Molecular characterization of the diurnal/circadian expression of the chlorophyll a/b-binding proteins in leaves of tomato and other dicotyledonous and monocotyledonous plant species

Abstract

Diurnal oscillations of steady-state mRNA levels encoding the chlorophyll a/b-binding proteins were monitored inLycopersicon esculentum, Glycine max, Phaseolus vulgaris, P. aureus, P. coccineus, Pisum sativum, Sinapis alba, Hordeum vulgare, Triticum aestivum andZea mays. In these plant speciescab mRNA accumulation increases and decreases periodically indicating i) that the expression of the genes for chlorophyll a/b-binding proteins (cab genes) is controlled by a circadian rhythm, and ii) that the rhythm is widely distributed among monocotyledonous and dicotyledonous plant species. A detailed characterization of the pattern ofcab mRNA expression in tomato leaves shows that the amplitude of the oscillation is dependent on i) the developmental stage of the leaves, ii) the circadian phase and duration of light and iii) the circadian phase and duration of darkness. In addition to the chlorophyll a/b-binding proteins, genes coding for other cellular functions were examined for cyclic variations of their mRNA levels. The analysis includes genes involved in i) carbon metabolism (e.g. phosphoenolpyruvate carboxylase, pyruvate orthophosphate dikinase, alpha amylase, fructose-1,6-bisphosphate aldolase, triosephosphate isomerase), ii) photosynthesis (large and small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase, QB-binding protein, reaction-center protein of photosystem I) and iii) other physiological or morphological reactions (e.g. ubiquitin, actin). However, no periodic fluctuation pattern was detected for the mRNA levels of these genes in tomato and maize leaves.

Diurnal Rhythmicity in the Pattern of mRNAs in the Leaves of Sinapis alba

“…Patterns 3 and 4, characterized by an increase at the beginning of the day and a decrease in the second part of the day, are similar to those found for the small subunit of ribulose 1,5-bisphosphate carboxylase in pea (13), for light-harvesting complex protein in tobacco (25), for cab in tomato (9,18), and for cab9 1 R in Petunia (28). All of these previously described rhythms are circadian.…”

“…On the other hand, several recent studies have demonstrated diurnal or circadian rhythmicity in the level of specific mRNAs (8,9,13,18,21,25,28 (6). Gels were prepared for fluorography using Amplify (Amersham, UK) and exposed to preflashed Kodak X-Omat AR film, 48 Leaves of S. alba were harvested and their mRNA analyzed at the beginning (0 h), middle (4 h), and end of the day (8 h) as well as three times during the following night (12,16, and 20 h).…”

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).…”