SYNTHESIS OF A FULL-LENGTH INFECTIOUS CDNA CLONE OF CUCURBIT APHID-BORNE YELLOWS VIRUS AND ITS USE IN GENE EXCHANGE EXPERIMENTS WITH STRUCTURAL PROTEINS FROM OTHER LUTEOVIRUSES

A full-length cDNA of cucurbit aphid-borne yellows virus (CABYV) has b een constructed and expressed either as an in vitro transcript, under control of a bacteriophage T7 RNA polymerase promoter, or in vivo, und er control of the cauliflower mosaic virus 35S promoter in an agroinfe ction vector. The biological activity of the cloned cDNA was demonstra ted by the ability of its in vitro transcript to replicate in protopla sts and of the agroinfection vector to infect agroinoculated plants. V irus in the agroinfected plants could be transmitted by the aphid vect ors Myzus persicae and Aphis gossypii. The specificity of luteovirus R NA packaging was investigated by replacing (1) the CABYV coat protein gene (and the overlapping ORF5) by the corresponding region of potato leafroll luteovirus or (2) the CABYV readthrough domain by the readthr ough domain of beet western yellows luteovirus. The resulting chimeric transcripts replicated in protoplasts and produced virions. (C) 1995 Academic Press, Inc.