twigs. Altogether, 5% of Pseudomonas strains highly pathogenic to detached apricot twigs were isolated from apricot scion samples originated in localities F2, F5, and G1. These strains were attributed to PG02 and PG03, and rpoD sequencing confirmed a similarity to strains of P. syringae pv. syringae and P. amygdali pv. morsprunorum known to be pathogenic to apricot, respectively. The occurrence of these pathogens in buds of scion materials increases the risk of bacterial canker and the premature death of young apricot trees.
Conditions associated with an unusually high occurrence of burrknots in two young commercial appl... more Conditions associated with an unusually high occurrence of burrknots in two young commercial apple orchards at two locations, Těšetice and Stošíkovice, South Moravia, the Czech Republic, were analysed. In the first orchard, planted in spring 2003, the occurrence of burrknot on trees of cvs. Early Smith, Jonagold and Gala on M.9 rootstock was evaluated. In the second orchard, planted in autumn 2002, cv. Gala on M.9 rootstock was assessed. Planting material used at each location was obtained from the same commercial propagator and had been established from the same propagation stock materials. Of 60 trees per cultivar surveyed in the first orchard, incidence of burrknots in cvs. Early Smith, Jonagold and Gala trees was 98, 97 and 92%, respectively. The burrknot severity (mean number of burrknots on above portion of rootstock) was significantly higher on Jonagold trees, i.e. 3.65, than on the other two cultivars. Of 60 Gala trees in the second orchard, symptoms of burrknot appeared on ...
For the first time in the Czech Republic, bacteria identified as Pseudomonas marginalis, Pectobac... more For the first time in the Czech Republic, bacteria identified as Pseudomonas marginalis, Pectobacterium carotovorum subsp. carotovorum and Pseudomonas putida were isolated from tubers of Zantedeschia spp. with symptoms of tuber soft rot. The symptoms occurred on mother tubers as well as on new daughter tubers of different calla lily hybrids with yellow spathe, calla lily cv. Mango with bright orange spathe and Zantedeschia rehmanii with pink spathe. The percentage of diseased plants of the total plants in the plot was around 10%. When inoculated into potato tuber slices, strains of P. marginalis and P. c. subsp. carotovorum produced soft rot. Pectolytic activity of P. marginalis strains was less intensive than that of the P. c. subsp. carotovorum strain. The results confirm that bacterial soft rot of Zantedeschia spp. may have several causes.
Plant pathogenic species Pseudomonas corrugata and P. marginalis were detected and determined in ... more Plant pathogenic species Pseudomonas corrugata and P. marginalis were detected and determined in collapsed tomato plants in rockwool slab hydroponic culture in southern Moravia, Czech Republic. Surprisingly, P. marginalis was also determined before planting in apparently healthy grafted tomato transplants grown in hydroponic culture. Moreover, non-pathogenic P. fluorescens, P. putida, P. synxantha, and Stenotrophomonas malthophilia were identified. The Biolog Identification GN2 MicroPlate™ System System (Biolog, Inc., Hayward, USA) was used for identification of bacterial isolates. Cultures of P. corrugata and P. marginalis were used in a greenhouse pathogenicity experiment. Seven weeks old tomato plants of cv. Moneymaker grown in sterilised perlite were inoculated into the stem with a hypodermic needle at one point above the cotyledon node. In inoculated tomato plants, disease symptoms were observed that included external and internal dark brown lesions around the inoculation site,...
Pseudomonas syringae pv. aesculi (Pae) causes bleeding canker, a destructive disease of horse che... more Pseudomonas syringae pv. aesculi (Pae) causes bleeding canker, a destructive disease of horse chestnut trees (Aesculus hippocastanum) that limits the breeding of horse chestnut genotypes. The susceptibility of 322 F 1 progeny from 20 horse chestnut parent tree sources to the pathogen Pae was evaluated using different inoculation methods. The resulting infection rates, in decreasing order, were caused by inoculation of apical buds, inoculation of annual stems, insertion of bacteria into cut wounds on trunks and foliar spraying of the pathogen. According to the resistance index (RI) results of the field pathogenicity tests, at 2 or 3 years after inoculation 40, 40 and 20 % of horse chestnut parent tree sources were resistant, tolerant and susceptible, respectively, to Pae. Microbiological analyses of plant tissues from buds, phloem in the main trunks and roots of infected F 1 progeny regardless of parent tree source showed long-term survival of Pae bacteria in 70 % of tolerant F 1 progeny plants that lacked bleeding canker symptoms. Initial RI results and microbial analyses indicated that there was some frequency of resistance in the natural horse chestnut population. Altogether, 41 F 1 progeny were the most promising lines based on their viability and the absence of Pae in their tissues.
