title: The COMATOSE ATP-binding cassette transporter is required for full fertility in Arabidopsis.
abstract: COMATOSE (CTS) encodes a peroxisomal ATP-binding cassette transporter required not only for beta-oxidation of storage lipids during germination and establishment, but also for biosynthesis of jasmonic acid and conversion of indole butyric acid to indole acetic acid. cts mutants exhibited reduced fertilization, which was rescued by genetic complementation, but not by exogenous application of jasmonic acid or indole acetic acid. Reduced fertilization was also observed in thiolase (kat2-1) and peroxisomal acyl-Coenzyme A synthetase mutants (lacs6-1,lacs7-1), indicating a general role for beta-oxidation in fertility. Genetic analysis revealed reduced male transmission of cts alleles and both cts pollen germination and tube growth in vitro were impaired in the absence of an exogenous carbon source. Aniline blue staining of pollinated pistils demonstrated that pollen tube growth was affected only when both parents bore the cts mutation, indicating that expression of CTS in either male or female tissues was sufficient to support pollen tube growth in vivo. Accordingly, abundant peroxisomes were detected in a range of maternal tissues. Although gamma-aminobutyric acid levels were reduced in flowers of cts mutants, they were unchanged in kat2-1, suggesting that alterations in gamma-aminobutyric acid catabolism do not contribute to the reduced fertility phenotype through altered pollen tube targeting. Taken together, our data support an important role for beta-oxidation in fertility in Arabidopsis (Arabidopsis thaliana) and suggest that this pathway could play a role in the mobilization of lipids in both pollen and female tissues.
authors.affiliation: Crop Performance and Improvement Division, Rothamsted Research, Harpenden, Hertfordshire, UK.
authors.forename: Steven
authors.initials: S
authors.lastname: Footitt
authors.forename: Daniela
authors.initials: D
authors.lastname: Dietrich
authors.forename: Aaron
authors.initials: A
authors.lastname: Fait
authors.forename: Alisdair R
authors.initials: AR
authors.lastname: Fernie
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Holdsworth
authors.forename: Alison
authors.initials: A
authors.lastname: Baker
authors.forename: Frederica L
authors.initials: FL
authors.lastname: Theodoulou
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000502:physiology*; D000251:Adenosine Triphosphatases; D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D003517:Cyclopentanes / Q000378:metabolism; D005298:Fertility / Q000502:physiology; D005306:Fertilization; D035264:Flowers / Q000378:metabolism; D007210:Indoleacetic Acids / Q000378:metabolism; D009154:Mutation; D010084:Oxidation-Reduction; D054883:Oxylipins; D020675:Peroxisomes; D010641:Phenotype; D053205:Pollen Tube / Q000254:growth & development* / Q000502:physiology; D015221:Potassium Channels / Q000235:genetics; D024642:Potassium Channels, Voltage-Gated; D013395:Sucrose / Q000378:metabolism; D014280:Triglycerides / Q000378:metabolism*; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
chemical_list: D018528:ATP-Binding Cassette Transporters; D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D007210:Indoleacetic Acids; C428126:KAT2 protein, Arabidopsis; D054883:Oxylipins; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D014280:Triglycerides; D005680:gamma-Aminobutyric Acid; D013395:Sucrose; C011006:jasmonic acid; C030737:indoleacetic acid; D000251:Adenosine Triphosphatases; C456843:At4g39850 protein, Arabidopsis