Arabidopsis thaliana endo-1,4-$-ß-glucanase (cell) Promoter Mediates uidA Expression in Elongating Tissues of Aspen (Populus tremula)

Transgenic aspen plants were transformed with a bacterial ß-glucuronidase gene (uidA) under the control of the Arabidopsis thaliana elongation-specific endo-1,4-ß-glucanase (cel 1) promoter. Transformed plants exhibited a high level of ß-glucuronidase (GUS) activity in young, fast-growing tissues. Unlike the cauliflower mosaique virus 35S promoter, the expression pattern of uidA in the shoots and leaves was clear-cut and highly controlled by cel 1 promoter. GUS-staining in the leaves mirrored the pattern of expanding cells in the organ. These results further substantiate the link between cel 1 expression and plant cell elongation. Moreover, our results suggest that the cel 1 promoter may be useful in the genetic engineering of forest trees and possibly other plants when gene expression is desired only in fast growing tissues.