This Article Full Text Full Text (PDF) All Versions of this Article: 134/2/801    most recent pp.103.032318v1 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 Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via CrossRef Citing Articles via Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Wei, H. Articles by Layzell, D. B. Search for Related Content PubMed PubMed Citation Articles by Wei, H. Articles by Layzell, D. B. Agricola Articles by Wei, H. Articles by Layzell, D. B.

PLANTS INTERACTING WITH OTHER ORGANISMS

Adenylate Gradients and Ar:O₂ Effects on Legume Nodules: I. Mathematical Models¹

Department of Biology, Queen's University, Kingston, Ontario, Canada K7L 3N6 (H.W., D.B.L.); and Botany, School of Plant Biology, The University of Western Australia, Nedlands, Western Australia 6907, Australia (C.A.A.)

Mathematical models were developed to test the likelihood that large cytosolic adenylate concentration gradients exist across the bacteria-infected cells of legume nodules. Previous studies hypothesized that this may be the case to account for the unusually low adenylate energy charge (AEC; 0.65) measured in the plant fraction of metabolically active nodules (M.M. Kuzma, H. Winter, P. Storer, I. Oresnik, C.A. Atkins, D.B. Layzell [1999] Plant Physiol 119: 399–407). Simulations coupled leghemoglobin-facilitated O₂ diffusion into the infected cell, through bacteroid nitrogenase activity, with the ATP demand for transport and ammonia assimilation in the plant fraction of ureide- and amide-producing nodules. Although large cytosolic adenylate gradients were predicted to exist in both nodule types, amide nodules were predicted to have steeper AEC gradients (0.82–0.52) than ureide nodules (0.82–0.61). The differences were attributed to an additional ATP demand for Asn synthesis in the amide nodule. Simulations for nodules transferred to an Ar:O₂ atmosphere predicted a major reduction in the magnitude of adenylate gradients and an increase in the AEC of the plant fraction. Results were consistent with a number of experimental studies and were used to propose an experimental test of the models.

¹ This work was supported by the National Science and Engineering Research Council of Canada (grants to D.B.L.).

^* Corresponding author; e-mail layzelld{at}biology.queensu.ca; fax 613–533–6617.

Received September 1, 2003; returned for revision September 26, 2003; accepted November 10, 2003.

This article has been cited by other articles:

				A. U. Igamberdiev and L. A. Kleczkowski Equilibration of adenylates in the mitochondrial intermembrane space maintains respiration and regulates cytosolic metabolism J. Exp. Bot., July 1, 2006; 57(10): 2133 - 2141. [Abstract] [Full Text] [PDF]

				H. Wei and D. B. Layzell Adenylate-Coupled Ion Movement. A Mechanism for the Control of Nodule Permeability to O2 Diffusion Plant Physiology, May 1, 2006; 141(1): 280 - 287. [Abstract] [Full Text] [PDF]

				H. Wei, C. A. Atkins, and D. B. Layzell Adenylate Gradients and Ar:O2 Effects on Legume Nodules. II. Changes in the Subcellular Adenylate Pools Plant Physiology, April 1, 2004; 134(4): 1775 - 1783. [Abstract] [Full Text] [PDF]