• Korean Journal of Plant Tissue Culture
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• v.24 no.4
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• pp.225-231
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• 1997

For genetic engineering to be commercially viable, an efficient transformation system is needed to produce transgenic plane from diverse genotypes ("generalized protocol"). Development of such a system requires optimization of a number of components such as gene transfer agent, plant tissues competent for both regeneration and transformation, and control of transgene expression. Although several novel gene transfer methods have been developed for plane, a majority of stably transformed plane express the introduced genes at low levels. Moreover, silencing of selectable marker genes shortly after their incorporation into plant chromosomes may result in low recovery of transgenic tissues from selection. Matrix attachment regions (MARs) are DNA sequences that bind to the cell's proteinaceous nuclear matrix to form DNA loop domains. MARs have been shown to increase transgene expression in tobacco cells, and reduce position in mature transgenic plants. Flanking an antibiotic resistance transgene with MARs should therefore lead to improved rates of transformation in a diversity of species, and may permit recalcitrant species and genotypes to be successfully transformed. Literature review and recent data from my laboratory suggest that MARs can serve as a transformation booster in recalcitrant plant species.

• Journal of The Korean Society of Grassland and Forage Science
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• v.21 no.2
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• pp.45-48
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• 2001

In an effort to optimize tissue culture responses of tall fescue, the effects of basic medium and carbon sources on seed culturability and genotypic difference of plant regenerability were investigated. The MS basal medium was superior to $N_{5}$ 6/ and $B_{medium}$ in enhancing callus growth and plant regeneration. To determine the effect of carbon sources on plant regeneration, the seeds were cultured on medium with 30 g/L sucrose and maltose, respectively. Medium supplemented with 30 g/L sucrose resulted in regeneration of shoots from 50% of the calli. The genotypic difference in plant regenerability was obvious among five cultivars of tall fescue tested. \\`KY31\\` and \\`Hokuryo\\` showed to have higher regenerability with the frequency of 33% and 51%, respectively.

• Plant Biotechnology Reports
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• v.3 no.3
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• pp.199-203
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• 2009

Rugosa rose (Rosa rugosa) is cultivated as a garden flower and an important genetic resource for the breeding of roses (R. hybrida). This study describes culture conditions for high frequency plant regeneration from zygotic embryo explants via somatic embryogenesis in rugosa rose. Mature zygotic embryo, cotyledon, and radicle explants formed embryogenic calluses at frequencies of 38, 6.7, and 8.8% when cultured on half-strength Murashige and Skoog medium (${\frac{1}{2}}MS$) supplemented with 2.26, 9.05, and $9.05{\mu}M$ 2,4-dichlorophenoxyacetic acid, respectively. Embryogenic calluses produced numerous somatic embryos, which then developed into plantlets on ${\frac{1}{2}}MS$ without growth regulators. Regenerated plantlets were grown to whole plants in a growth chamber.

• Horticultural Science & Technology
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• v.30 no.5
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• pp.477-483
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• 2012

This study was carried out to investigate the influence of copper concentrations in fertilizer solution on the growth of and nutrient uptake by domestically bred strawberries. The characterization of toxicity symptoms as well as tissue analyses based on dry weight of above ground tissue were also conducted to determine the threshold levels in plants when toxicity developed in copper. The dry weights of the above ground tissue were not significantly different among the treatments of 0.25 mM to 1.0 mM in 'Keumhyang' and 'Maehyang' strawberries and that of 0.25 mM to 3.0 mM in 'Seolhyang' strawberry. This indicates that the 'Seolhyang' strawberry is more tolerant to copper toxicity than 'Keumhyang' or 'Maehyang' strawberries. Application of copper at high concentrations resulted in severe toxicity such as death of extensive areas of leaves. The lower leaves became yellow and die rapidly as the symptoms spread up the plants. The leaf blades and petioles died back to the crown and hang on by mechanical attachment. Symptoms of copper toxicity in lower leaves developed as browning on leaf margins and in patches between leaf veins that became necrotic. The elevation of copper concentrations in fertilizer solution did not influence the tissue phosphorus, potassium, calcium, and magnesium contents based on the dry weight of the above ground tissue. The tissue copper contents increased lineally as the copper concentrations in fertilizer solution were elevated. But the tissue iron, manganese and boron contents were not influenced by the concentrations. When the concentration of copper at which growth of a plant is retarded by 10% is regarded as threshold level, the copper contents based on dry weight of above ground plant tissue should be lower than 71.4, 57.9 and 74.8 $mg{\cdot}kg^{-1}$ in 'Keumhyang', 'Maehyang' and 'Seolhyang' strawberries, respectively. The symptom characterization and established threshold level in copper toxicity would help growers to prevent the reduction of crop growth and yield in 'Seolhyang' strawberry cultivation.

