B1-type cyclin-dependent kinases are essential for the formation of stomatal complexes in Arabidopsis thaliana.
Cyclin-dependent kinases (CDKs) are key regulators of the cell cycle. In yeasts, only one CDK is sufficient to drive cells through the cell cycle, whereas higher eukaryotes developed a family of related CDKs. Curiously, plants contain a unique class of CDKs (B-type CDKs), whose function is still unclear. We show that the CDKB1;1 gene of Arabidopsis (Arabidopsis thaliana) is highly expressed in guard cells and stomatal precursor cells of cotyledons, suggesting a prominent role for B-type CDKs in stomatal development. In accordance, transgenic Arabidopsis plants with reduced B-type CDK activity had a decreased stomatal index because of an early block of meristemoid division and inhibition of satellite meristemoid formation. Many aberrant stomatal cells were observed, all of them blocked in the G2 phase of the cell cycle. Although division of stomatal precursors was inhibited, cells still acquired stomatal identity, illustrating that stomatal cell differentiation is independent of cellular and nuclear division.
Boudolf
Véronique
V
Department of Plant Systems Biology, Flanders Interuniversity Institute for Biotechnology, Ghent University, B-9052 Gent, Belgium.
Barrôco
Rosa
R
Engler
Janice de Almeida
Jde A
Verkest
Aurine
A
Beeckman
Tom
T
Naudts
Mirande
M
Inzé
Dirk
D
De Veylder
Lieven
L
D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002453:Cell Cycle; D002454:Cell Differentiation; D048429:Cell Size; D018844:Cyclin-Dependent Kinases / Q000235:genetics / Q000378:metabolism*; D018744:DNA, Plant / Q000235:genetics; D015870:Gene Expression; D017343:Genes, Plant; D018519:Meristem / Q000166:cytology / Q000378:metabolism; D009154:Mutation; D030821:Plants, Genetically Modified; D011401:Promoter Regions, Genetic
D029681:Arabidopsis Proteins; D018744:DNA, Plant; D018844:Cyclin-Dependent Kinases