Nuclear phytochrome A signaling promotes phototropism in Arabidopsis
| Autor: | Christian Fankhauser, Micha Hersch, Chitose Kami, Sven Bergmann, Thierry Genoud, Andreas Hiltbrunner, Martine Trevisan |
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| Rok vydání: | 2012 |
| Předmět: |
0106 biological sciences
Cytosol/metabolism genetic structures Light Phytochrome A/physiology Mutant Arabidopsis Plant Science 01 natural sciences Cytosol Gene Expression Regulation Plant Phytochrome A Research Articles Phototropism 0303 health sciences Phytochrome Intracellular Signaling Peptides and Proteins Cell biology Phosphoproteins/metabolism Arabidopsis Proteins/genetics Phytochrome/metabolism Intracellular Signaling Peptides and Proteins/metabolism Biochemistry Phototropin Phytochrome A/genetics Seedlings/physiology Biology 03 medical and health sciences Arabidopsis/physiology Transcription Factors/metabolism Arabidopsis/genetics Transcription factor 030304 developmental biology Cell Nucleus Arabidopsis Proteins Wild type Membrane Proteins Cell Biology Phosphoproteins biology.organism_classification Seedlings Mutation Cell Nucleus/metabolism Arabidopsis Proteins/metabolism Arabidopsis Proteins/physiology Transcription Factors 010606 plant biology & botany |
| Zdroj: | Plant Cell Plant Cell, vol. 24, no. 2, pp. 566-576 The Plant cell |
| Popis: | Phototropin photoreceptors (phot1 and phot2 in Arabidopsis thaliana) enable responses to directional light cues (e.g., positive phototropism in the hypocotyl). In Arabidopsis, phot1 is essential for phototropism in response to low light, a response that is also modulated by phytochrome A (phyA), representing a classical example of photoreceptor coaction. The molecular mechanisms underlying promotion of phototropism by phyA remain unclear. Most phyA responses require nuclear accumulation of the photoreceptor, but interestingly, it has been proposed that cytosolic phyA promotes phototropism. By comparing the kinetics of phototropism in seedlings with different subcellular localizations of phyA, we show that nuclear phyA accelerates the phototropic response, whereas in the fhy1 fhl mutant, in which phyA remains in the cytosol, phototropic bending is slower than in the wild type. Consistent with this data, we find that transcription factors needed for full phyA responses are needed for normal phototropism. Moreover, we show that phyA is the primary photoreceptor promoting the expression of phototropism regulators in low light (e.g., PHYTOCHROME KINASE SUBSTRATE1 [PKS1] and ROOT PHOTO TROPISM2 [RPT2]). Although phyA remains cytosolic in fhy1 fhl, induction of PKS1 and RPT2 expression still occurs in fhy1 fhl, indicating that a low level of nuclear phyA signaling is still present in fhy1 fhl. |
| Databáze: | OpenAIRE |
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