PRODUCTION OF TRANSGENIC WHEAT THROUGH PARTICLE BOMBARDMENT OF SCUTELLAR TISSUES - FREQUENCY IS INFLUENCED BY CULTURE DURATION

A transformation system for hexaploid wheat was developed by using scu tellar tissues of cultured immature embryos via particle bombardment. The scutellar tissues of immature embryos were cultured for 1 to 9 d p rior to bombardment with two plasmids, pBI221 or pAct1-F containing th e beta-glucuronidase (GUS) gene and pARK22 containing the bialaphos re sistant gene (bar). Transient expression of the reporter GUS gene was not influenced by culture duration prior to transformation. On the oth er hand, transgenic wheat plants of both spring and winter cultivars w ere obtained from immature embryos bombarded after culture for more th an 5 d, but not from those receiving less than 5 d. The integration an d inheritance of the bar gene as a selectable marker gene were confirm ed by the combination of PCR amplification and Southern analysis of T- 0 and T-1 plants. Some of the bialaphos resistant plants showed the ex pression of the GUS gene co-transformed with the bar gene.