title: Ethylene is differentially regulated during sugar beet germination and affects early root growth in a dose-dependent manner.
abstract: By integrating molecular, biochemical, and physiological data, ethylene biosynthesis in sugar beet was shown to be differentially regulated, affecting root elongation in a concentration-dependent manner. There is a close relation between ethylene production and seedling growth of sugar beet (Beta vulgaris L.), yet the exact function of ethylene during this early developmental stage is still unclear. While ethylene is mostly considered to be a root growth inhibitor, we found that external 1-aminocyclopropane-1-carboxylic acid (ACC) regulates root growth in sugar beet in a concentration-dependent manner: low concentrations stimulate root growth while high concentrations inhibit root growth. These results reveal that ethylene action during root elongation is strongly concentration dependent. Furthermore our detailed study of ethylene biosynthesis kinetics revealed a very strict gene regulation pattern of ACC synthase (ACS) and ACC oxidase (ACO), in which ACS is the rate liming step during sugar beet seedling development.
authors.affiliation: Division of Crop Biotechnics, Department of Biosystems, Katholieke Universiteit Leuven, Willem de Croylaan 42, bus 2427, 3001, Leuven, Belgium, willem.abts@biw.kuleuven.be.
authors.forename: Willem
authors.initials: W
authors.lastname: Abts
authors.forename: Bram
authors.initials: B
authors.lastname: Van de Poel
authors.forename: Bert
authors.initials: B
authors.lastname: Vandenbussche
authors.forename: Maurice P
authors.initials: MP
authors.lastname: De Proft
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000187:drug effects / Q000235:genetics; D000598:Amino Acids, Cyclic / Q000494:pharmacology*; D027461:Beta vulgaris / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D005030:Ethylenes / Q000378:metabolism*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D018525:Germination / Q000187:drug effects; D008190:Lyases / Q000187:drug effects / Q000235:genetics; D010641:Phenotype; D010937:Plant Growth Regulators / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000235:genetics / Q000254:growth & development*; D036226:Seedlings / Q000187:drug effects / Q000201:enzymology / Q000235:genetics
chemical_list: D000598:Amino Acids, Cyclic; D005030:Ethylenes; D010937:Plant Growth Regulators; C023863:1-aminocyclopropane-1-carboxylic acid; C036216:ethylene; D000594:Amino Acid Oxidoreductases; C059460:1-aminocyclopropane-1-carboxylic acid oxidase; D008190:Lyases; C021773:1-aminocyclopropanecarboxylate synthase