OPEN ACCESS ARTICLE

This Article Free via Open Access: OA OA Full Text Full Text (PDF) A correction has been published OA All Versions of this Article: 144/3/1587    most recent pp.107.096834v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via CrossRef Citing Articles via ISI Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Qi, R. Articles by John, P. C. L. Search for Related Content PubMed PubMed Citation Articles by Qi, R. Articles by John, P. C. L. Agricola Articles by Qi, R. Articles by John, P. C. L.

DEVELOPMENT AND HORMONE ACTION

Expression of Genomic AtCYCD2;1 in Arabidopsis Induces Cell Division at Smaller Cell Sizes: Implications for the Control of Plant Growth^[C],[OA]

Plant Cell Biology Group, Research School of Biological Sciences, Australian National University, Canberra, Australian Capital Territories 2600, Australia

The Arabidopsis (Arabidopsis thaliana) CYCD2;1 gene introduced in genomic form increased cell formation in the Arabidopsis root apex and leaf, while generating full-length mRNA, raised CDK/CYCLIN enzyme activity, reduced G1-phase duration, and reduced size of cells at S phase and division. Other cell cycle genes, CDKA;1, CYCLIN B;1, and the cDNA form of CYCD2;1 that produced an aberrantly spliced mRNA, produced smaller or zero increases in CDK/CYCLIN activity and did not increase the number of cells formed. Plants with a homozygous single insert of genomic CYCD2;1 grew with normal morphology and without accelerated growth of root or shoot, not providing evidence that cell formation or CYCLIN D2 controls growth of postembryonic vegetative tissues. At the root apex, cells progressed normally from meristem to elongation, but their smaller size enclosed less growth and a 40% reduction in final size of epidermal and cortical cells was seen. Smaller elongated cell size inhibited endoreduplication, indicating a cell size requirement. Leaf cells were also smaller and more numerous during proliferation and epidermal pavement and palisade cells attained 59% and 69% of controls, whereas laminas reached normal size. Autonomous control of expansion was therefore not evident in abundant cell types that formed tissues of root or leaf. Cell size was reduced by a greater number formed in a tissue prior to cell and tissue expansion. Initiation and termination of expansion did not correlate with cell dimension or number and may be determined by tissue-wide signals acting across cellular boundaries.

^[C] Some figures in this article are displayed in color online but in black and white in the print edition.

^[OA] Open Access articles can be viewed online without a subscription.

www.plantphysiol.org/cgi/doi/10.1104/pp.107.096834

^* Corresponding author; e-mail peter.john{at}anu.edu.au; fax 61–2–6125–4331.

Received January 29, 2007; accepted April 26, 2007; published May 18, 2007.