Genetics manipulations with recombinant DNA virus comprising sequences derived from RNA virus

A method of inducible production in tobacco or cowpea plants or plant cells of a non-viral sequence of interest selected from the group consisting of proteins, polypeptides and RNAs, comprising

• a) obtaining a nucleotide sequence derived from a RNA-based tobacco or cowpea plant virus which for its replication is dependent upon a viral RNA/RNA polymerase, said nucleotide sequence representing a stripped viral replicon comprising cis elements for replication but being devoid of genes coding for viral RNA/RNA polymerase and viral coat protein, said stripped viral replicon not being able to replicate independently but in the presence of the viral RNA/RNA polymerase replicating more efficiently than the RNA of the wild-type plant virus,
• b) preparing a recombinant DNA comprising an expression cassette functional in tobacco or cowpea plants or plant cells, said expression cassette comprising DNA corresponding to said RNA virus-derived nucleotide sequence and a nucleotide sequence encoding the non-viral sequence of interest to be produced, said DNA corresponding to said RNA-virus derived nucleotide sequence and said nucleotide sequence encoding the non-viral sequence of interest being situated between two inverted repeat nucleotide sequences of 12-250 bp, 250 bp,
• c) performing a genetic manipulation of the tobacco or cowpea plants or plant cells to incorporate said recombinant DNA into the genome of said tobacco or cowpea plants or plant cells, and
• d) growing said tobacco or cowpea plants or plant cells and causing the presence of a viral RNA/RNA polymerase to induce or amplify the expression of the non-viral sequence of interest.