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Arabidopsis peroxisomal malate dehydrogenase functions in β-oxidation but not in the glyoxylate cycle


Pracharoenwattana, I and Cornah, JE and Smith, SM, Arabidopsis peroxisomal malate dehydrogenase functions in β-oxidation but not in the glyoxylate cycle, The Plant Journal, 50, (3) pp. 381-390. ISSN 0960-7412 (2007) [Refereed Article]

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Copyright 2007 The Authors

DOI: doi:10.1111/j.1365-313X.2007.03055.x


The aim was to determine the function of peroxisomal NAD+-malate dehydrogenase (PMDH) in fatty acid β-oxidation and the glyoxylate cycle in Arabidopsis. Seeds in which both PMDH genes are disrupted by T-DNA insertions germinate, but seedling establishment is dependent on exogenous sugar. Mutant seedlings mobilize their triacylglycerol very slowly and growth is insensitive to 2,4-dichlorophenoxybutyric acid. Thus mutant seedlings are severely impaired in β-oxidation, even though microarray analysis shows that β-oxidation genes are expressed normally. The mutant phenotype was complemented by expression of a cDNA encoding PMDH with either its native peroxisome targeting signal-2 (PTS2) targeting sequence or a heterologous PTS1 sequence. In contrast to the block in β-oxidation in mutant seedlings, [14C]acetate is readily metabolized into sugars and organic acids, thereby demonstrating normal activity of the glyoxylate cycle. We conclude that PMDH serves to reoxidize NADH produced from fatty acid β-oxidation and does not participate directly in the glyoxylate cycle.

Item Details

Item Type:Refereed Article
Keywords:peroxisome, malate dehydrogenase, b-oxidation, glyoxylate cycle, fatty acids, Arabidopsis
Research Division:Biological Sciences
Research Group:Plant biology
Research Field:Plant physiology
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the biological sciences
UTAS Author:Smith, SM (Professor Steven Smith)
ID Code:101509
Year Published:2007
Web of Science® Times Cited:113
Deposited By:Plant Science
Deposited On:2015-06-25
Last Modified:2015-09-24

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