Journal of Experimental Botany, Vol. 54, No. 393, pp. 2669-2678,
December 1, 2003
© 2003 Oxford University Press
Activation of cell proliferation by brassinolide application in tobacco BY-2 cells: effects of brassinolide on cell multiplication, cell-cycle-related gene expression, and organellar DNA contents
Received 11 August 2003; Accepted 22 September 2003
,2
,5
1 Plant Functions Laboratory RIKEN, 2-1, Hirosawa, Wako, Saitama 351-0198, Japan
2 1-7-22, Suehirocho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045 Japan
3 Department of Biological Sciences, Nara Women’s University, Nara 630-8506, Japan
4 Department of Integrated Biosciences, Graduate School of Frontier Sciences, University of Tokyo, Chiba 277-8562, Japan
5 Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo 113-0033, Japan
* To whom corresponence should be addressed. Fax: +81 48 462 4674. E-mail: yutakam{at}postman.riken.go.jp Present address: National Institute of Fruit Tree Science, Shizuoka 424-0292, Japan. Present address: Department of Life Science, Rikkyo University, Tokyo 171-8501, Japan.
Brassinosteroids (BRs) are steroidal phytohormones that are essential for many processes in plant growth and development, such as cell expansion, vascular differentiation, and responses to stress. The effects of BRs on cell division are unclear, as attested by contradictory published results. To determine the effect of BRs on cell division, the tobacco (Nicotiana tabacum) BY-2 cell line, which is a widely-used model system in plant cell biology, was used. It was found that brassinolide (BL) promoted cell division only during the early phase of culture and in the absence of auxin (2,4-D). This promotion of cell division was confirmed by RNA gel blot analyses using cell-cycle-related gene probes. At later stages in the culturing periods of BL-supplied and 2,4-D-supplied BY-2 cells, differences in cell multiplication and cell-cycle-related gene expression were observed. Moreover, the BL-treated BY-2 cells had morphological differences from the 2,4-D-treated cells. To determine whether suppressed organellar DNA replication limited this promotion of cell division during the early culture phase, this replication was examined and it was found that BL treatment had no effect on activating organellar (plastid- and mitochondrial-) DNA synthesis. As preferential organellar DNA synthesis, which is activated by 2,4-D, is necessary during successive cell divisions in BY-2 cells, these data suggest that the mechanism of the promotion of cell division by BL treatment is distinct from that regulated by the balance of auxin and cytokinin.
Key words: Brassinosteroids, BY-2 cells, cell proliferation, organellar DNAs.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  M. R. Malik, F. Wang, J. M. Dirpaul, N. Zhou, J. Hammerlindl, W. Keller, S. R. Abrams, A. M. R. Ferrie, and J. E. Krochko Isolation of an embryogenic line from non-embryogenic Brassica napus cv. Westar through microspore embryogenesis J. Exp. Bot., July 1, 2008; 59(10): 2857 - 2873. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Gao, S. Wang, T. Asami, and J.-G. Chen Loss-of-Function Mutations in the Arabidopsis Heterotrimeric G-protein {alpha} Subunit Enhance the Developmental Defects of Brassinosteroid Signaling and Biosynthesis Mutants Plant Cell Physiol., July 1, 2008; 49(7): 1013 - 1024. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. Matsuoka, T. Demura, I. Galis, T. Horiguchi, M. Sasaki, G. Tashiro, and H. Fukuda A Comprehensive Gene Expression Analysis Toward the Understanding of Growth and Differentiation of Tobacco BY-2 Cells Plant Cell Physiol., September 15, 2004; 45(9): 1280 - 1289. [Abstract] [Full Text] [PDF]
|
|