Activities of Polygalacturonase, α-d-Mannosidase, and α-d- and β-d-Galactosidases in Ripening Tomato

Abstract

Abstract The activities of the enzymes polygalacturonase, α-d-mannosidase, and α-d- and β-d-galactosidase in tomato (Lycopersicon esculentum Mill) pericarp tissue were measured during ripening of two normal ripening cultivars, Sweet 100 and ACE 55 VF, the slow-ripening alcobaca mutant, and their F1 progeny. The activity of polygalacturonase increased as the fruit ripened from mature green to red stages for all tomato lines (‘Sweet 100 > ‘Sweet 100’ × alcobaca > ‘ACE 55 VF’ > ‘Ace 55 VF’ × alcobaca > alcobaca). Of the other enzymes, α-mannosidase showed the greatest quantitative differences between the tomato lines and consistently increased in activity during ripening. There was, however, no association between the activity of α-d-mannosidase and polygalacturonase. The highest β-galactosidase activity occurred in ‘Sweet 100’, but was generally similar in the other lines. The activity of α-galactosidase varied little between parents and progeny for any stage of ripeness.