• Current Research on Agriculture and Life Sciences
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• v.32 no.4
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• pp.179-183
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• 2014

Optimization of the protocorm-like body (PLB) formation of Phalaenopsis and Dendrobium hybrids was performed by determining the effects of plant growth regulators (PGRs) and different parts and division sizes of the PLB. For both genera, the base part was the best for the proliferation of PLBs, yielding the highest number of PLBs on a PGR-free medium for Phalaenopsis and medium containing $0.1{\mu}M$ NAA and $10.0{\mu}M$ BAP for Dendrobium. As regards the division size, four-division sections resulted in a higher PLB formation efficiency for Phalaenopsis, while two-division sections produced a higher PLB formation efficiency for Dendrobium. It is expected that these findings will be applicable to efficient PLB formation of other Phalaenopsis and Dendrobium orchids.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.145.1-145
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• 2003

This study was conducted to designing conserved regions of molecules for virus-derived resistance to transgenic Phlaenopsis orchids to protect against two major orchid viruses, Cymbidum mosaic virus (CymMV) and Odontoglossum ringspot virus (ORSV). Infected leaf samples of Phalaenopsis were randomly screened by the RT-PCR with specific primers to both of viruses. RT-PCR products of the viruses were cloned and their nucleotide sequences were determined. Multiple alignments of coat protein (CP) genes of the viruses revealed that over the 88 ％ and 94 ％ identities with CymMV and ORSV, respectively, were observed. These data can be useful for selection of highly conserved regions of CP gene of the viruses for transgenic orchid experiments.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2009.10a
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• pp.41-42
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• 2009

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1999.04a
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• pp.20.2-20
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• 1999

• The Plant Pathology Journal
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• v.26 no.2
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• pp.130-138
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• 2010

Orchid fleck virus (OFV) is an unassigned plant virus in the family Rhabdoviridae. OFV was isolated from Cymbidium sp. showing oval necrotic lesions on their leaves in Korea, and designated as OFV-NHHS1. The complete nucleotide sequence of the RNA1 (6,413 nt) (GenBank accession no. AB516442) and RNA2 (6,001 nt) (GenBank accession no. AB516441) was determined in this study. RNA1 and RNA2 contained five and one ORF respectively. RNA1 encodes nucleocapsid (N) of 49 kDa, ORF2 of 26 kDa, ORF3 of 38 kDa, ORF4 of 20 kDa and glycoprotein (G) of 61 kDa proteins, whereas RNA2 encodes a single polymerase of 212 kDa. OFV-NHHS1 shared extremely high similarity of 98.6-100% and 98.9-99.6% in nucleotidle and amino acid sequences with a Japanese isolate, OFV-so, respectively. However, the N, G and L of OFV-NHHS1 revealed 6.9-19.3%, 7.3-12.0%, and 13.4-26.6% identities to those of 29 Rhabdoviruses, respectively. To survey the infection rate of OFV in commercial orchids in Korea, 51 Cymbidium sp., 10 Phalaenopsis sp., 22 Oncidium sp. and 21 Dendrobium sp. plants that showed typical viral symptoms were collected. RT-PCR with specific primers for detection of Cymbidium mosaic virus (CymMV), ORSV and OFV showed high infection rate by ORSV alone and double infection by ORSV and CymMV. One of the orchids tested was infected with OFV. This is the first report of the complete nucleotide sequences of OFV isolated in Korea.

