The present invention discloses methods for interfering with expression of the
genes in plant cells by using replicating recombinant viral vectors. A host plant
is infected at one or more locations with a recombinant viral vector. The vector
is both an initiator and a target of the RNA-triggered gene silencing in plant
cells. The vector upon infection is capable of directing self-replication and producing
a transcription product of a nucleic acid segment. The transcription product interferes
with the expression of a specific gene in plant cells.