title: A mutation in the E2 subunit of the mitochondrial pyruvate dehydrogenase complex in Arabidopsis reduces plant organ size and enhances the accumulation of amino acids and intermediate products of the TCA cycle.
abstract: The mitochondrial pyruvate dehydrogenase complex (mtPDC) plays a pivotal role in controlling the entry of carbon into the tricarboxylic acid (TCA) cycle for energy production. This multi-enzyme complex consists of three components: E1, E2, and E3. In Arabidopsis, there are three genes, mtE2-1, mtE2-2, and mtE2-3, which encode the putative mtPDC E2 subunit but how each of them contributes to the total mtPDC activity remains unknown. In this work, we characterized an Arabidopsis mutant, m132, that has abnormal small organs. Molecular cloning indicated that the phenotype of m132 is caused by a mutation in the mtE2-1 gene, which results in a truncation of 109 amino acids at the C-terminus of the encoded protein. In m132, mtPDC activity is only 30% of the WT and ATP production is severely impaired. The mutation in the mtE2-1 gene also leads to the over-accumulation of most intermediate products of the TCA cycle and of all the amino acids for protein synthesis. Our results suggest that, among the three mtE2 genes, mtE2-1 is a major contributor to the function of Arabidopsis mtPDC and that the functional disruption of mtE2-1 profoundly affects plant growth and development, as well as its metabolism.
authors.affiliation: MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
authors.forename: Hailan
authors.initials: H
authors.lastname: Yu
authors.forename: Xiaoqiu
authors.initials: X
authors.lastname: Du
authors.forename: Fengxia
authors.initials: F
authors.lastname: Zhang
authors.forename: Fang
authors.initials: F
authors.lastname: Zhang
authors.forename: Yong
authors.initials: Y
authors.lastname: Hu
authors.forename: Shichang
authors.initials: S
authors.lastname: Liu
authors.forename: Xiangning
authors.initials: X
authors.lastname: Jiang
authors.forename: Guodong
authors.initials: G
authors.lastname: Wang
authors.forename: Dong
authors.initials: D
authors.lastname: Liu
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis / Q000378:metabolism; D000596:Amino Acids / Q000378:metabolism*; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D002874:Chromosome Mapping; D002952:Citric Acid Cycle / Q000235:genetics*; D003583:Cytokinins / Q000032:analysis / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D008928:Mitochondria / Q000201:enzymology* / Q000235:genetics; D016254:Mutagenesis, Insertional; D009929:Organ Size / Q000235:genetics; D010641:Phenotype; D035261:Plant Components, Aerial / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D030821:Plants, Genetically Modified; D017434:Protein Structure, Tertiary; D011768:Pyruvate Dehydrogenase Complex / Q000235:genetics* / Q000378:metabolism; D019289:Pyruvic Acid / Q000032:analysis / Q000378:metabolism; D036226:Seedlings / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D012639:Seeds / Q000201:enzymology / Q000235:genetics / Q000254:growth & development / Q000648:ultrastructure; D017422:Sequence Analysis, DNA
chemical_list: D000596:Amino Acids; D003583:Cytokinins; D011768:Pyruvate Dehydrogenase Complex; D019289:Pyruvic Acid; D000255:Adenosine Triphosphate