BIOLOGICAL PROPERTIES OF PSEUDORECOMBINANT AND RECOMBINANT STRAINS CREATED WITH CUCUMBER MOSAIC-VIRUS AND TOMATO ASPERMY VIRUS

Cucumber mosaic virus (CMV) and tomato aspermy virus (TAV) are closely related cucumoviruses, We have made pseudorecombinant viruses in whic h the RNAs 3 of these two viruses have been exchanged and recombinant viruses containing chimeric RNA 3 molecules, in which the coat protein s and the 3'-end regions of CMV and TAV have been exchanged, giving ri se to recombinants designated RT3 and TR3, The replication properties and the cell-to-cell and long-distance movement patterns of these pseu dorecombinant and recombinant viruses were examined in different hosts , All the viruses were able to replicate and accumulate RNA 4 in proto plasts, The pseudorecombinants and the R1R2RT3 recombinant infected to bacco systemically, but the R1R2TR3 recombinant was not detectable, ev en in the inoculated leaves, Comparison of the abilities of the viruse s to replicate in protoplasts and intact cucumber plants suggests that cell-to cell movement factors are also encoded by RNAs 1 and/or 2, Ma jor determinants of symptom severity in Nicotiana glutinosa are locali zed on the 3' part of RNA 3, and in Nicotiana benthamiana, more severe symptoms were observed with the T1T2R3 strain than,vith the others te sted.