Construction of recombinants carrying heterologous HC-Pro or/and CP from the resistance-breaking strain 5-19 using the in vitro infectious cDNA from the non-breaking strain YK as a backbone. Genomic regions of HC-Pro and CP (in yellow) amplified from 5-19 were used to replace one or both of the corresponding regions in YK to generate the recombinant viruses YK/519HC, YK/519CP3U and YK/519HCCP3U.
(B) Resistance evaluation of the PRSV single-virus-resistant transgenic line 18-2-4 (carrying a YK CP-3'UTR transgene as indicated in the upper panel) against YK, 5-19 and the recombinants. Non-transgenic (NT) plants of papaya cultivar Tainung No. 2 were used as a control. Symptoms were recorded 30 days post mechanical inoculation (dpi).
(C) Resistance evaluation of the PRSV-PLDMV double-resistant-transgenic line 14-1 (carrying a chimeric construct comprised of parts of PLDMV CP and PRSV CP-3'UTR, as indicated above the panel) against YK, 5-19 and the recombinants. Symptoms were recorded 30 dpi.