title: Oxygen control of ethylene biosynthesis during seed development in Arabidopsis thaliana (L.) Heynh.
abstract: An unforeseen side-effect on plant growth in reduced oxygen is the loss of seed production at concentrations around 25% atmospheric (50 mmol mol-1 O2). In this study, the model plant Arabidopsis thaliana (L.) Heynh. cv. 'Columbia' was used to investigate the effect of low oxygen on ethylene biosynthesis during seed development. Plants were grown in a range of oxygen concentrations (210 [equal to ambient], 160, 100, 50 and 25 mmol mol-1) with 0.35 mmol mol-1 CO2 in N2. Ethylene in full-sized siliques was sampled using gas chromatography, and viable seed production was determined at maturity. Molecular analysis of ethylene biosynthesis was accomplished using cDNAs encoding 1-aminocyclopropane-1-carboxylic acid (ACC) synthase and ACC oxidase in ribonuclease protection assays and in situ hybridizations. No ethylene was detected in siliques from plants grown at 50 and 25 mmol mol-1 O2. At the same time, silique ACC oxidase mRNA increased three-fold comparing plants grown under the lowest oxygen with ambient controls, whereas ACC synthase mRNA was unaffected. As O2 decreased, tissue-specific patterning of ACC oxidase and ACC synthase gene expression shifted from the embryo to the silique wall. These data demonstrate how low O2 modulates the activity and expression of the ethylene biosynthetic pathway during seed development in Arabidopsis.
authors.affiliation: Department of Plant Pathology and Crop Physiology, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, Baton Rouge, LA 70803, USA.
authors.forename: K M
authors.initials: KM
authors.lastname: Ramonell
authors.forename: G
authors.initials: G
authors.lastname: McClure
authors.forename: M E
authors.initials: ME
authors.lastname: Musgrave
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D002245:Carbon Dioxide / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D005030:Ethylenes / Q000096:biosynthesis*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D008190:Lyases / Q000235:genetics / Q000378:metabolism; D010100:Oxygen / Q000032:analysis / Q000494:pharmacology*; D012639:Seeds / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
chemical_list: D005030:Ethylenes; D002245:Carbon Dioxide; C036216:ethylene; D000594:Amino Acid Oxidoreductases; C059460:1-aminocyclopropane-1-carboxylic acid oxidase; D008190:Lyases; C021773:1-aminocyclopropanecarboxylate synthase; D010100:Oxygen