• The Plant Pathology Journal
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• 제17권5호
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• pp.295-299
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• 2001

The relative density of phytoplasmas in witches'broom (WB)-infected jujube trees was investigated using compatitive polymerase chain reaction (PCR). During dormant and defoliating seasons, the densities of phytoplasmas were about the same in roots and twigs. In early growing season, the density showed the highest rates in roots, then in twigs and in petioles. however, the density was highest in petioles and the lowest in roots during actively growing season. Throughout the year, root samples did not show any serious fluctuation compared with that of t2wigs and petioles. Density was lowest during actively growing season in root samples. In contrast, petiole sample densities varied to a great extent depending on the season, very high during actively growing season, but very low during the early growing season, In twig samples, the densities were very high and almost the same in both defoliating and dormant seasons. Among the parts of the trees, phytoplsma density was the most stable in root samples throughout the year. The highest densities of phytoplasmas were about the same in all tree parts. These results suggest that the phytoplasmas may overwinter not only in roots but also in twigs, and that multiplication rate of phytoplsma becomes very high right after the early growing season.

• Journal of Plant Biotechnology
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• 제42권3호
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• pp.265-270
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• 2015

더덕은 예로부터 약용으로 사용 되어 왔으며, 더덕의 뿌리에는 약용으로 가치가 높은 여러 종류의 triterpenoid 사포닌이 포함되어 있다. 본 연구에서는 더덕의 모상근 생육과 methyl jasmonate (MeJA)처리에 의한 사포닌 합성의 효과를 연구하였다. 더덕 모상근에 MeJA를 처리한 결과 주사포닌인 lancemaside A, B, E의 축적은 MeJA 무처리 모상근 보다 약 15% 정도 감소하였다. 반면 마이너사포닌(foetidissimoside A와 aster saponin Hb)의 함량은 무처리 모상근 보다 약15% 정도로 증가하였다. 이 결과를 통해 MeJA처리가 triterpene 사포닌의 생산조절을 위해 사용될 수 있는 것으로 판단된다.

• Journal of Plant Biology
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• 제34권4호
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• pp.283-288
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• 1991

This work was carried out to determined the effect of 2,4-dinitrophenol(DNP) on in vivo nitrate reductase activity in the root of 6 day old rye (Secale cereale L.) seedlings. The nitrate reductase activity in the roots of 6 day old rye seedlings pretreated with 0.5 mM DNP was higher than that of the control group in all the experimental conditions. The optimal concentration of KNO3 for maximum nitrate reductase activity was 10 mM in both control and treated group. The nitrate reductase activity in the treatment of 10 mM KNO3 gradually increased for 4 h in both groups, and then maintained constantly. The nitrate reductase activity occurred per hour was highest at 1 h in both groups, while it was declined by large degrees as time goes on. The daily pattern of nitrate reductase activity was gradually decreased in both groups with the passage of day. The optimal pH for this experiment and a previous paper (Kwon et al., 1991), it was determined that the nitrate reductase activity in both roots and shoots of rye seedlings was increased by the treatment of 0.5 mM DNP, and particulary in both groups, the nitrate reductase activity in the roots of rye seedlings was higher than that in shoots of them.

• 한국식물병리학회지
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• 제14권5호
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• pp.536-542
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• 1998

Ten isolates of the orchid mycorrhizal fungi were isolated from the roots of Korean native orchid plants (Cymbidium goeringii) which inhabitate mainly in southern and western areas of Korea. The growth rates and color of the isolates in potato dextrose agar (PDA) were various. Microscopic observations of the hyphae isolated were identified as Rhizoctonia repens and R. endophytica var endophytica or their related species. R. repens was isolated from the roots of the Korean native orchids, but R. endophytica var endophyica was only isolated from the roots of the commercial orchids introduced from foreign countries. Also, the polymorephic patterns of genomic DNA extracted from selected isolates were compared with those of DNA extracted from the orchid mycorrhizal fungi isolated previously and similar band patterns were observed among those isolates. Five isolates of R. repens were selected and cultured at the oatmeal agar for investigating their symbiosis with orchid plants. The symbiotic specificity between orchid plants and isolated orchid mycorrhizal fungi was observe by growing orchids about six months in the greenhouse. The symbiotic responses of the commercial orchid plants with selected isolates were quite different form different isolates due to the genetic variations.

