title: Alterations in the endogenous ascorbic acid content affect flowering time in Arabidopsis.
abstract: Ascorbic acid (AA) protects plants against abiotic stress. Previous studies suggested that this antioxidant is also involved in the control of flowering. To decipher how AA influences flowering time, we studied the four AA-deficient Arabidopsis (Arabidopsis thaliana) mutants vtc1-1, vtc2-1, vtc3-1, and vtc4-1 when grown under short and long days. These mutants flowered and senesced before the wild type irrespective of the photoperiod, a response that cannot simply be attributed to slightly elevated oxidative stress in the mutants. Transcript profiling of various flowering pathway genes revealed a correlation of altered mRNA levels and flowering time. For example, circadian clock and photoperiodic pathway genes were significantly higher in the vtc mutants than in the wild type under both short and long days, a result that is consistent with the early-flowering phenotype of the mutants. In contrast, when the AA content was artificially increased, flowering was delayed, which correlated with lower mRNA levels of circadian clock and photoperiodic pathway genes compared with plants treated with water. Similar observations were made for the autonomous pathway. Genetic analyses demonstrated that various photoperiodic and autonomous pathway mutants are epistatic to the vtc1-1 mutant. In conclusion, our transcript and genetic analyses suggest that AA acts upstream of the photoperiodic and autonomous pathways.
authors.affiliation: Department of Biology, West Virginia University, Morgantown, West Virginia 26506, USA.
authors.forename: Simeon O
authors.initials: SO
authors.lastname: Kotchoni
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Larrimore
authors.forename: Madhumati
authors.initials: M
authors.lastname: Mukherjee
authors.forename: Chase F
authors.initials: CF
authors.lastname: Kempinski
authors.forename: Carina
authors.initials: C
authors.lastname: Barth
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics; D001205:Ascorbic Acid / Q000378:metabolism*; D001206:Ascorbic Acid Deficiency / Q000235:genetics / Q000378:metabolism*; D016922:Cellular Senescence; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D010641:Phenotype; D010744:Phosphoric Monoester Hydrolases / Q000172:deficiency / Q000235:genetics; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism
chemical_list: D000975:Antioxidants; D029681:Arabidopsis Proteins; C522629:GDP-L-galactose phosphorylase, Arabidopsis; C512578:VTC4 protein, Arabidopsis; D010744:Phosphoric Monoester Hydrolases; D001205:Ascorbic Acid