Abstract
Our previous work demonstrated substantial accumulation of allantoate in leaf tissue of nodulated soybeans (Glycine max L. Merr., cv Williams) in response to nitrogen fertilization. Research was continued to determine the effect of nitrate and asparagine on ureide assimilation in soybean leaves. Stem infusion of asparagine into ureide-transporting soybeans resulted in a significant increase in allantoate concentration in leaf tissue. Accumulation of allantoate was also observed when asparagine was supplied in the presence of allopurinol, an inhibitor of xanthine dehydrogenase in the pathway of ureide biosynthesis. In vitro, asparagine was found to have an inhibitory effect on the activity of allantoate amidohydrolase, a Mn2+-dependent enzyme catalyzing allantoate breakdown in soybean leaves. The inhibition was partially overcome by supplemental Mn2+ in enzyme assays. Another inhibitor of allantoate amidohydrolase, boric acid, applied foliarly on field-grown nodulated soybeans, caused up to a 10-fold increase in allantoate content of leaf tissue. Accumulation of allantoate in response to boric acid was either eliminated or greatly reduced in plants presprayed with Mn2+. We conclude that elevated levels of allantoate in leaves of ureide-transporting soybeans fertilized with ammonium nitrate result from inhibition of allantoate degradation by asparagine and that Mn2+ is a critical factor in this inhibition. Furthermore, our studies with asparagine and boric acid indicate that availability of Mn2+ has a direct effect on ureide catabolism in soybean.
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- Fujihara S., Yamaguchi M. Effects of Allopurinol [4-Hydroxypyrazolo(3,4-d)Pyrimidine] on the Metabolism of Allantoin in Soybean Plants. Plant Physiol. 1978 Jul;62(1):134–138. doi: 10.1104/pp.62.1.134. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Grabau L. J., Blevins D. G., Minor H. C. Stem infusions enhanced methionine content of soybean storage protein. Plant Physiol. 1986 Dec;82(4):1013–1018. doi: 10.1104/pp.82.4.1013. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McClure P. R., Israel D. W., Volk R. J. Evaluation of the Relative Ureide Content of Xylem Sap as an Indicator of N(2) Fixation in Soybeans: GREENHOUSE STUDIES. Plant Physiol. 1980 Oct;66(4):720–725. doi: 10.1104/pp.66.4.720. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 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]
- Triplett E. W., Blevins D. G., Randall D. D. Allantoic Acid Synthesis in Soybean Root Nodule Cytosol via Xanthine Dehydrogenase. Plant Physiol. 1980 Jun;65(6):1203–1206. doi: 10.1104/pp.65.6.1203. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Winkler R. G., Blevins D. G., Polacco J. C., Randall D. D. Ureide Catabolism of Soybeans : II. Pathway of Catabolism in Intact Leaf Tissue. Plant Physiol. 1987 Mar;83(3):585–591. doi: 10.1104/pp.83.3.585. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Winkler R. G., Blevins D. G., Randall D. D. Ureide Catabolism in Soybeans : III. Ureidoglycolate Amidohydrolase and Allantoate Amidohydrolase Are Activities of an Allantoate Degrading Enzyme Complex. Plant Physiol. 1988 Apr;86(4):1084–1088. doi: 10.1104/pp.86.4.1084. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Winkler R. G., Polacco J. C., Blevins D. G., Randall D. D. Enzymic degradation of allantoate in developing soybeans. Plant Physiol. 1985 Nov;79(3):787–793. doi: 10.1104/pp.79.3.787. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Winkler R. G., Polacco J. C., Blevins D. G., Randall D. D. Enzymic degradation of allantoate in developing soybeans. Plant Physiol. 1985 Nov;79(3):787–793. doi: 10.1104/pp.79.3.787. [DOI] [PMC free article] [PubMed] [Google Scholar]