• 한국자원식물학회:학술대회논문집
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• 한국자원식물학회 2018년도 춘계학술발표회
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• pp.5-5
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• 2018

Ginseng (Panax ginseng C.A. Meyer), one of the most widely used medicinal plants in traditional oriental medicine, is used for the treatment of various diseases. It has been classified according to its cultivation environment, such as field cultivated ginseng (FCG) and mountain cultivated ginseng (MCG). However, little is known about differences in gene expression in ginseng roots between field cultivated and mountain cultivated ginseng. In order to investigate the whole transcriptome landscape of ginseng, we employed High-Throughput sequencing technologies using the Illumina HiSeqTM2500 system, and generated a large amount of sequenced transcriptome from ginseng roots. Approximately 77 million and 87 million high-quality reads were produced in the FCG and MCG roots transcriptome analyses, respectively, and we obtained 256,032 assembled unigenes with an average length of 1,171 bp by de novo assembly methods. Functional annotations of the unigenes were performed using sequence similarity comparisons against the following databases: the non-redundant nucleotide database, the InterPro domains database, the Gene Ontology Consortium database, and the Kyoto Encyclopedia of Genes and Genomes pathway database. A total of 4,207 unigenes were assigned to specific metabolic pathways, and all of the known enzymes involved in starch and sucrose metabolism pathways were also identified in the KEGG library. This study indicated that alpha-glucan phosphorylase 1, putative pectinesterase/pectinesterase inhibitor 17, beta-amylase, and alpha-glucan phosphorylase isozyme H might be important factors involved in starch and sucrose metabolism between FCG and MCG in different environments.

• Journal of Plant Biology
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• 제30권2호
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• pp.95-108
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• 1987

Effects of allopurinol (2mM), a specific inhibitor of xanthine oxidase, on the growth and metabolism of llantoin in dark grown Chinese cabbage (Brassica campestris L.) seedlings were investigated. Allopurinol treatment maintained the fresh and dry weights of cotyledons at higher levels, but inhibited the elongation of hypocotyls and roots of the seedlings. Total nitrogen content in the cotyledons decreased at slower rate by allopurinol. Accordingly, the levels of total nitrogen contents in the hypocotyls and roots, were depressed by the inhibitor. In the cotyledons, allopurinol began to elevate RNA levels after day 3, which it did not affect DNA level throughout the experiment. Activities of xanthine oxidase (XO:EC 1.2.3.2), uricase (UO:EC 1.7.3.3) and allantoinase (AL:EC 3.5.2.5) in the cotyledons were examined. The activity of XO was not detected, but the accumulation of xanthine by allopurinol treatment presented an indirect evidence of the existence of XO in the organ. Allopurinol kept UO activity high up to day 2 after sowing and depressed AL activity throughout the experiment. By allopurinol treatment, allantoin content was kept high over the control both in cotyledons and roots, but it was kept low in hypocotyls. The level of allantoic acid in the 3 organs were shown to be depressed by allopurinol. These results suggest that allantoin and allantoic acid produced by the degradation of stored and newly synthesized RNA are transported from the storage tissue to hypocotyls and roots as important nitrogen sources for the development of Chinese cabbage seedlings.

• Journal of Plant Biology
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• 제39권4호
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• pp.287-293
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• 1996

The effect of taxol and ethyl-N-phenylcarbamate (EPC) on the growth and gravitropism of maize roots and coleoptiles was studied. Taxol is known to promote the assembly of microtubules (MTs) and stabilizes MTs by preventing depolymerization. EPC, on the contrary, is an anti-microtubule drug that promotes disassembly of MTs. Taxol, at 1 $\mu$M, inhibited gravitropic response of maize roots to about 40%, but did not inhibit growth; at 10 $\mu$M, it inhibited the gravitropic response of coleoptile segments of maize by approximately 50%, but did not inhibit growth, while 0.5 mM EPC inhibited both the gravitropic response and growth of maize roots by approximately 50%. Taxol, which inhibited the gravitropic response of maize roots and coleoptile segments, had no effect on either the polar or the bilateral transport of auxin. These results indicated that MT polymerization could not occur normally with taxol or EPC, so that if there was any abnormal rearrangement of MT, the gravitropic response was inhibited, which resulted from the inhibition of neither growth nor auxin transport. This results suggested that gravitropic response was related to the MT arrangement, and that both straight growth and the differential growth in gravitropic response could be regulated by different mechanisms.

