Biosynthetic origin of the nitrogen atom in cyanamide in Vicia villosa subsp. varia
Article first published online: 25 MAR 2009
© 2009 Japanese Society of Soil Science and Plant Nutrition.
Soil Science & Plant Nutrition
Volume 55, Issue 2, pages 235–242, April 2009
How to Cite
KAMO, T., KATO, K., ABE, S., HIROTA, M., YAMAYA, H., HIRADATE, S. and FUJII, Y. (2009), Biosynthetic origin of the nitrogen atom in cyanamide in Vicia villosa subsp. varia. Soil Science & Plant Nutrition, 55: 235–242. doi: 10.1111/j.1747-0765.2008.00354.x
- Issue published online: 25 MAR 2009
- Article first published online: 25 MAR 2009
- Received 7 August 2008.; Accepted for publication 9 November 2008.
- stable isotope;
- Vicia villosa subsp. varia
Natural cyanamide (NH2CN) has recently been found in three Leguminosae plants: Vicia villosa subsp. varia, Vicia cracca and Robinia pseudo-acacia. As cyanamide has long been thought to be absent in nature, its physiological role and biosynthesis are totally unknown. In the present study, we demonstrated the incorporation of 15N from [15N]nitrate and [15N]ammonium into cyanamide using shoots of V. villosa subsp. varia, which ruled out the possibility that nodules are essential in cyanamide biosynthesis. We also applied [15N2]cyanamide to shoots of V. villosa subsp. varia to monitor its turnover, and detected [15N2]cyanamide in the leaves within 4 h; it was present without detectable degradation for more than 4 days. In contrast, maximum incorporation of 15N into cyanamide molecules was observed after 4 days of feeding the shoots with 15N-labeled inorganic ions and l-[amide-15N]-glutamine, indicating that these nitrogenous compounds are distant precursors of cyanamide. Although the guanidino group of l-arginine (-NH-C(NH2)=NH) and urea (NH2C(=O)NH2) were candidate precursors of cyanamide on the basis of structural similarity, direct incorporation of the guanidino group of l-[13C6,15N4]-arginine and [13C,15N2]urea into cyanamide was not observed. These results eliminated the possibility that cyanamide is biosynthesized by the addition of ammonia to an electrophilic carbon or by the conversion of the tested compounds that were structurally relevant to cyanamide.