• Journal of Plant Biotechnology
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• v.38 no.3
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• pp.209-214
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• 2011

Transgenic lettuce plants were successfully obtained from hypocotyl explants inoculated with Agrobacterium tumefaciens, which harbored a binary vector plasmid with Bcl-2 gene, related to apoptosis. After culture and selection on MS medium a number of kanamycin-resistant plantlets were regenerated. Polymerase chain reaction, Southern blot analysis and Northern blot analysis were used to identify and characterize the transgenic plants with the integrated Bcl-2 gene. Over 100 transgenic plants have been established in soil and flowered in the greenhouse. T1 progeny of 100 transgenic lettuce inbred lines were inoculated with Sclerotinia sclerotiorum. Expression of the Bcl-2 peptide in transgenic lettuce plants provides high levels of field resistance against Sclerotinia sclerotiorum, causal agent of the agronomically important fungal disease of lettuce.

• Journal of Plant Biotechnology
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• v.45 no.3
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• pp.257-265
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• 2018

Sweetener is one of the additives that makes you feel sweet. Artificial sweeteners and sugar are typical examples, and sweetness proteins with sweetness characteristics have been widely studied. These studies elucidated the transformation lettuce cells with Agrobacterium method for stable production of natural sweet proteins, brazzein, thaumatin, and miraculin. In this paper, we report use of a plant expression system for production of sweet proteins. A synthetic gene encoding sweet proteins was placed under the control of constitutive promoters and transferred to lettuce. High and genetically stable expression of sweetener was confirmed in leaves by RT-PCR and Western blot analysis. Sweet proteins expressed in transgenic lettuce had sweetness-inducing activity. Results demonstrate recombinant sweet proteins correctly processed in transgenic lettuce plants, and that this production system could be a viable alternative to production from the native plant.

• Korean Journal of Plant Tissue Culture
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• v.28 no.3
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• pp.147-151
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• 2001

Explants of Lactuce sativa cultivar, chungchima, were co-cultivated with Agrobacterium tumefaciences LBA4404, EHA101 strains containing nptll gene and ferritin gene encoding iron storage protein from soybean for transformation. Through initial selection of regenerated explants by culturing on a kanamycin and carbenicillin containing MS medium, multiple shoots were obtained after 2 months of culture. For a complementary step of selection, putative transgenic shoots were transferred to 1/2 MS basal medium supplemented with 100 mg/L kanamycin and 500 mg/L carbenicillin. The selected shoots were tested with PCR analysis using nptll, ferritin specific primers whether ferritin gene was introduced to genome of the plants. These results confirmed that produced the specific PCR bands in the putative transgenic lines. Additionally the Northern blot showed that transcripts of ferritin gene were detected in mature leaf of the transgenic lines. These results suggest that ferritin gene be successfully integrated and transcribed in the putative transgenic lettuce plants.

• Korean Journal of Plant Tissue Culture
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• v.25 no.4
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• pp.267-271
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• 1998

Cotyledon explants of lettuce were cocultured with Agrobacterium tumefaciens LBA4404::pBKS-GR1 harboring glutathione reductase(GR) gene in MS medium supplemented with 0.1 mg/L NAA and 1.0 mg/L 2ip for 48 hr. These explants were transferred to MS medium supplemented with 0.1 mg/L NAA and 1.0 mg/L 2ip, 50 mg/L kanamycin, and 500 mg/L carbenicillin. After 4 weeks of subculture, kanamycin-resistant shoots were obtained on selection medium. Leaves of putative transformants survived on selection medium containing 100 mg/L kanamycin. Incoporation of the GR gene into lettuce was confirmed by PCR analysis of genomic DNA. Southern blot analysis showed that ECL-labeled GR gene was hybridized to the expected amplified genomic DNA fragment of about 1.8 kb from transgenic lettuce. The presence of mRNA in transgenic lettuce was confirmed by RT-PCR with total RNA of transgenic lettuce. In progeny test of transformants, R$_1$ seeds were resistant to kanamycin (200mg/L) on MS medium.

• Proceedings of the Korean Society of Potoscience Conference
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• 2002.06a
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• pp.56-56
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• 2002

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.126-131
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• 2005

Richadella dulcifica, a native shrub in tropical West Africa, gives red berries that have the unusual property of modifying a sour taste into a sweet taste. The red berries contain a taste-modifying protein named miraculin. A synthetic gene encoding miraculin was placed under the control of constitutive promoters and transferred to lettuce. High expression of miraculin was obtained, with accumulation of up to 1% total soluble protein in lettuce leaf. In addition, the miraculin expressed in lettuce possesses a taste-modifying activity.

