• Journal of Korean Society of Forest Science
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• v.94 no.2 s.159
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• pp.103-107
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• 2005

Typical phytoplasma whiches' broom symptoms were observed in Ash (Fraxinus rhynchophylla Hence) in Korea. The symptoms of the disease were showing abnormally small leaves, shorted internodes and proliferation of shoots. Examination of fluorescent and electron microscopy of leaf midribs revealed numerous phytoplasma bodies localized in the phloem tube cells. The phytoplasmas were detected in all the symptomatic samples by the amplification with phytoplasma specific primer pair P1/P7 consistently, and the expected size was 1.8 kb. However, the phytoplasma DNA was not detected in healthy seedlings. Based on sequence analysis of amplified region, this phytoplasma has close homologies with eqilodium phyllody, mulberry dwarf, and aster yellow phytoplasmas, 99.95%, 99.79% and 99.78%, respectively, This phylogetic analysis indicates that ash witches' broom phytoplasma should be classified in the aster yellow group 16SrVI and clearly distinct from the ash yellow group 16SrVII.

• Korean Journal Plant Pathology
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• v.12 no.2
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• pp.191-196
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• 1996

위축, 황화, 총생 증상 등 전형적인 병징을 나타내는 phytoplasma에 감염된 식물에서 phytoplasma만을 특이적으로 검출하기 위하여 polymerase chain reaction(PCR) 방법을 이용하였다. Phytoplasma의 16S rRNA gence의 DNA 단편을 증폭하기 위하여 1.4 kb primers (forward, 5` -GTTGATCCTGGCTCAGGATT-3` 와 reverse, 5` -AACCCCGAGAACGTATTCACC -3`)를 사용하여 증폭한 결과, phytoplasma에 이병된 오동나무, 라일락 및 미역취에서는 약 1.4 kbp의 위치에서 특이 band가 검출되었으나 control로 사용한 건전주에서는 어떠한 band 검출되지 않았다. 위의 결과를 재확인 하기 위하여 약 0.5 kb의 primers(forward, 5` -ACGAAAGCGTGGGGAGCAAA-3` 와 reverse, 5` -GAAGTCGAGTTGCAGACTTC-3`)를 사용하여 증폭한 결과, 0.5 kb의 위치에서 특이 band가 검출되었으나 control로 사용한 건전주에서는 어떠한 band도 검출되지 않았다. Phytoplasma에 이병된 식물의 PCR 반응산물을 제한효소인 AluI으로 처리하 sruf과, 오동나무와 라일락에서는 동일한 band pattern을 나타내어 서로 유연관계가 가까운 phytoplasma인 것으로 생각되며, 미역취에서는 이들과는 다른 band pattern을 나타내어 오동나무와 라일락의 phytoplasma와는 유연관계가 먼 것으로 추측된다.

• Korean Journal Plant Pathology
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• v.14 no.5
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• pp.382-385
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• 1998

Molecular identification and genetic relationships between a phytoplasma associated with chestnut little leaf (CLL) and phytoplasma isolates of other trees in Korea were amplified by polymerase chain reaction (PCR). These 16S rDNA sequences amplified from the various phytoplasmas were used in DNA heteroduplex mobility assays (HMA). In DNA HMA combined with PCR, the mobility shift was observed for a heteroduoplex formed in combined with CLL and jujube witches broom, but not for those formed in combined with CLL and each of sumac witches broom, paulownia witches broom, and mulberry dwarf. HMA combined with PCR has been shown to be a very useful method for detection and differentiation of phytoplasmas.

• Plant Resources
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• v.3 no.3
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• pp.173-178
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• 2000

This test checked jujube witches'-broom disease, sumac witches'-broom disease, paulonia witches'- broom disease, and mulberry dwarf disease whether or not they were infected by phytoplasma, using universal and specific primers. Upon treatment of DNA amplified by PCR of phytoplasma with Alu I , Hpa II and Sat I restricted enzymes, distinction of phytoplasmas was possible. Particularly, phytoplasma of each host was distinguishable by treatment of Hpa II restricted enzyme. Meanwhile, analysis of restricted enzymes of jujube witches'-broom disease showed a higher infectivity of phytoplasmas of two origins. There were a lot of relations between jujube witches'-broom disease and sumac witches'-broom disease, and between paulonia witches'-broom disease and mulberry dwarf disease.

• The Plant Pathology Journal
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• v.18 no.6
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• pp.308-312
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• 2002

Heteroduplex mobility assay (HMA) and single-strand conformation polymorphism (SSCP) analyses combined with PCR were developed for genetic differentiation of various phytoplasma isolates. In the HMA and SSCP analyses, differences in the mobility shifts and the SSCP band patterns identified three distinct types of phyto-plasmas: Type Ⅰ, jujube witches'-broom (JWB) and ligustrum witches'-broom (LiWB); Type Ⅱ, mulberry dwarf（MD) and sumac witches'-broom (SuWB); and Type Ⅲ, paulownia witches'-broom (PaWB). Results of the sequence analyses revealed that phytoplasmas of JWB and MD had 100％ homology with LiWB and SuWB, respectively. On the other hand, PaWB phyto-plasma had 97.8% homology with MD phytoplasma. The PCR-HMA and SSCP techniques were very useful in determining variations in sequence among several isolates of phytoplasmas. Furthermore, the methods were rapid, economical, highly sensitive, and easy to handle with the gels.

