형질전환 토마토에서 Antisense Polygalacturonase 유전자의 발현

Expression of Antisense Polygalacturonase Gene in Transgenic Tomato

국내 재배종 토마토 서광 품종으로부터 분리한 Polygalacturonase 유전자(PG2)의 3'측 1.1 kb cDNA 단편을 식물 형질전환용 운반체에 antisense 방향으로 삽입한 후 자엽을 이용하여 토마토내 도입하여 형질전환 토마토를 획득하였다. 형질전환 토마토(T$^{0}$ )를 도입시켜 그 종자를 1 mg/mL 농도의 kanamycin 함유 MS 배지에서 발아시켜 분리 집단 중에서 T$_1$9 식물체를 얻었다. T$_1$9의 Genomic Southern blot 분석 결과, antisense PG 유전자 1개가 염색체 내로 삽입되었음을 확인하였고 RNA gel blot 분석으로 endogenous PG mRNA보다 antisense PG RNA가 강하게 발현됨을 확인하였다. T$_1$9 계통 10개체의 성숙 토마토 과피조직내의 PG 효소 활성도 4~60%까지 저해되었다.

A truncated Polygalacturonase (PG) cDNA was fused in reverse orientation to the CaMV 35S promoter of the binary vector pCA643, and introduced into tomato cells by Agrobaderium - mediated transformation. Transformed cells were selected using kanamycin as select agent then regenerated into plants. After selfed, one transgenic line (T9), was germinated and grown on MS medium containing 1 mg/mL of kanamycin Genomic Southern analysis of a T9 progeny with labelled PG2 cDNA probe showed a single antisense PC fragment as well as the endogenous PG2 gene, suggesting that PC antisense gene was integrated into tomato genome. Northern blot analysis demonstrated that the antisense RNA was produced from the transgene at much tiger level than the endogenous PG2 gene. Polygalacturonase activity analysis of the fruit from transgenic plants demonstrated that the antisense transgene expression caused 4 to 60% reduction of endogenous PG activity.