Evaluation of tomato plants with constitutive, root-specific, and stress-induced ACC deaminase gene expression

Transgenic tomato (Lycopersicon esculentum Mill, cv. Heinz 902) plants expressing 1-aminocyclo-propane-1-carboxylic acid (ACC) deaminase were compared with nontransformed plants in a number of traits that are thought to be affected by ACC and ethylene in plant tissues. In the transgenic plants, the ACC deaminase gene was under the transcriptional control of either two tandem 35S cauliflower mosaic virus promoters (constitutive expression), the rolD promoter from Agrobacterium rhizogenes (root-specific expression), or the PRB-1b promoter from tobacco (stress-induced expression). The parameters that were examined included plant growth, leaf fluorescence, protein and chlorophyll content, fruit weight, and also lycopene and P-carotene fruit content. Expression of ACC deaminase affected a number of these characteristics with the 35S and rolD promoters generally behaving similarly to one another and differently from either the nontransformed or the PRB-1b plants.