The importance of the urea cycle and its relationships to polyamine metabolism during ammonium stress in Medicago truncatula.

ABSTRACT: The ornithine-urea cycle (urea cycle) makes a significant contribution to the metabolic responses of lower photosynthetic eukaryotes to episodes of high nitrogen availability. In this study, we compared the role of the plant urea cycle and its relationships to polyamine metabolism in ammonium-fed and nitrate-fed Medicago truncatula plants. High ammonium resulted in the accumulation of ammonium and pathway intermediates, particularly glutamine, arginine, ornithine, and putrescine. Arginine decarboxylase activity was decreased in roots, suggesting that the ornithine decarboxylase-dependent production of putrescine was important in situations of ammonium stress. The activity of copper amine oxidase, which releases ammonium from putrescine, was significantly decreased in both shoots and roots.

SUBMITTER: Urra M 

PROVIDER: S-EPMC9467648 | biostudies-literature | 2022 Sep

REPOSITORIES: biostudies-literature