• Korean Journal of Plant Tissue Culture
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• v.27 no.6
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• pp.441-445
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• 2000

In order to improve phosphate use efficiency of rice using phosphate transporter (PT), transgenic rice plants containing a tobacco PT gene were developed. Calli from Dongjinbyeo (Oryza sativa L.) were cocultured with A. tumefaciens LBA 4404 harboring PT gene. Multiplied calli were transferred to MS medium supplemented with 50 mg/L hygromycin, 500 mg/L carbenicillin, 2 mg/L kinetin, 0.1 mg/L NAA. After 2 weeks, hygromycin resistant shoots were obtained from the calli on the selection medium. The putative transgenic shoots were transferred to rooting MS medium supplemented with 250 mg/L cabenicillin. Plant regeneration rate from the calli was about 52%. Stable incorporation of the tobacco PT gene into rice genomic DNA was confirmed by PCR and Southern blot analysis.

• Korean Journal of Plant Tissue Culture
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• v.26 no.4
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• pp.289-291
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• 1999

Hypocotyl explants from 7 days old seedlings of one $F_1$ hybrid cultivar and two pure lines of cucumber formed embryogenic calli at frequencies of up to 8% when cultured on Murashige and Skoog medium (MS) supplemented with 1 mg/L 2,4-D for 3 weeks. Embryogenic calli gave rise to somatic embryos. When slices of somatic embryos were cultured on the same medium for 4 weeks, they formed embryogenic calli. Embryogenic cell suspension cultures were established with embryogenic calli in MS liquid medium with 1 mg/L 2,4-D. Embryogenic potential of cell suspension cultures was maintained by subculturing every seven days. When the level of 2,4-D in the medium was lowered to 0.2 mg/L by diluting with liquid MS basal medium, embryogenic cell suspension cultures underwent development into numerous somatic embryos. When plated onto MS basal medium, over 95% of somatic embryos developed into plantlets. Plantlets were transplanted to potting soil and grown to maturity.

• Plant Biotechnology Reports
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• v.4 no.4
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• pp.269-280
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• 2010

Lilium ${\times}$ formolongi was genetically engineered by Agrobacterium-mediated transformation with the plasmid pCrtZW-N8idi-crtEBIY, which contains seven enzyme genes under the regulation of the CaMV 35S promoter. In the transformants, ketocarotenoids were detected in both calli and leaves, which showed a strong orange color. In transgenic calli, the total amount of carotenoids [133.3 ${\mu}g/g$ fresh weight (FW)] was 26.1-fold higher than in wild-type calli. The chlorophyll content and photosynthetic efficiency in transgenic orange plantlets were significantly lowered; however, after several months of subculture, they had turned into plantlets with green leaves that showed significant increases in chlorophyll and photosynthetic efficiency. The total carotenoid contents in leaves of transgenic orange and green plantlets were quantified at 102.9 and 135.2 ${\mu}g/g$ FW, respectively, corresponding to 5.6- and 7.4-fold increases over the levels in the wild-type. Ketocarotenoids such as echinenone, canthaxanthin, 3'-hydroxyechinenone, 3-hydroxyechinenone, and astaxanthin were detected in both transgenic calli and orange leaves. A significant change in the type and composition of ketocarotenoids was observed during the transition from orange transgenic plantlets to green plantlets. Although 3'-hydroxyechinenone, 3-hydroxyechinenone, astaxanthin, and adonirubin were absent, and echinenone and canthaxanthin were present at lower levels, interestingly, the upregulation of carotenoid biosynthesis led to an increase in the total carotenoid concentration (+31.4%) in leaves of the transgenic green plantlets.

