Photomorphogenesis Skotomorphogenesis (etiolation)
-
date post
20-Dec-2015 -
Category
Documents
-
view
220 -
download
0
Transcript of Photomorphogenesis Skotomorphogenesis (etiolation)
Photomorphogenesis Skotomorphogenesis(etiolation)
Light has an influence on seedling development
Photomorphogenesis
inhibition of hypocotyl elongation
opening of apical hook
cotyledon expansion
chloroplast development
Dark Light
Dark
Light
wild-type
cop/detmutants
COP and DET proteins inhibit photomorphogenesis
Development (realization of a phenotype from a genotype)
is controlled by
endogenous factors
intercellular regulation
phytohormones
exogenous factors
biotic factors
abiotic factors
Germination of lettuce seeds (photoreversibility)
Reversible R/FR response system controlled by phytochrome
germination germination
Pr PfrRed light
Far-red light
inactive active
Phytochrome dogma
synthesisgermination,flower Induction……
red light
far red light
Phytochrome: from synthesis to action
blue light red light
Arabidopsis: 5 phytochrome proteins (phyA - phy E),
differ in their apoproteins
Phytochrome: homodimeric chromoprotein:
apoprotein and phytochromobilin (open chained tetrapyrrol) as chromophor form holoprotein
Strasburger, 2002
R FR
PRinactive
PFRactive
PFR
active
PR
inactive
sensor signal transduction
Regulatory function
Strasburger, 2002
Structure of phytochrome proteins
N-terminal extension
Hinge region
PAS domain
Histidine kinase related 1
Histidine kinase related 2
Chromophore binding domain
The Phytochrome apoprotein (-chromophore) is a 125kD monomer
Chromophore binding domains
Two holoproteins (+chromophore) form a dimer
IIAIA
IIBIB
Red light
Far-red light
PrPfr
Two holoproteins (+chromophore) form a dimer
Histidine kinase related
Chromophore binding domain
IIAIA
IIBIB
IA IIA
IIBIB
Phytochrome responses vary with amount of light
VLFR: 0.00001 µmol x m-2
LFR: 1-1000 µmol x m-2
Arabidopsis seed germination
Lettuce seed germination
Anthocyanin synthesisInhibition of hypocotyl elong.Enlargement of cotyledonsApical hook opening
HIR: >1000 µmol x m-2 x s-1
Phytochrome responses vary with amount of light
Inhibition of hypocotyl elongation
HIR: >1000 µmol x m-2 x s-1
Phytochrome responses vary with amount of light
LFR: 1-1000 µmol x m-2
Lettuce seed germination
Strasburger, 2002
Shade avoidance reaction
Strasburger, 2002
Shade avoidance reaction
Strasburger, 2002
Shade avoidance reaction
Figure 17.9 Phytochrome is an autophosphorylating protein
kinase
PHYA-GFP and PHYB-GFP fusion proteins migrate into the nucleus
PHYA-GFP
PHYB-GFP
Dark Red
Dark Red