title: Arabidopsis A BOUT DE SOUFFLE is a putative mitochondrial transporter involved in photorespiratory metabolism and is required for meristem growth at ambient CO₂ levels.
abstract: Photorespiratory metabolism is essential in all oxygenic photosynthetic organisms. In plants, it is a highly compartmentalized pathway that involves chloroplasts, peroxisomes, mitochondria and the cytoplasm. The metabolic pathway itself is well characterized, and the enzymes required for its function have been identified. However, very little information is available on the transport proteins that catalyze the high metabolic flux between the involved compartments. Here we show that the A BOUT DE SOUFFLE (BOU) gene, which encodes a mitochondrial carrier, is involved in photorespiration in Arabidopsis. BOU was found to be co-expressed with photorespiratory genes in leaf tissues. The knockout mutant bou-2 showed the hallmarks of a photorespiratory growth phenotype, an elevated CO(2)  compensation point, and excessive accumulation of glycine. Furthermore, degradation of the P-protein, a subunit of glycine decarboxylase, was demonstrated for bou-2, and is reflected in strongly reduced glycine decarboxylase activity. The photorespiration defect in bou-2 has dramatic consequences early in the seedling stage, which are highlighted by transcriptome studies. In bou-2 seedlings, as in shm1, another photorespiratory mutant, the shoot apical meristem organization is severely compromised. Cell divisions are arrested, leading to growth arrest at ambient CO(2) . Although the specific substrate for the BOU transporter protein remains elusive, we show that it is essential for the function of the photorespiratory metabolism. We hypothesize that BOU function is linked with glycine decarboxylase activity, and is required for normal apical meristems functioning in seedlings.
authors.affiliation: Institut für Biochemie der Pflanzen, Heinrich-Heine Universität Düsseldorf, 40225 Düsseldorf, Germany.
authors.forename: Marion
authors.initials: M
authors.lastname: Eisenhut
authors.forename: Severine
authors.initials: S
authors.lastname: Planchais
authors.forename: Cécile
authors.initials: C
authors.lastname: Cabassa
authors.forename: Anne
authors.initials: A
authors.lastname: Guivarc'h
authors.forename: Anne-Marie
authors.initials: AM
authors.lastname: Justin
authors.forename: Ludivine
authors.initials: L
authors.lastname: Taconnat
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Renou
authors.forename: Marc
authors.initials: M
authors.lastname: Linka
authors.forename: David
authors.initials: D
authors.lastname: Gagneul
authors.forename: Stefan
authors.initials: S
authors.lastname: Timm
authors.forename: Hermann
authors.initials: H
authors.lastname: Bauwe
authors.forename: Pierre
authors.initials: P
authors.lastname: Carol
authors.forename: Andreas P M
authors.initials: AP
authors.lastname: Weber
mesh_terms: D000596:Amino Acids / Q000032:analysis / Q000378:metabolism; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000502:physiology / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism*; D019069:Cell Respiration; D020869:Gene Expression Profiling; D005816:Genetic Complementation Test; D005998:Glycine / Q000378:metabolism; D050841:Glycine Dehydrogenase (Decarboxylating) / Q000378:metabolism*; D008027:Light; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D018519:Meristem / Q000166:cytology / Q000235:genetics* / Q000502:physiology / Q000528:radiation effects; D053858:Metabolic Networks and Pathways; D008928:Mitochondria / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis; D010084:Oxidation-Reduction; D010788:Photosynthesis; D018515:Plant Leaves / Q000166:cytology / Q000235:genetics / Q000502:physiology / Q000528:radiation effects; D030821:Plants, Genetically Modified; D036226:Seedlings / Q000166:cytology / Q000235:genetics / Q000502:physiology / Q000528:radiation effects
chemical_list: D000596:Amino Acids; D029681:Arabidopsis Proteins; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; C469261:a bout de souffle protein, Arabidopsis; D002245:Carbon Dioxide; D050841:Glycine Dehydrogenase (Decarboxylating); D005998:Glycine