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Signal Transducer NPH3 Integrates the Phototropin1 Photosensor with PIN2-Based Polar Auxin Transport in Arabidopsis Root Phototropism.
- Source :
- Plant Cell; Feb2012, Vol. 24 Issue 2, p551-565, 15p
- Publication Year :
- 2012
-
Abstract
- Under blue light (BL) illumination, Arabidopsis thaliana roots grow away from the light source, showing a negative phototropic response. However, the mechanism of root phototropism is still unclear. Using a noninvasive microelectrode system, we showed that the BL sensor phototropin1 (phot1), the signal transducer NONPHOTOTROPIC HYPOCOTYL3 (NPH3), and the auxin efflux transporter PIN2 were essential for BL-induced auxin flux in the root apex transition zone. We also found that PIN2-green fluorescent protein (GFP) localized to vacuole-like compartments (VLCs) in dark-grown root epidermal and cortical cells, and phot1/NPH3 mediated a BL-initiated pathway that caused PIN2 redistribution to the plasma membrane. When dark-grown roots were exposed to brefeldin A (BFA), PIN2-GFP remained in VLCs in darkness, and BL caused PIN2-GFP disappearance from VLCs and induced PIN2-GFP-FM4-64 colocalization within enlarged compartments. In the nph3 mutant, both dark and BL BFA treatments caused the disappearance of PIN2-GFP from VLCs. However, in the phot1 mutant, PIN2-GFP remained within VLCs under both dark and BL BFA treatments, suggesting that phot1 and NPH3 play different roles in PIN2 localization. In conclusion, BL-induced root phototropism is based on the phot1/NPH3 signaling pathway, which stimulates the shootward auxin flux by modifying the subcellular targeting of PIN2 in the root apex transition zone. [ABSTRACT FROM AUTHOR]
- Subjects :
- PHOTOTROPISM
AUXIN
TRANSDUCERS
BLUE light
LIGHT sources
ARABIDOPSIS
Subjects
Details
- Language :
- English
- ISSN :
- 10404651
- Volume :
- 24
- Issue :
- 2
- Database :
- Complementary Index
- Journal :
- Plant Cell
- Publication Type :
- Academic Journal
- Accession number :
- 158017648
- Full Text :
- https://doi.org/10.1105/tpc.111.094284