Galactosidases

A recent report indicated that antisense suppression of galactosidase gene expression in ripening tomato fruit reduced softening by approximately 40% (Gross and Smith, USDA report). At least four of seven tomato β-fruit galactosidases are expressed during ripening (Smith and Gross, 2000), and the release of galactosyl residues is the most dynamic cell wall change during ripening. As breakdown of galactose-containing polymers in the fruit cell wall is abundant during ripening, reduction of galactosidases, perhaps in concert with other cell wall hydrolases and expansin proteins may provide the basis to regulate the softening process of ripening tomato fruit.