title: Microbial homoserine lactones (AHLs) are effectors of root morphological changes in barley.
abstract: While colonizing the rhizosphere, bacterial intra- and inter-specific communication is accomplished by N-Acyl-homoserine-lactones (AHLs) in a density-dependent manner. Moreover, plants are naturally exposed to AHLs and respond with tissue-specificity. In the present study, we investigated the influence of N-hexanoyl- (C6-HSL), N-octanoyl- (C8-HSL) and N-dodecanoyl-d/l-homoserine lactone (C12-HSL) on growth and root development in barley (Hordeum vulgare L.), and identified initial reactions in root cells after AHL exposures using physiological, staining, and electrophysiological methods. Treatment with short- and long-chain AHLs modulated plant growth and branched root architecture and induced nitric oxide (NO) accumulation in the calyptra and root elongation zone of excised roots in an AHL derivative-independent way. Additionally, C6- and C8-HSL treatments stimulated K+uptake in root cells only at certain concentrations, whereas all tested concentrations of C12-HSL induced K+uptake. In further experiments, C8-HSL promoted membrane hyperpolarization in epidermal root cells. Thus, we conclude AHLs promote plant growth and lateral root formation, and cause NO accumulation as an early response to AHLs. Furthermore, the AHL-mediated membrane hyperpolarization is leading to increased K+uptake of the root tissue.
authors.affiliation: Helmholtz Zentrum München, German Research Centre for Environmental Health, GmbH, Research Unit Environmental Genomics, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany.
authors.forename: Simone
authors.initials: S
authors.lastname: Rankl
authors.affiliation: Lab. Fisiología Vegetal, Facultad Biociencias, Universidad Autónoma de Barcelona, 08193 Bellaterra, Spain.
authors.forename: Benet
authors.initials: B
authors.lastname: Gunsé
authors.affiliation: Helmholtz Zentrum München, German Research Centre for Environmental Health, GmbH, Research Unit Environmental Genomics, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany.
authors.forename: Tina
authors.initials: T
authors.lastname: Sieper
authors.affiliation: Helmholtz Zentrum München, German Research Centre for Environmental Health, GmbH, Research Unit Environmental Genomics, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Schmid
authors.affiliation: Lab. Fisiología Vegetal, Facultad Biociencias, Universidad Autónoma de Barcelona, 08193 Bellaterra, Spain.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Poschenrieder
authors.affiliation: Helmholtz Zentrum München, German Research Centre for Environmental Health, GmbH, Research Unit Environmental Genomics, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany. Electronic address: peter.schroeder@helmholtz-muenchen.de.
authors.forename: Peter
authors.initials: P
authors.lastname: Schröder
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000502:physiology; D001467:Hordeum / Q000254:growth & development* / Q000378:metabolism; D063245:Plant Development; D018517:Plant Roots / Q000254:growth & development* / Q000378:metabolism; D011188:Potassium / Q000378:metabolism
chemical_list: C088386:homoserine lactone; D015107:4-Butyrolactone; D011188:Potassium
keywords: Hordeum vulgare; Membrane hyperpolarization; Nitric oxide; Nutrient uptake; Quorum sensing; Root development