title: Chloroplast Stromules Function during Innate Immunity.
abstract: Inter-organellar communication is vital for successful innate immune responses that confer defense against pathogens. However, little is known about how chloroplasts, which are a major production site of pro-defense molecules, communicate and coordinate with other organelles during defense. Here we show that chloroplasts send out dynamic tubular extensions called stromules during innate immunity or exogenous application of the pro-defense signals, hydrogen peroxide (H2O2) and salicylic acid. Interestingly, numerous stromules surround nuclei during defense response, and these connections correlate with an accumulation of chloroplast-localized NRIP1 defense protein and H2O2 in the nucleus. Furthermore, silencing and knockout of chloroplast unusual positioning 1 (CHUP1) that encodes a chloroplast outer envelope protein constitutively induces stromules in the absence of pathogen infection and enhances programmed cell death. These results support a model in which stromules aid in the amplification and/or transport of pro-defense signals into the nucleus and other subcellular compartments during immunity.
authors.affiliation: Department of Biological Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA. Electronic address: jcaplan@udel.edu.
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Caplan
authors.affiliation: Department of Biological Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA.
authors.forename: Amutha Sampath
authors.initials: AS
authors.lastname: Kumar
authors.affiliation: Department of Plant Biology and The Genome Center, College of Biological Sciences, University of California, Davis, Davis, CA 95616, USA.
authors.forename: Eunsook
authors.initials: E
authors.lastname: Park
authors.affiliation: Department of Plant Biology and The Genome Center, College of Biological Sciences, University of California, Davis, Davis, CA 95616, USA.
authors.forename: Meenu S
authors.initials: MS
authors.lastname: Padmanabhan
authors.affiliation: Department of Biological Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA.
authors.forename: Kyle
authors.initials: K
authors.lastname: Hoban
authors.affiliation: Department of Biological Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA.
authors.forename: Shannon
authors.initials: S
authors.lastname: Modla
authors.affiliation: Department of Biological Sciences, Delaware Biotechnology Institute, University of Delaware, Newark, DE 19711, USA.
authors.forename: Kirk
authors.initials: K
authors.lastname: Czymmek
authors.affiliation: Department of Plant Biology and The Genome Center, College of Biological Sciences, University of California, Davis, Davis, CA 95616, USA. Electronic address: spdineshkumar@ucdavis.edu.
authors.forename: Savithramma P
authors.initials: SP
authors.lastname: Dinesh-Kumar
mesh_terms: D017360:Arabidopsis / Q000187:drug effects / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002736:Chloroplasts / Q000187:drug effects* / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D007113:Immunity, Innate / Q000187:drug effects* / Q000276:immunology; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D006861:Hydrogen Peroxide