Differential usage of photoreceptors for chalcone synthase gene expression during plant development

Abstract

SummaryPhotoregulation of chalcone synthase (CHS) mRNA accumulation was analysed in parsley (Petroselinum crispum) and mustard (Sinapis alba) plants at different developmental stages. In both species, CHS mRNA accumulation in young etiolated seedlings was primarily under phytochrome control. In leaves of adult reetiolated plants, a UV-B photoreceptor was predominantly involved in photocontrol. The reduced red light control in mature leaves was not due to the absence of immunoreactive phytochrome. The apparent dependence of photoreceptor usage on the developmental state of the cell or organism was in accordance with observations on the photoregulation of fusion constructs between CHS promoters from parsley or mustard and the P-glucuronidase reporter gene (GUS). When tested in the parsley protoplast transient expression system, both constructs yielded the same type of photoregulation as observed for the endogenous CHS gene.

CUE1: A Mesophyll Cell-Specific Positive Regulator of Light-Controlled Gene Expression in Arabidopsis.

“…Their expression is regulated by phytochrome (Silverthorne and Tobin, 1987;), yet their expression can also be modulated by other photoreceptors, including a blue/UV-A photoreceptor (Fluhr and Chua, 1986;Schulze-Lefert et al, 1989;Gao and Kaufman, 1994). Moreover, the responsiveness of a particular gene to a given wavelength of light varies with the light intensity as well as the developmental stage of the plant (Ehmann et al, 1991;Frohnmeyer et al, 1992). These observations further reinforce the interplay of light and development in the regulation of gene expression in plants.…”

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

“…The light-regulated element of the parsley chs promoter, designated unit 1, is necessary and sufficient to mediate the responsiveness to continuous light of different quality (Dangl et al, 1987;Block et al, 1990;Weisshaar et al, 1991;Frohnmeyer et al, 1992Frohnmeyer et al, , 1994Rocholl et al, 1994;A. Batschauer, personal communication).…”

“…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 .…”

“…A similar picture is found in the light-regulated element of the chs promoter (termed unit 1) of parsley and mustard. Unit 1 is composed of two different nucleotide sequences, designated box I and box II, which mediate the functional integrity of the element and are necessary and sufficient for induction of the chs gene in response to continuous light of different quality (Block et al, 1990;Weisshaar et al, 1991;Frohnmeyer et al, 1992;Rocholl et al, 1994;A. Batschauer, personal communication).…”

Signal transduction in the photocontrol of chalcone synthase gene expression*

“…The photorcccplor dependence oi' CHS mRNA induction is additionally controlled by the dcvelopmenlal stage of the planl, at least iti parsley, mustard and Arabidopsis seedlings (Ehmann et al 1991;Frohnmeyer et al 1992). and this patlcni was also found in Iraiisgenic Arabidopsis seedlings containing the B-glucuronidase (GUS) reporter gene under control of the CHS promoter (Feinbaum et al 1991;Kaiser et al 1995).…”