The sensitivity of a modified agglutination test for the detection of Erwinia amylovora and Pseud... more The sensitivity of a modified agglutination test for the detection of Erwinia amylovora and Pseudomonas syringae pv. pisi antisera was examined. The bacterial polyclonal antisera were sensitized by Staphylococcus aureus bacteria. These antisera enhanced the sensitivity of the agglutination test by two or three times. The modification of the agglutination test described is recommended for the detection of E. amylovora in plant sap and in bacterial slime of hawthorns (Crataegus sp.) attacked by E. amylovora.
Theoretical approaches, methodology and experimental results of plant physiology, biochemistry an... more Theoretical approaches, methodology and experimental results of plant physiology, biochemistry and molecular biology have substantially influenced the development of plant pathology during the last 20 years. The nature of plant-microbe interactions, the initial signalling, signal transduction and defense response could be explained primarily at these levels. The rapid expansion of knowledge in this area is demonstrated by the increasing number of journals and papers dealing with this topic. The book "The Biochemistry and Physiology of Plant Disease" written by R. N.GOODMAN, Z. KIRÁLY and K.R. WOOD (1986) could without any doubt be considered as a bible in this field of plant pathology. However, we have been missing an updated, more general and comprehensive treatment of this topic. The book reviewed here can thus be taken as a welcome sequel of that by GOODMAN et al. The book is divided into four sections and ten chapters. Section I (Infection process) summarizes in one chapter the present knowledge on penetration of cuticles by plant pathogens. Section II (Plant pathogenesis) is divided into five chapters and deals with degradation of cell walls by plant pathogens, bioenergetics of plant-pathogen interactions, Rhizobium-legume symbiosis and the effect of diseases on nodulation, growth regulators and plant tumorogenesis, phytotoxins and plant pathogenesis. Section III (Signal transduction) focuses on host-pathogen specificity with emphasis on the role of signal molecules, their perception and transduction, host responses to signals, gene expression and regulation. Section IV (Dynamics of plant defense) presents an up-to-date overview of fortification of plant cell walls and accumulation of phytoalexins as a resistance mechanism, pathogenesis-related proteins and disease resistance. Throughout the book, individual chapters are divided into numerous subchapters and parts with easily understood numerical codes. The text is augmented by many tables and highly instructive figures. Each chapter is followed by a large number of references, mostly recent. Easy orientation is possible by a combined (subject, host, pathogen) index. Because of its high scientific level, the book should be useful for researchers, teachers and advanced undergraduate and graduate students of biology, plant sciences, plant pathology, physiology, biochemistry, molecular biology and related branches of life sciences. It could be considered as an exciting textbook of plant pathological physiology and biochemistry, but also as an excellent reference manual of recent literature in this area. Both author and publisher are to be commended for an extraordinary good work! ALEŠ LEBEDA (Olomouc)
Journal of Phytopathology and Pest Management, Nov 12, 2016
To maintain Clavibacter michiganensis subsp. sepedonicus-free (Cms-free) potato genetic resources... more To maintain Clavibacter michiganensis subsp. sepedonicus-free (Cms-free) potato genetic resources, a three-stage process of checking limited lots of initial and new breeding potato materials was designed for small breeders in terms of costs, personnel and facilities. For an intensified evaluation of the presence of Cms in different vegetative stages within one growing season a mixture of 10 randomly selected artificially infected and healthy tubers of individual cultivars and breeding materials were prepared. In the first stage, a visual assessment of the vascular vessels of mother tubers was performed and at least 20% of each material was deemed positive, indicating that it should be discarded. In the second stage, one half of mother tubers were grown in the greenhouse and the other in a netting house. Plants in bloom and daughter tubers were evaluated. Within the second stage 1.4%-28% of each individual potato material could be excluded based on double-antibody sandwich enzyme-linked immunosorbent assays and SYBR Green real-time PCR assays, including a melting point analysis using PSA 1/R and CelA F/R primer sets and biological tests on aubergines. In the third stage, in vitro plants transferred from potato resources that tested negative in the previous stages were evaluated using the methods used in the second stage. The specificity of the antibodies and the two primer sets, PSA1/R and CelA F/R, were evaluated with 100% success.