• The Plant Pathology Journal
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• v.18 no.2
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• pp.98-101
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• 2002

Using phytoplasma universal primer pair Pl and P7, a fragment of about 1.8 kb nucleotide sequences of 16S rRNA gene and 16S-23S rRNA intergenic spacer region, and a portion of 23S rRNA gene of jujube witches'broom (JWB) and mulberry dwarf(MD) phytoplasmas were determined. The nucleotide sequences of JWB and MD were 1,850 bp and 1,831 bp long, respectively. The JWB phytoplasma sequence was aligned with the homologous sequence of MD phytoplasma. Twenty-eight base insertions and nine base deletions were found in the JWB phytoplasma sequence compared with that of MD phytoplasma. The similarity of the aligned sequences of JWB and MD was 84.8%. The near-complete 16S rRNA gene DNA sequences of JWB and MD were 1,529 bp and 1,530 bp in length, respectively, and revealed 89.0% homology. The 16S-23S rRNA intergenic spacer region DNA sequences were 263 bp and 243 bp in lengths respectively, while homology was only 70% and the conserved tRNA-lle gene of JWB and MD was located into the intergenic space region between 16S-23S rRNA gene. The nucleotide sequences were 77 bp long in both JWB and MD, and showed 97.4% sequence homology. Based on the phylogenetic analysis of the two phytoplasmas, the JWB phytoplasma belongs to the Elm yellow phytoplasma group (16S rV), whereas, the MD phytoplasma belongs to the Aster yellow group (16S rI).

• Research in Plant Disease
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• v.26 no.3
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• pp.134-143
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• 2020

The goal of this manuscript is to determine seed-borne plant pathogenic bacteria and phytoplasmas among quarantine pests in Korea. Four and two prohibited bacteria and phytoplasmas, respectively, and 35 and 17 restricted bacteria and phytoplasmas, respectively, were assessed whether they are seed-borne or not based on preliminary reports. As results, two species of prohibited bacteria, eighteen species of restricted bacteria, and one species of restricted phytoplasma have been determined as being seed-borne plant pathogenic bacteria. Thus, quarantine fields must account for these lists once inspection has been conducted on imported seeds and also use of these lists can help to reduce the production of new diseases that can spread from infected imported seeds.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1999.04a
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• pp.47.2-47
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• 1999

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.136.2-137
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• 2003

In order to diagnose and differentiate jujube witches' broom (JWB) phytoplasma rapidly, oligonucleotide primer pair, 16Sr(V) F/R, for polymerase chain reactions (PCRs) was designed on the basis of 165 rRNA sequences of JWB phytoplasma. The PCR employing phytoplasma universal primer pair P1/P7 consistently amplified DNA in all tested phytoplasma isolates. But no phytoplasma DNA was detected in healthy jujube seedlings. The nested PCR, the primer pair 16S(V) F/R, about 460 bp fragment, amplified DNA in all tested JWB and related phytoplasmas including LiWB phytoplasma of the 165 rRNA group V, but no DNA amplification was detected from other phytoplasma strains such as group 16SrI (Aster yellows) and group 16SrⅩII (Stolbur group) phytoplasmas in which mulberry dwarf phytoplasma and chrysanthemum witches broom phytoplasma are belonged to, respectively The same results were obtained from both Korean- and Chinese-isolates of JWB. Nested-PCR using phytoplasma universal primer pair P1/P7 and 16S rRNA group V specific primer pair 16S(V) F/R could detect group V phytoplasma rapidly and easily, in particular JWB phytoplasma.

• The Plant Pathology Journal
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• v.25 no.1
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• pp.21-25
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• 2009

Jujube trees infected with phytoplasma exhibit symptoms of typical witches' broom, such as yellowing, abnormally small leaves, short internodes and proliferation of shoots. A 1.2 kb fragment of the 16S rDNA from jujube phytoplasma was generated by R16F2n/R16R2 primer pair from earlier amplified P1/P7 PCR products of cloned jujube witches' broom phytoplasmas. Enzymatic restriction fragment length polymorphism (RFLP) and sequence analysis of 16S rDNA revealed that the jujube tree was infected with 16S rDNA I and V groups of phytoplasmas. Extensive comparative analyses of restriction enzyme profiles from Alu I, Hha I, Msp I, and Rsa I clearly classified the two into different phytoplasma groups. The phylogenie analyses based on 16S rDNA showed that the similarity of the two different clones was 87.5%. This is the first report of a mixed phytoplasmal infection in a single jujube tree.