Hi,

Low copy number vector increases the stability of the plasmid in the bacteria only. The trait (low or high copy number) of the vector does not effect the efficiency of the recovery.  

I agree with Soroth Chey that the plasmid copy number is more relevant to stability within the bacteria where you are amplifying your plasmid. However, it's been documented in the literature that if you want to produce infectious virus from plasmid clones, it's better to use low-copy plasmids in order to reduce the amount of intrinsic mutations introduced by the bacterium into your viral gene/ genome cloned in the plasmid. The mutations may not directly affect your viral recovery / yield after you transfected your plasmid to your target host cell. However, the mutations introduced by the bacterium into your plasmid could have deleterious effects to your virus once it starts replicating in your host cell. In our lab, we always use low-copy plasmids for generating infectious clones of picornaviruses.

Thank you Soroth and Carla for your useful answers.

I will try subcloning into a low copy number transcription vector.

Regards

Bashir