The dominant carotenoid
accumulated in albedo, segment membranes, and
juice sacs is lycopene, which can reach levels that are
a 1000-fold higher than those in comparable wild-type
fruits. This mutation does not affect the carotenoid
composition of leaves. Carotenoid concentration and
biosynthetic gene expression of albedo, segment
membranes, and juice sacs were dramatically altered
by the mutation. Lycopene accumulation in the juice
sacs was regulated by co-ordinate expression of
carotenoid biosynthetic genes. However, in albedo
and segment membranes, the expression of downstream
carotenogenic genes seems to be feedback
induced by lycopene accumulation. This implies that
there must be at least two modes regulating lycopene
accumulation in ‘Hong Anliu’ fruit. Taken together,
these results suggest that massive amounts of lycopene
might be synthesized in the juice sacs and then
transported to the segment membrane and the albedo,
which leads to lycopene accumulation there.