Clavibacter michiganensis subsp. sepedonicus (Spieckermann & Kotthoff 1914) according to Davis et... more Clavibacter michiganensis subsp. sepedonicus (Spieckermann & Kotthoff 1914) according to Davis et al. (1984) (Cms), the causal agent of bacterial ring rot of potato, is a quarantine organism which constitutes a worldwide threat to potato growers and the potato industry. Cms can cause damage of different types-by direct crop loss during growth and storage, by rejection of infected seed lots and the cost of control measures, by loss of export markets or by difficulties experienced in opening new markets. In Europe, Cms annually causes an estimated 15 million Euro in economic damage (van der Wolf et al. 2005). According to Straňák (1917), a disease named bacterial ring rot (BRR) occurred in potato crops around the Czech Lands at the beginning of the 20 th century. Among the Czech Lands, South Bohemia was supposed to be most severely threatened by BRR. Towards the end of the 20 th century in the CR, a relatively high percentage of potato tuber samples proved to be infected by Cms, namely 1.14% in seed potatoes in 1998 and 4.13% in com-Supported by the Ministry of Agriculture of the Czech Republic, Project No. QF 4105.
The susceptibility of 14 pear cultivars to the bacterium Erwinia amylovora, the causal agent of f... more The susceptibility of 14 pear cultivars to the bacterium Erwinia amylovora, the causal agent of fire blight disease, was evaluated using three different methods of in vivo inoculation-the leaf inoculation method on detached shoots of pear cultivars in a climate chamber, and the terminal shoot and blossom inoculation methods on potted trees of the same pear cultivars in a net house. The results of the artificial inoculations of the European and Asian pear cultivars were compared using the susceptibility score scale, as well as the ANOVA and post hoc methods. The differences among the pear cultivar susceptibility increased during the evaluation periods in the given year, but there were no significant differences between the annual evaluation in 2020 and 2021. The results of the pear cultivar susceptibility after inoculation of the detached shoots differed significantly from the results of the terminal shoot and blossom inoculation. The detached shoot susceptibility under pathogen-favourable conditions in the climate chamber was lower than the terminal shoot and blossom susceptibility in the net house for most pear cultivars. In both years, the highest values of the terminal shoot and blossom susceptibility were coincidently calculated for the Ananaska česká European old cultivar and the Nijissejkii Asian cultivar.
Polyclonal antisera to detect and determine two related pathovars, Pseudomonas syringae pv. pisi ... more Polyclonal antisera to detect and determine two related pathovars, Pseudomonas syringae pv. pisi and Pseudomonas syringae pv. syringae, were prepared Untreated bacterial cells, or fixed by formaldehyde or glutaraldehyde were used as antigens. After cross-absorption with heterologous antigens, antisera revealed a high level of specificity in slide agglutination, Ouchterlony gel double-diffusion and in DAS-ELISA and PTA-ELISA. Each of 14 P s. pisi prepared polyclonal antisera could detect and deter mine all strains of P s. pisi, regardless of race. PTA-ELISA was the most appropriate serological test to distinguish Pseudomonas syringae pathovars on peas. Most of the P s. pisi strains from foreign collections were in serological tests confirmed asP. s. pisi, while most of the Czech strains suspected as P s. pisi were determined as P s. syringae strains. The principal biochemical reaction, i.e., use of DL-homoserine as a carbon source to grow P s. pisi but not P s. syringae , was proved...
