TOMATO CELL-DEATH MEDIATED BY COMPLEMENTARY PLANT VIRAL SATELLITE RNASEQUENCES

Cell death (necrosis) and severe yellowing (chlorosis) in tomato are i nduced by cucumber mosaic virus (CMV) supporting particular satellite RNAs. To determine whether CMV RNA sequences also are needed to induce necrosis or chlorosis, tomato seedlings were infected with the potato virus X vector expressing either a necrogenic or chlorosis-inducing s atellite RNA of CMV, The infected plants did not develop chlorosis, al though they did develop necrosis, but only when all or part of a 335-n ucleotide necrogenic satellite RNA was expressed in the (-) polarity; i.e,, the strand not packaged in virus particles. Computer-assisted se condary structure analysis suggests that the necrogenicity domain is a n octanucleotide loop and adjacent base-paired stem of a thermodynamic ally stable hairpin structure.