Vitamins in Fleshy Fruits - Fruit Ripening: Physiology, Signalling and Genomics - page 156

8

Promoter cytosine demethylation

Ethylene responsiveness

Transcription factor binding

Induction of ripening genes

9

Strategy 1: Seedlessness induced by ovule-specific regulation of auxin synthesis

Auxin synthesis

LB mas-KAN DefH9-iaaM Ubi3-GUS RB

pDU04, 1602

iaa

iaa

Gm

Tr IA

(Indole acetamine)

IA

LB mas-KAN INO-iaaM Ubi3-GUS RB

Increased
auxin/GA
synthesis

Ovule-specific expression

pDU04, 1004

Gm

Strategy 2: Seedlessness induced by ovule-specific modulation of auxin response

Auxin response

LB mas-KAN DefH9-rolB Ubi3-GUS RB

pDU04, 4001

Gm

rolA rolC -

rolB

mas-KAN INO-rolB Ubi3-GUS RB

Increased
auxin/GA
response

Ovule-specific expression

pDU04, 4622

Gm

Plate 8. Model of epigenome and transcription factor interaction during ripening. The ability of 5-azacytodine to in-
duce early ripening indicates a role of epigenome dynamics in regulating this developmental process. Demethylation
of specific promoter sites co-localizes with RIN binding. Reduced demethylation in the rin and Cnr mutants suggests
a feedback loop in which promoter demethylation processes and transcription factor binding influence each other
to provide regulatory fidelity.
Plate 9. The two strategies used to obtain transformed parthenocarpic tomatoes.