• Journal of Plant Biology
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• v.24 no.1
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• pp.13-19
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• 1981

In order to investigate the effects of ammonium citrate and ammonium succinate on the growth and absorption of nitrogen compounds supplied in the medium, Korean ginseng (Panax ginseng C. A. Meyer) calli were suspension cultured in MS medium with various concentrations of ammonium citrate and ammonium succinate. When Korean ginseng calli were cultured with 10 mM ammonium citrate, 10 mM ammonium succinate, and 10 mM ammonium nitrate (control) in MS media as the nitrogen sources, the growth, $NO_3$-N absorption and total nitrogen content of the Korean ginseng cells were greatest in the ammonium citrate and ammonium succinate concentrations. When Korean ginseng calli were cultured with 5 mM ammonium citrate and 5 mM ammonium succinate, the growth and nitrogen content were superior to those of the control: however, $NO_3$-N and $NH_4$-N absorptions were similar to those of the control. In conclusion, the 10 mM ammonium citrate and 10 mM ammonium succinate may be better able to facilitate the growth and $NO_3$

• Journal of Plant Biotechnology
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• v.5 no.2
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• pp.87-93
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• 2003

Brachiaria (Poaceae) is the most important forage genus for cattle production in Brazil. The genetic breeding of this genus is limited by the incompatibility among species, differences in ploidy level and the natural cloning of plants by apomixis (Valle and Miles 1992). However, plant regeneration via tissue culture methods and genetic engineering provide an opportunity to introduce new characteristics in plants of this genus. We have developed methods for the 'genetic modification of Brachiaria brizantha cv. Marandu via biolistic transformation. A higher number of shoots was obtained with 4 mg/L 2.4-diclorophenoxyacetic acid and 0.2 mg/L benzylaminopurine in calli induction medium and 0.1 mg/L naphtaleneacetic acid and 4.0 mg/L kinetin in shoot regeneration medium. A selection curve for mannose was determined to use phospho mannose isomerase (PMI) gene of Escherichia coli as a selection marker. Calli formation was inhibited from 5 g/L mannose, even in the presence of sucrose while calli that were formed in the presence of mannose failed to develop embryos showing that PMI gene can be used for selection of transformants of this grass. Different promoters were tested to evaluate the efficiency based on the detection of the GUS gene expression (Jefferson et al. 1987). The monocot promoters, act1-D and ubi-1, resulted in higher expression levels than dicot promoters, ubi-3 and act-2, or the CaMV35S and CVMV promoters.

• Korean Journal of Plant Tissue Culture
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• v.22 no.4
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• pp.189-194
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• 1995

Calli were successfully induced from immature embryos of Citrus junos SIEB. cultured on 1/2 MS medium supplemented with 40.4 BA. Plant were regenerated from immature embryo derived callus on MS medium with 5 $\mu$M BA. The calli were morphologically characterized by two types: one was whitish and the other was yellowish. After 16 weeks of culture, shoots and root were formed on calli. Plantlets were transplanted to soil and successfully grown to a whole plant Also, the arrangement of the cells showed many differences according to developmental stages of callus and organogenesis. The small cells were compact in callus cultured for 6 weeks and the extended cells which divided actively appeared in it after 8 weeks of culture. The globular protrusion of compacted cells occurred in callus after 10 weeks of culture, and the neighboring cells were liquefied. Oil sac surrounded by the liquefied cell was observed in the leaf and was formed by rupture of liquefied cells.

• Korean Journal of Plant Resources
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• v.36 no.6
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• pp.588-596
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• 2023

Long-term culture of cell lines is an important issue in in vitro culture and in plant science. In this study, the regeneration ability and ex vitro acclimatization of regenerants were evaluated. The ploidy level of regenerants derived from long-term cultured cell lines was measured in Imperata cylindrica 'Rubra', Poaceae. Adventitious buds (shoots) were successfully induced from five-year-cultured calli on MS medium containing 0.1 mg/L BA or 2.0 mg/L TDZ, combined with 0.01 mg/L auxins (IAA, IBA, NAA and 2,4-D), respectively. Adventitious roots were also induced on MS medium containing 0.01 mg/L auxins (IBA, NAA and 2,4-D), respectively. Interestingly, regenerants with both red and green leaf were successfully obtained when regenerants were cultured on MS medium with 9% sucrose. Regenerants derived from long-term cultured calli were transferred to pots using an optimal acclimatization process and successfully adapted to both pot and soil conditions. Moreover, the ploidy level was measured using calli and regenerants that had been kept on MS medium containing various kinds of plant growth regulators (PGRs).

