Among the nine ACSs and five ACOs genes identified in tomato, we studied and compared the transcript levels of three ACSs (SlACS1A, SlACS2 and SlACS4) and two ACOs (SlACO1 and SlACO4) in the wounded leaves and roots under ectopic expression of EgCBF3 and the wild type tomato plants. These enzymes are the main enzymes in the ethylene biosynthesis pathway in tomato, and the ethylene levels in different tissues of the tomato are directly associated with their expression ( Barry and Giovannoni, 2007). In the present study, expression of the ethylene biosynthesis-related genes decreased significantly in the wounded leaves and roots of the transgenic tomato plants compared to the wild type (Fig. 8). Expression of SlACS2 in the transgenic leaves was reduced compared to the wild type leaves, but its expression in the roots was not significantly different between the two. Further, expression of SlACS2, SlACS4, SlACO1 and SlACO4 showed down-regulation while the transcript level of SlACS1A was increased in the transgenic tomato plants. It was reported that expression of SlACS1A is negatively regulated by