• The Plant Pathology Journal
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• v.21 no.2
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• pp.119-126
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• 2005

Genomic and phenotypic characteristics of the bacterial strains of Pseudomonas syringae pv. actinidiae and P. syringae pv. syringae collected from several kiwifruit orchards of Korea were investigated and compared with those from Japan to elucidate their phylogenic relationships. All the strains of P. syringae pv. actinidiae and pv. syringae tested were sensitive to copper sulfate but Korean and Japanese strains showed quite different responses to streptomycin. Korean strains were sensitive to streptomycin, but most of the Japanese strains of P. syringae pv. actinidiae were highly resistant to streptomycin. Japanese strains were also relatively more resistant to oxytetracycline than Korean strains. Plasmid profiles were not valuable to distinguish Korean strains of P. syringae pv. actinidiae frombJapanese strains. One or more indigenous plasmids with more than 15 kb in size were detected in all strains of P. syringae pv. actinidiae, but the number and sizes of plasmids harbored in P. syringae pv. actinidiae were variable among the strains regardless of their geographic origins. There also observed no significant relationship among resistance levels of the strains of P. syringae pv. actinidiae to antibiotics, their pathogenicity and plasmid profiles. RAPD profiles were useful to analyze the strains of P. syringae pv. actinidiae and pv. syringae. All the strains of P. syringae pv. actinidiae fell into a wide cluster separated from the strains of P. syringae pv. syringae, but Korean strains of P. syringae pv. actinidiae were separated from Japanese strains. The results support that Korean and Japanese strains of P. syringae pv. actinidiae may have different phylogenic origins.

• Journal of Microbiology and Biotechnology
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• v.13 no.1
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• pp.110-118
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• 2003

Pseudomonas syringae pv. actinidiae strains, which cause canker disease in kiwifruit, were collected from kiwifruit orchards in Korea and identified using biochemical and physiological tests. The nucleotide sequences of the 16s rDNA and 16s-23s internally transcribed spacer of the isolates were found to be Identical to those of' the pathotype strain, Kwl 1, of P syringae pv. actinidiae. Remarkably, no coding sequence for phaseolotoxin biosynthesis or phaseolotoxin- resistant ornithine carbamoyltransferase was found by PCR amplification in any of the new Korean isolates of pseudomonas syringae pv. actinidiae, although this was clearly identified in the control pathotype Kwl 1 reference strain. In contrast, three primer sets derived from the coronatine biosynthetic gene cluster and DNA from the Korean strains yielded amplified DNA fragments of the expected size. A sequence analysis of the PCR products revealed that P. syringae pv. actinidiae and the Korean strains of pv. actinidiae contain coronafncate ligase genes (cfl)with identical sequences, whereas their. corR genes exhibited 91% sequence similarity. The production of coronatine, instead of phaseolotoxin, by the Korean strains of P. syringae pv. actinidiae was confirmed by a bioassay using reference pathovars known to produce coronatine and phaseolotoxin. The genes for coronatine biosynthesis in the Korean strains of P. syringae pv. actinidiae were found to be present on plasmids.

• The Plant Pathology Journal
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• v.30 no.1
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• pp.96-101
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• 2014

The molecular features of Pseudomonas syringae pv. actinidiae strains isolated in Korea were compared with strains isolated in Japan and Italy. Sequencing of eight P. syringae pv. actinidiae and three P. syringae pv. theae strains revealed a total of 44 single nucleotide polymorphisms across 4,818 bp of the concatenated alignment of nine genes. A multiplex PCR assay was developed for the detection of P. syringae pv. actinidiae and for the specific detection of recent haplotype strains other than strains isolated since the 1980s in Korea. The primer pair, designated as TacF and TacR, specifically amplified a 545-bp fragment with the genomic DNA of new haplotype of P. syringae pv. actinidiae strains. A multiplex PCR conducted with the TacF/TacR primer pair and the universal primer pair for all P. syringae pv. actinidiae strains can be simultaneously applied for the detection of P. syringae pv. actinidiae and for the differentiation of new haplotype strains.

• Research in Plant Disease
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• v.10 no.4
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• pp.310-312
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• 2004

Pseudomonas syringae pv. actinidiae is the causative agent of bacterial canker in kiwifruit. A nested PCR detection method that uses primers designed from the cfl gene, involved in production of the phytotoxin coronatine, was applied on soil samples. These primers yielded 665 and 310-bp fragments in consecutive PCR amplification step with DNA from soil inoculated with Korean strain of P. syringae pv. actinidiae. This system was applied to survey soil samples from a kiwifruit orchard destroyed by bacterial canker. A specific 310-bp PCR product was obtained from all six samples of soil tested.

• Research in Plant Disease
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• v.23 no.1
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• pp.35-41
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• 2017

Pseudomonas syringae pv. actinidiae is the causative agent of bacterial canker of kiwifruit. The population of this pathogen is differentiated into three biovars, biovar 1, 2 and 3, according to their molecular characteristics. In this work, we determined biovars of P. syringae pv. actinidiae strains isolated in Korea since 1997 and stored in Department of Biology, Sunchon National University, Suncheon, Korea. The biovars of P. syringae pv. actinidiae strains were determined by PCR using biovar specific primers developed previously. Of 682 strains investigated, 288 strains belonged to biovar 2, while 394 strains were biovar 3. There were no P. syringae pv. actinidiae strains belonging to biovar 1 among the strains isolated in Korea. Sudden outbreak and spreading of bacterial canker caused by biovar 3 strain suggest that this strain has character of rapid transmission.

• Korean Journal Plant Pathology
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• v.13 no.2
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• pp.125-128
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• 1997

Reactions of Pseudomonas syringae pv. actinidiae to 95 carbon sources in a 96-well microplate (BiOLOG GN MicroPlateTM) were investigated. The bacterium used 9 carbon sources such as D-mannitol, sucrose, etc., but did not use 62 carbon sources such as $\alpha$-cyclodextrin, dextrin, etc. Based on the reactions, a user data base for identification of P. syringae pv. actinidiae was constructed in Biolog program (BiOLOG MicroLogTM 2 system). P. syringae pv. actinidiae isolates collected from kiwifruits could be identified automatically with high similarity using the user data base, which could diagnose rapidly and easily whether the tree was infected with bacterial canker or not.

• 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.

• 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.

• The Plant Pathology Journal
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• v.17 no.6
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• pp.361.5-362
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• 2001

Identification and characterization of Coronatine-producing Pseudomonas syringae pv. actinidiae isolated from 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.