Abstract
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.
겨울 상추 품종인 청치마 상추의 자엽조직을 ${\gamma}$-TMT유전자가 도입된 A. tumefaciens LBA 4404와 공동배양한 후, 50 mg/L kanamycin, 500 mg/L carbenicillin, 0.1 mg/L NAA, 0.5mg/L BA가 첨가된 MS재분화 배지에 옮겨 약4주 배양하여 재분화된 신초를 얻었다. 재분화된 신초를 50 mg/L kanamycin, 250mg/L carbenicillin이 포함된 MS 기본 배지에 옮겨 발근된 소식물체를 얻었다. 선발된 형질전환 식물체의 genomic DNA에 대한 PCR분석과 Southern분석을 수행하여 애기장대 ${\gamma}$-TMT유전자 특이적 DNA단편이 상추의 genomic DNA내에 삽입되었음을 확인하였다. 선발된 상추 형질전환체 잎의 $\alpha$-tocopherol/${\gamma}$-tocopherol 함량 비율이 대조 식물체에 비하여 약 4배 증가하여 도입된 ${\gamma}$-TMT유전자가 안정적으로 발현함을 나타내었다.