Variability in the responses of plants propagated from in vitro tissue cultures of 52 ware and in... more Variability in the responses of plants propagated from in vitro tissue cultures of 52 ware and industrial potato cultivars to different Clavibacter michiganensis subsp. sepedonicus inoculum size was tested during 2015–2017. Bacterial ring rot symptoms on plants and tubers xylem vessels were recorded for 8 weeks and the susceptibility index (SI) for individual cultivars was calculated. Based on foliage symptoms, potato cultivars were placed into three symptoms groups. The symptomless group had SIs ≤ 1, for the moderate symptom group SIs ranged from 1.01 to 2.99, and the severe symptom group had SIs ≥ 3.0. The pathogen concentrations in vascular vessels of all infected potato plants increased during the experiment regardless of the foliage symptom group.
The strict use of healthy propagating materials as the most important preventive measures against... more The strict use of healthy propagating materials as the most important preventive measures against the bacterial canker of apricot Knowledge of various reservoirs of Pseudomonas bacteria and their traits relative to the aptitude to survive and spread in apricot orchards is particularly pertinent for implementing
The methodology includes a method of artificial infection of plants and potato tubers as a prereq... more The methodology includes a method of artificial infection of plants and potato tubers as a prerequisite for the study of migration and localization of the pathogen in tubers and within the plant vascular tissues, time schedule and recommended size of samples of individual parts of plants and potato tubers during the growing season, depending on external conditions and potato genotype, how to deal with samples of the plants and potato tubers prior to treatment, method of processing samples of individual plant parts and tuber depending on the detection method and the optimization of methods for detection of the pathogen Clavibacter michiganensis subsp. sepedonicus. In compliance with the proposed methodological procedure should be interrupted vertical transmission of the pathogen in the process of breeding, the possibility of detection of the pathogen in breeding and propagation material and reduction of suspicious samples should be increased and the late positive determination of rin...
The methodology is to assessment the level of resistance of potato genotypes to soft rot bacteria... more The methodology is to assessment the level of resistance of potato genotypes to soft rot bacteria of Dickeya, Pectobacterium and Pseudomonas genera using slice test
The aim of this study was to find out whether causal agents of bacterial canker and the premature... more The aim of this study was to find out whether causal agents of bacterial canker and the premature death of apricot trees are present in the internal tissues of propagating material of various origins. In total, 33 samples of apricot (Prunus armeniaca L.) scion materials from eight and six samples of rootstocks from four European localities were analysed for the presence of the pathogenic Pseudomonas species. Significant differences were found in the diversity of the culturable bacterial population and the incidence of Pseudomonas bacteria in internal tissues of scion and rootstock buds. In most of the rootstocks, no Pseudomonas bacteria were detected. A total of 148 Pseudomonas-like strains isolated from scion samples were collected mainly from localities F1-F5 (in France) and G1-G2 (in Germany). These strains were clustered into 11 groups by means of fatty acid methyl ester (FAME) analysis; 91.9% of them were able to induce a hypersensitive reaction on tobacco leaves and 37.8% were positive in ice nucleation activity. A set of 89 Pseudomonas strains was characterised by means of Psy-PCR targeting of the Pseudomonas syringae (Ps) complex, complex phylogroup (PG), syrB-PCR targeting of the syringomycin synthesis, pathogenicity on detached apricot twigs, and the ability to survive within epiphytic microflora. Pseudomonas strains attributed to PG01, PG04, and PG07-08 were slightly pathogenic to detached apricot twigs. Altogether, 5% of Pseudomonas strains highly pathogenic to detached apricot twigs were isolated from apricot scion samples originated in localities F2, F5, and G1. These strains were attributed to PG02 and PG03, and rpoD sequencing confirmed a similarity to strains of P. syringae pv. syringae and P. amygdali pv. morsprunorum known to be pathogenic to apricot, respectively. The occurrence of these pathogens in buds of scion materials increases the risk of bacterial canker and the premature death of young apricot trees.
