title: Plant innate immunity--sunny side up?
abstract: Reactive oxygen species (ROS)- and calcium- dependent signaling pathways play well-established roles during plant innate immunity. Chloroplasts host major biosynthetic pathways and have central roles in energy production, redox homeostasis, and retrograde signaling. However, the organelle's importance in immunity has been somehow overlooked. Recent findings suggest that the chloroplast also has an unanticipated function as a hub for ROS- and calcium-signaling that affects immunity responses at an early stage after pathogen attack. In this opinion article, we discuss a chloroplastic calcium-ROS signaling branch of plant innate immunity. We propose that this chloroplastic branch acts as a light-dependent rheostat that, through the production of ROS, influences the severity of the immune response.
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Department of Medical Protein Research, VIB, 9000 Ghent, Belgium; Department of Biochemistry, Ghent University, 9000 Ghent, Belgium.
authors.forename: Simon
authors.initials: S
authors.lastname: Stael
authors.affiliation: Department of Ecogenomics and Systems Biology, Vienna University, Vienna, Austria.
authors.forename: Przemyslaw
authors.initials: P
authors.lastname: Kmiecik
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium; Department of Medical Protein Research, VIB, 9000 Ghent, Belgium; Department of Biochemistry, Ghent University, 9000 Ghent, Belgium.
authors.forename: Patrick
authors.initials: P
authors.lastname: Willems
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium.
authors.forename: Katrien
authors.initials: K
authors.lastname: Van Der Kelen
authors.affiliation: Department of Molecular Genetics, Centre for Research in Agricultural Genomics, CSIC-IRTA-UAB-UB Consortium, 08193 Barcelona, Spain.
authors.forename: Nuria S
authors.initials: NS
authors.lastname: Coll
authors.affiliation: Department of Ecogenomics and Systems Biology, Vienna University, Vienna, Austria; Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences, Vienna, Austria.
authors.forename: Markus
authors.initials: M
authors.lastname: Teige
authors.affiliation: Department of Plant Systems Biology, VIB, 9052 Ghent, Belgium; Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Ghent, Belgium. Electronic address: frank.vanbreusegem@psb.vib-ugent.be.
authors.forename: Frank
authors.initials: F
authors.lastname: Van Breusegem
mesh_terms: D002118:Calcium / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism; D008027:Light; D057865:Plant Immunity; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D017382:Reactive Oxygen Species; D002118:Calcium
keywords: calcium signaling; chloroplast; effector-triggered immunity; light; pathogen; pathogen-triggered immunity; reactive oxygen species signaling