The primary metabolic fate of phenylalanine, following its deamination in plants, is conscription of its carbon skeleton for lignin, suberin, flavonoid, and related metabolite formation. Since this accounts for 30-40% of all organic carbon, an effective means of recycling the liberated ammonium ion must be operative. In order to establish how this occurs, the uptake and metabolism of various N-labeled precursors (N-Phe, NHCl, N-Gln, and N-Glu) in lignifying Pinus taeda cell cultures was investigated, using a combination of high performance liquid chromatography, N NMR, and gas chromatography-mass spectrometry analyses. It was found that the ammonium ion released during active phenylpropanoid metabolism was not made available for general amino acid/protein synthesis. Rather it was rapidly recycled back to regenerate phenylalanine, thereby providing an effective means of maintaining active phenylpropanoid metabolism with no additional nitrogen requirement. These results strongly suggest that, in lignifying cells, ammonium ion reassimilation is tightly compartmentalized.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				S. A. Harding, M. M. Jarvie, R. L. Lindroth, and C.-J. Tsai A comparative analysis of phenylpropanoid metabolism, N utilization, and carbon partitioning in fast- and slow-growing Populus hybrid clones J. Exp. Bot., June 10, 2009; (2009) erp180v1. [Abstract] [Full Text] [PDF]

				M.-H. Cho, O. R. A. Corea, H. Yang, D. L. Bedgar, D. D. Laskar, A. M. Anterola, F. A. Moog-Anterola, R. L. Hood, S. E. Kohalmi, M. A. Bernards, et al. Phenylalanine Biosynthesis in Arabidopsis thaliana: IDENTIFICATION AND CHARACTERIZATION OF AROGENATE DEHYDRATASES J. Biol. Chem., October 19, 2007; 282(42): 30827 - 30835. [Abstract] [Full Text] [PDF]

				F. M. Canovas, C. Avila, F. R. Canton, R. A. Canas, and F. de la Torre Ammonium assimilation and amino acid metabolism in conifers J. Exp. Bot., July 1, 2007; 58(9): 2307 - 2318. [Abstract] [Full Text] [PDF]

				L. A. Rogers, C. Dubos, I. F. Cullis, C. Surman, M. Poole, J. Willment, S. D. Mansfield, and M. M. Campbell Light, the circadian clock, and sugar perception in the control of lignin biosynthesis J. Exp. Bot., June 1, 2005; 56(416): 1651 - 1663. [Abstract] [Full Text] [PDF]

				O. Fliniaux, F. Mesnard, S. Raynaud-Le Grandic, S. Baltora-Rosset, C. Bienaime, R. J. Robins, and M.-A. Fliniaux Altered nitrogen metabolism associated with de-differentiated suspension cultures derived from root cultures of Datura stramonium studied by heteronuclear multiple bond coherence (HMBC) NMR spectroscopy J. Exp. Bot., May 1, 2004; 55(399): 1053 - 1060. [Abstract] [Full Text] [PDF]

				D.-K. Ro and C. J. Douglas Reconstitution of the Entry Point of Plant Phenylpropanoid Metabolism in Yeast (Saccharomyces cerevisiae): IMPLICATIONS FOR CONTROL OF METABOLIC FLUX INTO THE PHENYLPROPANOID PATHWAY J. Biol. Chem., January 23, 2004; 279(4): 2600 - 2607. [Abstract] [Full Text] [PDF]

				A. M. Anterola, J.-H. Jeon, L. B. Davin, and N. G. Lewis Transcriptional Control of Monolignol Biosynthesis in Pinus taeda. FACTORS AFFECTING MONOLIGNOL RATIOS AND CARBON ALLOCATION IN PHENYLPROPANOID METABOLISM J. Biol. Chem., May 17, 2002; 277(21): 18272 - 18280. [Abstract] [Full Text] [PDF]

				D. R. Gang, H. Kasahara, Z.-Q. Xia, K. Vander Mijnsbrugge, G. Bauw, W. Boerjan, M. Van Montagu, L. B. Davin, and N. G. Lewis Evolution of Plant Defense Mechanisms. RELATIONSHIPS OF PHENYLCOUMARAN BENZYLIC ETHER REDUCTASES TO PINORESINOL-LARICIRESINOL AND ISOFLAVONE REDUCTASES J. Biol. Chem., March 12, 1999; 274(11): 7516 - 7527. [Abstract] [Full Text] [PDF]