• 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.

• Mycobiology
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• v.30 no.3
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• pp.146-153
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• 2002

Two types of mycorrhizae, orchid(OM) and arbuscular mycorrhizae(AM), were observed in the cortical cells of Botrychium ternatum roots. The vesicles or arbuscules of AM fungi were examined and the fresh or digestive pelotons by other species of basidiomycetes were also observed in the roots under light microscope. These symbioses were, as the genomic DNAs extracted from roots of B. ternatum reacted with the specific primers, confirmed with PCR technique, being added to more strong evidences. These discoveries were rarely happened in the roots, especially a fern in nature. OM was observed in the roots of B. ternatum collected from the nationwide areas, whereas AM was only in the roots of B. ternatum collected from Chung-Buk areas. It is speculated that OM are associated with the nitrogen cycle in Islands and the growth of B. ternatum in the inland of Central Korea is related to both the phosphate and nitrogen cycle in the nature. The results suggest that B. ternatum is a typical species with two types of mycorrhizae under various growing conditions.

• Mycobiology
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• v.43 no.4
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• pp.475-480
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• 2015

A fungal internal transcribed spacer region was used to identify the mycorrhizae of Cymbidium kanran. The family Russulaceae was found to be the most frequently occurring group in both root and soil samples. In phylogenetic analyses, the majority of the Russulaceae clones were clustered with Russula brevipes and R. cyanoxantha. Therefore, C. kanran may form symbiotic relationships with the genus Russula.

• Mycobiology
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• v.28 no.1
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• pp.17-26
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• 2000

The orchid symbiotic fungi were isolated from the roots of Korean native orchid (Cymbidium goeringii) collected and Chinese orchid (C. sinense) obtained from greenhouses. They were identified as a species of Rhizoctonia, based on the sequences of 18r rDNA, the microscopic observations of mycelia, and the symbiotic relationships with commercial orchids. The isolate collected from Chinese orchids was revealed to be a species of Ceratobasidium endophytica, and to be different from the other isolates at the thickness of the mycelia stained in the root cells of Korean native orchids. The other isolates collected from the Korean native orchids were considered to be a species of Tulsanella repens (anamorphic: Epulorhiza repens) or its related one. The physiologic or microscopic variations were oftenly observed among them, but the tendency of grouping these in the 18s rDNA sequences were observed to be consistent with those of the localities collected. The further taxonomical segregating for Korean symbiotic fungi was not made because the information concerned were limited in this moment, but was recognized as based on the sequences of 18s DNA.

• The Korean Journal of Mycology
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• v.25 no.2 s.81
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• pp.101-110
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• 1997

This study was to identify the orchid mycorrhizal fungi and to test whether the orchid plants antificially inoculated with this fungus showed better growth them uninoculated plants. Symbioses in the root cells of the native plants of Cymbidium goeringii collected were observed and the digestive forms of peletons were also observed in various native roots. Two types of hyphae, thick $(7{\sim}10\;{\mu}m)$ and thin $(2{\sim}4\;{\mu}m)$ in thickness, were conclusively found to be from various native orchid roots. The symbiotic fungus was isolated by several agars and identified as a Rhizoctonia repens or a R. endophytica var. endophytica. Symbioses on the plantlets of C. karnan and Cymbidium hybrid 'Onomoron' were evaluated as the isolates inoculated on oatmeal agars. The growth of plantlets were measured with the formations of mycorrhizae in the roots. R. repens was shown to be the better isolate than the other in growth stimulation of plantlets on oatmeal agars when grown for two months. The two types of hyphae in the root cells under nature were speculated from the different fungal isolates of Rhizoctonia. Further isolates would be needed for application works for the orchid industries.

