• Journal of Korean Society of Forest Science
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• v.78 no.4
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• pp.372-380
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• 1989

The widely cultivated hybrid poplar Populus alba ${\times}$ P. glandulosa in Korea was transformed with Agrobacterium rhizogenes agropine type strain A4. Genetic transformation was confirmed by the presence of agropine. Alteration in growth rate of hairy roots was seen following changes in the dilution rate of medium and concentration of sucrose, suggesting that improved growth might be achieved by more precise manipulation of the nutrient medium. Plant regeneration occurred from transformed hairy roots on MS medium supplemented with 0.5 mg/l BAP. Transformed plantlets grown in vitro exhibited a more developed root system characterized by fast growth behavior in comparison to normal plantlets. This work demonstrates that the root transformation would be useful in improving plantlet establishment and growth through the effective root system.

• KSBB Journal
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• v.9 no.2
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• pp.157-164
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• 1994

Hairy root clones of Panax ginseng were established by selection of some hairy roots formed on the leaf, stem and root segments transformed with Agrobacterium rhizogenes strain $A_4$. The transformed roots grew well in MS medium under the dark condition. To confirm the transformation with Ri-T-DNA, dot blot hybridization and opine analysis were Performed. Among four hairy roots induced from different part of ginseng, the HB3 hairy roots were examined for selection of high-saponin-producing clones. Four clones isolated from HB3 hairy root cultures displayed various phenotypes characterized by growth and total saponin content. Maximum growth was obtained for cultures of HB3-10 clone and the content of total saponin was 0.55 wt%. However, higher amount of total saponin was obtained with HB3-2 clone cultures(0.74 wt%) in spite of lower growth. Dot blot hybridization confirmed the introduction of Ri-T-DNA in the plant genome. In the opine test, agropine and mannopine were detected from all hairy root clones.

• Journal of Plant Biotechnology
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• v.34 no.4
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• pp.285-291
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• 2007

This study describes conditions for the mass production of activation-tagged mutant hairy root lines of ginseng by cocultivation with Agrobacterium rhizogenes. Because it is not currently possible to produce progeny from transgenic ginseng, a loss-of-function approach for functional genomics cannot be appliable to this species. A gain-of-function approach is alternatively the choice and hairy root production by cocultivation of A. rhizogenes would be most practical to obtain a large number of mutants. Various sources of explants were subjected to genetic transformation with various strains of A. rhizogenes harboring the activation-tagging vector pKH01 to determine optimum conditions for the highest frequency of hairy root formation on explants. Petiole explants cocultivated with A. rhizogenes R1000 produced hairy roots at a frequency of 85.9% after 4 weeks of culture. Conditions for maximum growth or branching rate of hairy roots were also investigated by using various culture media. Petiole explants cultured on half strength Schenk and Hildebrandt medium produced vigorously growing branched roots at a rate of 2.6 after 4 weeks of culture. A total of 1,989 lines of hairy root mutants were established in this study. These hairy root lines will be useful to determine functions of genes for biosynthesis of ginsenosides.

• Journal of Plant Biology
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• v.35 no.1
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• pp.37-43
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• 1992

The hairy root culture of Raphanus sativus cv. Chungpihongsim was established by transformation with Agrobacterium rhizogenes $A_4$. The transformed roots grew well in adjusted Murashige and Skoog medium to 1/2 basal salts, pH 5.2, 3% sucrose. Agropine and mannopine, opine synthesized in the transformed tissue were detected in the extract of hairy roots. When 2, 4-D and kinetin were added in culture medium of hairy roots, the synthesis of anthocyanin was induced with disorganization of hairy root. Especially, addition of $0.45\;\mu\textrm{M}$ 2, 4-D and $2.3\;\mu\textrm{M}$ kinetin showed the maximum synthesis of anthocyanin. Pattern of anthocyanin synthesized in transformed roots was somewhat different from that of ordinary roots. However, aglycone part of all anthocyanin was identified as pelargonidin. The content of total anthocyanin in this sample was tentatively calculated 0.49 mg/g fresh weight.weight.

