Germination of lettuce seeds (photoreversibility) Reversible R/FR response system controlled by phytochrome (1952) Taiz-Zeiger 2010

Phytochrome: from synthesis to action red light germination, flower Induction…… synthesis far red light

Phytochrome: homodimeric chromoprotein: apoprotein and phytochromobilin (open chained tetrapyrrol) as chromophor form holoprotein Arabidopsis: 5 phytochrome proteins (phyA - phy E), differ in their apoproteins

Bacterial and plant phytochrome structure and function Taiz-Zeiger 2010

PHYA-GFP and PHYB-GFP fusion proteins migrate into the nucleus Dark Red PHYA-GFP PHYB-GFP Dark Red

Phytochrome and GA action mediate light and dark responses Taiz-Zeiger 2010

Light - dark regulation of COP1 activity HFR1: long hypocotyl in Far-red LAF1: long after far-red light SPA1: phytochrome A suppressor COP1: constitutive photomorphogenesis HY5: long hypocotyl5 Taiz-Zeiger 2010

Life on earth depends on light derived from the sun PP01021.jpg Life on earth depends on light derived from the sun

Photosynthesis PS1 PS2 Light is required to help water reduce NADP+ Light energizes jumps in energy potential to get electrons run through an electron transfer chain NADPH PP0103.jpg PS1 700 nm ATP PS2 680nm H2O 2H+ + 1/2O2

Engelmann experiment What is an action spectrum?? And what is an absorption spectrum?? PP0116B.jpg Engelmann experiment

Action spectrum vs. absorption spectrum PP1804.jpg

Directionality of blue light induced bending (Action spectrum) PP1804.jpg

Directionality of blue light induced bending PP1804.jpg

Kinetics of blue light effects Hypocotyl elongation Membrane depolarization PP1804.jpg Gene induction Hypocotyl elongation

Stomata opening regulated by blue light

Stomata opening regulated by blue light Protoplasts dark Protoplasts blue light

How are light regulation and metabolism interconnected Zeaxanthin cycle in guard cells

Dark and light form of carotenoid protein in stomata opening

Measuring irradiation: chloroplast movements (Lemna) depending on light intensity Dunkelheit Schwachlicht Starklicht

Blue light induced bending of coleoptiles PP1804.jpg

phot1 (phototropin1) wild-type blue light PP1804.jpg phot1 mutant

PHOT genes in Arabidopsis LOV-domains change redox status in proteins through (Light, Oxygen, Voltage)  LOV-domains are flavin binding sites (FMN)

Phototropism chloroplast stomata movement opening

cryptochrome, together with phytochromes deetiolation of seedlings photoperiodic induced morphoses (e.g. flower induction) circadian rhythms

cry1 : inhibition of hypocotyl elongation is insensitiv against blue light dark blue red WT cry1 phyB WT cry1 phyB WT cry1 phyB

cry1 : analysis of cry1 mutants and over-producers dark blue WT cry1 phyB WT cry1 phyB

CRY1 shows similarity to prokaryotic DNA photolyases 70% 30% 70% bacterial photolyase Chromophor 1: Chromophor 2: MTHF (pterin) 8-HDF (deazaflavin) FADH-

Adduct formation in FMN in PHOT1