• The Plant Pathology Journal
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• v.23 no.3
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• pp.223-225
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• 2007

Many plant growth-promoting rhizobacteria (PGPRs) have been known for beneficial effects on plants including biological control of soilborne pathogens, induced systemic resistance to plant pathogens, phytohormone production, and improvement of nutrient and water uptake of plants. We developed a simple and rapid method for screening potential PGPR, especially phytohormone producing rhizobacteria, or for analyzing their functions in plant growth using cucumber seedling cuttings. Surface-sterilized cucumber seeds were grown in a plastic pot containing steamed vermiculite. After 7 days of cultivation, the upper part 2 cm in length of cucumber seedling, was cut and used as cucumber cuttings. The base of cutting stem was then dipped in a microcentrifuge tube containing 1.5ml of a bacterial suspension and incubated at $25^{\circ}C$ with a fluorescent light for 10 days. Number and length of developed adventitious roots from cucumber cuttings were examined. The seedling cuttings showed various responses to the isolates tested. Some isolates resulted in withering at the day of examination or in reduced number of roots developed. Several isolates stimulated initial development of adventitious roots showing more adventitious root hair number than that of untreated cuttings, while some isolate had more adventitious root hair number and longer adventitious roots than that of untreated control. Similar results were obtained from the trial with rose cuttings. Our results suggest that this bioassay method may provide a useful way for differentiating PGPR's functions involved in the development of root system.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.27 no.3
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• pp.193-197
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• 1982

1t is well known that the stem is filed with shoot units in the rice plant and each internode bears several crown roots. But it has not yet been ascertained that what controls the differential elongation of the crown roots in the same internode. Thereupon, author had been carried out this experiment to ascertain what controls the elongation of the crown roots in the same internode, especially on the conception of sink-source by leaf-cutting method. Generally, one shoot unit has two important sinks: one axillary bud (tiller) and several crown roots. When we removed the axillary bud, namely shoot unit has one sink: several crown roots, the crown roots formed near the midvein (source) were longer than the crown roots born near the axillary bud. And when the shoot unit has two sinks: one axillary bud and several crown roots, the other way, the crown roots formed at the prophyll unit of the tiller were longest, and the crown roots formed near the midvein were shortest and the crown roots born the near the tiller showed interim length. Juding from the present results, we can suppose that, when shoot unit has two sinks, axillary bud is superior sink than the crown roots. So that axillary bud grows faster than crown roots and tiller becomes a new source. Therefore the crown roots which formed at the new source and the crown roots born the near the new source are longer than others.

• Journal of Ginseng Research
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• v.38 no.4
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• pp.278-288
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• 2014

Background: Panax ginseng Meyer is a traditional medicinal plant famous for its strong therapeutic effects and serves as an important herbal medicine. To understand and manipulate genes involved in secondary metabolic pathways including ginsenosides, transcriptome profiling of P. ginseng is essential. Methods: RNA-seq analysis of adventitious roots of two P. ginseng cultivars, Chunpoong (CP) and Cheongsun (CS), was performed using the Illumina HiSeq platform. After transcripts were assembled, expression profiling was performed. Results: Assemblies were generated from ~85 million and ~77 million high-quality reads from CP and CS cultivars, respectively. A total of 35,527 and 27,716 transcripts were obtained from the CP and CS assemblies, respectively. Annotation of the transcriptomes showed that approximately 90% of the transcripts had significant matches in public databases.We identified several candidate genes involved in ginsenoside biosynthesis. In addition, a large number of transcripts (17%) with different gene ontology designations were uniquely detected in adventitious roots compared to normal ginseng roots. Conclusion: This study will provide a comprehensive insight into the transcriptome of ginseng adventitious roots, and a way for successful transcriptome analysis and profiling of resource plants with less genomic information. The transcriptome profiling data generated in this study are available in our newly created adventitious root transcriptome database (http://im-crop.snu.ac.kr/transdb/index.php) for public use.

• Journal of Plant Biotechnology
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• v.5 no.3
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• pp.187-191
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• 2003

This paper reported the establishment of mass production system of adventitious roots of Eleutherococcus sessiliflorus through the shake flask and bio-reactor culture. Induction of adventitious roots was started from the explants of germinated somatic embryos on half-strength Murashing and Skoog (MS) solid medium. The frequency of adventitious root formation was better in the explants comprising the basal hypocotyl parts than root explants alone. Among the different auxins tested (NAA, IBA and IAA), frequency of adventitious root induction was highest on medium with 0.5 mg/L NAA, and produced $16.3\pm1.9$ roots per explant. In shake-flask culture, deletion of $NH_4NO_3$ of MS medium was effective for induction of adventitious root compared with both full and half-strength MS media. Fresh weight increase of induced adventitious roots was performed well in medium with 0.5 mg/L IBA. When adventitious roots produced in shake-flask culture were transferred to 10-liter bioreactor, 5.5 times of fresh weight increase was gained after one month of culture. HPLC analysis revealed that the amount of eleutheroside E and E1 was higher in in vitro cultured adventitious roots than the 3 year-old field cultivated root barks of Eleutherococcus sessiliflorus. The content of eltutheroside B was much lower in adventitious roots than that of field cultivated one.

