오이모자이크바이러스 2b 유전자 발현 담배의 형태 및 전사체 분석 = Phenotypic and Transcriptomic Analysis of Nicotiana benthamiana Expressing Cucumber mosaic virus 2b gene

국문 초록 (Abstract)

오이모자이크바이러스 2b 유전자는 전사후유전자침묵(PTGS)을 억제하는 기능을 가진 억제인자이다. 식물체내 2b 유전자 기능을 분석하기 위해 Nicotiana benthamiana에 형질전환하였고 형태변화와 유전자 발현변화를 분석하였다. 8계통의2b 유전자 형질전환체 중에서 1개의 유전자가 T0 개체에 삽입된 계통은 3개였다. 2b 유전자 형질전환체는 일반적으로 종자확보가 어려웠지만 다행히 일부 배수화되지 않은 계통(hemizygote) 에서는 소량의 종자가 확보되어 계통유지가 가능하였다.
고정계통의 전사체를 해독하여 대조와 비교분석한 바, 2b 유전자는 특정유전자의 발현을 선택적으로 증대시키는 것이 아닌다수의 유전자를 비선택적으로 발현을 증대시키는 것으로 판단되었다. 이러한 결과는 2b 유전자가 세포질에 존재하는 다양한 RNA의 대사중 분해를 억제하여 세포질내 RNA가 축적되고이로 인해 단백질 합성도 증대되어 정상적 생장발달이 저해되고 기형적인 형태의 식물체가 되는 요인으로 판단된다.

다국어 초록 (Multilingual Abstract)

Cucumber mosaic virus possesses 2b gene known as a suppressor of post-transcriptional gene silencing (PTGS). To investigate its function and effect in plant, transgenic Nicotiana benethamiana expressing 2b gene was developed and analyzed in phenotypic characteristics and differential gene expression (DEG) comparing with wild-type. Eight lines of transgenic plants (T0) were obtained with difficulty and showed severe deformed phenotypes in leaves, flowers, petioles and etc. Moreover, transgenic plants were hardly able to set seeds, but small amounts of seeds were barely produced in some of transgene-hemizygous plants. DEG analysis showed that transgenic plant ectopically accumulated diverse RNA transcripts at higher levels than wild-type probably due to the disturbance in RNA metabolism, especially of RNA decay, caused by 2b-mediated inhibition of PTGS. These ectopic accumulations of RNAs disrupt protein and RNA homeostasis and then subsequently lead to abnormal phenotypes of transgenic plants.

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