Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2014;9(8):e29248.
doi: 10.4161/psb.29248.

Light-sensitive Phytochrome-Interacting Factors (PIFs) are not required to regulate phytoene synthase gene expression in the root

M Águila Ruiz-Sola  1 , Antía Rodríguez-Villalón, Manuel Rodríguez-Concepción
Affiliations

Light-sensitive Phytochrome-Interacting Factors (PIFs) are not required to regulate phytoene synthase gene expression in the root

M Águila Ruiz-Sola et al. Plant Signal Behav. 2014.

Abstract

Carotenoids are plastidial isoprenoids essential for the protection of photosynthetic tissues against excess light. They also serve as precursors of apocarotenoid hormones such as abscisic acid (ABA) and strigolactones. The first enzyme of the carotenoid pathway, phytoene synthase (PSY), is also the main rate-limiting step. Unlike that observed in most plants, PSY is encoded by a single gene in Arabidopsis thaliana. Whereas the PSY gene is induced by light in photosynthetic tissues, a root-specific upregulation of PSY expression by salt stress and ABA has been recently demonstrated. Here we report that transcription factors of the Phytochrome-Interacting Factor (PIF) family, previously shown to repress PSY expression in etiolated seedlings and mature leaves, do not influence PSY expression in roots. Together, our results suggest that organ-specific pathways regulate PSY expression and hence carotenoid production in response to different environmental cues.

Keywords: Arabidopsis; PIF; carotenoid; dark; phytoene synthase; root; salt.

PubMed Disclaimer

Figures

None
Figure 1. Electronic fluorescent pictographic (eFP) representations of the levels of transcripts encoding PIFs (PIF1, PIF3, PIF4, and PIF5) in Arabidopsis roots. Data were obtained from the Arabidopsis eFP browser at www.bar.utoront.ca and correspond to root material from 5- to 6-d-old seedlings collected by fluorescence-activated cell sorting.
None
Figure 2. Analysis of PIF protein levels and their effect on PSY gene expression in roots. (A) Experimental setup. Seeds were germinated and grown on a mesh on top of solid Murashige and Skoog (MS) medium under long day (LD) photoperiod (8h of darkness and 16h under fluorescent white light at a photosynthetic photon flux density of 60 μmol m−2 s−1) at 22 °C. In the subjective morning of day 7 (5h after the lights went on in the LD chamber), the plates were either transferred to constant dark or left under LD for 24h. Then, samples were collected for GUS staining (B) or transferred to new plates containing solid MS medium either supplemented or not with 200 mM NaCl (C). Times and treatments were selected to compare conditions in which PIF proteins were either present (in the dark) or absent (after 5h of light) at the same moment of the day, hence preventing any possible circadian effect on PSY expression. (B) Representative images of roots from transgenic 35S:GUS-GFP and 35S:GUS-PIF3 seedlings grown as described in (A) and collected in the light or in the dark. Roots were separated from shoots and stained for GUS activity as described. The images correspond to the differentiation zone of the root. (C) Wild-type (WT) and mutant pifQ lines were grown and exposed for 2h to salt (+NaCl) or mock (-NaCl) treatments as described in (A). Then, root samples were collected for RNA extraction and qPCR analysis of PSY transcript levels using the UBC gene for normalization as described. Values are represented relative to those in mock-treated WT plants. Mean and standard deviation of n = 4 independent samples are shown. No statistically significant differences were found between WT and pifQ samples.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Fraser PD, Bramley PM. The biosynthesis and nutritional uses of carotenoids. Prog Lipid Res. 2004;43:228–65. doi: 10.1016/j.plipres.2003.10.002. - DOI - PubMed
    1. Botella-Pavía P, Rodríguez-Concepción M. Carotenoid biotechnology in plants for nutritionally improved foods. Physiol Plant. 2006;126:369–81. doi: 10.1111/j.1399-3054.2006.00632.x. - DOI
    1. Niyogi KK. PHOTOPROTECTION REVISITED: Genetic and Molecular Approaches. Annu Rev Plant Physiol Plant Mol Biol. 1999;50:333–59. doi: 10.1146/annurev.arplant.50.1.333. - DOI - PubMed
    1. Hirschberg J. Carotenoid biosynthesis in flowering plants. Curr Opin Plant Biol. 2001;4:210–8. doi: 10.1016/S1369-5266(00)00163-1. - DOI - PubMed
    1. Howitt CA, Pogson BJ. Carotenoid accumulation and function in seeds and non-green tissues. Plant Cell Environ. 2006;29:435–45. doi: 10.1111/j.1365-3040.2005.01492.x. - DOI - PubMed

Publication types

MeSH terms

LinkOut - more resources