• Korean Journal of Plant Tissue Culture
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• v.21 no.4
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• pp.247-252
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• 1994

The effects of explant sources, plant growth regulators on callus induction and plantlet differentiation from leaf blade, petiole, and meristem tissue of Pelalgonium citrosa were investigated under illumination or in dark condition Leaf blade explants cultured on Murashige and Skoog's medium containing 2,4-D and kinetin did not form callus or organ. But those cultured on medium with NAA and BA produced callcus and shoots. Dark condition was more effective than light condition to callus induction and showed that some of shoot were differentiated directly from leaf blade explane. Callus proliferated vigorously on meristem tissue after 7 days of culture, and multiple shoots were obtained Sum callus on medium with 0.5 mg/L NAA and BA. Roots formed readily from about 80% of the shoots cultured on medium with 1.0 mg/L NAA. Regenerated plantlets regenerated had phenotypically normal leaves and roots.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.52-52
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• 2018

Development of herbicide resistant transgenic legume plants through Agrobacterium-mediated transformation has been worked in many previous studied. Plant regeneration after infection is the important step to obtain successful transgenic plants. Many attempts try to find the optimum media condition for plant regeneration after infection. However, the transformation efficiency of legume plants is still low. In this study, regeneration of some Korean legume species including two soybean cultivars (Dawon and Pungsan) and pea have been done with organogenesis which is used various kind of explants such as cotyledonary-nodes in soybean and bud-containing tissue in pea. We developed the optimum media condition for plant regeneration regulators under Agrobacterium-mediated transformation using different kind and various concentration of plant growth. As the results, B5 medium containing 2 mg/L of 6-benzylaminopurine was selected in this study for the optimum plant regeneration media. The segments were inoculated with Agrobacterium suspension harbored an IG2 vector containing bar gene which confers resistance to phosphinotricin (PPT) in 3, 5 and 7 days. The transformation efficiency was achieved in Dawon 3.03 % and pea 1.46 % with co-cultivation period of 7 days which is showed a high number of GUS positive expression period.

• Journal of The Korean Society of Grassland and Forage Science
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• v.28 no.3
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• pp.165-170
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• 2008

Timothy (Phleum pratense L.) is an important grass species as forage. In order to optimize tissue culture conditions of timothy, the effects of plant growth regulators on callus induction and plant regeneration was investigated with mature seeds of colt cultivar. The optimal concentration of 2,4-D for the induction of primary callus from mature seeds was 3 mg/L. The highest embryogenic callus frequenc (25%) was observed when the mature seed were cultured on MS medium supplemented with 3 mg/L 2,4-D and 0.1 mg/L BA. The highest plant regeneration frequency was observed when type B callus was transferred to N6 medium supplemented with 1 mg/L 2,4-D and 3 mg/L BA. Regenerated plants were grown normally when shoots were transplanted to the soil. A short tissue culture period and regeneration system would be beneficial for molecular breeding of timothy by the production of transgenic plant.

• Korean Journal of Plant Tissue Culture
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• v.26 no.2
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• pp.137-142
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• 1999

This study was carried out to investigate the effects of bulb size, type of media, depth of planting, and nutrient compositions on sprouting and growth of tissue cultured garlic microbulbs in hydroponic culture. Early and increased sprouting were observed when the microbulbs were transplanted into soil planted in shallow (1 cm in depth), while bulb size and fresh weight of the whole plant increased in deep planting (3 cm in depth). Bulb size have greatly influenced on not only sprouting rate but also plant growth after planting. Large bulbs resulted in high growth rate such as number of leaves, stem width, plant height, and increase in bulb size after planting. It was shown that Oriental nutrient solution (N=0.17, P=0.45, K=1.29, Ca=2.44, and Mg=0.98 me/L) was more effective in sprouting and further growth of microbulbs as compared to Yamazaki solution (N=0.27, P=0.16, K=1.50, Ca=1.36 and Mg=0.78 me/L). Microbulbs grown in mixture of leaf mould + bark + sand or Baroko showed the most vigrous growth.