• 한국자원식물학회지
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• 제21권6호
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• pp.444-448
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• 2008

An adventitious root formation protocol from Smilax china L. was established for in vitro production of dioscin, a steroidal saponin having various bioactivities such as anticancer, antifungal, antiviral, and antiobesity. Optimal medium for root initiation from leaf explant was MS medium containing $30\;g{\cdot}L^{-1}$ of sucrose supplemented with $1.0\;mg{\cdot}L^{-1}$ kinetin + $2.0\;mg{\cdot}L^{-1}$ NAA. The induction of adventitious roots from in vitro initiated root segments was most favorable to MS liquid medium with $0.1\;mg{\cdot}L^{-1}$ kinetin + $2.0\;mg{\cdot}L^{-1}$ NAA. Among the 20 different adventitious roots originated from different plants, strain No. 10 was selected based on production ability of dioscin, and its stability through the successive suspension culture. The maximum growth stage of adventitious roots was noticed at 5 weeks after subculture while that of dioscin production in the adventitious root was at 7 weeks after subculture in suspension culture system. These results provide that suspension culture of adventitious roots of Smilax china L. have a potential for in vitro mass production of dioscin.

• Journal of Plant Biotechnology
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• 제35권3호
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• pp.223-228
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• 2008

This study was conducted to investigate an optimal condition for shoot proliferation and regenerate shoots from in vitro leaflet and embryogenic calli from in vitro roots in rose. The effect of BAP on shoot proliferation was somewhat different depending upon genotypes or gelling agents. Leaflets with petiole cut from donor shoots which had been cultured in MS medium supplemented with 0.1 $mg{\cdot}L^{-1}$ NAA for six weeks was effective for regeneration of adventitious buds(ABs) as well as shoot elongation of Rosa hybrida cv. Sweet Pink. Culturing seven leaflet explants per petri plate($100mm{\times}15mm$) was effective for regeneration of ABs. Embryogenesis was shown in the calli induced from roots of Rosa hybrida cv. Sweet Pink cultured in the SH medium supplemented with 11 $mg{\cdot}L^{-1}$ 2, 4-D for four weeks. Color of calli induced from roots was yellow although their color was a little different as type of basal medium.

• The Plant Pathology Journal
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• 제17권4호
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• pp.227-230
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• 2001

Bioassay techniques using young leaves and roots were developed to screen resistance of Atractylis spp. against Phytophthora drechsleri. Among 638 plants collected from various regions of Korea from 1994 to 1996, 67 were pre-screened in fields naturally infested with P. drechsleri, which is the causal pathogen of rhizome rot of Atractylis. Among the pre-screened sources, 18 (ca. 26.8%) were highly resistant to the pathogen in leaf inoculation. In the root inoculation test, abundant sporangia were formed in susceptible plant roots, while only a few or no sporangia were produced on the roots which were found resistant in the leaf inoculation test. Among the selected resistant plants, A. japonica 96066 and 96104 were used to cross with another species, A. macrocephala 96362 that showed high yield with good quality of rhizome but susceptible to the pathogen. The F$_1$hybrids designated as HA03 turned out to be resistant to the pathogen, indicating that resistant gene(s) was inherited. Among intra-species hybrids of A. japonica, HA07 and HA09 were resistant to the pathogen in leaf inoculation and moderate in root inoculation. However, HA08 was susceptible in both inoculation tests. This result suggests that the parent material might be genetically heterogeneous. Further genetic study should be carried out to verify this phenomenon.