title: Systems-wide analysis of acclimation responses to long-term heat stress and recovery in the photosynthetic model organism Chlamydomonas reinhardtii.
abstract: We applied a top-down systems biology approach to understand how Chlamydomonas reinhardtii acclimates to long-term heat stress (HS) and recovers from it. For this, we shifted cells from 25 to 42°C for 24 h and back to 25°C for ≥8 h and monitored abundances of 1856 proteins/protein groups, 99 polar and 185 lipophilic metabolites, and cytological and photosynthesis parameters. Our data indicate that acclimation of Chlamydomonas to long-term HS consists of a temporally ordered, orchestrated implementation of response elements at various system levels. These comprise (1) cell cycle arrest; (2) catabolism of larger molecules to generate compounds with roles in stress protection; (3) accumulation of molecular chaperones to restore protein homeostasis together with compatible solutes; (4) redirection of photosynthetic energy and reducing power from the Calvin cycle to the de novo synthesis of saturated fatty acids to replace polyunsaturated ones in membrane lipids, which are deposited in lipid bodies; and (5) when sinks for photosynthetic energy and reducing power are depleted, resumption of Calvin cycle activity associated with increased photorespiration, accumulation of reactive oxygen species scavengers, and throttling of linear electron flow by antenna uncoupling. During recovery from HS, cells appear to focus on processes allowing rapid resumption of growth rather than restoring pre-HS conditions.
authors.affiliation: Molekulare Biotechnologie and Systembiologie, TU Kaiserslautern, D-67663 Kaiserslautern, Germany Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany.
authors.forename: Dorothea
authors.initials: D
authors.lastname: Hemme
authors.affiliation: Molekulare Biotechnologie and Systembiologie, TU Kaiserslautern, D-67663 Kaiserslautern, Germany Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany.
authors.forename: Daniel
authors.initials: D
authors.lastname: Veyel
authors.affiliation: Molekulare Biotechnologie and Systembiologie, TU Kaiserslautern, D-67663 Kaiserslautern, Germany Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany.
authors.forename: Timo
authors.initials: T
authors.lastname: Mühlhaus
authors.affiliation: Molekulare Biotechnologie and Systembiologie, TU Kaiserslautern, D-67663 Kaiserslautern, Germany Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany.
authors.forename: Frederik
authors.initials: F
authors.lastname: Sommer
authors.affiliation: Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany.
authors.forename: Jessica
authors.initials: J
authors.lastname: Jüppner
authors.affiliation: Zellbiologie/Elektronenmikroskopie, Universität Bayreuth, D-95440 Bayreuth, Germany.
authors.forename: Ann-Katrin
authors.initials: AK
authors.lastname: Unger
authors.affiliation: Institut für Biochemie und Biologie, Universität Potsdam, D-14476 Potsdam-Golm, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Sandmann
authors.affiliation: Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany.
authors.forename: Ines
authors.initials: I
authors.lastname: Fehrle
authors.affiliation: Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Schönfelder
authors.affiliation: Institut für Biochemie und Biologie, Universität Potsdam, D-14476 Potsdam-Golm, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Steup
authors.affiliation: Zellbiologie/Elektronenmikroskopie, Universität Bayreuth, D-95440 Bayreuth, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Geimer
authors.affiliation: Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany.
authors.forename: Joachim
authors.initials: J
authors.lastname: Kopka
authors.affiliation: Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Giavalisco
authors.affiliation: Molekulare Biotechnologie and Systembiologie, TU Kaiserslautern, D-67663 Kaiserslautern, Germany Max-Planck-Institut für Molekulare Pflanzenphysiologie, D-14476 Potsdam-Golm, Germany schroda@bio.uni-kl.de.
authors.forename: Michael
authors.initials: M
authors.lastname: Schroda
mesh_terms: D000064:Acclimatization; D016825:Chlamydomonas reinhardtii / Q000235:genetics / Q000502:physiology* / Q000648:ultrastructure; D006358:Hot Temperature; D008055:Lipids / Q000032:analysis; D055442:Metabolome; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D010788:Photosynthesis; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D020543:Proteome
chemical_list: D008055:Lipids; D018832:Molecular Chaperones; D010940:Plant Proteins; D020543:Proteome