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Opposite fates of the purine metabolite allantoin under water and nitrogen limitations in bread wheat.

Authors :
Casartelli A
Melino VJ
Baumann U
Riboni M
Suchecki R
Jayasinghe NS
Mendis H
Watanabe M
Erban A
Zuther E
Hoefgen R
Roessner U
Okamoto M
Heuer S
Source :
Plant molecular biology [Plant Mol Biol] 2019 Mar; Vol. 99 (4-5), pp. 477-497. Date of Electronic Publication: 2019 Feb 05.
Publication Year :
2019

Abstract

Key Message: Degradation of nitrogen-rich purines is tightly and oppositely regulated under drought and low nitrogen supply in bread wheat. Allantoin is a key target metabolite for improving nitrogen homeostasis under stress. The metabolite allantoin is an intermediate of the catabolism of purines (components of nucleotides) and is known for its housekeeping role in nitrogen (N) recycling and also for its function in N transport and storage in nodulated legumes. Allantoin was also shown to differentially accumulate upon abiotic stress in a range of plant species but little is known about its role in cereals. To address this, purine catabolic pathway genes were identified in hexaploid bread wheat and their chromosomal location was experimentally validated. A comparative study of two Australian bread wheat genotypes revealed a highly significant increase of allantoin (up to 29-fold) under drought. In contrast, allantoin significantly decreased (up to 22-fold) in response to N deficiency. The observed changes were accompanied by transcriptional adjustment of key purine catabolic genes, suggesting that the recycling of purine-derived N is tightly regulated under stress. We propose opposite fates of allantoin in plants under stress: the accumulation of allantoin under drought circumvents its degradation to ammonium (NH <subscript>4</subscript> <superscript>+</superscript> ) thereby preventing N losses. On the other hand, under N deficiency, increasing the NH <subscript>4</subscript> <superscript>+</superscript> liberated via allantoin catabolism contributes towards the maintenance of N homeostasis.

Details

Language :
English
ISSN :
1573-5028
Volume :
99
Issue :
4-5
Database :
MEDLINE
Journal :
Plant molecular biology
Publication Type :
Academic Journal
Accession number :
30721380
Full Text :
https://doi.org/10.1007/s11103-019-00831-z