RNA Catabolites Contribute to the Nitrogen Pool and Support Growth Recovery of Wheat

A - Papers appearing in refereed journals

Melino, V. J., Casartelli, A., George, J., Rupasinghe, T., Roessner, U., Okamoto, M. and Heuer, S. 2018. RNA Catabolites Contribute to the Nitrogen Pool and Support Growth Recovery of Wheat. Frontiers in Plant Science. 9, p. 1539. https://doi.org/10.3389/fpls.2018.01539

AuthorsMelino, V. J., Casartelli, A., George, J., Rupasinghe, T., Roessner, U., Okamoto, M. and Heuer, S.
Abstract

Turn-over of RNA and catabolism of nucleotides releases one to four ammonia molecules; the released nutrients being reassimilated into primary metabolism. Preliminary evidence indicates that monocots store high levels of free nucleotides and nucleosides but their potential as a source of internal organic nitrogen for use and remobilization is uncharted. Early tillering wheat plants were therefore starved of N over a 5-day time-course with examination of nucleic acid yields in whole shoots, young and old leaves and roots. Nucleic acids constituted ∼4% of the total N pool of N starved wheat plants, which was comparable with the N available from nitrate (NO3-) and greater than that available from the sum of 20 proteinogenic amino acids. Methods were optimized to detect nucleotide (purine and pyrimidine) metabolites, and wheat orthologs of RNA degradation (TaRNS), nucleoside transport (TaENT1, TaENT3) and salvage (TaADK) were identified. It was found that N starved wheat roots actively catabolised RNA and specific purines but accumulated pyrimidines. Reduced levels of RNA corresponded with induction of TaRNS2, TaENT1, TaENT3, and TaADK in the roots. Reduced levels of GMP, guanine, xanthine, allantoin, allantoate and glyoxylate in N starved roots correlated with accumulation of allantoate and glyoxylate in the oldest leaf, suggesting translocation of allantoin. Furthermore, N starved wheat plants exogenously supplied with N in the form of purine catabolites grew and photosynthesized as well as those plants re-supplied with NO3-. These results support the hypothesis that the nitrogen and carbon recovered from purine metabolism can support wheat growth.

KeywordsNitrogen recycling; Nitrate; Purines; Nucleosides; Triticum aestivum; Equilibrative nucleoside transporter; Ribonuclease; Adenosine kinase
Year of Publication2018
JournalFrontiers in Plant Science
Journal citation9, p. 1539
Digital Object Identifier (DOI)https://doi.org/10.3389/fpls.2018.01539
PubMed ID30455708
PubMed Central IDPMC6230992
Open accessPublished as ‘gold’ (paid) open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeDesigning Future Wheat (DFW) [ISPG]
DFW - Designing Future Wheat - Work package 1 (WP1) - Increased efficiency and sustainability
Publisher's version
Output statusPublished
Publication dates
Online02 Nov 2018
Publication process dates
Accepted01 Oct 2018
Copyright licenseCC BY
ISSN1664-462X
PublisherFrontiers Media SA

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