Arabidopsis thaliana endo-1,4-beta-glucanase (cel1) promoter mediates uidAexpression in elongating tissues of aspen (Populus tremula)

Transgenic aspen plants were transformed with a bacterial beta-glucuronidas e gene (uidA) under the control of the Arabidopsis thaliana elongation-spec ific endo-1,4-beta-glucanrise (cell) promoter. Transformed plants exhibited a high level of P-glucuronidase (GUS) activity in young, fast-growing tiss ues. Unlike the cauliflower mosaique virus 35S promoter, the expression pat tern of uidAA in the shoots and leaves was clear-cut and highly controlled by cell promoter. GUS-staining in the leaves mirrored the pattern of expand ing cells in the organ. These results further substantiate the link between cell expression and plant cell elongation. Moreover, our results suggest t hat the cell promoter may be useful in the genetic engineering of forest tr ees and possibly other plants when gene expression is desired only in fast growing tissues.