• KSBB Journal
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• v.4 no.2
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• pp.94-98
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• 1989

In vitro attachment experiments of bacteria to surface of host plant cell were carried out using C14 labeled cells of A. rhizogenes strain A4 and carrot protoplasts isolated from suspension culture of cells. Protoplasts were cocultivated with A. rhizogenes at various times after their isolation. Attachment kinetics showed that adherence of bacteria to protoplasts attained a maximum level within 120mins of co-cultivation. Maximum attachment occured at pH 6.0 and 24-35$^{\circ}C$. Bacterial attachment was observed at botg carrot cells with and without primary cell wall. The inhibition of transformation on the carrot root discs by A. rhizogenes was observed when non-related strain and heat inactivated bacterial strain cells were pretreated.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.3
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• pp.299-306
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• 2009

In nitrogen-limited conditions, rhizobia lead to formation of nitrogen-fixing nodules on the roots of leguminous plants. The process of nodulation is autoregulated by pre-existing nodules in the same root system. The altered profile of sap proteins by inoculation with B. japonicum may indicate presence of a signal responsible for autoregulation transferred through stem. The 20 kDa protein enhanced by innoculation significantly decreased in intensity from 2.5 to 7 days after inoculation (DAI). However 6 kDa protein did increase during such a transition period. Western blot analysis showed that both 20 kDa and 6 kDa were cross-reacted with the SKTI antiserum. This suggests that SKTI may be involved in soybean nodulation by specific induction and degradation in stem sap during early stage of nodulation. RNAi technique and Agrobacterium rhizogenes-mediated transformation were applied to investigate the function of SKTI in nodulation. We have found that the number of rhizobium-induced nodule was much less in SKTIi-silenced hairy roots than the non-silenced. Indeed the quantitative RT-PCR showed that the expression level of SKTI gene was reduced over 40% in the transgenic hairy roots compared to the non-transgenic. It appears that the observed early induction of SKTI and degradation into small peptide in a specific time manner may be involved in autoregulation of nodulation in soybean and the specific mechanism of such regulation remains to be investigated.

• Korean Journal of Pharmacognosy
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• v.23 no.3
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• pp.137-141
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• 1992

The cells of Rubia cordifolia var. pratensis were transformed by Agrobactrium tumefaciens strain 11157. Surface-sterilized young leaves and stems of the plants were cocultivated with bacterial suspensions. Crown galls induced from stems were cultured with variation of culturing conditions and compared with untransformed cells. The growth rates and production of anthraquinone pigments of cells were remarkably improved by transformation. Furthermore, hairy roots were induced by inoculation or cocultivation with Agrobacterium rhizogenes strains.

• Horticultural Science & Technology
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• v.18 no.6
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• pp.802-807
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• 2000

This study was conducted to propagate the arbuscular mycorrhizal fungi in vitro using the hairy root of carrot transformed by Agrobacterium rhizogenes with Ri t-DNA. Mycorrhizal spores and roots in sudangrass plants were wet-sieved, surface-sterilized and inoculated onto the hairy root of carrot on the Modified Strullu & Romand (MSR) medium. The mycorrhizal spores of Glomus sp. propagated in vitro for 12 weeks was about $50{\mu}m$, and the shapes of spores were round or elliptic. Spores were formed mainly at the middle of the hyphae. Number of mycorrhizal spores propagated using dual culture of the transformed carrot roots and the mycorrhizal inoculum for 12 weeks were about 1,200 per plates.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.88-94
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• 2005

Plant tissue culture studies have been done for the preservation of medicinal plant resources and efficient production of pharmaceutically important secondary metabolites. Micropropagation methods for Cephaelis ipecacuanha have been established and these methods enabled much more efficient propagation of the plants than the conventional methods using seedling or layering. The C. ipecacuanha plants derived from tissue culture grew uniformly in the field and they showed higher alkaloid contents compared to the plants grown from seedlings. Hairy root cultures of C. ipecacuanha and Panax ginseng have been established by infection with Agrobacterium rhizogenes, and the production of important pharmaceuticals by these cultures have been successfully demonstrated. In the case of C. ipecacuanha, the highest alkaloid yields from the hairy roots cultured for 8 weeks were 2.75-fold cephaeline (5.5 mg) and one third emetine (0.7 mg) compared with those from the roots of one-year old plant propagated through shoot-tip culture and cultivated in a greenhouse (2.0 mg cephaeline and 2.0 mg emetine). In the case of P. ginseng, ginsenoside contents in the hairy roots optimally cultured for 4 weeks were much higher than those in the roots of 4-year old field-grown plant. Thus our medicinal plant tissue cultures demonstrate desirable properties. However, they are always exposed to danger of microbial contamination or unexpected trouble of culture facilities. Cryopreservation of plant tissue cultures is a reliable method for long-term preservation. Cryopreservation studies on these cultures are also presented.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.10a
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• pp.218-218
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• 2017