• Journal of People, Plants, and Environment
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• v.23 no.5
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• pp.545-554
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• 2020

Background and objective: Moth orchids in the vegetative stage are suitable for a multi-layer growing environment in a closed-type plant factory which can be a good alternative that can reduce production costs by reducing cultivation time and energy cost per plant. This study was conducted to find out the optimal rhizospheric environment for different irrigation methods without a potting medium and rhizospheric ventilation for the vegetative growth of young Phalaenopsis hybrid 'Blanc Rouge' (P. KV600 × P. Kang 1) and Phalaenopsis Queen Beer 'Mantefon' in a closed-type plant factory system. Methods: The one-month-old clonal micropropagules with bare roots rapped with a sponges were fixed on the holes of styrofoam plates above growth beds, and were watered using the ebb-and-flow (EBB) and aeroponic (AER) methods with Ichihashi solution (0.5 strength) once a day at 06:00 (P) or 18:00 (S), and both (PS). Rhizospheric ventilation (V) was also applied to change the temperature, relative humidity, and CO₂ concentration of the beds. Plants potted into sphagnum moss and watered once a week were used as the control group. Results: After 12 months of treatment, the growth characteristics of the EBB groups were the best among the treatment groups without a medium, but no effect of irrigation timing was observed. V reduced the temperature, relative humidity and CO₂ concentration of the beds. Whereas, EBB+V (ebb-and-flow with ventilation) improved plant growth and reduced the occurrence of disorders and withering. Especially, EBB+V showed a similar performance to the control group. Conclusion: The results indicated that the optimal irrigation method without a potting medium for producing middle-aged potted moth orchids was the EBB system with forced rhizospheric ventilation. Therefore, further studies on the optimal ventilation method and moisture control of the crown need to be carried out to develop the irrigation system without a potting medium for vertical farming in closed-type plant factories.

• The Plant Pathology Journal
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• v.38 no.6
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• pp.665-672
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• 2022

Cymbidium mosaic virus (CymMV) is one of economically important viruses that cause significant losses of orchids in the world. In the present study, a reverse transcription recombinase polymerase amplification (RT-RPA) assay combined with a lateral flow immunostrip (LFI) assay was developed for the detection of CymMV in orchid plants. A pair of primers containing fluorescent probes at each terminus that amplifies highly specifically a part of the coat protein gene of CymMV was determined for RT-RPA assay. The RT-RPA assay involved incubation at an isothermal temperature (39℃) and could be performed rapidly within 30 min. In addition, no cross-reactivity was observed to occur with odontoglossum ringspot virus and cymbidium chlorotic mosaic virus. The RT-RPA with LFI assay (RT-RPA-LFI) for CymMV showed 100 times more sensitivity than conventional reverse transcription polymerase chain reaction (RT-PCR). Furthermore, the RT-PCR-LFI assay demonstrated the simplicity and the rapidity of CymMV detection since the assay did not require any equipment, by comparing results with those of conventional RT-PCR. On-site application of the RT-RPA-LFI assay was validated for the detection of CymMV in field-collected orchids, indicating a simple, rapid, sensitive, and reliable method for detecting CymMV in orchids.

• Korean journal of applied entomology
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• v.15 no.3 s.28
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• pp.137-145
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• 1976

Orchids have been propagated vegetatively for a long time without adequate control measures against virus diseases in Korea. As a result, it is presumed that most of the orchid varieties in Korea may have been degenerated. Nevertheless there has been little work on the virus diseases of orchids in Korea. Therefore studies were initiated to isolate an4 characterize the orchid viruses occurring in Korea. The results obtained are summerized as follows. 1. Symptoms of virus diseases on orchid varieties can be grouped 1) mosaic, 2) necrotic streak with mosaic, 3) ring necrosis, 4) chlorotkc ring and 5) necrotic spot. 2. A total of 102 orchid plants representing 4 genera were investigated on the occurrence of Cymbidium mosaic virus and tobacco mosaic virus by serological agar-gel double diffusion test. The test revealed that approximately $45\%$ of the orchids were infected with Cymbidium mosaic virus. None of the plants were found to be infected with tobacco mosaic virus. 3. Local lesions appeared on the inoculated leaves of Chenopodium amaranticolor Cassia occidentalis and Datura stramonium 7-12 days after mechanical inoculation with Cymbidium mosaic virus. 4. Physical properties of the Cymbidium mosaic virus determined by inoculation on Chenopodium amaranticolor were as follows: Thermal inactivation Point; $75-80^{\circ}C$, dilution end Point; $10^{-5}-10^{-6}\%$ aging in vitro; 8 days. 5. Three different buffers at pH 7.0 and pH 9.0 were compared for the efficiency of agar-gel double diffusion test with Cymbidium mosaic virus. Phosphate, imidazol and tris buffer at pH 7.0 gave equally satisfactory results. 6. Electron microscopic examination of the Cymbidium mosaic virus revealed rod shaped particles measuring 460-580mu.

