The ribokinases of Arabidopsis thaliana and Saccharomyces cerevisiae are required for ribose recycling from nucleotide catabolism, which in plants is not essential to survive prolonged dark stress

authored by
Rebekka Y. Schroeder, Anting Zhu, Holger Eubel, Kathleen Dahncke, Claus Peter Witte
Abstract

Nucleotide catabolism in Arabidopsis thaliana and Saccharomyces cerevisiae leads to the release of ribose, which requires phosphorylation to ribose-5-phosphate mediated by ribokinase (RBSK). We aimed to characterize RBSK in plants and yeast, to quantify the contribution of plant nucleotide catabolism to the ribose pool, and to investigate whether ribose carbon contributes to dark stress survival of plants. We performed a phylogenetic analysis and determined the kinetic constants of plant-expressed Arabidopsis and yeast RBSKs. Using mass spectrometry, several metabolites were quantified in AtRBSK mutants and double mutants with genes of nucleoside catabolism. Additionally, the dark stress performance of several nucleotide metabolism mutants and rbsk was compared. The plant PfkB family of sugar kinases forms nine major clades likely representing distinct biochemical functions, one of them RBSK. Nucleotide catabolism is the dominant ribose source in plant metabolism and is highly induced by dark stress. However, rbsk cannot be discerned from the wild type in dark stress. Interestingly, the accumulation of guanosine in a guanosine deaminase mutant strongly enhances dark stress symptoms. Although nucleotide catabolism contributes to carbon mobilization upon darkness and is the dominant source of ribose, the contribution appears to be of minor importance for dark stress survival.

Organisation(s)
Institute of Plant Nutrition
Institute of Plant Genetics
External Organisation(s)
Freie Universität Berlin
Type
Article
Journal
New Phytologist
Volume
217
Pages
233-244
No. of pages
12
ISSN
0028-646X
Publication date
28.11.2017
Publication status
Published
Peer reviewed
Yes
ASJC Scopus subject areas
Physiology, Plant Science
Electronic version(s)
https://doi.org/10.1111/nph.14782 (Access: Open)