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.237-242
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• 2004

A system for the production of transgenic plants has been developed for tall fescue (Festuca arundinacea Schreb.) via Agrobacterium-mediated transformation of mature seed-derived embryogenic callus. Seed-derived calli were infected and co-cultured with Agrobacterium EHA101 carrying standard binary vector pIG121Hm encoding the hygromycin phosphotransferase (HPT), neomycin phosphotransferase II (NPTII) and intron-containing $\beta$-glucuronidase (intron-GUS) genes in the T-DNA region. The effects of several factors on transformation and the expression of the GUS gene were investigated. Inclusion of $200\mu\textrm{M}$ acetosyringone (AS) in inoculation and co-culture media lead to a increase in stable transformation efficiency. Transformation efficiency was increased when embryogenic calli were co-cultured for 5 days on the co-culture medium. The highest transformation efficiency was obtained when embryogenic calli were inoculated with Agyobacterium in the presence of 0.1% Tween20 and $200\mu\textrm{M}$ AS. Hygromycin resistant calli were developed into complete plants via somatic embryogenesis. GUS histochemical assay and Southern blot analysis of transgenic plants demonstrated that transgenes were successfully integrated into the genome of tall fescue.

• Korean Journal of Plant Tissue Culture
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• v.25 no.1
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• pp.51-56
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• 1998

This study was carried out in order to establish plant regeneration via somatic embryogenesis from leaf explant of Ostericum koreanum Kitagawa and to elucidate the effects of NAA and cytokinins (kinetin, BA) on the abnormalities of somatic embryo and the relationship between thecotyledon numberand germinability. Calli were formed on leaf explants cultured on MS agar medium supplemented with various concentrations (0, 0.1, 0.5, 1, 2 mg/L) of NAA and cytokinins. The calli were white, watery and soft, became browning during cultures. Somatic embryos were formed from pale yellowish calli derived browning calli. High frequency somatic embryos were observed on MS medium containing 1 mg/L NAA and 0.1 mg/L BA after 60 days of culture. The mature somatic embryos germinated into plantlets without subculture after 2 weeks. The frequency of normal somatic embryo with two cotyledons was 39.8%. On the other hand, cotyledonary abnormalities of somatic embryos were observed at considerable frequency: 33.6% of somatic embryo with one cotyledon, 15.3% cotyledons with three, 8.2% four cotyledons and 3.1% jar shaped cotyledon. Germination frequency of somatic embryos with two cotyledons was 97.4%, and that of the embryos with abnormal cotyledon was almost similar to that of embryos with two cotyledons, except jar shaped somatic embryos (33.3%).

• Journal of Plant Biotechnology
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• v.44 no.4
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• pp.379-387
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• 2017

Various sizes (0.2 ~ 1.2 mm) and developmental stages (referred to as Stage 1 ~ 3) of apical and lateral meristems were excised, together or separately, directly from dormant buds of apple 'Hongro'. They were mixed infected by Apple scar skin viroid (ASSVd), Apple chlorotic leaf spot virus (ACLSV), Apple stem pitting virus (ASPV) and Apple stem grooving virus (ASGV), which are major viruses attacking apples. A total of 31 callus lines (> 10 mm in diameter) were obtained by culturing the explants on Murashige and Skoog (MS) medium supplemented with 3% sucrose, 3.0 mg/L benzyladenine (BA) and 0.1 mg/L indole-3-butyric acid (IBA), and they were subjected to RT-PCR analysis for virus detection. A high rate of virus elimination (expressed as the percentage of calli that did not amplify during RT-PCR, i.e., RT-PCR negative calli per total number of calli obtained) was achieved for ACLSV (100%), ASSVd (93.7%), and ASPV (93.7%), whereas it was only 25.8% for ASGV. ASPV was detected in the presence of 2 ~ 3 bracts. Simultaneous virus elimination of ASSVd, ASPV, ACLSV, and ASGV occurred during the meristem culture, in which the early stages of the dormant buds (Stage 1) were used, because ASGV was mostly eliminated during that stage. The results of the present study will be valuable for the production of virus-free apple trees.

