A stable blue-light-derived signal modulates ultraviolet-light-induced activation of the chalcone-synthase gene in cultured parsley cells

Abstract

Run-off transcription assays were used to demonstrate that both the ultraviolet (UV)-B and blue-light receptors control transcription rates for chalcone-synthase mRNA in the course of light-induced flavonoid synthesis in parsley (Petroselinum crispum Miller (A.W. Hill)) cell-suspension cultures. Blue and red light alone, presumably acting via a blue-light receptor and active phytochrome (far-red absorbing form) respectively, can induce accumulation of chalcone-synthase mRNA. The extent of the response is however considerably smaller than that obtained when these wavebands are applied in combination with UV light. A preirradiation with blue light strongly increases the response to a subsequent UV pulse and this modulating effect of blue light is stable for at least 20 h. The modulating effect is abolished by a UV induction but can be reestablished by a second irradiation with blue light.

G-Protein-Coupled Receptor 1, G-Protein Gα-Subunit 1, and Prephenate Dehydratase 1 Are Required for Blue Light-Induced Production of Phenylalanine in Etiolated Arabidopsis

“…Irradiation resulted in a greater than 100-fold induction in phenylpropanoid synthesis. This is consistent with published studies where BL initiates phenylpropanoid production (Long and Jenkins, 1998;Noh and Spalding, 1998), and preirradiation of parsley (Petroselinum crispum) cells in culture prior to UV treatment reduces a lag period for expression of Phe derivatives (Bruns et al, 1986;Ohl et al, 1989). Lag elimination is often indicative of precursor synthesis.…”

“…In higher plants, blue light (BL) is known to affect the phenylpropanoid pathway, which initiates with Phe, and for which Phe can be a limiting component (Bruns et al, 1986;Ohl et al, 1989;Long and Jenkins, 1998;Noh and Spalding, 1998). At least three photoreceptor systems are known to act in BL-mediated phenomena: PHOTOTROPIN, CRYPTOCHROME, and PHYTOCHROME (Ahmad, 1999;Briggs and Huala, 1999;Casal, 2000;Lin, 2000;Chen et al, 2004).…”

Ultraviolet-B Radiation-Mediated Responses in Plants. Balancing Damage and Protection

“…Because some UV-B responses, e.g. chalcone synthase (CHS) expression, can be modulated by blue or red light, there is evidence that a complex web exists between phytochrome-, cryptochrome-, and UV-B-signaling chains in cell cultures (Ohl et al, 1989) and plants (Boccalandro et al, 2001;Wade et al, 2001).…”

“…Synchronous transcriptome changes of flavonoid biosynthetic genes have been first described in parsley cell cultures. Early components of this metabolic pathway are transcriptionally activated in a timely coordinated manner within a few hours (Hahlbrock and Scheel, 1989;Ohl et al, 1989;Loyall et al, 2000). Several light-responsive promoters of this pathway were analyzed (Logemann and Hahlbrock, 2002) and a number of conserved cisacting elements were described that confer light responsiveness.…”

Light-regulated modification and nuclear translocation of cytosolic G-box binding factors in parsley.

“…The parsley suspension culture and the protoplasts and evacuolated protoplasts derived from this culture have been intensively analyzed for the light regulation of different genes, including those encoding CHS and phytochrome. Detailed studies have shown that all known photoreceptors are physiologically active in this system (Ohl et al, 1989;Frohnmeyer et al, 1992;Merkle et al, 1994;Rocholl et al, 1994; C. Poppe, E. Ehmann, H. Frohnmeyer, and E. Schafer, manuscript submitted). We have recently established a silicon oil gradient centrifugation technique to isolate a pure and highly concentrated plasma membranecontaining cytosolic fraction from parsley protoplasts that have first been evacuolated by Percoll gradient centrifugation .…”