Organ-Specific Putrescine Biosynthesis

Example 10

The relative contribution of ADC and ODC to putrescine biosynthesis was evaluated by measuring the activity of each enzyme in the leaves (leaf 23) and roots of the NA and LA plants at topping and harvest. ADC and ODC activity varied in an organ-specific and developmental stage-specific manner in both lines (FIG. 4). Whereas ADC activity was high in the leaves but minimal in the roots of both lines, ODC activity was higher in the younger leaves and roots, indicating that ODC is mainly responsible for putrescine biosynthesis in the roots. ADC activity was significantly higher (1.4-fold, p<0.05) in the leaves of the LA plants compared to the NA controls at topping and harvest (FIG. 4A). Similarly, ODC activity was significantly higher (p<0.05) in the LA plants compared to the NA controls in the roots at topping (1.8-fold) and at harvest (1.7-fold), and in young leaves at topping (1.5-fold) (FIG. 4B).