Use of a defective RNA of broad bean mottle bromovirus for stable gene expression in legumes.

A viral vector that expressed foreign genes was engineered using a cDNA clone of broad bean mottle bromovirus (BBMV) defective interfering (DI) RNA. The expression vector required an active ORF to ensure efficient accumulation and replication in the host plants. After mechanical inoculation with BBMV RNAs, expression of the green fluorescent protein (GFP) reporter was driven by DI RNA constructs during consecutive passages through broad bean plants. Our data prove that BBMV DI RNAs, whose yield is similar to the virus genomic components, are useful as gene vectors after mechanical inoculation on legume plants.