Plastid and nuclear mRNA fluctuations in tomato leaves ? diurnal and circadian rhythms during extended dark and light periods

Abstract

Steady-state mRNA levels of nuclear (rbcS, cab, tubA) and plastid (rbcL, psbA) encoded genes were determined in tomato leaves of different developmental stages. Transcripts were analyzed at four-hour intervals throughout a diurnal cycle in 4 cm-long terminal leaflets, while mRNA levels of the chlorophyll a/b-binding protein (cab), and the small and large subunit of RuBPC/Oase (rbcS, rbcL) are high. At different time points during the day the mRNAs accumulate to characteristic levels. Minor fluctuations of such mRNA levels were determined in the case of rbcS, rbcL, psbA and tubA, while significant alterations are observed for the chlorophyll a/b-binding protein transcript levels. LHCP II transcripts accumulate during the day, reach highest levels at noon and decline to non-detectable levels at 5 a.m. The cab mRNA fluctuates with a periodic length of approximately 24 hours suggesting the existence of a circadian rhythm ("biological clock"), which is involved in gene activation and inactivation. The mRNA oscillation with the same periodic length, but altered amplitude, continues to be present in plants which are kept under extended dark or light conditions. Different mRNA fluctuation patterns are observed for rbcS, rbcL, and psbA under such experimental conditions.

Expression of cab Genes in Douglas-Fir Is Not Strongly Regulated by Light

“…The outlying peak during the continuous dark period may be an anomally. However, erratic fluctuations and somewhat higher levels of psbA expression during dark phases have also been found in tomato (16 (19). Our study showed that diurnal fluctuations of the steady-state cab mRNA in Douglas-fir were relatively minor and the fluctuations that occurred did not appear to be highly influenced by factors associated with photoperiodicity.…”

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

“…To provide a comparison with a gene of known function, we identified the P. nil Cab gene as a well-characterized gene known to be regulated by light and an endogenous rhythm (Piechulla, 1988;Meyer et al, 1989;Millar and Kay, 1991 O'Neilletal. Plant Physiol.…”

“…The involvement of circadian rhythms in light-regulated gene expression of plants is widely recognized (Kloppstech, 1985;Guilano et al, 1988;Nagy et al, 1988;Piechulla, 1988;Meyer et al, 1989;Millar and Kay, 1991). In the majority of studies of circadian-regulated gene expression in plants, light rather than darkness is the extemal signal influencing the amplitude of cycling mRNA levels (Guilano et al, 1988;Taylor, 1989).…”

“…Recently, it has been recognized that circadian rhythms regulate expression of a number of light-regulated plant genes, notably nuclear-encoded photosynthetic genes, and in certain cases, this regulation occurs at the leve1 of gene transcription (Kloppstech, 1985;Piechulla and Gruissem, 1987;Guilano et al, 1988;Nagy et al, 1988;Piechulla, 1988;Meyer et al, 1989;Taylor, 1989;Millar and Kay, 1991). Phase shifting by red light or temperature of the circadian rhythm of cycling mRNA levels has also been reported, strongly suggesting control of gene expression by the biological clock (Tavladoraki et al, 1989;Piechulla and Riesselmann, 1990).…”

Abundantly and Rarely Expressed Lhc Protein Genes Exhibit Distinct Regulation Patterns in Plants

“…Together with the rbcS gene, Lhc genes were the first to be cloned (Broglie et al, 1981) and were used in some of the first gene expression studies. Lhc gene expression is primarily regulated by the intensity and quality of light on a transcriptional level (for review, see Brunner and Ruediger, 1995), and Lhc mRNA levels are subject to pronounced circadian and diurnal fluctuations (Kloppstech, 1985;Pichulla, 1988). Lhc gene promoters have subsequently also been used in mutant screening experiments to elucidate the different light-sensing pathways in plants (Chory et al, 1995).…”