title: Tubulin marker line of grapevine suspension cells as a tool to follow early stress responses.
abstract: Plant microtubules (MTs), in addition to their role in cell division and cell expansion, respond to various stress signals. To understand the biological function of this early response requires non-destructive strategies for visualization in cellular models that are highly responsive to stress signals. We have therefore generated a transgenic tubulin marker line for a cell line from the grapevine Vitis rupestris that readily responds to stress factors of defense-related and abiotic stresses based on a fusion of the green fluorescent protein with Arabidopsis β-tubulin 6. By a combination of spinning-disk confocal microscopy with quantitative image analysis, we could detect early and specific responses of MTs to defense-related and abiotic stress factors in vivo. We observed that Harpin Z (HrpZ), a bacterial elicitor that can trigger programmed cell death, rapidly eliminated radial MTs, followed by a slower depletion of the cortical array. Jasmonic acid (JA), in contrast, induced bundling of cortical MTs. Auxin reduced the thickness of cortical MTs. This effect followed a characteristic bell-shaped dose-dependency and could revert JA-induced bundling. Impeded cell expansion as a consequence of stress treatment or superoptimal auxin was linked with the appearance of intranuclear tubulin speckles. The early and stimulus-specific responses of MTs are discussed with respect to a function in processing or decoding of stress signals.
authors.affiliation: Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Kaiserstraße 2, D-76128 Karlsruhe, Germany. Electronic address: xinguan.cnde@googlemail.com.
authors.forename: Xin
authors.initials: X
authors.lastname: Guan
authors.affiliation: RLP AgroScience/AlPlanta - Institute for Plant Research, Breitenweg 71, D-67435 Neustadt an der Weinstraße, Germany.
authors.forename: Günther
authors.initials: G
authors.lastname: Buchholz
authors.affiliation: Molecular Cell Biology, Botanical Institute, Karlsruhe Institute of Technology, Kaiserstraße 2, D-76128 Karlsruhe, Germany.
authors.forename: Peter
authors.initials: P
authors.lastname: Nick
mesh_terms: D017360:Arabidopsis / Q000378:metabolism; D001425:Bacterial Outer Membrane Proteins / Q000494:pharmacology; D003517:Cyclopentanes / Q000494:pharmacology; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007210:Indoleacetic Acids / Q000494:pharmacology; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism; D054883:Oxylipins / Q000494:pharmacology; D030821:Plants, Genetically Modified; D013312:Stress, Physiological / Q000187:drug effects; D013535:Suspensions; D014404:Tubulin / Q000378:metabolism*; D027843:Vitis / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*
chemical_list: D001425:Bacterial Outer Membrane Proteins; D003517:Cyclopentanes; D007210:Indoleacetic Acids; D054883:Oxylipins; D013535:Suspensions; D014404:Tubulin; D049452:Green Fluorescent Proteins; C087295:HrpZ protein, Pseudomonas syringae; C011006:jasmonic acid
keywords: Auxin; Grapevine, transgenic; Green fluorescent protein (GFP); Microtubule; Vitis rupestris