OPEN ACCESS ARTICLE

This Article Free via Open Access: OA OA Full Text Full Text (PDF) Supplemental Data OA All Versions of this Article: 149/2/653    most recent pp.108.130518v1 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 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 (3) Citing Articles via Google Scholar Google Scholar Articles by van der Merwe, M. J. Articles by Fernie, A. R. Search for Related Content PubMed PubMed Citation Articles by van der Merwe, M. J. Articles by Fernie, A. R. Agricola Articles by van der Merwe, M. J. Articles by Fernie, A. R.

BIOCHEMICAL PROCESSES AND MACROMOLECULAR STRUCTURES

Decreased Mitochondrial Activities of Malate Dehydrogenase and Fumarase in Tomato Lead to Altered Root Growth and Architecture via Diverse Mechanisms^1,[W],[OA]

Max Planck Institute of Molecular Plant Physiology, D–14476 Potsdam-Golm, Germany (M.J.v.d.M., S.O., A.N.-N., A.R.F.); and Umeå Plant Science Center, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE–90183 Umeå, Sweden (T.M.)

Transgenic tomato (Solanum lycopersicum) plants in which either mitochondrial malate dehydrogenase or fumarase was antisense inhibited have previously been characterized to exhibit altered photosynthetic metabolism. Here, we demonstrate that these manipulations also resulted in differences in root growth, with both transgenics being characterized by a dramatic reduction of root dry matter deposition and respiratory activity but opposite changes with respect to root area. A range of physiological, molecular, and biochemical experiments were carried out in order to determine whether changes in root morphology were due to altered metabolism within the root itself, alterations in the nature of the transformants' root exudation, consequences of alteration in the efficiency of photoassimilate delivery to the root, or a combination of these factors. Grafting experiments in which the transformants were reciprocally grafted to wild-type controls suggested that root length and area were determined by the aerial part of the plant but that biomass was not. Despite the transgenic roots displaying alteration in the expression of phytohormone-associated genes, evaluation of the levels of the hormones themselves revealed that, with the exception of gibberellins, they were largely unaltered. When taken together, these combined experiments suggest that root biomass and growth are retarded by root-specific alterations in metabolism and gibberellin contents. These data are discussed in the context of current models of root growth and biomass partitioning.

The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Alisdair R. Fernie (fernie{at}mpimp-golm.mpg.de).

^[W] The online version of this article contains Web-only data.

^[OA] Open Access articles can be viewed online without a subscription.

www.plantphysiol.org/cgi/doi/10.1104/pp.108.130518

^* Corresponding author; e-mail fernie{at}mpimp-golm.mpg.de.

Received September 29, 2008; accepted November 19, 2008; published November 21, 2008.

This article has been cited by other articles:

				A. Sienkiewicz-Porzucek, R. Sulpice, S. Osorio, I. Krahnert, A. Leisse, E. Urbanczyk-Wochniak, M. Hodges, A. R. Fernie, and A. Nunes-Nesi Mild Reductions in Mitochondrial NAD-Dependent Isocitrate Dehydrogenase Activity Result in Altered Nitrate Assimilation and Pigmentation But Do Not Impact Growth Mol Plant, January 1, 2010; 3(1): 156 - 173. [Abstract] [Full Text] [PDF]

				M. I. Zanor, S. Osorio, A. Nunes-Nesi, F. Carrari, M. Lohse, B. Usadel, C. Kuhn, W. Bleiss, P. Giavalisco, L. Willmitzer, et al. RNA Interference of LIN5 in Tomato Confirms Its Role in Controlling Brix Content, Uncovers the Influence of Sugars on the Levels of Fruit Hormones, and Demonstrates the Importance of Sucrose Cleavage for Normal Fruit Development and Fertility Plant Physiology, July 1, 2009; 150(3): 1204 - 1218. [Abstract] [Full Text] [PDF]