Until now many strategies have been used to produce marker-free transgenic plants such as co-transformation with negative selectable markers, site-specific recombination system, transposable elements mediated transformation, and etc. In this research, embryogenic calli induced from japonica rices, Ilmibyeo and Dongjinbyeo, were tranformed with the vector which simultaneously constructed with cre/loxP and argE genes in T-DNA. Transformation efficiencies were comparably lower than those of our previous studies, since the constructed genome size was relatively big (>10Kb). For eliminate the transformed tissues which contained positive selectable marker gene, tunicamycin was treated at regeneration and selection stages, since cre recombinase gene is expressed under the presence of this antibiotics. The plants were selected first under 50 mg․L-1 hygromycin at 28℃ for 2 weeks after the Agrobacterium-infection at 25℃ for 7 days. And then, the regeneration plants were successfully obtained on MS basal regeneration medium containing 0.1 mg․L-1 tunicamycin. The regenerated plants are now acclimatizing in greenhouse and molecular analysis are currently accomplished with these plants.

We carried out to study the function of ArgE in transgenic rice plants, which were confirmed by PCR analysis and hygromycin selection. Transgenic rice plants were with selectable marker gene(HPT) inserted in genome of the rice. Southern analysis with hpt probe confirmed by two restriction enzymes that copy numbers of the selectable gene was introduced into the plant genome. We displayed that the relationship between drought stress and ArgE gene with the overexpressing rice plants. From this result, we observed that the degree of leaves damage has no difference in control and transgenic lines. The total RNAs were extracted from 6 weeks-seedling in normal condition in order to examine their expression levels with ArgE-overexpressed transgenic rice. In particular, expression patterns of genes encoding enzymes involved in abiotic stress, including drought and salt stresses. OsGF14a and OsSalt were investigated by reverse transcription-PCR(RT-PCR). Expression levels of the OsSalt gene decreased significantly in transgenic rice plants compared to control plant. However, ion leakage measurement did not demonstrate any leaves damage change between control and ArgE transgenic plants exposure to mannitol treatment. These results suggest that expression of the ArgE is not involved in tolerance for drought stress in rice but may playa role of signaling networks for salt-induced genes.

Agrobacterium tumefaciens에 의해 일미벼 품종에 도입하여 많은 형질전환벼를 생산했다. 배발생 캘러스는 hygromycin 저항성 선발마커를 포함한 pCAMBIA1300 벡터를 이용하여 Agrobacterium strain AGL1으로 공동배양하였다. 공동배양 후 50mg/L hygromycin에 저항성을 보이는 형질전환체가 선발되었다. T0 세대 형질전환벼로부터 genomic DNA를 추출하여 PCR과 Southern blot을 통한 외래 유전자의 안정한 삽입을 검정하였다. 형질전환된 벼라인에서 650bp의 HPT 유전자 단편이 나타났다. 그리고 argE의 특이적 priomer를 이용하여 검정한 결과 230bp 단편이 검출되었다. SEM을 이용하여 형태학적 분석을 한 결과 기공 분포와 배열상의 특징에 있어서 형질전환체는 대조구와 비교하여 기공형태가 불규칙적인 차이를 보여 주었다.