• Journal of Microbiology
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• v.41 no.1
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• pp.16-21
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• 2003

We have collected eight high-level streptomycin-resistant strains of Pseudomonas marginalis and P. syringae pv. actinidiae which were isolated from kiwifruit orchards in Korea and Japan, The molecular mechanisms of resistance were investigated by the PCR, susceptibility tests, and nucleotide sequence analysis. Of the eight high-level streptomycin-resistant strains, four harbored strA-strB genes, which encode streptomycin-inactivating enzymes. While the three Korean strains of R marginalis did not have plasmid and carried the resistant genes in the chromosomes, the Japanese strain of P. syringae pv. actinidiae had a plasmid containing strA-strB genes. The myomycin susceptibility test demonstrated that the high-level resistance to streptomycin of the remaining four strains is associated with mutations in the rpsL gene. Nucleotide sequence analyses revealed that they contain a single base-pair mutation in codon 43 of their rpsL gene.

• Korean Journal of Microbiology
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• v.32 no.1
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• pp.60-64
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• 1994

Pseudomonas syringae pv. tabaci produces tabtoxin and causes wildfire disease on tabacco and bean plants. In this study, bacteriophage of P. syringae pv. tabaci were isolated from sewage by top agar overlay method, and physiological and genetical characteristics of the phage were investigated. Plaques of isolated phage were turbid and ranged in size from 1 to 2 mm. The stability range of pH was between 6.0 and 9.0, and stability of temperature was up to 30${\circ}C$ and inactivated at 70${\circ}C$. The adsorption rate of phage was about 85% for 30min. The latent period and mean burst size as dertermined in one step growth experiments were 3 hrs and 200 PFU/bacterium, respectively. Genomic material of isolated phage was dsDNA of which size was about 30kb.

• Korean Journal of Microbiology
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• v.27 no.3
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• pp.310-315
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• 1989

Tabtoxin produced in Pseudomonas syringae pv. tabace irreversibly inhibits its known physiological target, glutamine synthetase so that causes wildfire disease on leaves of host plant. In this study, we examined a rapid and sensitive microbiological method for tabtoxin assay in several media. In minimal A agar medium nd minimal glucose agar medium, growth inhibition zone of Agrobacterium tumefaciens was larger than that of other indicator strain. However, mostly, growth inhibition zone of indicator strains on the minimal glucose agar medium was smaller than that of on the miniaml A agar medium. In complex agar medium, growth inhibithiton zone was not observed in all the tested indicator strains. Pseudomonas syringae pv. tabaci produced more tabtoxin according to the incubation time. When glutamine was added to the minimal glucose agar medium, growth inhkbition zone of Agrobacterium tumefaciens was reduced.

• Research in Plant Disease
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• v.11 no.1
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• pp.80-84
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• 2005

Bacterial canker of sweet cherry (Prunus avium L.) was observed in farmers\' orchards in Goesan, Chungbuk in 2003. Typical canker symptoms occurred on the branches or twigs of sweet cherry in early spring and bacterial exudates oozed out of the cracked barks of diseased trees. Watersoaked brown symptoms appeared on the leaves and severe infection caused thorough defoliation on the branches or twigs of sweet cherry. When severely infected branches or twigs were cut, irregular and rusty-colored symptoms in sapwood and heartwood were clearly found, indicating that they can serve as specific symptoms of bacterial canker of sweet cherry. The causal bacterium responsible for the symptoms was isolated purely from the infected sapwood of sweet cherry. Based on its morphological, physiological and biochemical characteristics, the causal bacterium was identified as Pseudomonas syringae pv. morsprunorum. The bacterium was pathogenic on sweet cherry and Japanese apricot, but not on peach, cherry, and kiwifruit. It is proposed that the disease be named as bacterial canker of sweet cherry.

• Research in Plant Disease
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• v.26 no.1
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• pp.44-47
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• 2020

Streptomycin resistant isolates of Pseudomonas syringae pv. actinidiae, the causal agent of bacterial canker in kiwifruit, were found in Korea. A total of 734 isolates of P. syringae pv. actinidiae collected between 2008 and 2017 from bacterial canker infections in 111 kiwifruit orchards were assessed for streptomycin resistance. The survival of each isolate was screened against 100 ㎍/ml of streptomycin. Among 734 isolates, 38 streptomycin resistant P. syringae pv. actinidiae isolates originated from nine orchards were found. Streptomycin resistant isolates belonging to biovar 2 were found in several individual years, but ones belonging to biovar 3 were found in Korea only since 2016. Therefore, to use streptomycin for control of bacterial canker in kiwifruit orchards should be very careful, and it is necessary to check the streptomycin susceptibility of the pathogen before use in kiwifruit orchards.

