title: Chasing stress signals - Exposure to extracellular stimuli differentially affects the redox state of cell compartments in the wild type and signaling mutants of Botrytis cinerea.
abstract: Reactive oxygen species (ROS) are important molecules influencing intracellular developmental processes as well as plant pathogen interactions. They are produced at the infection site and affect the intracellular redox homeostasis. However, knowledge of ROS signaling pathways, their connection to other signaling cascades, and tools for the visualization of intra- and extracellular ROS levels and their impact on the redox state are scarce. By using the genetically encoded biosensor roGFP2 we studied for the first time the differences between the redox states of the cytosol, the intermembrane space of mitochondria and the ER in the filamentous fungus Botrytis cinerea. We showed that the ratio of oxidized to reduced glutathione inside of the cellular compartments differ and that the addition of hydrogen peroxide (H2O2), calcium chloride (CaCl2) and the fluorescent dye calcofluor white (CFW) have a direct impact on the cellular redox states. Dependent on the type of stress agents applied, the redox states were affected in the different cellular compartments in a temporally shifted manner. By integrating the biosensor in deletion mutants of bcnoxA, bcnoxB, bctrx1 and bcltf1 we further elucidated the putative roles of the different proteins in distinct stress-response pathways. We showed that the redox states of ΔbcnoxA and ΔbcnoxB display a wild-type pattern upon exposure to H2O2, but appear to be strongly affected by CaCl2 and CFW. Moreover, we demonstrated the involvement of the light-responsive transcription factor BcLtf1 in the maintenance of the redox state in the intermembrane space of the mitochondria. Finally, we report that CaCl2 as well as cell wall stress-inducing agents stimulate ROS production and that ΔbcnoxB produces significantly less ROS than the wild type and ΔbcnoxA.
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, Schlossplatz 8, D-48143 Münster, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Marschall
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, Schlossplatz 8, D-48143 Münster, Germany.
authors.forename: Julia
authors.initials: J
authors.lastname: Schumacher
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, Schlossplatz 8, D-48143 Münster, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Siegmund
authors.affiliation: Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms-Universität, Schlossplatz 8, D-48143 Münster, Germany. Electronic address: tudzyns@uni-muenster.de.
authors.forename: Paul
authors.initials: P
authors.lastname: Tudzynski
mesh_terms: D015374:Biosensing Techniques / Q000379:methods; D020171:Botrytis / Q000166:cytology / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D003600:Cytosol / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D054884:Host-Pathogen Interactions; D008928:Mitochondria / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology; D010935:Plant Diseases / Q000382:microbiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D017384:Sequence Deletion; D015398:Signal Transduction; D013312:Stress, Physiological / Q000502:physiology*; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D005656:Fungal Proteins; D017382:Reactive Oxygen Species; D014157:Transcription Factors; D005978:Glutathione
keywords: Botrytis cinerea; Phytopathogenic fungi; Redox signaling; Stress; roGFP2