I think TA cloning would only work if you either restriction digested the RCA product with an enzyme that produced an A overhang, or a blunt enzyme then added an A overhang with a non-proof reading polymerase.

Since you digested with only a single enzyme, did you dephosphorylate pUC19 after digesting it so it has less of a chance of self ligating? If not the majority of your clones will be re-ligated vector, since that's the most simple ligation reaction that can happen.

Thank you ma'am for the answer.

And yes I used CIAP for the dephosphorylation but didn't get result. In the first two attempts, I didn't get any anything in the colony pcr but in third attempt I got the amplification of 700 bp in colony pcr while my clone is of 2.7 kb.

Is there a specific reason you need to amplify the product with RCA rather than PCR?

Check the given links you may get some information.

Best Wishes.

Direct sequencing of bacterial colonies using rolling circle amplification (RCA)

(https://eurofinsgenomics.com/en/products/dna-sequencing/direct-colony-sequencing/#:~:text=Rolling%20circle%20amplification%20(RCA)%20is,double%2Dstranded%20circular%20DNA%20templates.)

Research Progress on Rolling Circle Amplification

(RCA)-Based Biomedical Sensing

(https://pmc.ncbi.nlm.nih.gov/articles/PMC6027247/pdf/pharmaceuticals-11-00035.pdf)

Alexandra Johnson yes, It should be a 2.7 kb begomovirus genome, which I have to confirm by the sequencing. The sequence is not known, so I can't amplify with PCR.