XVI International Botanical Congess

The radialis (rad) gene is one of several genes that control the shape of the flower in Antirrhinum majus. Strong rad mutant alleles give a phenotype similar to that of cycloidea (ref. - D. Luo et al, Nature, 1996, 383:794). A retrotransposon insertion was identified in a stable rad allele. Sequence flanking the retrotransposon was obtained and used to isolate the rad gene. The rad amino acid sequence shows homology to the DNA binding domain of MYB transcription factors. RNA in situ hybridisation revealed that the gene is expressed in the dorsal region of of wild type floral meristems. Preliminary experiments suggest that rad may be regulated by cycloidea.