• Proceedings of the Plant Resources Society of Korea Conference
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• 2021.04a
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• pp.24-24
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• 2021

The Cassava (Manihot esculenta Crantz) is one of the major food crops in the tropical or subtropical regions. Recently, clean planting materials of improved cassava cultivars are in high demand. Problems in the propagation of cassava are virus vulnerable and low rates of seed germination. Thus, the study was undertaken to develop an efficient in vitro mass propagation protocol of Manihot esculenta Crantz. So we tried to optimize protocols for mass production from axillary buds of Cassava. Young and actively growing stem segments were excised from adult plants of cassava. Samples were cut into a 3~4 cm nodal segments with axillary buds, and cultivated in the different medium supplemented with various plant growth regulators for 4 weeks. For shoot multiplication, axillary buds approximately 1 cm in length were taken from in vitro derived shoots and subcultured. After 4~6 weeks, the shoot generation rate showed 55.6%. The shoot number and its length was 1.0/explant and 2.3 cm in the most favorable medium composition. The auxin β-indolebutyric acid(IBA) 0~2.0 mg/L was proved to be effective on root development. Plantlets with fibrous roots easily generated tuberous roots in vitro. The tuberous roots were induced only when both kinetin and IBA were used in combination. after 8 weeks, the root generation rate showed 100%. The root number and its length was 17.2/explant and 2.2 cm in the most promising medium composition. Our experiments confirmed that in vitro growth and multiplication of plantlets could depend on its reaction to the different medium composition, and this micropropagation techniques could be a useful system for healthy and vigorous plant production.

• Korean Journal of Plant Resources
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• v.10 no.1
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• pp.50-57
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• 1997

Using a bioassay for tuber enlargement activity, which was carried out with culture of microtuber of nodal stem segments in vitro, the endogenous substances was detected from leaves of yam(Diosorea alata L., cv. Solo Yam) treated under the short and the long day length condition. Tuber enlargement activity was found in both the aqueous and ethyl acetate phase of extract obtained from leaves of yams. Those activity was found in both the aqueous and ethyl acetate phase of extract obtained from leaves of yams. Those activities increased under the short day length, whereas not increased under the long day length. Guided by bioassay, the active substances in the ethyl acetate phase were purified by charcoal adsorption chromatography. The result obtained indicated that the 40% ethanol fraction contained the most prominent tuber enlargement activity. In seasonal changes of the leaves, tuber enlargement activity remained almost constant during summer(June-August), but after. the middle of September, the activity increased gradually and then reached a maximum in early October. Jasmonic acid (JA) was isolated with the guidance of microtuber test and identified by gas chromatography. The level of endogenous JA in the leaves of plants was more than $290{\mu}g/kg$ at the 10 hr day length. These results seem evidences for the occurrence of the tuber enlargement activity which is formed in leaves under the short days and transmitted to under ground part to induce growth and enlargement of tuber.

• Journal of Korean Society of Forest Science
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• v.86 no.3
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• pp.391-398
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• 1997

Present study describes a method on the application of efficient tissue culture systems for the micro-propagation of juvenile and mature sawtooth oak(Quercus acutissima). Nodal segments with axillary buds were used as initial explant sources. WPM(Woody Plant Medium) was the best in growth and proliferation of shoot among the media tested. Although the single effect of zeatin revealed on two dorminant shoot elongation with normal growth until the elevation of levels up to 3.0mg/l, BAP($N^6$-benzyl amino purine) usually showed better response than zeatin on shoot multiplication and/or elongation. In addition, the incorporation of BAP and zeatin onto the culture media represents more effectiveness in shoot proliferation and its growth. Optimum concentrations of BAP and zeatin were 0.5 and 0.05~1.0mg/l, respectively. Ninety percent of the proliferated shoots was rooted on half-strength GD (Gresshoff and Doy, 1972) medium containing 0.5mg/l IBA(indole butyric acid) in 4 weeks after culture. More than 70% of the rooted plantlets survived after 5 months of transplanting into artificial soil mix containing equal amount of peatmoss and perlite. Among 27 plus tree clones which were grafted twice onto the juvenile rootstocks, only 4 clones revealed the possibility for shoot multiplication through tissue culture system. The capacity for the micropropagation using mature explant sources was highly depended on clonal differences compared with those of octet age. More than 90% of rooting ratio was obtained from the best responding clone. Among the 7 rooting media tested, GD medium was the best far rooting. The most effective rooting was obtained on half-strength GD medium containing 0.2 to 2.0mg/l IBA. More than 60% of rooted plantlets survived after 5 months of transplanting into the artificial soil mix.

