• 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.

• Plant Disease and Agriculture
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• v.1 no.1
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• pp.30-36
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• 1995

Infection rate of witches'-broom disease (WB) was observed yearly in transplanted jujube seedlings for 7 years. Seedlings of‘Hongan’grafted either on the rootstock from seed (RS) or on the rootstock from rooting (RR) were planted in separate farms. Occurrence of the disease was determined 4 years after transplanting with the witches'-broom symptom. Only 1 seedling of RS was infected with WB, while 56 seedlings of RR showed WB. Yearly infection rates of WB were observed in several varieties of jujube including‘Boeun’,‘Keumsung’,‘Moodeung’,‘Bokjo’,‘Koori’(10 trees for each in Cheongjoo), and‘Hongan’(165 trees in Boeun). In most varieties, WB first appeared in the third year from transplanting, and in the seventh year, more than 80% of the total tree showed WB. The yearly infection rate of newly infected trees was almost. stable during the first years. However, the ratio sharply increased from the sixth year. The accumulated infection rate of WB increased double, year by year from the third to seventh year. Between Cheongjoo and Boeun, no difference in infection rates was found.

• The Plant Pathology Journal
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• v.21 no.1
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• pp.55-58
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• 2005

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 16S 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 from 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 ligustrum witches' broom phytoplasma of the 16S rRNA group V, but no DNA amplification was detected from other phytoplasma strains such as groups 16SrI (Aster yellows) and 16SrXII (Stolbur group) in which mulberry dwarf phytoplasma and chrysanthemum witches' broom phytoplasma belong to, respectively. The same results were obtained from both Korean and Chinese isolates of JWB phytoplasma. Nested-PCR using phytoplasma universal primer pair P1/P7 and 16SrV group-specific primer pair 16S(V) F/R could detect group V phytoplasmas 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.

• Journal of Korean Society of Forest Science
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• v.67 no.1
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• pp.28-30
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• 1984

Distribution of mycoplasma-like organisms (MLO) in the phloem tissue of witches'-broom infected jujube trees was investigated by fluorescence microscopy applying new fluorochrome DAPI (4'-6-diamidino-2-phenylindole, 2HCl). MLO were detected from the phloem of leaf and stem sections of diseased branches exhibiting typical witches'-broom symptom but not detected from those of symptomless branches of an infected tree. MLO were also present in the healthy looking leaves frequently found in the diseased shoots. Fluorescence microscopy revealed the presence of MLO in the phloem of root sections of infected trees.

• The Plant Pathology Journal
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• v.23 no.2
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• pp.106-108
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• 2007

The Symptoms of witches' broom disease caused by phytoplasma including general stunting and yellowing, were observed in leafy lespedeza (Lespedeza cyrtobotrya M.) on Doam-myeon, Pyeongchang-gun, in 2006. Based on the sequence analysis of PCR-amplified 16S ribosomal DNA and 16S-23S spacer region DNA products using universal phytoplasma primers, the phytoplasma associated with leafy lespedeza witches' broom (LLWB) disease was identified as a member of Candidatus Pytoplasma trifolii. It was most closely related to alsike clover proliferation phytoplasma (99.8% similarity, accession no. AY390261), Candidatus Pytoplasma trifolii strain. RFLP patterns generated with AluI, HpaII clearly differentiated LLWB phytoplasma from the referenced phytoplasma strains, water dropwort witches' broom, mulberry dwarf, glehni aster yellow dwarf and jujube witches' broom. This paper is the first report on Candidatus Phytoplasma trifolii in leafy lespedeza identified at a molecular level.

• 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.

• Journal of Korean Society of Forest Science
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• v.96 no.6
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• pp.737-741
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• 2007

Typical phytoplasma witches' broom symptoms were observed in black locust (Robinia pseudoacacia L.) in Korea. The symptoms of the disease were showing abnormally small leaves, shortened intemodes and proliferation of shoots. The phytoplasmas were detected consistently in all the symptomatic samples by the amplification with phytoplasma universal primer pairs P1/P7 and R16F2n/R2, and the expected size was 1.8 kb and 1.2 kb. However, the phytoplasma DNA was not detected in healthy seedling. Based on sequence analysis of amplified region, this phytoplasma has close homologies with aster yellow, mulberry dwarf, maize bushy stunt, ash witches' broom and sumac witches' broom phytoplasmas, more than 99.2% but showed homologies with black locust witches' broom (GeneBank Accession No. AF 244363), and jujube witches' broom, 88.6% and 87.7%, respectively. This phylogetic analysis indicates that the black locust witches' broom phytoplasma founded in korea should be classified in the Candidatus phytoplasma asteris (16Sr I) group and clearly distinct from the black locust witches' broom group 16Sr III (peach X-disease phytoplasma group).

• 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.

• Korean journal of applied entomology
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• v.15 no.3 s.28
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• pp.107-110
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• 1976

A Witches'-broom disease of jujube (Zizyphus jujuba) with which mycoplasma-like bodies are associated is wide spread in South Korea. Jujube trees with witches'-broom symptoms were selected from 15-20 year old planting and treated with solution of oxytetracycline hydrochloride (Terramycin). Treatments were 1) one injection on April; 2) one postharvest injection on October; 3) two injections (April and July); 4) three injections (April, June and August) and 5) an untreated control. Each injection consisted of 500ml of 1,000 p.p.m. solution of oxytetracycline HCl transfused into affected trees from plastic reservoir through plastic tubes connected to 3 small holes drilled in the basal part of the tree trunks. Complete remission of witches'-broom symptoms was accomplished within one growing season by one spring (April) injection. One postharvest (Oct.) injection also prevented the symptoms in the following growing season. Two and three injection treatments prevented the symptoms for at least two growing seasons and restored previously severely diseased trees to normal or near normal conditions. Remission of symptoms was found only above the injection site while current season witches'-brooms developed from areas below the injection site and from untreated main scaffolds. The results of this experiment demonstrates that transfusion treatment with oxytetracyclin HCl is feasible for the practical control of witches'-broom of jujube.