JXB Advance Access originally published online on May 28, 2003
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Journal of Experimental Botany, Vol. 54, No. 388, pp. 1685-1690,
July 1, 2003
© 2003 Oxford University Press
Nitrate-independent expression of plant nitrate reductase in Lotus japonicus root nodules
Received 9 January 2003; Accepted 3 April 2003
Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan
* To whom correspondence should be addressed. Fax: +81 (0)22 717 8642. E-mail: kanayama@bios.tohoku.ac.jp
Abbreviations: L. japonicus, Lotus japonicus; M. loti, Mesorhizobium loti; NR, nitrate reductase.
Nitrate-independent nitrate reductase (NR) activity is generally found in legume root nodules. Therefore, the effects of nitrate on plant NR activity and mRNA were investigated in the root nodules of Lotus japonicus (L. japonicus). Both NR activity and mRNA levels in roots and root nodules were up-regulated by the addition of nitrate. In the absence of nitrate, NR activity and mRNA were detected in root nodules but not in roots. Southern blotting analysis indicates that NR is encoded by a single gene in L. japonicus. No nitrate was detected in the root nodules or roots of plants grown in the absence of nitrate, while its accumulation was observed in plants supplied with exogenous nitrate. These results indicate that inducible-type NR can be expressed in root nodules in the absence of nitrate. The activation state of the nitrate-independent activity of NR was as high as that of NR activity induced by nitrate. NR mRNA expressed independently of nitrate in root nodules without nitrate was localized in the infected regions of the root nodules. Thus, the expression could be related to the specific structure and environment of root nodules.
Key words: Lotus japonicus, nitrate, nitrate reductase, nitrogen fixation, root nodule.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
N. Pauly, C. Pucciariello, K. Mandon, G. Innocenti, A. Jamet, E. Baudouin, D. Herouart, P. Frendo, and A. Puppo Reactive oxygen and nitrogen species and glutathione: key players in the legume-Rhizobium symbiosis J. Exp. Bot., May 1, 2006; 57(8): 1769 - 1776. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. J. Marquez, M. Betti, M. Garcia-Calderon, P. Pal'ove-Balang, P. Diaz, and J. Monza Nitrate assimilation in Lotus japonicus J. Exp. Bot., July 1, 2005; 56(417): 1741 - 1749. [Abstract] [Full Text] [PDF] |
||||