• Korean Journal of Agricultural Science
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• v.37 no.2
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• pp.191-197
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• 2010

The objective of this research was to determine the influence of the physical and chemical properties of root substrates used during the production of 'Maehyang' strawberry propaguleson the growth of the mother plants and the rate of daughter plant formation. Plants were cultured in plastic bags containing six different formulations of root substrates composed of: a) 50% coir dust and 50% perlite (5:5 by volume, A), b) 60% coir dust and 40% perlite (6:4, B), c) 70% coir dust and 30% perlite (7:3, C), d) 70% coir dust and 30% coconut chip (7:3 D), e) 60% coir dust and 40% coconut chip (60:40, E), or f) 50% sphagnum peat and 50% vermiculite (50:50, F). All media formulations contained a moderate level of base fertilizers. Physical and chemical properties of each formulation were determined before plant establishment and after 120 days of stock plant culture and runner production. Total porosity (TP) and container capacity (CC) of all substrate formulations were higher than 85% and 55%, respectively, allowing a suitable range of air and water holding characteristics. Formulation F provided the highest TP and CC values among the all substrate modifications evaluated. Substrate formulations A, B, C and F had higher electrical conductivity (EC) and $NO_3{^-}$-N concentrations than formulations D and E, when determined before and after plant culture. Formulations A, B, C, and F, having higher EC readings, also performed better as root substrates thanthe formulations D and E in increasing fresh and dry weights of the runners as well as the production of daughter plants per plant. The 'Maehyang' strawberry plants grown in the formulation F had the highest tissue N content, followed by those grown in substrate B, A, C, or D for 120 days after transplanting. Formulation F also facilitated accumulation of higher tissue phosphorus (P) and copper (Cu) contents compared to other treatments. Results of this experiment suggest that the chemical properties, rather than physical properties, of root substrates had a major influence on the growth of mother plants and the occurrence of healthy daughter plants during the bag-culture phase of propagation.

• Journal of Ecology and Environment
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• v.45 no.3
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• pp.143-151
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• 2021

Background: Plants are able to optimize defense responses induced by various herbivores, which have different feeding strategies. Local and systemic responses within a plant after herbivory are essential to modulate herbivore-specific plant responses. For instance, leaf-chewing herbivores elicit jasmonic acid signaling, which result in the inductions of toxic chemicals in the attacked leaf (tissue-specific responses) and also in the other unattacked parts of the plant (systemic responses). Root herbivory induces toxic metabolites in the attacked root and alters the levels of transcripts and metabolites in the unattacked shoot. However, we have little knowledge of the local and systemic responses against stem-boring herbivores. In this study, we examined the systemic changes in metabolites in the wild tobacco Nicotiana attenuata, when the stem-boring herbivore Trichobaris mucorea attacks. Results: To investigate the systemic responses of T. mucorea attacks, we measured the levels of jasmonic acid (JA), JA-dependent secondary metabolites, soluble sugars, and free amino acids in 7 distinct tissues of N. attenuata: leaf lamina with epidermis (LLE), leaf midrib (LM), stem epidermis (SE), stem pith (SP), stem vascular bundle (SV), root cortex with epidermis (RCE), and root vascular bundle (RV). The levels of JA were increased in all root tissues and in LM by T. mucorea attacks. The levels of chlorogenic acids (CGAs) and nicotine were increased in all stem tissues by T. mucorea. However, CGA was systematically induced in LM, and nicotine was systematically induced in LM and RCE. We further tested the resource allocation by measuring soluble sugars and free amino acids in plant tissues. T. mucorea attacks increased the level of free amino acids in all tissues except in LLE. The levels of soluble sugars were significantly decreased in SE and SP, but increased in RV. Conclusions: The results reveal that plants have local- and systemic-specific responses in response to attack from a stem-boring herbivore. Interestingly, the level of induced secondary metabolites was not consistent with the systemic inductions of JA. Spatiotemporal resolution of plant defense responses against stem herbivory will be required to understand how a plant copes with attack from herbivores from different feeding guilds.