• Journal of Plant Biotechnology
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• v.32 no.4
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• pp.263-268
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• 2005

Porcine epidemic diarrhea virus (PEDV) causes acute enteritis in pigs of all ages and is often fatal for neonates. In order to develop sweetpotato plants expressing PEDV antigen, we constructed the vector expressing spike gene of PEDV under the control of sweetpotato sporamin promoter or constitutive CaMV 35S promoter. The spike protein region of PEDV was synthesized by PCR and linked to each promoter, Transgenic sweetpotato [Ipomoea batatas (L.) Lam. cv. Yulmi] plants were developed from embryogenic calli following Agrobacterium tumefaciens-mediated transformation. The co-cultured embryogenic calli transferred to selective MS medium containing 1 mg/L 2,4-D, 100 mg/L kanamycin, and 400 mg/L claforan. These embryogenic calli were subcultured to the same selection medium at 3 weeks interval. Kanamycin-resistant calli transferred to hormone-free MS medium with kanamycin gave rise to somatic embryos and then converted into plantlets in the same medium. Southern blot analysis confirmed that the spike gene of PEDV was inserted into the genome of the sweetpotato plants. RT-PCR revealed that the spike gene of PEDV was highly expressed in transgenic sweetpotato plants.

• Journal of Plant Biotechnology
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• v.32 no.4
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• pp.301-306
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• 2005

Conditions for efficient organogenesis and plant regeneration from Dianthus gratianopol suspension cultured cells were established. Shoot-forming calli of glossy surface, pale green and knobby type were selected from leaf explant-derived calli and were suspension-subcultured every week in CP liquid medium with 1.0 mg/L 2,4-D and 0.5 mg/L BAP. Combinations of 1.0 mg/L 2,4-D and 0.5 mg/L BAP, and 1.5 mg/L 2,4-D and 0.5 mg/L BAP were effective for the induction of regenerative callus from the suspension cultured cell clusters. Multiple shoot primordia were initiated from the green spots of these regenerative callus and formed shoots on MS medium with 1.0 mg/L TDZ and 0.5 mg/L PAA. Shoot regeneration frequency (calli regenerating at least one shoot) was about 87%. For plant regeneration, proliferated shoots were excised and transferred to MS medium with 0.1 mg/L NAA for root initiation after 9 weeks of culture. The regenerants were potted in soil and formed the flowering buds and petals. Also, adventitious shoots were formed from the excised green shoot primordia of regenerative callus and these shoots proliferated successfully and regenerated to whole plants.

• Current Research on Agriculture and Life Sciences
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• v.9
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• pp.21-28
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• 1991

The effect of subculture intervals and passages on plant regeneration from seed-derived callus was determined. Regeneration capacity of callus varied with rice cultivars and subculture intervars tested. The callus subcultured every 2 weeks produced more plants than that of 4 weeks. The calli from a Tongil-type rice cultivar, Milyang 23, lost easily their regeneration ability when the calli were subcultured every 2 weeks and 4 weeks. The callus induced from a japonica cultivar, "Yeongdeogbyeo", showed to maintain high frequency(>70%) of plant regeneration when it was subcultured every 2-week intervals. Casein hydrolysate supplemented in callus induction medium enhanced callus growth and its regeneration. High frequency of plant regeneration was obtained from the calli transferred on $N_6$ medium supplemented with kinetin(2mg/1) and NAA(1mg/1). The subcultured calli in the medium supplemented with casein hydrolysate(2 g/1), myo-inositol(200mg/1) and thiamine-HCl(2mg/1) increased the frequency of embryogenic callus formation and plant regeneration.