A stable, efficient, and reliable selection system using bar and hpt as selectable markers for Agrobacterium mediatedco-transformation of rice with two separate vectors was developed. Two plasmids, pMJC-GB-IFS2 and pMJC-GH-CHR carryingbar or hpt gene as s

The coat protein (CP) gene of the G5H and G7H strains of Soybean mosaic virus (SMV) were cloned, sequenced and transformed into the tobacco plant (Nicotiana tabacum. cv. Havana SR1) via Agrobacterium-mediated transformation. Transformation was confirmed b

A reproducible transformation system via optimized regeneration media for Korean rice cultivars was established using Agrobacterium tumefeciens LBA4404 (pSBM-PPGN; gusA and bar). Although japonica rice genotypes were easier to produce transgenic plants compared to Tongil type cultivars, transformation efficiencies were not always correlated with regeneration efficiencies of non-transgenic callus on the control medium. Regeneration efficiencies of Donganbyeo, Ilmibyeo, and Manchubyeo were over 50% in non-transgenic control, however, transformation efficiencies were significantly low when only sucrose was added to the media as a carbon source. However, the medium, MSRK5SS-Pr (or MSRK5SM-Pr), that contains 5~textrmmgL-1 kinetin, 0.5~textrmmgL-1 NAA, 2 % sucrose (or maltose), 3% sorbitol, and 500~textrmmgL-1 proline, was the most efficient not only for regeneration of non-transgenic callus but also for regeneration of transgenic callus in the presence of L-phosphinotricin (PPT). Average transformation efficiencies of 16 Korean rice cultivars were significantly enhanced by using the optimized medium from 1.5% to 5.8% in independent callus lines and from 2.9% to 19.4% in tromsgenic plants obained. Approximately 98.9% (876 out of 885) transgenic plants obtained on optimized media showed basta resistance. Stable integration, inheritance and expression of gusA and bar genes were continued by GUS assay and PCR and Southern analysis of the bar gene. With Pst1 digestion of genomic DNA of transgenic plants, one to five copies of T-DNA segment were observed; however, 76% (19 out of 25 transgenic plants) has low copy number of T-DNA. The transformants obtained from one callus line showed the same copy numbers with the same fractionized band patterns.

The optimized in vitro culture system was investigated for improvement of regeneration efficiencies by observing the responses of scutella-derived callus of Korean rice (Oryza sativa L.). Large variations of callus induction (43.9-93.9%) and shoot regeneration (0-88.7%) were observed among the rice cultivars depending on medium. However, shoot regeneration was significantly improved by selected utilization of basal medium, growth regulators, and carbon sources. N6 basal medium was more efficient for embryogenic callus induction than MS or LS basal medium, while MS was superior to N6 for shoot regeneration. The calli of highly regenerative cultivars grew faster and showed higher rates of green tissue formation (GT) and shoot regeneration (SR) and lower rate of callus browning (CB) than those of recalcitrant cultivars. Although a higher level of kinetin stimulated the GT and SR in highly regenerative cultivars, 10~textrmmgL-1 kinetin generally suppressed the GT and SR, while CB was accelerated compared to 2~textrmmgL-1 kinetin. Additional benefits of sorbitol combined with maltose (or sucrose) under 5~textrmmgL-1 kinetin were certainly confirmed on regeneration efficiencies compared to sucrose alone as carbon source and osmotic regulator. This combination showed high rate of GT and SR with multiple shoots while low rate of CB. With MSRK5SM-Pr medium (5~textrmmgL-1 kinetin, 3% sorbitol, 2% maltose, 500~textrmmgL-1 proline), the regeneration efficiencies of total 17 out of 24 cultivars were practically improved 160% on average compared to MSRK2S (2~textrmmgL-1 kinetin, 3% sucrose) control medium. Especially, the medium was most effective to the cultivars showing a medium level of regenerability such as Daesanbyeo and Dongjinbyeo and Suwon477, enhancing efficiencies more than 300-600% compared to MSRK2S medium.

This study was conducted to determine the efficient regeneration condition for perilla (Perilla frutescens cv. Yeupcildllggae). Leaf, cotyledon and hypocotyl explants were excised from perilla plants 10-12 days after germination and subjected to regenerat

Regeneration ability of plant is very important for producing transgenic plants by genetic engineering. Fifty rice cultivars and lines were screened for their regeneration ability in vitro and an attempt was made to increase shoot regeneration by substitu