• Journal of Plant Biotechnology
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• v.39 no.3
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• pp.182-188
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• 2012

Iris dichotoma Pall. is an important endangered plant belonging to the family Iridaceae. A method was developed for the rapid micropropagation of I. dichotoma through plant regeneration from leaf, rhizome, and root explant-derived calli. Leaf, rhizome, and root segments were cultured on Murashige and Skoog (MS) medium supplemented with 2,4-dichlorophenoxy acetic acid (2,4-D; $0-3.0mg{\cdot}L^{-1}$) for callus induction. Callus production was highest at $1.0mg{\cdot}L^{-1}$ 2,4-D, where 73.8% and 45.5% of cultured rhizome and root cuttings, respectively, produced calli. The viable calli were maintained at an induced concentration of 2,4-D ($3.0mg{\cdot}L^{-1}$). They were then transferred to MS medium supplemented with various concentrations of 2,4-D ($0-3.0mg{\cdot}L^{-1}$) in combination with 6-benzyladenine (BA: 0, 1.0 and $3.0mg{\cdot}L^{-1}$) for adventitious shoot regeneration. The addition of a low concentration of 2,4-D into BA-containing medium significantly increased the frequency of shoot regeneration in leaf, rhizome, and root-derived calli. The highest number of adventitious shoots (26.4 per callus) formed at $0.5mg{\cdot}L^{-1}$ 2,4-D and 1.0 mg/l BA. For rooting of the shoots, half- strength MS medium supplemented with different concentrations of indole 3-butyric acid (IBA) $0-3.0mg{\cdot}L^{-1}$ was tested. The optimal results were observed using half-strength MS medium supplemented with $1.0mg{\cdot}L^{-1}$ IBA, on which 98% of the regenerated shoots developed roots with an average of 3.5 roots per shoot within 45 days. The plantlets raised in vitro were acclimatized and transferred to soil with 95% success. This in vitro propagation protocol will be useful for conservation and mass propagation of this endangered plant.

• Plant Biotechnology Reports
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• v.2 no.4
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• pp.245-252
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• 2008

The genetic status of somatic embryo-derived plantlets of Cymbopogon flexuosus was examined by randomly amplified polymorphic DNA (RAPD) analysis. Auxins such as 2, 4-dichlorophenoxyacetic acid (2, 4-D) (1-4 mg/l) were used in Murashige and Skoog (MS) medium for induction of calli from rhizomatous explants of Cymbopogon flexuosus. Optimum calli were induced on MS medium supplemented with 2, 4-dichlorophenoxyacetic acid (2, 4-D) (3.5 mg/l) alone or in combination with $N^6-benzyladenine$ (2 mg/l). Somatic embryogenesis was achieved from long term calli when cultured on MS medium containing 2, 4-dichlorophenoxyacetic acid (2, 4-D) (2 mg/l) along with $N^6-benzyladenine$ (BA) (1-2 mg/l). Regeneration was achieved when freshly induced embryogenic calli were sub-cultured on MS medium supplemented with $N^6-benzyladenine$ (3 mg/l) alone. Long-term cultured embryos showed profuse minute rooting on regeneration medium supplemented with N6 -benzyladenine (3 mg/l). Microshoots were rooted in the presence of indole-butyric acid (IBA) (2 mg/l). DNA samples from the mother plant and 18 randomly selected regenerated plants from a single callus were subjected to RAPD analysis with 6 arbitrary decamer primers for the selection of putative somaclones. A total of 64 band positions were scored, out of which 19 RAPD bands were polymorphic. From genetic similarity coefficient based on RAPD band data sharing, it was found that the majority of the clones were almost identical or more than 92% similar to the mother plant, except CL2 and CL9 (66%) which showed highest degree of genetic change with CL2 and CL9 showing presence of two non-parental bands each.