• Korean Journal of Plant Tissue Culture
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• v.27 no.6
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• pp.435-439
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• 2000

Explants of lettuce (Lactuca sativa L.) were cocultured with A. tumefaciens LBA 4404 harboring ${\gamma}$-tocopherol methyltransferase (${\gamma}$-TMT) gene from Arabidopsis thaliana. These explants were transferred to MS medium supplemented with 50 mg/L kanamycin, 500 mg/L carbenicillin, 0.1 mg/L NAA and 0.5 mg/L BA. After 4 weeks, kanamycin resistant shoots were obtained from the explants on the selection medium. The putative transgenic shoots were transferred to rooting MS medium supplemented with 50 mg/L kanamycin and 250 mg/L carbenicillin. Stable incorporation of the Arabidopsis ${\gamma}$-TMT cDNA into lettuce genomic DNA was confirmed by PCR and Southern analysis. HPLC analysis showed that $\alpha$- to ${\gamma}$-tocopherol ratio increased over four fold in a transgenic lettuce line indicating successful expression of the transgenic Arabidopsis ${\gamma}$-TMT in lettuce.

• Journal of Plant Biotechnology
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• v.30 no.1
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• pp.97-102
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• 2003

Lettuce (Lactuca sativa) was transformed with Agrobacterium tumefacience LBA4404 containing human granulocyte macrophage colony stimulating factor (hGM-CSF) gene to produce in cell suspension cultures. Cell suspension culture was established using callus from transgenic lettuce plant. Integration of hGM-CSF gene into plant chromosome was confirmed through genomic PCR and Southern blot analysis. In addition, Northern blot analysis indicated the expression of the introduced hGM-CSF gene in transformed lettuce. The recombinant hGM-CSF was expressed in transgenic cell cultures derived from transgenic plants as a yield of about 149.0 $\mu\textrm{g}$/L in culture filtrate, which was determined by ELISA. These results demonstrated that transformed lettuce cell suspension cultures could be used as a production system of therapeutic proteins such as hGM-CSF.

• Molecules and Cells
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• v.19 no.1
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• pp.16-22
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• 2005

A cDNA encoding ${\gamma}-tocopherol$ methyltransferase (${\gamma}-TMT$) from Arabidopsis thaliana was overexpressed in lettuce (Latuca sativa L.) to improve the tocopherol composition. Seven lines of lettuce ($T_0$) containing the ${\gamma}-TMT$ transgene were produced by Agrobacterium-mediated transformation. The inheritance and expression of the transgene were confirmed by DNA and RNA gel blot analyses as well as quantification of tocopherols and ${\gamma}-TMT$ activities. The ratio of ${\alpha}-/{\gamma}-tocopherol$ content (TR) varied from 0.6 to 1.2 in non-transformed plants, while the $T_0$ plants had ratios of 0.8 to 320. The ratio ranged from 0.4 to 544 in 41 $T_1$ progenies of the $T_0$ transgenic line gTM3, and the phenotypic segregation indicated monogenic inheritance of the transgene (i.e., 3:1 = dominant:wild-type classes). There was a tight relationship between the TR phenotype and ${\gamma}-TMT$ activity, and enzyme activities were affected by the copy number and transcript levels of the transgene. The TR phenotype was stably expressed in $T_2$ progenies of $T_1$ plants. The results from this study indicated that a stable inheritance and expression of Arabidopsis ${\gamma}-TMT$ transgene in lettuce results in a higher enzyme activity and the conversion of the ${\gamma}-tocopherol$ pool to ${\alpha}-tocopherol$ in transgenic lettuce.

• Journal of Plant Biotechnology
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• v.33 no.1
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• pp.27-32
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• 2006

To clarify the roles of bromelain in plants, we isolated BL1 gene encoding bromelain from pineapple stem tissues and sequenced. The full length cDNA is 933 bp and encodes a polypeptide of 311 amino acid residues. The cDNA is most similar 94% at the amino acid level to bromelain previously isolated from pineapple (BAA21929). Explants of Lactuca sativa were co-cultivated with Agrobacterium tume-faciences LBA 4404 strains containing nptII and BL1 gene for transformation. Through initial selection of regenerated explants by culturing on a kanamycin and carbenicillin containing MS medium, multiple shoots were obtained after 2 months of culture. For a complementary step of selection, putative transgenic shoots were transferred to 1/2 Ms basal medium supplemented with 100 mg/L kanamycin and 500 mg/L carbenicillin. The selected shoots were obtained T1 generation seeds with emasculation, and tested with PCR analysis using 35S promoter and BL1 specific primers whether BL1 gene was introduced to genome of the plants. These results confirmed that produced the specific PCR bands in the putative transgenic lines. Additionally the Northern blot and endo protease activity showed that transcripts of BL1 gene were detected in transgenic lines. Theses results suggest that BL1 gene be successfully integrated and transcripted in the transgenic lettuce plants.