title: Analysis of plant growth-promoting properties of Bacillus amyloliquefaciens UCMB5113 using Arabidopsis thaliana as host plant.
abstract: This study showed that Bacillus amyloliquefaciens UCMB5113 colonizing Arabidopsis roots changed root structure and promoted growth implying the usability of this strain as a novel tool to support sustainable crop production. Root architecture plays a crucial role for plants to ensure uptake of water, minerals and nutrients and to provide anchorage in the soil. The root is a dynamic structure with plastic growth and branching depending on the continuous integration of internal and environmental factors. The rhizosphere contains a complex microbiota, where some microbes can colonize plant roots and support growth and stress tolerance. Here, we report that the rhizobacterium Bacillus amyloliquefaciens subsp. plantarum UCMB5113 stimulated the growth of Arabidopsis thaliana Col-0 by increased lateral root outgrowth and elongation and root-hair formation, although primary root elongation was inhibited. In addition, the growth of the above ground tissues was stimulated by UCMB5113. Specific hormone reporter gene lines were tested which suggested a role for at least auxin and cytokinin signaling during rhizobacterial modulation of Arabidopsis root architecture. UCMB5113 produced cytokinins and indole-3-acetic acid, and the formation of the latter was stimulated by root exudates and tryptophan. The plant growth promotion effect by UCMB5113 did not appear to depend on jasmonic acid in contrast to the disease suppression effect in plants. UCMB5113 exudates inhibited primary root growth, while a semi-purified lipopeptide fraction did not and resulted in the overall growth promotion indicating an interplay of many different bacterial compounds that affect the root growth of the host plant. This study illustrates that beneficial microbes interact with plants in root development via classic and novel signals.
authors.affiliation: Department of Plant Biology, Uppsala Biocenter, Swedish University of Agricultural Sciences and Linnéan Center for Plant Biology, Box 7080, S75007, Uppsala, Sweden.
authors.forename: Shashidar
authors.initials: S
authors.lastname: Asari
authors.affiliation: Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR and Palacký University, Šlechtitelů 11, CZ-783 71, Olomouc, Czech Republic.
authors.forename: Danuše
authors.initials: D
authors.lastname: Tarkowská
authors.affiliation: Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR and Palacký University, Šlechtitelů 11, CZ-783 71, Olomouc, Czech Republic.
authors.forename: Jakub
authors.initials: J
authors.lastname: Rolčík
authors.affiliation: Laboratory of Growth Regulators, Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany ASCR and Palacký University, Šlechtitelů 11, CZ-783 71, Olomouc, Czech Republic.
authors.forename: Ondřej
authors.initials: O
authors.lastname: Novák
authors.affiliation: Department of Plant Biology, Uppsala Biocenter, Swedish University of Agricultural Sciences and Linnéan Center for Plant Biology, Box 7080, S75007, Uppsala, Sweden.
authors.forename: David Velázquez
authors.initials: DV
authors.lastname: Palmero
authors.affiliation: Department of Plant Biology, Uppsala Biocenter, Swedish University of Agricultural Sciences and Linnéan Center for Plant Biology, Box 7080, S75007, Uppsala, Sweden.
authors.forename: Sarosh
authors.initials: S
authors.lastname: Bejai
authors.affiliation: Department of Plant Biology, Uppsala Biocenter, Swedish University of Agricultural Sciences and Linnéan Center for Plant Biology, Box 7080, S75007, Uppsala, Sweden. johan.meijer@slu.se.
authors.forename: Johan
authors.initials: J
authors.lastname: Meijer
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000254:growth & development* / Q000382:microbiology*; D000069977:Bacillus amyloliquefaciens / Q000187:drug effects / Q000502:physiology*; D060406:Brassinosteroids / Q000494:pharmacology; D003583:Cytokinins / Q000494:pharmacology; D005875:Gibberellins / Q000494:pharmacology; D054884:Host-Pathogen Interactions / Q000187:drug effects; D007210:Indoleacetic Acids / Q000494:pharmacology; D055666:Lipopeptides / Q000494:pharmacology; D010937:Plant Growth Regulators / Q000494:pharmacology; D018517:Plant Roots / Q000033:anatomy & histology / Q000187:drug effects; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development
chemical_list: D060406:Brassinosteroids; D003583:Cytokinins; D005875:Gibberellins; D007210:Indoleacetic Acids; D055666:Lipopeptides; D010937:Plant Growth Regulators
keywords: Beneficial bacteria; Biocontrol; Growth promotion; Phytohormones; Rhizosphere; Root structure