Changes in mRNA level rhythmicity in the leaves ofSinapis alba during a lengthening of the photoperiod which induces flowering

Abstract

A previous study has shown that mRNAs exhibit complex patterns of diurnal rhythms in their quantity in the leaves of Sinapis alba during an 8 h light/16 h dark short day (SD). In order to determine whether this situation is rapidly modified in plants subjected to an extended light treatment, we have used in vitro translation and two-dimensional polyacrylamide gel electrophoresis, together with a strict gel comparison procedure giving a P = 0.03 certitude level, to analyse the mRNA complement at different times during a 22 h light/2 h dark long day (LD). During this LD, complex changes affected about 10% of the mRNAs. Thirty-four different patterns were observed. Some diurnal rhythms present in SD are not modified by the lengthening of the light period, but most are affected. Moreover, we have shown that some mRNAs presenting a constant quantity under a SD regime show an increase or a decrease during the first hours of the photoperiod lengthening. In Sinapis, this LD also induces flowering. All the changes in mRNA quantity detected thus parallel the photoperiodic induction of flowering in the leaves and are quantitative; no mRNA was shown to appear or to disappear.

A complex pattern of changes in polysomal mRNA populations is evident in the leaves of Arabidopsis thaliana (L.) Heynh. during photoperiodic induction of flowering

“…Cremer et al (1991) analyzed the photoperiodic induction of flowering in the leaves of the SD plant Sinapis alba by looking for changes in the mRNA patterns throughout one photoperiod, comparing SD and LD conditions. They also demonstrated that a lengthening of the light period was able to produce a rapid change in the quantity of some mRNAs.…”

Circadian Oscillations of a Transcript Encoding a Germin-Like Protein That Is Associated with Cell Walls in Young Leaves of the Long-Day Plant Sinapis alba L

“…These changes have been taken as an indication of underlying rhythmic changes in mRNA levels. Lengthening of the light period that induces flowering led to a transient modification of most of the rhythms observed in short days (Cremer et al, 1991).…”

“…Quantitative changes in in vitro translation products of leaf mRNAs have been found to accompany the photoperiodic flower induction process in S. alba. Some of these changes exhibit a certain periodicity, indicating that they might be under circadian control (Cremer et al, 1990(Cremer et al, , 1991. The nature of transcripts undergoing such alterations has remained elusive, however.…”

Dark and Circadian Regulation of mRNA Accumulation in the Short-Day Plant Pharbitis nil

“…It is well established that photoperiodic floral induction is regulated by light interacting with underlying endogenous rhythms (Bünning, 1936;Hamner and Takimoto, 1964;reviewed by Vince-Prue, 1986), yet few investigators have analyzed changes in gene expression in relation to photoperiodic floral induction over a 24-h cycle. A single report describes rhythmic changes in mRNA levels associated with photoperiodic induction of flowering in the LDP Sinapis alba (Cremer et al, 1991).…”