Tomato fruit ripening is a complex physiological process that involves morphological, anatomical, biochemical, and molecular alterations. One of these changes occurring during ripening is the softening of the fruit, which is attributed to modifications in the biosynthesis and degradation of individual cell wall components, i.e. polysaccharides and proteoglycans. In addition, ripening is affected by redox processes, and interplay of the reactive oxygen species (ROS) and specific antioxidants, enzymes, ascorbate, and phenolic compounds. The present study aims to determine the impact of the overexpression of the GDP-l-galactose phosphorylase (GGP1) gene under the control of two fruit-specific promoters, namely PPC - phosphoenolpyruvate carboxylase and PG - polygalacturonase on cell wall properties, activities of H