Transient expression of anthocyanin in developing wheat coleoptile by maize C1 and B-peru regulatory genes for anthocyanin synthesis

Maize transcription factors for the genes of anthocyanin synthesis pathway, C1/B-peru, were delivered into developing wheat coleoptiles by a particle bombardment method. Anthocyanin pigments were induced as discrete red spots and their number reached about 60 spots per coleoptile, compared to about 20 diffused blue GUS spots, which were induced by the GusA gene transferred concomitantly. Coleoptiles of seedlings collected 36h after germination were most suitable tissue for the expression of delivered foreign genes. One to five μg of plasmid DNA for coating gold particles was sufficient for induction of anthocyanin and GUS, indicating that the transferred gene was expressed efficiently in coleoptile cells. Helium gas pressure (900, 1100, 1300 or 1500 pounds per square inch) and distances (10, 15, or 20 cm) between the stopping screen and coleoptile did not affect significantly the efficiency of gene transfer. Seedlings arranged in a circle with a 1-cm radius on a MS medium plate were targeted well by gold particles. The results showed that the wheat coleoptile was a good target tissue for transient assay of wheat genes and that C1/B-peru can be used as a reporter gene.