• Proceedings of the Korean Society of Life Science Conference
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• 2007.10a
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• pp.46.1-46.1
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• 2007

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• The Plant Pathology Journal
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• v.33 no.1
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• pp.21-33
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• 2017

Citrus blast caused by bacterium Pseudomonas syringae is a very important disease of citrus occuring in many areas of the world, but with few data about genetic structure of the pathogen involved. Considering the above fact, this study reports genetic characterization of 43 P. syringae isolates obtained from plant tissue displaying citrus blast symptoms on mandarin (Citrus reticulata) in Montenegro, using multilocus sequence analysis of gyrB, rpoD, and gap1 gene sequences. Gene sequences from a collection of 54 reference pathotype strains of P. syringae from the Plant Associated and Environmental Microbes Database (PAMDB) was used to establish a genetic relationship with our isolates obtained from mandarin. Phylogenetic analyses of gyrB, rpoD, and gap1 gene sequences showed that P. syringae pv. syringae causes citrus blast in mandarin in Montenegro, and belongs to genomospecies 1. Genetic homogeneity of isolates suggested that the Montenegrian population might be clonal which indicates a possible common source of infection. These findings may assist in further epidemiological studies of this pathogen and for determining mandarin breeding strategies for P. syringae control.

• The Plant Pathology Journal
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• v.28 no.4
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• pp.423-427
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• 2012

Pseudomonas syringae pv. actinidiae strains, the causal agents of bacterial canker on kiwifruit, were isolated from Korea and Italy in 2011. Among 87 isolates, a total of six representative strains, three from Korea and three from Italy, were identified on the basis of biochemical and physiological tests. Identities were confirmed by PCR using P. syringae pv. actinidiae-specific primers PsaF1/R2, which amplified a 280-bp DNA fragment. The strains isolated from Korea in this study displayed BOX-PCR patterns similar to those isolated from Italy but different from those isolated previously in Korea or the pathotype P. syringae pv. actinidiae strain. The effector hopA1 and hopH1 genes, which are known to be present in strains isolated recently from France and Italy, were also present in P. syringae pv. actinidiae strains, SYS1, SYS2 and SYS4, isolated from Korea in this work. However, no amplicons of the expected size were obtained from strains previously isolated from Korea and Japan. In addition, the Korean strains isolated in this work belonged to haplotype I for the cts gene identical to those strains isolated from recent outbreaks in Italy. These results suggest that P. syringae pv. actinidiae strains isolated from Korea and examined in this work are a new type of strain similar to those found from recent outbreaks in Italy. This is the first report on the occurrence of cts haplotype I strains of P. syringae pv. actinidiae affecting kiwifruit plants in Korea.

• Research in Plant Disease
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• v.9 no.3
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• pp.116-120
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• 2003

A PCR method that combines biological and enzymatic amplification of PCR targets was developed for the detection of Pseudomonas syringae pv. actinidiae on kiwifruit leaves. A nested PCR was performed with primers designes from the coding sequence of the cfl gene, which is involved in production of the phytotoxin coronatine. The first and second primer sets efficiently amplified expected 665 and 310-bp fragments, respectively. With two successive amplifications, as few as 20 CFU/ml of P. syringae pv. actinidiae could be detected on ethidium bromide-stained agarose gel. Leaf samples were collected from 4 kiwifruit trees showing yellow halo spots on leaves and incubated in pepton-sucrose broth for 12 h at $16^{\circ}$C before PCR amplification. Positive detection was obtained with one sample, which was proved as a diseased plant in the next spring.

• Research in Plant Disease
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• v.9 no.4
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• pp.213-216
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• 2003

A bacterial disease of tea plants(Camellia sinensis L.) was found in the graftage nursery grown under vinyl house conditions in Suncheon city, Korea, in spring of 2002. The primary symptoms of the disease include small, water-soaked and dark brown spot development on the young leaves. This spot gradually increases in size, especially taking on elongate shape along the midrib or vein of the leaf, and then turns black. The diseased leaves were defoliated easily. Ten strains were isolated from the infected leaf. Inoculation on tea leaf with these isolates produced the same symptoms of naturally infected plants. On the basis of stain reactions, morphological characterization, colony pattern, physiological and biochemical reactions, the bacterium was identified as Pseudomonas syringae pv. theae. This is the first report of brown blight of tea plant in Korea.