Abstract
Coat-protein (CP) hybrids between Cucumber mosaic virus (CMV) and Tomato aspermy virus (TAV) were engineered to analyse reported CP-associated differences between these viruses. CP portions delimited by aa 159, 60148 and 149219 were exchanged in all possible combinations within TAV RNA3. The seven possible chimeras were able to replicate in tobacco protoplasts to similar levels, but only those having residues 159 or 60148 from CMV were infectious to tobacco plants, a common host for CMV and TAV, and formed stable particles. When most of the movement protein (MP) of TAV was substituted for that of CMV, infectivity of CP hybrids did not vary. No hybrid was able to infect cucumber plants, a host for CMV and not for TAV. Need for MPCP compatibility could explain these results, but shows that MPCP compatibility conditions the use of CP chimeras to map CP-associated differences between CMV and TAV.