• Korean Journal of Weed Science
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• v.11 no.2
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• pp.137-141
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• 1991

This study was conducted to determine the response of newly developed chlorophyllous cells against photosynthesis inhibitory herbicides in LS medium. Inhibition of the growth of the selected chlorophyllous cells in the LS medium containing sucrose 1%, NAA $10^{-5}$ M and BA $10^{-6}$ M under light condition increased as the concentrations of paraquat increased from $10^{-6}$ M to $10^{-4}$ M. The calli died in $10^{-4}$ M paraquat treatment and the inhibition of calli growth was greater when $CO_2$ was supplied. In the treatment of herbicide diuron, the inhibition of calli growth also increased as the concentrations of diuron increased from $10^{-6}$ M to $10^{-3}$ M and more inhibition was observed at 1% sucrose than 2% sucrose.

• Korean Journal of Plant Tissue Culture
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• v.22 no.4
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• pp.212-216
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• 1995

These experiments were carried out to examine the effect of explant sources and plant growth regulators on callus induction and plantlet differentiation. Cotyledon and petiole explants of Cyclamen persium were cultured on MS medium supplemented with different concentrations of auxins and cytokinins. Cotyledon cultured on medium containing 2, 4-D and kinetin did not form callus or shoots. But when calli induced from petiole explants on medium with 1.0 mg/L 2, 4D and 1.0 mg/L kinetin were subcultured on the same medium the formation of shoots from calli occurred after 150 days of culture. The combination of NAA and BA were more effective than that of 2, 4 D and kinetin in the formation of shoots from calli, cotyledon culture was most effective on medium with 0.2 mg/L NAA and 0.5 mg/L BA. Shoots excised from calli were rooted on medium with 1.0 mg/L NAA. The plantlets were subsequently transplanted to potting soil.

• Korean Journal of Plant Tissue Culture
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• v.28 no.2
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• pp.97-101
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• 2001

The transport and allocation of photosynthetic assimilate is an important regulatory factor in plant productivity, In order to modify assimilate partitioning in rice, transgenic plants containing a potato sucrose transporter (SuT) gene were developed. Calli derived from rice seeds (Oryza sativa L. cv Dongjin) were cocultured with A. tumefaciens LBA 4404 harboring the SuT gene. Calli were transferred to MS medium supplemented with 50 mg/L hygromycin, 500 mg/L carbenicillin, 2 mg/L kinetin, 0.1 mg/L NAA. After 2 weeks, hygromycin resistant shoots were obtained from the calli on the selection medium. Roots were induced from the putative transgenic shoots on rooting MS medium supplemented with 250 mg/L cabenicillin. Plant regeneration rate from the calli was about 150%. Stable incorporation of the potato SuT gene into rice genomic DNA was confirmed by PCR and Southern blot analysis.

• Molecules and Cells
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• v.42 no.5
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• pp.406-417
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• 2019

RICE FLOWERING LOCUS T 1 (RFT1) is a major florigen that functions to induce reproductive development in the shoot apical meristem (SAM). To further our study of RFT1, we overexpressed the gene and examined the expression patterns of major regulatory genes during floral transition and inflorescence development. Overexpression induced extremely early flowering in the transgenics, and a majority of those calli directly formed spikelets with a few spikelets, thus bypassing normal vegetative development. FRUITFULL (FUL)-clade genes OsMADS14, OsMADS15, and OsMADS18 were highly induced in the RFT1-expressing meristems. OsMADS34 was also induced in the meristems. This indicated that RFT1 promotes the expression of major regulatory genes that are important for inflorescence development. RFT1 overexpression also induced SEPALLATA (SEP)-clade genes OsMADS1, OsMADS5, and OsMADS7 in the greening calli before floral transition occurred. This suggested their possible roles at the early reproductive stages. We found it interesting that expression of OsFD1 as well as OsFD2 and OsFD3 was strongly increased in the RFT1-expressing calli and spikelets. At a low frequency, those calli produced plants with a few leaves that generated a panicle with a small number of spikelets. In the transgenic leaves, the FUL-clade genes and OsMADS34 were induced, but SEP-clade gene expression was not increased. This indicated that OsMADS14, OsMADS15, OsMADS18, and OsMADS34 act immediately downstream of RFT1.

• Journal of Plant Biotechnology
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• v.35 no.3
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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.