Abstract: This invention provides: (A) a protein the sequence of which is in FIG. 8 (SEQ. ID n° 14), or a fragment thereof having at least 15 amino acids, or a variant thereof, having at least 70% identity with FIG. 8 (SEQ. ID n° 14) over a length of at least 400 amino acids; (B) a peptide comprising a fragment of salutaridinol 7-O-acetyltransferase of at least 6 consecutive amino acids not present in other plant acetyltransferases as in FIG. 2 (SEQ. IDs n° 8 to 12); (C) a nucleic acid (i) the sequence of which is in FIG. 9 (SEQ. ID n° 13) or FIG. 10 (SEQ. ID n° 15), or (ii) a fragment thereof of at least 45 nucleotides, or (iii) a variant thereof, having at least 70% identity with FIG. 9 (SEQ. ID n° 13) or FIG. 10 (SEQ.

Abstract: A method of activating the rice tungro bacilliform virus (RTBV) promoter in vivo is disclosed. The RTBV promoter is activated by exposure to at least one protein selected from the group consisting of Rf2a and Rf2b.