• Korean Journal Plant Pathology
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• v.10 no.1
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• pp.7-12
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• 1994

Incidence of radish disease caused by Rhizoctonia solani ranged from 1 to 30% in fields located at Hwaseong, Naju and Yeoncheon in Korea during the growing seasons in 1989, 1990 ad 1993. A total of 133 isolates of R. solani was obtained from the diseased seedlings, leaves and roots of radish collected. The fungus was most commonly isolated from the roots. Among 133 isolates of R. solani, 56 isolates were classified as anastomosis group AG-1 by anastomosis test, 37 isolates as AG-2-1, and 40 isolates as AG-4. Among the isolates of AG-1, 26 isolates were grouped as cultural type IA, and the others as cultural type IB. Cultural types IA and IB of AG-1, were isolated from the leaves, AG-2-1 from the roots, and AG-4 from the seedlings, leaves and roots. Pathogenicity tests revealed that the AG-1(IA) isolates were highly virulent on leaves of radish, but avirulent on the seedlings, petioles and roots. The AG-1(IB) isolates were highly virulent on the leaves, but mildly virulent on the seedlings and avirulent or mildly virulent on the petioles and roots. The AG-2-1, isolates were mildly virulent on the leaves and seedlings and mildly or highly virulent on the petioles and roots. The AG-4 isolates were highly virulent on the seedlings and mildly or highly virulent on the leaves, petioles and roots.

• Korean Journal of Plant Resources
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• v.7 no.1
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• pp.13-15
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• 1994

Some known coumarins, decursin, nodakenetin, umbelliferone, 7-demethylsuberosin, columbianetin, decursinol angelate and decursinol, showing significant cytotoxic activities against P388 cell lines,were isolated from the roots of Angelica gigas (Umbelliferae) . 7-Demethylsuberosin and columbianetinwere obtained from Angelica gigas for the first time. Chernotaxonornic difference about coumarins com-ponents between the roots of Angelica gigas and those of A. acutiloba is also discussed.

• Journal of Ginseng Research
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• v.13 no.2
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• pp.147-152
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• 1989

The statistical characteristics of three year old American ginseng (Panax quinquefolium 1.) root yields from Lytton, British Columbia, Canada are presented. Ginseng root yield is related to plant density, with the highest yields generally obtained from the sites with the highest plant densities. However, these higher yields are made up of a larger proportion of smaller roots while the proportion of larger roots remains almost constant throughout the range of plant densities sampled. Further, it is suggested that relatively small samples can provide significant insight into crop performance and growth.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.315-315
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• 2005

• Korean Journal of Plant Tissue Culture
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• v.25 no.6
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• pp.525-530
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• 1998

These studies were carried out to select the active grow hairy root lines induced from various ginseng(Panax ginseng C. A. Meyer) parts. Hairy roots were induced in root explants, stem and petiole in vitro by A. rhizogenes R1000 or A. rhizogenes $A_4$. These hairy roots could be grown on the phytohormone free medium, and PCR analysis of rol C and vir C gene fragments confirmed that hairy roots were transgenic tissues. We have selected 11 hairy root lines with active growing characters among 300 hairy root lines selected based on growth and morphological characteristics on 1/2MS solid media with 250 mg/L carbenicillin. Morphological characteristics of selected 11 hairy root lines were thickness and thiness of main roots, and many projection for lateral roots, active grow of lateral roots. Among selected 11 hair root lines prominent characteristics of hairy roots with active growing characters were thiness of main roots and active grow of lateral roots. But characteristics of low growing hairy roots were thickness of main roots and low grow of lateral roots. Finally we have selected actively growing hairy roots, KGHR-1, KGHR-5, KGHR-8 among 11 hairy root lines.

• Mycobiology
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• v.31 no.2
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• pp.68-73
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• 2003

Roots of Glycine max and Miscanthus sinensis and soil samples were collected from various field sites at Goesan, Chungbuk in Korea. Microscopic observations of the roots indicated high colonization rates of both arbuscular mycorrhizal fungi(AMF) and other fungi. The partial small subunit of ribosomal DNA genes were amplified with the genomic DNA extracted from their roots by nested polymerase chain reaction(PCR) with universal primer NS1 and fungal specific primers AML Restriction fragment length polymorphism(RFLP) was analyzed using the combinations of three restriction enzymes, HinfI, AluI and AsuC21. Nucleotides sequence analysis revealed that ten sequences from Miscanthus sinensis and one sequence from Glycine max were close to those of arbuscular mycorrhizal fungi. Also, 33% of total clones amplified with NS31-AM1 primers from M. sinensis and 97% from G. max were close to Fusarium oxysporum or other pathogenic fungi, and they were successfully distinguished from AME Results suggested that these techniques could help to distinguish arbuscular mycorrhizal fungi from root pathogenic fungi in the plant roots. Especially, DNA amplified by these primers showed distinct polymorphisms between AMF and plant pathogenic species of Fusarium when digested with AsuC21.