Conditions associated with an unusually high occurrence of burrknots in two young commercial appl... more Conditions associated with an unusually high occurrence of burrknots in two young commercial apple orchards at two locations, Těšetice and Stošíkovice, South Moravia, the Czech Republic, were analysed. In the first orchard, planted in spring 2003, the occurrence of burrknot on trees of cvs. Early Smith, Jonagold and Gala on M.9 rootstock was evaluated. In the second orchard, planted in autumn 2002, cv. Gala on M.9 rootstock was assessed. Planting material used at each location was obtained from the same commercial propagator and had been established from the same propagation stock materials. Of 60 trees per cultivar surveyed in the first orchard, incidence of burrknots in cvs. Early Smith, Jonagold and Gala trees was 98, 97 and 92%, respectively. The burrknot severity (mean number of burrknots on above portion of rootstock) was significantly higher on Jonagold trees, i.e. 3.65, than on the other two cultivars. Of 60 Gala trees in the second orchard, symptoms of burrknot appeared on ...
For the first time in the Czech Republic, bacteria identified as Pseudomonas marginalis, Pectobac... more For the first time in the Czech Republic, bacteria identified as Pseudomonas marginalis, Pectobacterium carotovorum subsp. carotovorum and Pseudomonas putida were isolated from tubers of Zantedeschia spp. with symptoms of tuber soft rot. The symptoms occurred on mother tubers as well as on new daughter tubers of different calla lily hybrids with yellow spathe, calla lily cv. Mango with bright orange spathe and Zantedeschia rehmanii with pink spathe. The percentage of diseased plants of the total plants in the plot was around 10%. When inoculated into potato tuber slices, strains of P. marginalis and P. c. subsp. carotovorum produced soft rot. Pectolytic activity of P. marginalis strains was less intensive than that of the P. c. subsp. carotovorum strain. The results confirm that bacterial soft rot of Zantedeschia spp. may have several causes.
Plant pathogenic species Pseudomonas corrugata and P. marginalis were detected and determined in ... more Plant pathogenic species Pseudomonas corrugata and P. marginalis were detected and determined in collapsed tomato plants in rockwool slab hydroponic culture in southern Moravia, Czech Republic. Surprisingly, P. marginalis was also determined before planting in apparently healthy grafted tomato transplants grown in hydroponic culture. Moreover, non-pathogenic P. fluorescens, P. putida, P. synxantha, and Stenotrophomonas malthophilia were identified. The Biolog Identification GN2 MicroPlate™ System System (Biolog, Inc., Hayward, USA) was used for identification of bacterial isolates. Cultures of P. corrugata and P. marginalis were used in a greenhouse pathogenicity experiment. Seven weeks old tomato plants of cv. Moneymaker grown in sterilised perlite were inoculated into the stem with a hypodermic needle at one point above the cotyledon node. In inoculated tomato plants, disease symptoms were observed that included external and internal dark brown lesions around the inoculation site,...
Pseudomonas syringae pv. aesculi (Pae) causes bleeding canker, a destructive disease of horse che... more Pseudomonas syringae pv. aesculi (Pae) causes bleeding canker, a destructive disease of horse chestnut trees (Aesculus hippocastanum) that limits the breeding of horse chestnut genotypes. The susceptibility of 322 F 1 progeny from 20 horse chestnut parent tree sources to the pathogen Pae was evaluated using different inoculation methods. The resulting infection rates, in decreasing order, were caused by inoculation of apical buds, inoculation of annual stems, insertion of bacteria into cut wounds on trunks and foliar spraying of the pathogen. According to the resistance index (RI) results of the field pathogenicity tests, at 2 or 3 years after inoculation 40, 40 and 20 % of horse chestnut parent tree sources were resistant, tolerant and susceptible, respectively, to Pae. Microbiological analyses of plant tissues from buds, phloem in the main trunks and roots of infected F 1 progeny regardless of parent tree source showed long-term survival of Pae bacteria in 70 % of tolerant F 1 progeny plants that lacked bleeding canker symptoms. Initial RI results and microbial analyses indicated that there was some frequency of resistance in the natural horse chestnut population. Altogether, 41 F 1 progeny were the most promising lines based on their viability and the absence of Pae in their tissues.
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