Control of in vitro organogenesis by cyclin-dependent kinase activities in plants.
Little is known concerning the mechanisms by which auxin and cytokinin exert their effects on proliferation and differentiation. Cyclin-dependent kinases (CDKs) are major regulators of the eukaryotic cell cycle, thus they are assumed to control cell differentiation as well as proliferation in response to phytohormone signals. Here, we overexpressed rice R2 cDNA, which encodes a CDK-activating kinase, in tobacco leaf explants by using the glucocorticoid-mediated transcriptional induction system. Transient expression of R2 during the first 7 days of culture triggered callus formation in the absence of cytokinin. This phenotype was enhanced by higher expression of R2 or coexpression of cyclin H, and suppressed by treatment with roscovitine, a CDK inhibitor. R2 expression at a later stage did not prevent cells from differentiation into roots, suggesting a restricted period for sensing CDK activities that control differentiation fate of cells during organogenesis.
Yamaguchi
Masatoshi
M
Institute of Molecular and Cellular Biosciences, University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-0032, Japan.
Kato
Hisashi
H
Yoshida
Shigeo
S
Yamamura
Saburo
S
Uchimiya
Hirofumi
H
Umeda
Masaaki
M
D002454:Cell Differentiation; D002455:Cell Division; D018844:Cyclin-Dependent Kinases / Q000502:physiology*; D003583:Cytokinins / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008954:Models, Biological; D012275:Oryza / Q000235:genetics* / Q000502:physiology*; D010641:Phenotype; D018515:Plant Leaves / Q000378:metabolism; D018521:Plant Physiological Phenomena; D030821:Plants, Genetically Modified; D011687:Purines / Q000494:pharmacology; D000077546:Roscovitine; D013997:Time Factors; D014026:Nicotiana / Q000235:genetics
D003583:Cytokinins; D004791:Enzyme Inhibitors; D011687:Purines; D000077546:Roscovitine; D018844:Cyclin-Dependent Kinases