2004 Volume 21 Issue 4 Pages 251-259
A highly regenerating cotton (Gossypium hirsutum L.) cultivar, Coker 310FR, was used to generate transgenic plants expressing the herbicide resistance gene, bar, encoding phosphinothricin acetyltransferase (PAT), under the transcriptional control of the ribulose-1, 5-bisphosphate carboxylase (Rubisco) small subunit (rbcS) atslA gene promoter from Arabidopsis thaliana. Expression levels of the rbcS ats1A-bar transgenes were compared to bar transgenes under the control of the high level constitutive promoter from the Cauliflower Mosaic Virus 35S gene containing a dual enhancer region (2xE CaMV 35S). Significantly higher levels of bar mRNA, PAT protein and enzymatic activity, and enhanced levels of resistance to the herbicide Basta were observed in transgenic plants expressing bar under the rbcS ats1A promoter compared to the 2xE CaMV 35S promoter. Transgenic plants containing 2xE CaMV 35S-bar transgenes tolerated the maximum herbicide (Basta) application up to 200 mg l-1 PPT whereas rbcS ats1A-bar transgenic plants were capable of detoxifying Basta up to 400 mg l-1 PPT. These findings indicate that the rbcS ats1A promoter may be useful for higher expression of transgenes in developing tissues of cotton for improving it further through genetic engineering.
