This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 18/12/3564    most recent tpc.106.044958v1 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 ISI 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 ISI Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Joshi, V. Articles by Jander, G. Search for Related Content PubMed PubMed Citation Articles by Joshi, V. Articles by Jander, G. Agricola Articles by Joshi, V. Articles by Jander, G.

Two Arabidopsis Threonine Aldolases Are Nonredundant and Compete with Threonine Deaminase for a Common Substrate Pool^[W]

^a Boyce Thompson Institute for Plant Research, Ithaca, New York 14853
^b Max Planck Institute for Molecular Plant Physiology, Potsdam-Golm 14766, Germany

² To whom correspondence should be addressed. E-mail gj32{at}cornell.edu; fax 607-254-2958.

Amino acids are not only fundamental protein constituents but also serve as precursors for many essential plant metabolites. Although amino acid biosynthetic pathways in plants have been identified, pathway regulation, catabolism, and downstream metabolite partitioning remain relatively uninvestigated. Conversion of Thr to Gly and acetaldehyde by Thr aldolase (EC 4.1.2.5) was only recently shown to play a role in plant amino acid metabolism. Whereas one Arabidopsis thaliana Thr aldolase (THA1) is expressed primarily in seeds and seedlings, the other (THA2) is expressed in vascular tissue throughout the plant. Metabolite profiling of tha1 mutants identified a >50-fold increase in the seed Thr content, a 50% decrease in seedling Gly content, and few other significant metabolic changes. By contrast, homozygous tha2 mutations cause a lethal albino phenotype. Rescue of tha2 mutants and tha1 tha2 double mutants by overproduction of feedback-insensitive Thr deaminase (OMR1) shows that Gly formation by THA1 and THA2 is not essential in Arabidopsis. Seed-specific expression of feedback-insensitive Thr deaminase in both tha1 and tha2 Thr aldolase mutants greatly increases seed Ile content, suggesting that these two Thr catabolic enzymes compete for a common substrate pool.

This article has been cited by other articles:

				B. S. Zheng, E. Ronnberg, L. Viitanen, T. A. Salminen, K. Lundgren, T. Moritz, and J. Edqvist Arabidopsis sterol carrier protein-2 is required for normal development of seeds and seedlings. J. Exp. Bot., August 6, 2008; (2008) ern201v1. [Abstract] [Full Text] [PDF]

				H. Less and G. Galili Principal Transcriptional Programs Regulating Plant Amino Acid Metabolism in Response to Abiotic Stresses Plant Physiology, May 1, 2008; 147(1): 316 - 330. [Abstract] [Full Text] [PDF]

				Y. Lu, L. J. Savage, I. Ajjawi, K. M. Imre, D. W. Yoder, C. Benning, D. DellaPenna, J. B. Ohlrogge, K. W. Osteryoung, A. P. Weber, et al. New Connections across Pathways and Cellular Processes: Industrialized Mutant Screening Reveals Novel Associations between Diverse Phenotypes in Arabidopsis Plant Physiology, April 1, 2008; 146(4): 1482 - 1500. [Abstract] [Full Text] [PDF]