|JOUNG, YOUNG HEE|
Submitted to: BMC Plant Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/21/2012
Publication Date: 9/12/2012
Citation: Kamo, K.K., Joung, Y. 2012. The 5'UTR-intron of the Gladiolus polyubiquitin promoter GUBQ1 enhances translation efficiency in Gladiolus and Arabidopsis. Biomed Central (BMC) Plant Biology. 12:79-88.
Interpretive Summary: Genetic engineering of Gladiolus for disease resistance requires the use of a strong promoter that will direct high levels of expression of the disease resistance gene. Many of the currently available promoters have been tested in Gladiolus, and only one promoter, the patented CaMV 35S promoter, has been found to be effective. We have isolated a polyubiquitin promoter from Gladiolus, and characterized it in this manuscript. The uidA gene that codes for GUS expression was subcloned under control of the full-length polyubiquitin promoter, and high levels of GUS expression were expressed in the leaves, callus, and roots of Gladiolus plants comparable to that of the CaMV 35S promoter. A deletion analysis of this promoter showed that its intron is necessary for the high levels of gene expression.
Technical Abstract: A GUBQ1 polyubiquitin promoter isolated from Gladiolus was used for transformation of Gladiolus plants. The levels of GUS expression were determined by measuring specific activity of ß–glucuronidase, and it was found that GUS expression with the GUBQ1 promoter in callus, roots, and young leaves was comparable to that of the CaMV 35S promoter in the same organs and callus. A significant decrease in GUS expression to background levels occurred in roots and young leaves when the GUBQ1 promoter’s entire intron and 5’UTR were deleted. Deletion of 70% of the 3’end of the intron resulted in a 50% decrease in expression in callus, roots, and young leaves. Southern hybridization confirmed the presence of the promoter in transgenic plants although three plant lines did not express GUS in callus, roots, and young leaves. This study demonstrates the potential application of the GUBQ1 promoter for attaining high levels of transgene expression in Gladiolus and shows the importance of the promoter’s intron to expression.