title: Chloroplast Membrane Remodeling during Freezing Stress Is Accompanied by Cytoplasmic Acidification Activating SENSITIVE TO FREEZING2.
abstract: Low temperature is a seasonal abiotic stress that restricts native plant ranges and crop distributions. Two types of low-temperature stress can be distinguished: chilling and freezing. Much work has been done on the mechanisms by which chilling is sensed, but relatively little is known about how plants sense freezing. Recently, Arabidopsis (Arabidopsis thaliana) SENSITIVE TO FREEZING2 (SFR2) was identified as a protein that responds in a nontranscriptional manner to freezing. Here, we investigate the cellular conditions that allow SFR2 activation. Using a combination of isolated organelle, whole-tissue, and whole-plant assays, we provide evidence that SFR2 is activated by changes in cytosolic pH and Mg(2+) Manipulation of pH and Mg(2+) in cold-acclimated plants is shown to cause changes similar to those of freezing. We conclude that pH and Mg(2+) are perceived as intracellular cues as part of the sensing mechanism for freezing conditions. This evidence provides a specific molecular mechanism to combat freezing.
authors.affiliation: Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588 (A.C.B., R.L.R.); andMichigan State University-Department of Energy Plant Research Laboratory, Michigan State University, Plant Biology Laboratories, East Lansing, Michigan 48824 (C.B.).
authors.forename: Allison C
authors.initials: AC
authors.lastname: Barnes
authors.affiliation: Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588 (A.C.B., R.L.R.); andMichigan State University-Department of Energy Plant Research Laboratory, Michigan State University, Plant Biology Laboratories, East Lansing, Michigan 48824 (C.B.).
authors.forename: Christoph
authors.identifier: 0000-0001-8585-3667
authors.initials: C
authors.lastname: Benning
authors.affiliation: Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588 (A.C.B., R.L.R.); andMichigan State University-Department of Energy Plant Research Laboratory, Michigan State University, Plant Biology Laboratories, East Lansing, Michigan 48824 (C.B.) rroston@unl.edu.
authors.forename: Rebecca L
authors.identifier: 0000-0002-3063-5002
authors.initials: RL
authors.lastname: Roston
mesh_terms: D019342:Acetic Acid / Q000494:pharmacology; D017360:Arabidopsis / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D003600:Cytosol / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D005615:Freezing; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000378:metabolism / Q000494:pharmacology; D030821:Plants, Genetically Modified; D013312:Stress, Physiological; D020524:Thylakoids / Q000378:metabolism; D001617:beta-Glucosidase / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; C492903:SFR2 protein, Arabidopsis; D001617:beta-Glucosidase; D008274:Magnesium; D019342:Acetic Acid