• Journal of Plant Biotechnology
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• v.29 no.2
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• pp.117-121
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• 2002

We have developed an in vitro micropropagation system via shoot formation from axillary buds using nodal segments of Corylopsis coreana. Explants from both juvenile tree (one-year-old greenhouse stock seedlings) and mature tree (ten-years-old tree in nursery) were compared with regard to propagation efficiency. Combined treatment of both BA and zeatin were effective on shoot proliferation since the best result was obtained on MS medium supplemented with 0.5∼3.0 mg/L zeatin and 0.2 mg/L BA. Generally, juvenile explants were better in both shoot proliferation and growth than mature explants. However, as the duration of in vitro culture was proceed to 6 months, explants from mature tree also produced three shoots per explant. Distinctive differences in rooting and adaptability to soil of shoots obtained from mother trees. Whereas shoots originated from juvenile explants rooted as high as 97%, those from adult explants showed 62% rooting. Similar result was also observed in soil acclimatization. The plantlets derived from juvenile plants survived 67%, while only 48% of those from adult trees survived. The results showed a possibility of the micropropagation of Corylopsis coreana through shoot formation from axillary buds. In addition, the advance of the research still remain to enhance the frequency of acclimatization of plantlets from mature trees for practical application.

• Journal of Plant Biotechnology
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• v.40 no.3
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• pp.147-155
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• 2013

In this experiment, we report for the first time mass propagation by in vitro mircrotuberization of Codonopsis lanceolata. We first examined the effect of cytokinins on multiple shoot induction. 2.0 $mg{\cdot}L^{-1}$ of kinetin not only gave the highest rate of shoot induction (19.1%) but also the elongation of shoot (17.1 mm). Secondly, we investigated the effect of sugars on in vitro microtuberization from nodal segments. The diameter of tuberous roots was enlarged in the half-strength MS medium supplemented with 145.9 mM sucrose. Histological analysis revealed that the number of parenchymatous cell containing starch grains increased in the tuberous roots. In addition, unlike in non-tuberous root, vascular bundles were scattered inner cortex layer. Thirdly, in order to preserve and stimulate the germination, microtubers were stored at $4^{\circ}C$ refrigerator during 9 months and then transplanted to the artificial soils (vermiculrite : peatmoss = 1:1 v/v), resulting that the rates of survival and germination were 75% and 70%, respectively. These results indicated that mass propagation of C. lanceolata was achieved by in vitro microtuber formation, suggesting that this protocol might be applied for not only the propagation of elite clones but also conservation of C. lanceolata germplasm.

• 한국균학회소식:학술대회논문집
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• 2015.05a
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• pp.53-53
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• 2015