• Mycobiology
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• v.31 no.3
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• pp.151-156
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• 2003

Two fungal isolates obtained from roots of Cymbidium goeriingii in Jeju island were confirmed to be symbiotic with orchid plantlets, and were compared with other orchid mycorrhizal(OM) fungi previously isolated. The two isolates differed in their peloton structures formed in the roots of Cymbidium kanran hybrid 'Chungsu' and in responses of orchid plant. These two isolates differed from the additionally tested OM fungi in some features, and from root damaging species of Rhizoctonia and Fusarium as based on cluster analysis after PCR-RAPD with the primers, Bioneer-28 and OPO-2. With this simple and fast technique, it was possible to distinguish OM fungi from the plant root pathogenic fungi based on calculation of their polymorphic bands. This technique can therefore be helpful to distinguish the OM fungi from the root pathogens. Particularly, the new isolates are considered as new resource of symbiotic fungi for horticultural industries.

• Journal of Mushroom
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• v.18 no.1
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• pp.1-9
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• 2020

Mycorrhiza refers to the association between a plant and a fungus colonizing the cortical tissue of the plant's roots during periods of active plant growth. The benefits afforded by plants from mycorrhizal symbioses can be characterized either agronomically, based on increased growth and yield, or ecologically, based on improved fitness (i.e., reproductive ability). In either case, the benefit accrues primarily because mycorrhizal fungi form a critical linkage between plant roots and the soil. The soilborne or extramatrical hyphae take up nutrients from the soil solution and transport them to the root. This mycorrhizae-mediated mechanism increases the effective absorptive surface area of the plant. There are seven major types of mycorrhizae along with mycoheterotrophy: endomycorrhizae (arbuscular mycorrhizae, AM), ectomycorrhizae (EM), ectendomycorrhizae, monotropoid, arbutoid, orchid, and ericoid. Endomycorrhizal fungi form arbuscules or highly branched structures within root cortical cells, giving rise to arbuscular mycorrhiza, which may produce extensive extramatrical hyphae and significantly increase phosphorus inflow rates in the plants they colonize. Ectomycorrhizal fungi may produce large quantities of hyphae on the root and in the soil; these hyphae play a role in absorption and translocation of inorganic nutrients and water, and also release nutrients from litter layers by producing enzymes involved in mineralization of organic matters. Over 4,000 fungal species, primarily belonging to Basidiomycotina and to a lesser extent Ascomycotina, are able to form ectomycorrhizae. Many of these fungi produce various mushrooms on the forest floor that are traded at a high price. In this paper, we discuss the benefits, nutrient cycles, and artificial cultivation of mycorrhizae in Korea.

• Horticultural Science & Technology
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• v.17 no.5
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• pp.578-580
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• 1999

The effects of the orchid mycorrhizal fungi isolated from Cymbidium goeringii were investigated on the growth of orchid plants. The plants, a hybrid of Cymbidium kanran Jeju${\times}$C. kanran Nangoku and Phalaenopsis were inoculated with the fungal isolates of Rhizoctonia repens (P1), R. endophytica (P2) and R. repens (P3; different from P1) on the oatmeal agars for two months. Then the orchid plants were cultivated in the greenhouse for eighteen months. The difference of plant growth after cocultivation for two months was not found among the treatments. After cultivation for four months, the growth of hybrid plants of Cymbidium kanran Jeju${\times}$C. kanran Nangoku was observed to be distinguished in the Rhizoctonia repens (P1). After cultivation in the greenhouse for eighteen months, the plant height, the number of shoots, the number of leaves, the number of roots and plant fresh weight of the hybrid of Cymbidium kanran Jeju${\times}$C. kanran Nangoku, inoculated with Rhizoctonia repens (P1), were significantly increased compared to those of the control. The plants inoculated with Rhizoctonia repens (P3) were not different and the plants inoculated with R. endophytica were poor compared to the control. The plant height and fresh weight of the Phalaenopsis, inoculated with Rhizoctonia repens (P1), increased significantly compared to those of the control. Overall, Rhizoctonia repens (P1), was the most effective for the growth of a hybrid of Cymbidium kanran Jeju${\times}$C. kanran Nangoku.