Plaque phenotypes of all the selected PanAsia-1 strains and rescued FMDVs on BHK-21 cells and two CHO cell lines. Subconfluent monolayers of cultured cells infected with the specific viruses were stained with 0.2% crystal violet at 48 h post-infection (BHK-21 cells) and 72 h post-infection (WT-CHO and pgsD-677 cells). Virus titres (PFU/mL) are listed at the bottom of each image. The infection of rHN/FJ9-VP0L2080Q collected from the supernatant of pOFS/FJ9-VP0L2080Q (see Figure 2) co-transfected with pCT7RNAP after 48 h was not detected in BHK-21 cells as determined by the plaque forming assay. Only two cell-adapted PanAsia-1 viruses (O/Tibet/CHA/6/99tc and O/Fujian/CHA/9/99tc) and two chimeric viruses (rHN/TAR6-VP0 and rHN/FJ9-VP1) formed plaques on WT-CHO cells.