Plant Developmental Biology (Coupland)

Plant Developmental Biology (Coupland)

• Elucidation of signaling pathways that control flowering in response

to daylength (photoperiodism).

• Brassinosteroid synthesis and signaling and sugar signaling

• Protein modification by Ubiquitin and SUMO

• Development of technologies (T-DNA tagging approaches, gene

targeting, fluorescent-marker proteins, Mass Spec)

• The circadian-clock system

How do plants measure daily changes inenvironmental stimuli?

How do plants decide the timing of development?

Interests...

Roles of the Circadian Clock

12

6

39

Cytosolic calcium

Stomatal opening

Leaf movement

Protein phosphorylation

Gene expression

Chloroplast movement

Flower opening

Flowering time

Hypocotyl growth

Simple feedback model

promoter luciferase

Firefly luciferase system

LHY CCA1 CAB GRP7

QuickTime™ and a decompressor

are needed to see this picture.

Imaging system

• Thousands seedlings, every 1 hour

• Quantitative and statistical analyses

7-day-old seedlings

Luminescence assay

Data analysis

CAB::LUC defects in tic

0

100

200

300

400

0 24 48 72Time (h)

WTtic

TIC functions at dawn

0

12

24

36

48

0 12 24 36 48 60

Tim

e in

ligh

t (h

) ticWT

0

12

24

36

48

0 12 24 36 48 60Time of first peak in darkness (h)

Tim

e in

ligh

t (h

)

tic dataelf3 data

Simple feedback model

tic and elf4

0

0.5

1

1.5

2

2.5

0:00 48:00 96:00 144:00 192:00ZT (hours)

Rel

ativ

e lu

min

esce

nce

elf4 CAB2::LUCtic CAB::2LUCelf4 tic CAB2::LUC

(tic doubles to elf3 and toc1 are similar)

tic and lhy

0

0.5

1

1.5

2

2.5

3

0:00 48:00 96:00 144:00

ZT (hours)

Rel

ativ

e lu

min

esce

nce

tic CAB2::LUC

lhy CAB2::LUC

lhy tic CAB2::LUC

TICCCA1LHY

ELF4ELF3TOC1

Wouldn’t it be great ifwe could turn onflowering at will?

Floral induction of pineapple plantsby application of auxin

Introducing the CDS(the Cassava Dating Service)

The ethanol AlcR/AlcA system

The Davis Lab