Lysine (Lys) connects the mitochondrial electron transport chain to amino acid catabolism and the tricarboxylic acid cycle. However, our understanding of how a deficiency in Lys biosynthesis impacts plant metabolism and growth remains limited. Here, we used a previously characterized Arabidopsis mutant (dapat) with reduced activity of the Lys biosynthesis enzyme L,L-diaminopimelate aminotransferase to investigate the physiological and metabolic impacts of impaired Lys biosynthesis. Despite displaying similar stomatal conductance and internal CO2 concentration, we observed reduced photosynthesis and growth in the dapat mutant. Surprisingly, whilst we did not find differences in dark respiration between genotypes, a lower storage and consumption of starch and sugars was observed in dapat plants. We found higher protein turnover but no differences in total amino acids during a diurnal cycle in dapat plants. Transcriptional and two-dimensional (isoelectric focalization/SDS-PAGE) proteome analyses revealed alterations in the abundance of several transcripts and proteins associated with photosynthesis and photorespiration coupled with a high glycine/serine ratio and increased levels of stress-responsive amino acids. Taken together, our findings demonstrate that biochemical alterations rather than stomatal limitations are responsible for the decreased photosynthesis and growth of the dapat mutant, which we hypothesize mimics stress conditions associated with impairments in the Lys biosynthesis pathway.
Bibliographical noteFunding Information:
We thank the Biomolecules Analysis Core (NUBIOMOL) at the Universidade Federal de Viçosa and Fiocruz (Rio de Janeiro, Brazil) for providing the facilities allowing metabolomics and proteomics analyses. This work was supported by funding from the Max Planck Society (to WLA), the National Council for Scientific and Technological Development (CNPq-Brazil, Grant 402511/2016-6 to WLA), and the Foundation for Research Assistance of the Minas Gerais State (FAPEMIG; Grant APQ-01357-14, APQ-01078-15, and RED-00053-16 to WLA). Scholarship granted by CNPq and FAPEMIG to JHFC, by the Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES-Brazil) to IAPL and CGSQ as well as research fellowships granted by CNPq-Brazil to ANN and WLA are gratefully acknowledged.The work performed by TAW was supported by Minerva, Alexander von Humboldt, and EMBO fellowships. The authors declare that there is no conflict of interest.
© The Author(s) 2018. Published by Oxford University Press on behalf of the Society for Experimental Biology. This is an Open Access article distributed under the terms of the Creative Commons Attribution License
- Alternative respiration
- Amino acid
- Carbon partition
- L-diaminopimelate aminotransferase
- Lysine biosynthesis
- Primary metabolism