Skip to main content
PMC home page
Plant Physiology logoLink to Plant Physiology
. 1978 Oct;62(4):495–498. doi: 10.1104/pp.62.4.495

Allantoin and Allantoic Acid in the Nitrogen Economy of the Cowpea (Vigna unguiculata [L.] Walp.) 1

David F Herridge 1, Craig A Atkins 1, John S Pate 1, Ross M Rainbird 1
PMCID: PMC1092158  PMID: 16660546

Abstract

The ureides, allantoin and allantoic acid, represented major fractions of the soluble nitrogen pool of nodulated plants of cowpea (Vigna unguiculata [L.] Walp. cv. Caloona) throughout vegetative and reproductive growth. Stem and petioles were the principal sites of ureide accumulation, especially in early fruiting.

Labeling studies using 14CO2 and 15N2 and incubation periods of 25 to 245 minutes indicated that synthesis of allantoin and allantoic acid in root nodules involved currently delivered photosynthate and recently fixed N, and that the ureides were exported from nodule to shoot via the xylem. From 60 to 80% of xylem-borne N consisted of ureides; the remainder was glutamine, asparagine, and amino acids. Allantoin predominated in the soluble N fraction of nodules and fruits, allantoin and allantoic acid were present in approximately equal proportions in xylem exudate, stems, and petioles.

Extracts of the plant tissue fraction of nitrogen-fixing cowpea nodules contained glutamate synthase (EC 2.6.1.53) and glutamine synthetase (EC 6.3.1.2), but little activity of glutamate dehydrogenase (EC 1.4.1.3). High levels of uricase (EC 1.7.3.3) and allantoinase (EC 3.5.2.5) were also detected. Allantoinase but little uricase was found in extracts of leaflets, pods, and seeds.

Balance sheets were constructed for production, storage, and utilization of ureide N during growth. Virtually all (average 92%) of the ureides exported from roots was metabolized on entering the shoot, the compounds being presumably used as N sources for protein synthesis.

Full text

PDF
497

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Atkins C. A., Pate J. S., Sharkey P. J. Asparagine metabolism-key to the nitrogen nutrition of developing legume seeds. Plant Physiol. 1975 Dec;56(6):807–812. doi: 10.1104/pp.56.6.807. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Herridge D. F., Pate J. S. Utilization of net photosynthate for nitrogen fixation and protein production in an annual legume. Plant Physiol. 1977 Nov;60(5):759–764. doi: 10.1104/pp.60.5.759. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. LOWRY O. H., ROSEBROUGH N. J., FARR A. L., RANDALL R. J. Protein measurement with the Folin phenol reagent. J Biol Chem. 1951 Nov;193(1):265–275. [PubMed] [Google Scholar]
  4. O'Neal D., Joy K. W. Glutamine synthetase of pea leaves. I. Purification, stabilization, and pH optima. Arch Biochem Biophys. 1973 Nov;159(1):113–122. doi: 10.1016/0003-9861(73)90435-9. [DOI] [PubMed] [Google Scholar]
  5. Pate J. S., Sharkey P. J., Atkins C. A. Nutrition of a developing legume fruit: functional economy in terms of carbon, nitrogen, water. Plant Physiol. 1977 Mar;59(3):506–510. doi: 10.1104/pp.59.3.506. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Theimer R. R., Beevers H. Uricase and allantoinase in glyoxysomes. Plant Physiol. 1971 Feb;47(2):246–251. doi: 10.1104/pp.47.2.246. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Trijbels F., Vogels G. D. Degradation of allantoin by Pseudomonas acidovorans. Biochim Biophys Acta. 1966 Feb 14;113(2):292–301. doi: 10.1016/s0926-6593(66)80068-1. [DOI] [PubMed] [Google Scholar]

Articles from Plant Physiology are provided here courtesy of Oxford University Press

RESOURCES