• Korean Journal Plant Pathology
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• v.13 no.4
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• pp.239-243
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• 1997

In August 1996, phyllody disease of sesame (Sesamum indicum L.) caused by phytoplasmas was observed at Boeun, Chungbuk Province, Korea. Symptoms included extreme proliferation of growing tips and numerous small leaves, giving the infected plant a witche's-broom effect. Parts or all of the floral parts were transformed into green leaf-like structures, and little or no seeds were produced. Transmission Electron microscopy revealed the presence of phytoplasmas in the phloem sieve elements of infected plant. Since the infected sesame plants were growing near by phytoplasma infected jujubes (Zizyphus jujubu), we tried a polymerase chain reaction (PCR) technique to identify these two causal phytoplasmas. The DNA extracted from the stems of infected sesame plant was PCR-amplified using a primer set specific to 16S rRNA gene of known phytoplasmas. The amplification generated a 1.4kb band in both sesame samples and phytoplasma-infected jujubes, which also suggests the sesame plants were infected with phytoplasmas. The restriction digestion of the amplified band by four different enzymes, AluI, HaeIII, HinfI or TaqI revealed that the phytoplasmas infecting jujubes and sesame plants were of different groups.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.714-719
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• 2013

The bent peduncle phenomenon (BPP) is known as a kind of physiological disorders found in cut rose plants, which causes the reduction of cut flower yields. As yet unknown mechanisms, however, it has not been easy to find solutions for BPP. To address this challenge, this study was conducted to investigate the characteristics of floral morphology, growth, and endogenous phytohormone level of BPP shoots in cut rose plants (Rosa hybrida L. 'Beast'). Morphological observation confirmed the fact that BPP was accompanied by the early formation and being phyllody of a specific sepal among five sepals, which gave rise to peduncle bending in the upper part of the phyllody with fasciation. Year-round BPP frequency in 'Beast' cultivar was in the range of 5 to 20% with seasonal change, increasing rapidly with an average temperature rise in summer. Except bent peduncle, the BPP shoots appeared to grow normally in terms of speed and size of floral development in comparison with normal. However, carbohydrate distribution to the floral part in BPP shoots was significantly reduced. The level of endogenous IAA (3-Indoleacetic acid) within the floral part in BPP shoots was highly maintained during floral development, in contrast to normal shoots. $GA_3$ contents were not significantly different between normal and BPP shoots. This study indicates that BPP would be induced by a series of courses: abnormally early formation of a specific sepal relative to high temperature, being phyllody of the sepal with fasciation, and continuous supply of endogenous IAA by phyllody.

• The Plant Pathology Journal
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• v.24 no.3
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• pp.279-282
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• 2008

This study describes a phytoplasmal disease occurring in Petunia leaves grown in the glasshouse of the National Horticultural Research Institute, Suwon, Korea. Abnormal growth like flattened stem with flower malformation or phyllody was observed from the plant. The DNA extracted from the diseased leaves was amplified using a universal primer pair of P1/P6 derived from the conserved 16S rRNA gene of Mollicutes giving the expected polymerase chain reaction(PCR) product of 1.5 kb. In the nested PCR assays, the expected DNA fragment of 1.1 kb was amplified with the specific primer pair R16F1/R16R1 that was designed on the basis of aster yellows(AY) phytoplasma 16S rDNA sequences. The 1.1 kb PCR products were cloned and nucleotide sequences were determined, and the sequences of the cloned 168 rRNA gene were deposited in the GenBank database under the accession no. of EU267779. Analysis of the homology percent of the 168 rDNA of PFS-K showed the closest relationship with Hydrangea phyllody phytoplasma(AY265215), Brassica napus phytoplasma(EU123466) and AY phytoplasma CHRY(AY180956). Phytoplasma isolated from the diseased Petunia was designated as Petunia flat stem phytoplasma Korean isolate(PFS-K) in this study. Flattened stem occurring in Petunia was confirmed as infection of AY group of phytoplasma by determination of 16S rRNA gene sequences of phytoplasma and microscopic observation of phytoplasma bodies. This is the first report on the phytoplasmal disease in Petunia in Korea.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.73.2-73
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• 2003

Typical whiches broom symptoms caused by phytoplasma were observed in Ash (Fraxinus rhynchophylla Hence) in Korea. The symptoms were showing abnormally small leaves, short internodes, and proliferation of shoots. Fluorescence and electron microscopy of leaf midribs revealed phytoplasma positive DAPI fluorescence and numerous phytoplasma bodies localized in the phloem sieve tubes. Phytoplasma DNA of 1.8 Kb was detected consistently from all symptomatic samples by the amplification of phytoplasma DNA with the phytoplasma specific primer pair Pl/P7. But no phytoplasma DNA was detected in healthy ash seedlings. Based on sequence analyses of an amplified region, this phytoplasma is closely related to Eqilodium phyllody, Mulberry dwarf, and Aster yellows phytoplasmas with the homology of 99.95 ％, 99.79 ％ and 99.78 ％, respectively, This phylogenetic analyses indicate that ash witches broom phytoplasma but is evidently distinct from the ash yellows group 16SrⅦ and should be classified into the Aster yellows group 16SrⅥ.

• 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.