Submitted to: HortScience
Publication Type: Abstract Only
Publication Acceptance Date: May 20, 2003
Publication Date: October 3, 2003
Citation: Bassett, C.L., Callahan, A.M., Scorza, R., Srinivasan, C. 2003. Tissue specific experssion of gus in tomato under the control of a type ii chlorophyll a/b binding protein promoter from peach. Hortscience 38 2003. Technical Abstract: We have isolated a small (550 bp) DNA fragment upstream of a peach chlorophyll a/b-binding (cab) protein gene. The fragment contains promoter elements, such as a consensus TATA box with two CAAT box elements approximately 60 bases upstream. A third CAAT box lies 10 bp 5' of a Gbox [ACGT core] region with considerable similarity to light responsive elements (LREs). This promoter was placed immediately upstream of a beta-glucuronidase (GUS) gene containing an intron, and the fragment generated was placed in opposite orientations relative to the left and right border regions of the vector pBINPLUSARS. These constructs were transformed into tomato plants via Agrobacterium. A control plasmid was constructed with the cab promoter replaced by the CAMV 35S promoter. Transformants were selected on kanamycin and tested for the presence of the GUS gene and the cab promoter by PCR analysis. When the transformed plants were mature, samples of leaves, flower parts, roots and fruit (green and ripe) were assayed for GUS expression. Analysis of the cab promoter/GUS constructs indicated a high level of GUS expression in leaves of greenhouse-grown plants sampled during the day. Expression of GUS driven by the 35S promoter was slightly higher in leaves sampled at the same time. In contrast, little expression of GUS under control of the cab promoter was observed in either roots or flower parts, including pistils. Significantly higher expression levels were seen with the 35S/GUS construct in these tissues. All constructs conferred relatively high levels of GUS expression in young, green tomato fruit, but the levels in mature, ripe fruit were on average about 3-fold lower in transgenic tomatoes carrying the cab/GUS constructs, than those harboring the 35S/GUS plasmid.