Analysis of SDR4 and its
Role in Seed Dormancy
Jessica Tran
Mentor: Dr. Hiro Nonogaki
Jaworski/HHMI Summer Research
Summer 2012
Importance
— Agriculture and
food source
PHS
— Ability to
control seed
dormancy
— Pre-harvest
sprouting (PHS)
Photo: Courtesy of Dr. Henk Hilhorst,
Wageningen University
h"p://www.scielo.br/img/revistas/sa/v63n6/
a09fig01.gif Seed Morphology
Embryo
Coleoptile
Endosperm
Radicle
sciencephoto.com
Pericap + Testa
sciencephoto.com
Hypothesis
— SDR4 mediates hormonal
signals and modulates seed
dormancy.
Molecular Mechanisms
Hormone
Receptor
Signal
Signal
Transduction
Transduction
Phenotype
Seed Dormancy - Hypothesis
Abscisic
Hormone
Acid (ABA)
Receptor
PYR1
ABI
Signal
Signal
SDR4
Transduction
Transduction
DOG1
Dormancy
Phenotype
Objectives
— Generate SDR4 inducible lines
— Examine the effect of ABA on
SDR4 expression
— Identify genes regulated by SDR4
Objectives
— Generate SDR4 inducible lines
— Examine the effect of ABA on
SDR4 expression
— Identify genes regulated by SDR4
Plant Gene Switch System (PGSS)
Switch
VP16
CsMV
Ecdysone
Activation DNA binding Receptor
Gene of Interest
V
E
Active
form
E
Promoter
GAL4
G G
E V
Chemical Ligand
(Intrepid)
Inactive
form
Gene of Interest (GOI)
Promoter
SDR4
Martinez-Andujar et al. 2011; PNAS 108, 17225-17229
Induction
Martinez-Andujar et al (2011); PNAS 108: 17225-17229
Objectives
— Generate SDR4 inducible lines
— Examine the effect of ABA on
SDR4 expression
— Identify genes regulated by SDR4
Hormonal Regulation of SDR4
NCED6 Induction
(ABA biosynthesis)
-
+
NCED6
SDR4
ACTIN2
J. Tran and H. Nonogaki, unpublished data
Objectives
— Generate SDR4 inducible lines
— Examine the effect of ABA on
SDR4 expression
— Identify genes regulated by SDR4
Transformation & Screening
— Transformation
- Gene switch
vector
— Screening
- Recovery of
transformant
Seed Production
— Harvested
seeds
— Plated T2 on
hygromycin
media
http://www3.uis.no/araperoxv1/pictures/entire_plant_2.jpg
Gene Induction Experiments
—  Verification of gene
induction by leaf
painting
Gene Expression
Profiling
— How seed
dormancy is
affected
http://thefutureofthings.com/upload/image/news/gene-chipenables-personalized-cancer-treatment/expression-analysis.jpg
— Analysis of
expressed genes
— Comparison of
induction
http://www.broadinstitute.org/news/1511
Impacts
— Solve PHS in cereals
(e.g., sorghum)
— Ensure food security
Acknowledgments
—  Ernest and Pauline Jaworski
—  Howard Hughes Medical Institute
—  Dr. Kevin Ahern
—  Dr. Roger Beachy
—  Dr. Hiro Nonogaki
—  Seed biology lab
—  Hiroaki Uto
—  Mariko Nonogaki
—  Chi-Lan Tran
—  Jenna Lennon