Comparison of constitutive promoters for sorghum [Sorghum bicolor (L.) Moench] transformation

Sorghum [Sorghum bicolor (L.) Moench] transformation using microprojectile bombardment was achieved in 1993. Since then there have been very few additional reports on the topic. To develop a reliable method for foreign gene introduction, a promoter sequence capable of expression in the recipient cells is a critical requirement. Transient expression of the dual 35S cauliflower mosaic virus, rice actin-1, maize alcohol dehydrogenase-1, and maize ubiquitin-1 promoters driving the GUS (beta -glucuronidase) gene in sorghum were compared. Transient beta -glucuronidase activity in embryonic tissue was very low. It was concluded that there would be a significant benefit in investigating and isolating new constitutive promoter sequences potentially resulting in a higher level of transient expression in sorghum.