title: Change in ATP-binding cassette B1/19, glutamine synthetase and alcohol dehydrogenase gene expression during root elongation in Betula pendula Roth and Alnus glutinosa L. Gaertn in response to leachate and leonardite humic substances.
abstract: Humic substances (HS) are complex and heterogeneous compounds of humified organic matter resulting from the chemical and microbiological decomposition of organic residues. HS have a positive effect on plant growth and development by improving soil structure and fertility. They have long been recognized as plant growth-promoting substances, particularly with regard to influencing nutrient uptake, root growth and architecture. The biochemical and molecular mechanisms through which HS influence plant physiology are not well understood. This study evaluated the bioactivity of landfill leachate and leonardite HS on alder (Alnus glutinosa L. Gaertn) and birch (Betula pendula Roth) during root elongation in vitro. Changes in root development were studied in relation to auxin, carbon and nitrogen metabolisms, as well as to the stress adaptive response. The cDNA fragments of putative genes encoding two ATP-binding cassette (ABC) transporters (ABCB1 and ABCB19) belonging to the B subfamily of plant ABC auxin transporters were cloned and sequenced. Molecular data indicate that HS and their humic acid (HA) fractions induce root growth by influencing polar auxin transport (PAT), as illustrated by the modulation of the ABCB transporter transcript levels (ABCB1 and ABCB19). There were also changes in alcohol dehydrogenase (ADH) and glutamine synthetase (GS) gene transcript levels in response to HS exposure. These findings confirmed that humic matter affects plant growth and development through various metabolic pathways, including hormonal, carbon and nitrogen metabolisms and stress response or signalization.
authors.affiliation: Walloon Agricultural Research Centre (CRA-W), Dept. of Life Sciences, Chaussée de Charleroi, 234, B-5030 Gembloux, Belgium; University of Liège, Gembloux Agro-Bio Tech, Walloon Center for Industrial Biology (CWBI), Passage des Déportés 2, B-5030 Gembloux, Belgium. Electronic address: atahiri@doct.ulg.ac.be.
authors.forename: Abdelghani
authors.initials: A
authors.lastname: Tahiri
authors.affiliation: Walloon Agricultural Research Centre (CRA-W), Dept. of Life Sciences, Chaussée de Charleroi, 234, B-5030 Gembloux, Belgium.
authors.forename: Fabienne
authors.initials: F
authors.lastname: Delporte
authors.affiliation: Walloon Agricultural Research Centre (CRA-W), Dept. of Life Sciences, Chaussée de Charleroi, 234, B-5030 Gembloux, Belgium.
authors.forename: Yordan
authors.initials: Y
authors.lastname: Muhovski
authors.affiliation: University of Liège, Gembloux Agro-Bio Tech, Walloon Center for Industrial Biology (CWBI), Passage des Déportés 2, B-5030 Gembloux, Belgium.
authors.forename: Marc
authors.initials: M
authors.lastname: Ongena
authors.affiliation: University of Liège, Gembloux Agro-Bio Tech, Walloon Center for Industrial Biology (CWBI), Passage des Déportés 2, B-5030 Gembloux, Belgium.
authors.forename: Philippe
authors.initials: P
authors.lastname: Thonart
authors.affiliation: Walloon Agricultural Research Centre (CRA-W), Dept. of Life Sciences, Chaussée de Charleroi, 234, B-5030 Gembloux, Belgium.
authors.forename: Philippe
authors.initials: P
authors.lastname: Druart
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D000426:Alcohol Dehydrogenase / Q000235:genetics / Q000378:metabolism; D029661:Alnus / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D000595:Amino Acid Sequence; D029662:Betula / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D001692:Biological Transport; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005974:Glutamate-Ammonia Ligase / Q000235:genetics / Q000378:metabolism; D006812:Humic Substances; D007210:Indoleacetic Acids / Q000378:metabolism; D008903:Minerals / Q000494:pharmacology*; D008969:Molecular Sequence Data; D010937:Plant Growth Regulators / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology / Q000254:growth & development; D016415:Sequence Alignment; D014874:Water Pollutants, Chemical / Q000494:pharmacology*
chemical_list: D018528:ATP-Binding Cassette Transporters; D006812:Humic Substances; D007210:Indoleacetic Acids; D008903:Minerals; D010937:Plant Growth Regulators; D010940:Plant Proteins; D014874:Water Pollutants, Chemical; C568542:leonardite; D000426:Alcohol Dehydrogenase; D005974:Glutamate-Ammonia Ligase
keywords: ATP-binding cassette; Alcohol dehydrogenase; Auxin; Glutamine synthetase; Humic substances