To identify specific effects of anthocyanins on extension of
shelf life, we silenced dihydroflavonol 4-reductase (SlDFR), a
key gene in anthocyanin biosynthesis, using VIGS in purple
tomatoes. On the same fruit, VIGS-SlDFR-silenced, orange
sectors showed similar expression levels of Del and Ros1 to
nonsilenced, purple sectors, whereas SlDFR expression was
substantially reduced (Figure S4A). Anthocyanin levels were
reduced by 80%, although other flavonoids accumulated in
the silenced sectors, giving them an orange color (Figures
S4B and S4C). SlDFR-silenced sectors were sensitive to
B. cinerea, whereas purple sectors on the same fruit remained
resistant (Figure 3A). Compared to nonsilenced sectors,
SlDFR-silenced sectors had reduced hydrophilic antioxidant capacity (Figure 3B), although this was
higher than the hydrophilic antioxidant
capacity of WT red fruit, due to the accumulation
of flavonols. Storage tests indicated
that VIGS-SlDFR-silenced fruit
could be kept longer than WT fruit
but not as long as purple tomatoes
(Figure 3C).