Improving transformation efficiency of plants - by introducing a construct contg. cDNA fragment encoding luteovirus envelope protein

The transformation efficiency of plants is increased by (i) combining a transcription-regulating signal (TRS) with a DNA fragment (I) of a Inteovirus which contains 3 open reading frames (ORF) and corresponds to the 3'-terminal region of the viral genome, (2) introducing the resulting construct into Agrobacterium lumefaciens (A.t.), then (3) transforming plants with the selected A.t. Also new are (i) constructs consisting of TRS and (I), (2) gene structures (GS) consisting of a 3'-terminal region of a luteovirus genome (having an ORF for a viral envelope protein, this ORF including a small sequence of a second ORF which includes the 3'-terminal region of the first ORF but sepd. from it by a VAG stop codon) coupled to regulation and expression elements functional in plants, and (3) plant cells contg. GS. Pref. the specification includes the sequence of a GS (and amino acid sequences encoded by the ORFs) including about 1.8 Peb. USE/ADVANTAGES - Insertion of (I) into the T-DNA of a Ti plasmid greatly increases transformation efficiency, e.g. by a factor of 10. The TRS-(I) construct becomes incorporated stably into the plant genome.