Related Experiment Video
Updated: Sep 29, 2026

Investigating Tissue- and Organ-specific Phytochrome Responses using FACS-assisted Cell-type Specific Expression Profiling in Arabidopsis thaliana
Published on: May 29, 2010
Loss of nuclear gene expression during the phytochrome A-mediated far-red block of greening response
Alex C McCormac1, Matthew J Terry
1School of Biological Sciences, University of Southampton, Southampton SO16 7PX, United Kingdom.
Abstract:
We have examined the expression of the HEMA1 gene, which encodes the key chlorophyll synthesis enzyme glutamyl-tRNA reductase, during the phytochrome A-mediated far-red light (FR) block of greening response in Arabidopsis. Our results demonstrate that the FR block of greening comprises two separate responses: a white light (WL) intensity-independent response that requires 3 d of FR and is associated with a loss of expression of the nuclear genes HEMA1 and Lhcb following the transfer to WL (transcriptionally coupled response) and a WL intensity-dependent response that is induced by 1 d of FR and is transcriptionally uncoupled. Both responses required phytochrome A. The transcriptionally uncoupled response correlated with a deregulation of tetrapyrrole synthesis and potential photooxidative damage and was inhibited by cytokinin. The transcriptionally coupled FR response was additive with the loss of expression following Norflurazon-induced photobleaching and was absent in the presence of sucrose or after lower fluence rate (1 micromol m(-2) s(-1)) FR treatments. Both pathways leading to the loss of nuclear gene expression were inhibited by overexpression of NADPH:protochlorophyllide oxidoreductase, indicating a role for plastid signaling in the FR-mediated pathway. The significance of identifying a distinct phytochrome A-mediated plastid signaling pathway is discussed.
More Related Videos
Related Concept Videos
Cell Signaling in Plants
Photoreceptors and Plant Responses to Light
Reporter Genes
Commonly used reporter...
Biological Clocks and Seasonal Responses
Position-effect Variegation
Diversity in Cell Signaling Responses
Graded and Abrupt Responses
Some signaling systems generate...

