The invention relates to transgenic expression cassettes for expressing two nucleic acid sequences in a plant cell comprising at least one regulatory sequence selected from the group consisting of a) the promoter shown in SEQ ID NO: 1 or 2, b) functional equivalents of the promoter shown in SEQ ID NO: 1 or 2 which have an identity of at least 80% to the sequence shown in SEQ ID NO: 1 or 2 and which have substantially the same promoter activity as the promoter shown in SEQ ID NO: 1 or 2, c) functional equivalents of the promoter shown in SEQ ID NO: 1 or 2 which comprise at least 25 consecutive nucleotides of the sequences shown in SEQ ID NO: 1 or 2 and which have substantially the same promoter activity as the promoter shown in SEQ ID NO: 1 or 2, and d) functionally equivalent fragments of sequences a) or b) or c), which have at least 25 consecutive nucleotides of said sequences a) or b) or c) and have substantially the same promoter activity as the promoter shown in SEQ ID NO: 1 or 2, where said regulatory element is disposed between two nucleic acid sequences and is heterogeneous in relation to said nucleic acid sequences and is functionally linked to said nucleic acid sequences in such a way that the expression of two different ribonucleic acid sequences is brought about in at least one plant cell, where said ribonucleic acid sequences are selected from ribonucleic acid sequences coding for i) amino acid sequences or ii) ribonucleic acid sequences which bring about a reduction in the expression of at least one endogenous gene of said plant cell.