Agrobacterium tumefaciens-mediated transformation(ATMT) of Flammulina velutipes was used to produce a diverse number of transformants to discover the functions of gene that is vital for its variation color, spore pattern and cellulolytic activity. Futhermore, the transformant pool will be used as a good genetic resource for studying gene functions. Agrobacterium-mediated transformation was conducted in order to generate intentional mutants of F. velutipes strain KACC42777. Then Agrobacterium tumefaciens AGL-1 harboring pBGgHg was transformed into F. velutipes. This method is use to determine the functional gene of F. velutipes. Inverse PCR was used to insert T-DNA into the tagged chromosomal DNA segments and conducting sequence analysis of the F. velutipes. But this experiment had trouble in diverse morphological mutants because of dikaryotic nature of mushroom. It needed to make monokaryotic fruiting varients which introduced genes of compatible mating types. In this study, next generation sequencing data was generated from 28 strains of Flammulina velutipes with different phenotypes using Illumina Hiseq platform. Filtered short reads were initially aligned to the reference genome (KACC42780) to construct a SNP matrix. And then we built a phylogenetic tree based on the validated SNPs. The inferred tree represented that white- and brown- fruitbody forming strains were generally separated although three brown strains, 4103, 4028, and 4195, were grouped with white ones. This topological relationship was consistently reappeared even when we used randomly selected SNPs. Group I containing 4062, 4148, and 4195 strains and group II containing 4188, 4190, and 4194 strains formed early-divergent lineages with robust nodal supports, suggesting that they are independent groups from the members in main clades. To elucidate the distinction between white-fruitbody forming strains isolated from Korea and Japan, phylogenetic analysis was performed using their SNP data with group I members as outgroup. However, no significant genetic variation was noticed in this study. A total of 28 strains of Flammulina velutipes were analyzed to identify the genomic regions responsible for producing white-fruiting body. NGS data was yielded by using Illumina Hiseq platform. Short reads were filtered by quality score and read length were mapped on the reference genome (KACC42780). Between the white- and brown fruitbody forming strains. There is a high possibility that SNPs can be detected among the white strains as homozygous because white phenotype is recessive in F. velutipes. Thus, we constructed SNP matrix within 8 white strains. SNPs discovered between mono3 and mono19, the parental monokaryotic strains of 4210 strain (white), were excluded from the candidate. If the genotypes of SNPs detected between white and brown strains were identical with those in mono3 and mono19 strains, they were included in candidate as a priority. As a result, if more than 5 candidates SNPs were localized in single gene, we regarded as they are possibly related to the white color. In F. velutipes genome, chr01, chr04, chr07,chr11 regions were identified to be associated with white fruitbody forming. White and Brown Fruitbody strains can be used as an identification marker for F. veluipes. We can develop some molecular markers to identify colored strains and discriminate national white varieties against Japanese ones.

• Journal of Korean Society of Forest Science
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• v.82 no.1
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• pp.26-33
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• 1993

In vitro shoot proliferation and rooting were tested for 2-0 seedlings of half-sib families of 4 plus oaks trees. Nodal segments having axillary buds from 37 families(16 of Quercus acutissima, 10 of Q. variabilis, 7 of Q. serrata, and 4 of Q. mongolica) were cultured on WPM(Woody Plant Medium) supplemented with 0.5 mg/l BA (6-benzyladenine) and 0.01 mg/l NAA(${\alpha}$-naphthalene acetic acid) and subcultured at 2-3 weeks of intervals fur 6 months. In vitro rooting was carried out on GD(Gresshoff and Doy) medium supplemented with 0.5mg/l IBA(indole butyric acid). The capacity for shoot proliferation and rooting was highly varied with families. Generally, white oaks(Q. serrata and Q. mongolica) showed poor response than black oaks(Q. acutissima and Q, variabilis) in shoot proliferation and rooting. Among the total of 37 families, 7 of Q. acutissima, each 2 of Q. variabilis, Q. serrata, and Q. mongolica revealed abilities for continuous shoot proliferation, and the others failed to proliferate. Rooting of the selected oak trees also greatly varied among the families. In Q. acutissima, rooting ratio ranged from 10.0%(CB 25. KG 4) to 89.8%(CB 18). Although 26.7% of KG 16 in Q. variabilis, 3.3% of JN 15 in Q. serrata were rooted, Q. mongolica was not rooted at all in this experimental conditions. No relationship between shoot growth and the rooting ability was observed. Present results suggest the possibility of large-scale micropropagation, but further studies on family differences, shoot-tip necrosis, and callusing of rooting junction are still required to develop reliable micropropagation systems.