A nucleic acid molecule for expressing a foreign gene in a plant, said nucleic acid molecule carrying, in this order, a right border (RB) sequence derived from the T-DNA sequence of an agrobacterium, an expression promoter sequence capable of functioning in the aforesaid plant, a sequence corresponding to the RNA2 genome of cucumber mosaic virus wherein a 2b protein-encoding gene has been partly or entirely substituted by the aforesaid foreign gene, and a left border (LB) sequence derived from the T-DNA sequence of an agrobacterium.
