Presented by: Theresa Nguyen
M e n t o r : D r. H i r o N o n o g a k i
SEED BIOLOGY LABORATORY
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2
Endosperm
Embryo
Testa
3
26S Proteasome
Murase et al.,
2008; Nature 456:
459-463
Ub
Ub
Ub
Ub
F-box (SLY)
S
C
GA
RGL2
SCF complex
GID1
“De-Repression”
Motif?
GA inducible gene
4
Hypothesis
Germination is the point of radical emergence
RGL2 inhibits germination of Arabidopsis seed through
the repression of growth potential of the embryo
Determine the localization of RGL2 and SLY1
genes through expression analysis
Elongation
Zone
Approach 1
Grow ß-glucuronidase (GUS) promoter lines
Harvest and extract seeds
Dissect and stain embryos at different stages
Visualize through DIC microscopy
RGL2:GUS
RGL2 and
SLY genes
have similar
expression
patterns
SLY1:GUS
Mutant
Wild Type
DELLA
Mutants lack
DELLA domain
Germination
Germination
90
90
80
80
Germination Percentage
100
Germination Percentage
100
70
60
50
40
30
20
10
0
70
60
50
40
30
20
10
0
Wild
Type
mRGL2
Wild
Type
mRGL2
RGL2 mutants displayed phenotypic differences during
the early stage of development.
mRGL2
Wild Type
13 days after
imbibition
RGL2 mutants displayed
dwarfish characteristics
even after 46 days of
growth
Wild Type
mRGL2
1 cm
1 cm
Wild Type
mRGL2
Wild Type
mRGL2
SLY
Mechanical
Resistance
Germination
mRGL2
Growth
Potential
Elongation
Zone
Destruction or deactivation of RGL2 is essential for the
stimulation of germination by GA and normal growth of
germinated embryos.
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Howard Hughes Medical Institute
Dr. Kevin Ahern
Dr. Hiro Nonogaki
Dr. Camille Steber (WSU)
Seed Biology Laboratory Members:
 Natalya Goloviznina
 Mariko Nonogaki
 Dr. Cristina Martinez-Andujar