Application Study On Post-transcriptional Gene Silencing In Tobacco Resistance To PVY And CMV

Tobacco virus disease is the main disease of tobacco. PVY and CMV spread widely on tobacco in our country, and their co-infection is very frequent. Controlling the virus, resistance breeding is the most effective and economic measure. Conventional breeding has some defects such as the conjunction between resistance and harmful agricultural characters. Transgene engineering is a feasible route to make up the conventional breeding's defects. Gene silence was observed at the end of last century. Now the mechanism of gene silence is more particular than before; there have many studies on the application in plant anti-virus. According to those data, it can gain high level or immune resistance by gene silencing. So gene silencing has more foregrounds in anti-virus breeding.Generation of binary virus resistance transgenic tobacco is studied using post-transcriptional gene silence. It is the first study on binary virus resistance which targeted the conserved sequences of the silence suppressor PVY HC-Pro and CMV 2b at home. We cloned the sequence fragment of PVY HC-Pro and CMV 2b by RT-PCR. The virus strains we used are the prevalent strains in our country. We connected these fragments and gained the inverted repeat sequence via anti-sense orientation interim vector and sense and anti-sense orientation interim vector. We inserted the inverted repeat sequence into binary plant expression vector pCAMBIA1300-221 instead of the GUS gene. We transformed the Agrobacterium tumefaciens EHA105 strain, and then transformed the tobacco. We had 27 regenerated seedlings. We gained 11 positive transgenic plants by PCR. Inoculating viruses, we had 3 binary virus resistance plants. Our technical routes and methods are very helpful for the application of post-transcriptional gene silence in the binary resistance, and exploit the new route for control tobaccovirus diseases.