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First published online January 5, 2007; 10.1104/pp.106.093948 Plant Physiology 143:1429-1438 (2007) © 2007 American Society of Plant Biologists OPEN ACCESS ARTICLE
Cold Nights Impair Leaf Growth and Cell Cycle Progression in Maize through Transcriptional Changes of Cell Cycle Genes1,[W],[OA]Department of Plant Systems Biology, Flanders Institute for Biotechnology, and Department of Molecular Genetics, Ghent University, B9052 Gent, Belgium
Low temperature inhibits the growth of maize (Zea mays) seedlings and limits yield under field conditions. To study the mechanism of cold-induced growth retardation, we exposed maize B73 seedlings to low night temperature (25°C /4°C, day/night) from germination until the completion of leaf 4 expansion. This treatment resulted in a 20% reduction in final leaf size compared to control conditions (25°C/18°C, day/night). A kinematic analysis of leaf growth rates in control and cold-treated leaves during daytime showed that cold nights affected both cell cycle time (+65%) and cell production (22%). In contrast, the size of mature epidermal cells was unaffected. To analyze the effect on cell cycle progression at the molecular level, we identified through a bioinformatics approach a set of 43 cell cycle genes and analyzed their expression in proliferating, expanding, and mature cells of leaves exposed to either control or cold nights. This analysis showed that: (1) the majority of cell cycle genes had a consistent proliferation-specific expression pattern; and (2) the increased cell cycle time in the basal meristem of leaves exposed to cold nights was associated with differential expression of cell cycle inhibitors and with the concomitant down-regulation of positive regulators of cell division.
1 This work was supported by the Institute for the Promotion of Innovation by Science and Technology in Flanders (Contractueel Landbouwkundig Onderzoek no. 030816) and the Research Fund of Ghent University (Geconcerteerde Onderzoeksacties no. 12051403), by the Research Foundation-Flanders (postdoctoral fellowship to K.V.), and by the Marie Curie Intra-European Fellowship scheme (postdoctoral fellowship FP6MEIFCT2004009388 to F.F.). 2 Present address: Department of Biology, Karadeniz Technical University, 61080 Trabzon, Turkey. The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Dirk Inzé (dirk.inze{at}psb.ugent.be). [W] The online version of this article contains Web-only data. [OA] Open Access articles can be viewed online without a subscription. www.plantphysiol.org/cgi/doi/10.1104/pp.106.093948 * Corresponding author; e-mail dirk.inze{at}psb.ugent.be; fax 3293313809. Received November 30, 2006; accepted December 12, 2006; published January 5, 2007. This article has been cited by other articles:
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