A new anaplerotic respiratory pathway involving lysine biosynthesis in isocitrate dehydrogenase-deficient Arabidopsis mutants
Article first published online: 30 MAY 2013
© 2013 The Authors. New Phytologist © 2013 New Phytologist Trust
Volume 199, Issue 3, pages 673–682, August 2013
How to Cite
Boex-Fontvieille, E. R. A., Gauthier, P. P. G., Gilard, F., Hodges, M. and Tcherkez, G. G. B. (2013), A new anaplerotic respiratory pathway involving lysine biosynthesis in isocitrate dehydrogenase-deficient Arabidopsis mutants. New Phytologist, 199: 673–682. doi: 10.1111/nph.12319
- Issue published online: 11 JUL 2013
- Article first published online: 30 MAY 2013
- Manuscript Accepted: 7 APR 2013
- Manuscript Received: 29 JAN 2013
- Research National Agency. Grant Number: 08-330055
- isocitrate dehydrogenase;
- The cornerstone of carbon (C) and nitrogen (N) metabolic interactions – respiration – is presently not well understood in plant cells: the source of the key intermediate 2-oxoglutarate (2OG), to which reduced N is combined to yield glutamate and glutamine, remains somewhat unclear.
- We took advantage of combined mutations of NAD- and NADP-dependent isocitrate dehydrogenase activity and investigated the associated metabolic effects in Arabidopsis leaves (the major site of N assimilation in this genus), using metabolomics and 13C-labelling techniques.
- We show that a substantial reduction in leaf isocitrate dehydrogenase activity did not lead to changes in the respiration efflux rate but respiratory metabolism was reorchestrated: 2OG production was supplemented by a metabolic bypass involving both lysine synthesis and degradation.
- Although the recycling of lysine has long been considered important in sustaining respiration, we show here that lysine neosynthesis itself participates in an alternative respiratory pathway. Lys metabolism thus contributes to explaining the metabolic flexibility of plant leaves and the effect (or the lack thereof) of respiratory mutations.