Arabidopsis peroxisomal citrate synthase is required for fatty acid respiration and seed germination
journal contribution
posted on 2023-05-18, 11:22authored byPracharoenwattana, I, Cornah, JE, Steven SmithSteven Smith
We tested the hypothesis that peroxisomal citrate synthase (CSY) is required for carbon transfer from peroxisomes to mitochondria during respiration of triacylglycerol in Arabidopsis thaliana seedlings. Twogenes encoding peroxisomal CSYare expressed in Arabidopsis seedlings, and seeds from plants with both CSY genes disrupted were dormant and did not metabolize triacylglycerol. Germination was achieved by removing the seed coat and supplying sucrose, but the seedlings still did not use triacylglycerol. The mutant seedlings were resistant to 2,4-dichlorophenoxybutyric acid, indicating a block in peroxisomal b-oxidation, and were unable to develop further after transfer to soil. The mutant phenotype was complemented with acDNAencodingCSYwith either its native peroxisomal targeting sequence (PTS2) or a heterologous PTS1sequence from pumpkin (Cucurbita pepo) malate synthase. These results suggest that peroxisomal CSY in Arabidopsis is not only a key enzyme of the glyoxylate cycle but also catalyzes an essential step in the respiration of fatty acids. We conclude that citrate is exported from the peroxisome during fatty acid respiration, whereas in yeast, acetylcarnitine is exported.
History
Publication title
Plant Cell
Volume
17
Issue
7
Pagination
2037-2048
ISSN
1040-4651
Department/School
School of Natural Sciences
Publisher
Amer Soc Plant Biologists
Place of publication
15501 Monona Drive, Rockville, USA, Md, 20855
Rights statement
Copyright 2005 American Society of Plant Biologists