title: Cyclic monoterpene mediated modulations of Arabidopsis thaliana phenotype: effects on the cytoskeleton and on the expression of selected genes.
abstract: Monoterpenes at high atmospheric concentrations are strong growth inhibitors in allelopathic interactions. Effects depend on dose, molecular structure of the monoterpene and on the species of the receiver plant. Stomata are among the first targets affected by camphor and menthol. Previously, it could be demonstrated that the compounds induce swelling of the protoplasts, prevent stomatal closure and enhance transpiration. In this study, we show that the block of stomatal closure is accompanied by changes to the cytoskeleton, which has a direct role in stomatal movements. Although MPK3 (MAP3 kinase) and ABF4 gene expressions are induced within six hours, stomatal closure is prevented. In contrast to ABF4, ABF2 (both transcription factors) is not induced. MPK3 and ABF4 both encode for proteins involved in the process of stomatal closure. The expression of PEPCase, an enzyme important for stomatal opening, is down regulated. The leaves develop stress symptoms, mirrored by transient changes in the expression profile of additional genes: lipoxygenase 2 (LOX2), CER5, CER6 (both important for wax production) and RD29B (an ABA inducible stress protein). Non-invasive methods showed a fast response of the plant to camphor fumigations both in a rapid decrease of the quantum yield and in the relative growth rate. Repeated exposures to the monoterpenes resulted finally in growth reduction and a stress related change in the phenotype. It is proposed that high concentrations or repeated exposure to monoterpenes led to irreversible damages, whereas low concentrations or short-term fumigations may have the potential to strengthen the plant fitness.
authors.affiliation: Institut für Molekulare Physiologie und Biotechnologie der Pflanzen, Universität Bonn, Karlrobert Kreiten Str, Bonn, Germany.
authors.forename: Bettina
authors.initials: B
authors.lastname: Kriegs
authors.forename: Marcus
authors.initials: M
authors.lastname: Jansen
authors.forename: Ka
authors.initials: K
authors.lastname: Hahn
authors.forename: Helga
authors.initials: H
authors.lastname: Peisker
authors.forename: Olga
authors.initials: O
authors.lastname: Samajová
authors.forename: Martina
authors.initials: M
authors.lastname: Beck
authors.forename: Silvia
authors.initials: S
authors.lastname: Braun
authors.forename: Andreas
authors.initials: A
authors.lastname: Ulbrich
authors.forename: František
authors.initials: F
authors.lastname: Baluška
authors.forename: Margot
authors.initials: M
authors.lastname: Schulz
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002164:Camphor / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects*; D008610:Menthol / Q000494:pharmacology; D020929:Mitogen-Activated Protein Kinase Kinases / Q000235:genetics / Q000378:metabolism; D039821:Monoterpenes / Q000494:pharmacology*; D010641:Phenotype; D054046:Plant Stomata
chemical_list: D029681:Arabidopsis Proteins; D039821:Monoterpenes; D008610:Menthol; D002164:Camphor; C458516:AtMPK3 protein, Arabidopsis; D020929:Mitogen-Activated Protein Kinase Kinases