SITE-DIRECTED MUTAGENESIS AT THE COAT PROTEIN GENE OF CUCUMBER MOSAIC VIRUS INVOLVING VIRUS MOVEMENT IN SQUASH

Abstract

The cucumber mosaic virus is a multipartite virus consisting of three genomic and two subgenomic RNAs. All gene products were found to play a role in viral movement. The coat protein, encoded by RNA 4, was found to determine viral movement in many CMV strains. M-CMV is unable to move systemically in Curcubita pepo cv. Black Beauty. However, Fny-CMV can. Two amino acid positions (129 and 214) in the coat protein were shown to determine viral movement. Reciprocal mutants of both strains were constructed and confirmed by automated sequencing. Full-length in vitro infectious transcripts of all Fny and M-CMV original and mutant constructs were successfully constructed. The movement of these mutant virions in squash cotyledons were studied.