• Korean Journal of Plant Taxonomy
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• v.36 no.4
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• pp.335-360
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• 2006

The distribution on 88 taxa of wild orchids in the Korean Peninsula was investigated by the examinations of specimens and the distribution maps were presented. The species numbers distributed at each eight floral regions in the Korean Peninsula are as the followings; Gapsan Province 27 taxa, Gwanbuk 21, Gwanseo 13, Middle 37, South 39, Southern-coast 33, Jeju 64 and Ulleung 19. Most species (72.7%) of Korean wild orchids are found in the Jeju Island. Eighteen taxa of them are restricted to the island in the Korean Peninsula. Among Korean species, 30 taxa grow at evergreen broad-leaved forests, and 16 are northern elements distributed at high mountains or northern part. In terms of distribution, the Korean wild orchid species are classified into IUCN Red List Categories by a modified criterion for Korean plants. No orchid species included EX or EW categories is found in the Korean Peninsula. Ten species are designated to be in CR category; Cymbidium kanran, C. lancifolium, C. ensifolium, Cypripedium japonicum, Cyrtosia septentrionalis, Dendrobium moniliforme, Habenaria chejuensis, H. radiata, Neofinetia falcata and Sedirea japonica, of which C. ensifolium and H. chejuensis are regarded as CR species for the first time. On the other hand, 22 taxa are classified into EN category, and the following nine taxa are newly proposed to be EN species; Gastrochilus japonicum, G. fuscopunctatus, Gastrodia verrucosa, Habenaria flagellifera, Herminium lanceum var. longicrure, Chamaegastrodia sikokiana, Lecanorchis kiusiana, Neottia hypocastanoptica and Tipularia japonica.

• The Plant Pathology Journal
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• v.18 no.4
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• pp.169-178
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• 2002

Orchids are evolutionally known to be the most advanced plants in the order Liliales, and comprise approximately 1,000 genera and 35,000 species world-wide. In Korea, more than 110 species of Orchidaceae have been reported to be cultivated or to be collected in the wild. Orchids aye mostly dependant on orchid mycorrhizae(OM) throughout or in part of their life cycle. The OM endomycorrhizae belonging to basidiomycetes or rarley ascomycetes are needed for orchid seed germination. Various fungi, including plant pathogenic, antagonistic and symbiotic fungi, were isolated from the roots of orchid native to Korea. The OM fungi collected from the roots of Cymbidium goeringii were three species of Rhizoctonia namely, R. repens (anamorph state of Tulsanella repens), R. endophytica (Ceratobasidium cornigerum), and an unidentified species (possibly an anamorph of T. calospora). These symbiotic fungi induced peloton in the cortical cells of orchid roots, and differed biologically and in 18s rDNA sequences from plant pathogenic Rhizoctonia species. Also, the mycorrhyzal fungi enhanced the orchid root absorption of nitrogen sources and minerals from the soil. The activity of mycorrhizal fungal hyphae in the roots caused prevention from pathogenic fungi. In nature, the peloton is observed in the cortical cells of Cymbidium goeriingii roots, indicating mycorrhizal colonization in the native orchid roots. On the other hand, pathogenic fungi such as Fusarium and/or Rhizoctonia species are mostly isolated from commercial orchid plants. These suggest that application of symbiotic mycorrhizal fungi should be needed for orchid cultivation in nurseries and at the time of transplanting.