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S-allantoin, a major ureide compound, is produced in plant peroxisomes from oxidized purines. Sequence evidence suggested that the Transthyretin-like (TTL) protein, which interacts with brassinosteroid receptors, may act as a bifunctional enzyme in the synthesis of S-allantoin. Here, we show that
Environmental variations resulting in biotic and abiotic stresses demand adaptive changes in the photosynthetic machinery. To cope with these challenges, plant scientists are constantly striving to enhance photosynthetic activity. The photorespiration pathway, which fixes O2 and releases
The single cell alga Chlamydomonas reinhardtii is capable of importing purines as nitrogen sources. An analysis of the annotated C. reinhardtii genome reveals at least three distinct gene families encoding for known nucleobase transporters. In this study the solute transport and binding properties
Allantoin is a purine oxidative product that serves for long distance transport of organic nitrogen in nodulating legumes and was recently related with stress tolerance in other plants. The subcellular localization of enzymes that lead to allantoin synthesis and degradation indicates that allantoin
We report the identification and cloning of an allantoate amidohydrolase (allantoate deiminase, EC 3.5.3.9) cDNA from Arabidopsis thaliana (L.) Heynh. This sequence, which we term Arabidopsis thaliana Allantoate Amidohydrolase (AtAAH), was shown to be functional by complementation of Saccharomyces
A wide spectrum of soil heterocyclic nitrogen compounds are potential nutrients for plants. Here, it is shown that Arabidopsis plants are able to use allantoin as sole nitrogen source. By functional complementation of a yeast mutant defective in allantoin uptake, an Arabidopsis transporter, AtUPS1
Plants apply various molecular, physiological and morphological strategies in response to undesirable environmental conditions. One of the possible responses which may contribute to surviving stressful conditions is the accumulation of ureides. Ureides are recognized as important nitrogen-rich
Ureides are nitrogenous compounds derived from purine catabolism which contribute to nitrogen recycling in plants. Accumulation of ureide compounds has been reported in a number of plant species under stress conditions, suggesting their involvement in plants' response to stress. In this research a
Allantoin, a metabolite generated in the purine degradation pathway, was primarily considered an intermediate for recycling of the abundant nitrogen assimilated in plant purines. More specifically, tropical legumes utilize allantoin and allantoic acid as major nodule-to-shoot nitrogen transport
Plants can respond and adapt to changes in the internal content of carbon and nitrogen by using organic compounds that widely differ in their carbon/nitrogen ratio. Among them, the amides asparagine and glutamine are believed to be preferred by most plants, including Arabidopsis. However, increases
Allantoate amidohydrolases (AAHs) hydrolize the ureide allantoate to ureidoglycolate, CO(2), and two molecules of ammonium. Allantoate degradation is required to recycle purine-ring nitrogen in all plants. Tropical legumes additionally transport fixed nitrogen via allantoin and allantoate into the
The nitrogen (N)-rich ureides allantoin and allantoate, which are products of purine catabolism, play a role in N delivery in Leguminosae. Here, we examined their role as an N source in nonlegume plants using Arabidopsis (Arabidopsis thaliana) plants mutated in XANTHINE DEHYDROGENASE1 (AtXDH1), a
The solute specificity profiles (transport and binding) for the nucleobase cation symporter 1 (NCS1) proteins, from the closely related C4 grasses Zea mays and Setaria viridis, differ from that of Arabidopsis thaliana and Chlamydomonas reinhardtii NCS1. Solute specificity profiles for NCS1 from Z.
Several ureides are intermediates of purine base catabolism, releasing nitrogen from the purine nucleotides for reassimilation into amino acids. In some legumes like soybean (Glycine max), ureides are used for nodule-to-shoot translocation of fixed nitrogen. Four enzymes of Arabidopsis (Arabidopsis
Cytokinins are distributed through the vascular system and trigger responses of target cells via receptor-mediated signal transduction. Perception and transduction of the signal can occur at the plasma membrane or in the cytosol. The signal is terminated by the action of extra- or intracellular