第五节 植物的光形态建成——植物生理学课件PPT

Phototropins 向光素
拟南芥的phot突变体
拟南芥的 phot突变体
PHOT1 and PHOT2 mediate blue light-dependent stomatal opening
Kinoshita et al. 2001 Nature: 414, 656
Phototropin proteins contain two LOV (Light, Ogen, Voltage sensitive) domains and a downstream serine/threonine kinase.
The chromophore is a Flavin mononucleotide (FMN) which is noncovalently bound within each LOV domain.
Schematic illustration of the LOV and kinase domains of phototropin in lightinduced phosphorylation.
Volume 9, Issue 5, October 2006, Pages 503-508
Cryptochromes 隐花色素
/Research/cryptochrome/
Cryptochrome and the avian "pass"
The HY4 gene may define a blue light photoreceptor
CRYPTOCHROME 1 (CRY1)
Phenotypes of cry2 mutant
cyr2 is late flowering under long day conditions
The structure of cryptochromes
Cryptochrome controlled
第五节 植物的光形态建成
1. 光形态建成的概念(photomorphogenesis) 2. 向光色素(phototropin) 3. 隐花色素(cryptochrome) 4. 光敏素(phytochrome) 5. 避荫反应（shade avoidance）
自然界中的光
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Light Controls
• Photosynthesis • Rate of Growth • Direction of Growth • Pigmentation • Flowering • Fruiting • Leaf Fall • Onset of Dormancy
向光蛋白
光敏素
隐花色素
Apical hook opens or coleoptile splits open Leaf growth promoted Chlorophyll produced Stem elongation suppressed Radial expansion of stem Root elongation promoted Lateral root development accelerated
deetiolation.
In Arabidopsis, cry1 and y2 regulate most of the blue-light-specific developmental programs. Shown are only phenotypic effects during deetiolation caused by mutations in cry1 or cry2. Arabidopsis wild type (WT) and photoreceptor mutants grown for 3 days in darkness (D), white light (WL) or continuous blue light of 30 µmol m-2 s-1 (high blue, HB) or 1 µmol m 2 s 1 (low blue, LB), respectively given from the top. In wild type seedlings, hypocotyl growth is inhibited by blue light whereas opening of the hypocotyl hook and cotyledon opening and expansion is promoted by blue light. HB is more efficient than LB. The lack of cry1 (cry1) is most evident under HB conditions, whereas the lack of cry2 (cry2) bees more evident under LB conditions, which is seen in particular for the double mutant (cry1/cry2) (taken from Batschauer et al., 2007).
(a) In the dark, the phosphorylation activity of the kinase domain of phototropin is inhibited by the binding of the LOV2 domain. (b) Under light conditions, the phosphorylation activity of the kinase is induced by the release of the LOV2 domain.
Wavelength(nanometers)
植物的光形态建成 （photomorphogenesis）
Light-grown
Arabidopsis
Etiolated characteristics
De-etiolated characteristics
Distinct "apical hook" (dicot) or coleoptile (monocot) No leaf growth No chlorophyll Rapid stem elongation Limited radial expansion of stem Limited root elongation Limited production of lateral roots